Revised draft Deliverable on Smart Grid Architecture
|INTERNATIONAL TELECOMMUNICATION UNION |Focus Group on |
| |Smart Grid |
|TELECOMMUNICATION |Smart-O-33Rev.6 |
|STANDARDIZATION SECTOR | |
|STUDY PERIOD 2009-2012 | |
| |English only |
| |Original: English |
|WG(s): |WG3 (Architecture) |Geneva, 18-21 December 2011 |
|DOCUMENT |
|Source: |Editor, WG3 |
|Title: |Deliverable on Smart Grid Architecture |
Smart Grid Architecture
Summary
This Deliverable describes architecture for smart grid.
Keywords
Contents
Summary 2
Keywords 2
1 Scope 5
2 References 5
3 Definition 5
4 Abbreviations and acronyms 5
5 Conventions 6
6 Reference architecture 6
6.1 Simplified Domain Model in ICT perspective 6
6.2 Reference Architecture of Smart Grid 8
7 Functional Architecture 9
7.1 Functional Model of Smart Grid 9
7.2 Detailed Functional Architecture of Smart Grid 13
7.2.1 Functional Architecture of Smart Metering and Load Control 13
7.2.1.1 End-User Functions 14
7.2.1.2 Application Functions in Smart Metering and Load Control 15
7.2.1.3 Smart Metering Functions 16
7.2.1.4 Energy Control Functions 16
7.2.1.5 Network Functions 17
7.2.1.6 Management Functions 17
7.2.1.7 Security Functions 17
7.2.2 Functional Architecture of Energy Distribution and Management 17
7.2.2.1 End-User Functions 19
7.2.2.2 Power Grid Functions 20
7.2.2.3 Application Functions 21
7.2.2.4 Energy Control Functions 22
7.2.2.5 Smart Metering Functions 22
7.2.2.6 Network Functions 23
7.2.2.7 Management Functions 23
7.2.2.8 Security Functions 23
8 Deployment Model of Smart Grid 23
8.1 Networks in Smart Grid 23
8.2 Smart Grid Network Architecture 24
8.2.1 Home Area Network Architecture 24
8.2.1.1 HAN Topology 24
8.2.1.2 Energy Service Interface (ESI) 25
8.2.1.3 Interactions with Other Networks 26
8.2.2 Neighborhood Area Network Architecture 27
8.2.2.1 NAN Topology 27
8.2.3 Wide Area Network Architecture 29
8.2.3.1 IP-Based Network 29
8.2.3.2 Next Generation Network Architecture 30
8.2.3.2.1 Transport Stratum 31
8.2.3.2.2 Service Stratum 31
8.2.3.2.3 Identity Management (IdM) Functions 32
8.2.3.3 Consideration of the M2M Service Layer aspects 33
9 Sample Implementation of Smart Grid Applications 35
9.1 ITU-T G.9970 Home Network Transport and Application Layer Architecture 35
9.2 Architecture with the HAN and Relevant External Interactions 37
9.3 Architecture Focusing on Interface between HGW and PEV 38
9.4 Example of Implementation Platforms to Support Energy Management Services 39
9.5 Architecture of a Communication Infrastructure to Provide Energy Related Services 40
10 Standards Gap Analysis 42
10.1 Functions across Reference Points and Applicable Standards 42
10.2 Recommendations for Future Work 49
Annex A. Comparisons of Architectures among ITU-T FG-Smart, IEEE P2030 and ETSI M2M 51
Annex B. Network Configuration Scenarios for Smart Grid 53
Smart Grid Architecture
Scope
This deliverable document describes architecture for smart grid. First, this document describes the reference architecture, including the simplified domain model in ICT perspective and mapped domain model based on NIST smart grid Interoperability framework. Second, the smart grid functional architecture and two representative applications, namely “smart metering and load control” and “energy distribution and management” are introduced. Lastly, the deployment models of smart grid are introduced and they consist of the networking and communication techniques, network architecture, and deployment model and implementation.
References
[1] NIST Special Publication 1108, NIST Framework and Roadmap for Smart Grid Interoperability Standards, Release 1.0, January, 2010
[2] IETF RFC 6272; F. Baker, D. Meyer, ”Internet Protocols for the Smart Grid”
[3] ETSI TS 102690-V1.1.1 (2011-10) Technical Specification Machine- to- Machine communications (M2M); Functional architecture
[4] ETSI TS 102921-V1.1.1 (2011-12) Technical Specification Machine- to- Machine communications (M2M); mIa, dIa and mId interfaces
[5] ITU-T G.9970; Recommendation ITU-T G.9970 (2009), Generic home network transport architecture.
[6] ITU-T G.9971; Recommendation ITU-T G.9971 (2010), Requirements of transport functions in IP networks.
[7] ITU-T Y.2011; Recommendation ITU-T Y.2011 (2004), General principles and general reference model for Next Generation Networks
[8] ITU-T Y.2012; Recommendation ITU-T Y.2012 (2010), Functional requirements and architecture of next generation networks
[9] NIST Interagency or Internal Report (NISTIR) 7628, Guidelines for Smart Grid Cyber Security, August 2010. The website for accessing this document can be found at .
Definition
Definitions of terms in this document are included in the terminology deliverable.
Abbreviations and acronyms
Abbreviations and acronyms in this document are included in the terminology deliverable.
Conventions
There are no particular notations, styles, presentations, etc. used within the deliverable.
Reference architecture
1 Simplified Domain Model in ICT perspective
This deliverable document has been based on NIST’s conceptual model [1] as a starting point of consideration. The model organizes the fields related to Smart Grid into seven domains. Based on the considerations from ICT perspective that is essential to ITU-T studies, this document simplified it into a five-domain model as shown in Figure 1 below. These five domains are viewed in three different areas: Smart Grid Service/Applications, Communication, and Physical Equipment; each covering one or more of the five domains:
• Grid domain (bulk generation, distribution and transmission);
• Smart metering (AMI);
• Customer domain (smart appliances, electric vehicles, premises networks (Home/ Building/ Industrial Area Network));
• Communication network; and
• Service provider domain (markets, operators, service providers).
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Figure 1: Simplified Smart Grid Domain Model in ICT Perspective
Figure 1 also shows five interfaces between domains, marked with numbers in circles. These are places where communications and exchange of information between the Communication network and other four domains, and between Smart metering domain and Customer domain take place. They are the focal point of standards specifications and thus are called Reference Point. Samples functions at each of these reference points are listed below:
• Reference Point 1 – Between Grid domain and Communication Network: It enables the exchange of information and control signals between devices in Grid domain and the Service provider domain, the examples of SCADA (Supervisory Control and Data Acquisition) and other operations are listed below:
o Remote Terminal Unit (RTU) in transmission systems to enable SCADA operations;
o Intelligent Electronic Devices (IED) in transmission systems to interact with SCADA operations in the Service provider domain;
o Plant control system interacts with SCADA and EMS (Energy Management System) in the Service provider domain;
o Plant control system interacts with Regional Transmission Organizations (RTO)/ Independent Systems Operators (ISO) wholesale market in market operations (e.g., the control signals of monitoring, reporting, and telephony between bulk storage domain and markets to enable wholesale markets operations control hence optimizing portfolios of sources);
o Information and control signals and power generation information between Grid domain (e.g., Bulk generation) and Service provider domain (e.g., control and operations);
o Grid domain (e.g., transmission sensors and measurement devices) provides information from the transmission line to the Service provider domain (e.g., transmission operation, protection and control) for transmission line maintenance information, monitoring, reporting, and SCADA;
o Information exchange and coordination between Grid domain (e.g., power generation) and Service provider domain (e.g., power transmission operation and control);
o Distribution sensors and measurement devices provide distribution system information for use by Distributed Energy Resources (DER).
• Reference Point 2 - Between Smart metering domain and Communication Network: It enables the exchange of metering information and interactions through operators and service providers in the Service provider domain towards customers in the Customer domain. Some examples are listed below:
o Management of meters, retrieval of aggregated meter readings from Advanced Metering Infrastructure (AMI) head-end/controller in operations and service provider in Service provider domain;
o Interacting with customer Energy Management System (EMS) to exchange pricing, data related to Demand Response (DR), including the load shedding information, and relevant information enabling automation of tasks involved in a better use of energy;
o Billing in Service provider domain that interacts with the meters in Customer domain.
o Smart meters interact with billing in Service provider domain;
o Smart meters form a metering infrastructure to ensure reliable communication to the meter head-end through this reference point.
• Reference Point 3 – Between Customer domain and Communication Network domain: It enables the interactions between operators and service providers in Service provider domain and devices in Customer domain. Some examples are listed below:
o The HAN communicates over this Reference point either through a secure energy service gateway or through public network (e.g., Internet);
o Energy Services Interface (ESI) / HAN gateway interacts with the metering/ billing / utility back office in Service provider domain (Operations);
o ESI / HAN gateway interacts with the load management system / demand-response management system in Service provider domain (Operations);
o Customer EMS interacts with energy service provider in Service provider domain;
o Billing in Service provider domain interacts with customers in Customer domain;
o Customer EMS interacts with distribution management system in Grid domain;
o Customer EMS interacts with aggregator/ retail energy provider in Service provider domain;
o Monitoring and controlling the information exchange for distributed generation and DER in Customer domain;
• Reference Point 4 – Between Service provider domain and Communication Network domain, it enables communications between services and applications in the Service provider domain to actors in others domains to perform all Smart Grid functions illustrated above.
• Reference Point 5 – Between Smart metering and Customer domain, it conducts services through ESI. Some examples are listed below:
o Smart meter interacts with devices, including customer EMS, ESI in home, customer appliances and equipment;
o Devices in Customer domain, including customer EMS, ESI in home, customer appliances and equipment interact with smart meters.
2 Reference Architecture of Smart Grid
Corresponding to the domain model in the NIST Framework and Roadmap document [1], there is a reference architecture diagram showing conceptual data flow between domains. Based on the simplified domain model shown in Figure 1, the reference architecture was modified accordingly and is shown in Figure 2 below. The Reference Points identified in Figure 1 are also shown here to illustrate their relationships with components in the domains.
Figure 2 represents a logical view of the smart grid system with a focus on communication interactions. The communications cloud represents the communications networks that connect logical devices in the smart grid. These communications networks may reside within a domain or cross-domain boundaries. The communications network may carry grid related data only or may be a general purpose network carrying grid data along with generic data. The choice of what type of network is needed to support a particular smart grid function shall be driven by the requirements of that function.
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Figure 2: Reference Architecture of Smart Grid
Functional Architecture
7.1 Functional Model of Smart Grid
For Smart Grid functional model, a diagram for Smart Grid architecture framework is shown in Figure 3. For Smart Grid, the following functions should be addressed in each domain.
- Grid domain: power grid functions
- Smart metering: smart metering functions
- Customer domain: end-user functions
- Communication network: telecommunication, including IP-based, network functions
- Service provider domain: application functions
In addition, management/ security functions are required for all domains. Figure 3 shows relevant functions of Smart Grid and their relations between functions using a line with circles at the both ends.
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Figure 3: Functional Model of Smart Grid
The Functional model shown in Figure 3 identifies the principle functional groups for Smart Grid, including the End-User Functions, the Application Functions, the Smart Metering Functions, the Energy Control Functions, the Power Grid Functions, the Network Functions, the Management Functions, and the Security Functions. Key functions within each functional group are shown within each box, and they summarize the Key Elements for Smart Grid discussed in the Overview document. The lines across the function boxes indicate data flows, and interactions between them.
The functions related to end users and end systems (e.g., power system devices) are shown on the left of Figure 3, while the core functions for smart grid, the Application Functions, the Network Functions, and the Energy Control Functions are shown in the middle column. A key focus of the smart grid, the Smart Metering Function is also shown in the middle. Two key function areas: (i) the Management and (ii) Security Functions have interaction with other functions and are shown on the right of Figure 3.
The key functions in each functional group are listed below:
• Power Grid Functions: This function group performs functions to efficiently and intelligently distribute energy and integrate distributed renewable energy generation and distribution. It interacts with Application and Energy Control Functions through Network Functions, and interacts with End-User Functions for energy transmission.
• Network Functions: This function group interacts with all other function groups to provide functions such as Resilience and Recovery, QoS management, reliable data transport, metering data transfer, data aggregation, real-time data transfer, and others.
o Resilience and Recovery Function: This function provides the capability of effectively preventing and responding to disruptions due to cyber attacks, physical phenomena, software and hardware failures, upgrades and human mistakes.
NOTE: Reliable communications networks and services are now critical to public welfare and economic stability. Attacks on Internet, disruptions due to physical phenomena, software and hardware failures, and human mistakes all affect the proper functioning of public Communications networks. Such disruptions reveal the increased dependency of our society to these networks and their services. The experience has revealed that any country, acting independently, may face difficulties in effectively preventing and responding to this type of attacks which often originate from beyond national and regional borders.
o QoS Management Function: The QoS Management Function is used to guarantee the performance (e.g., bandwidth, end-to-end delay, jitter, and others). It provides the capabilities to differentiate and prioritize the data sent from a variety of devices (e.g., meters, appliances, substation, and others) thus enabling the delivery of information across the grid for different applications. QoS management differentiates operational data, non-operational data, and asynchronous events generated by the Smart Grid devices in reaction to physical activities. For example, QoS management will differentiate traffic related to DR signals and SCADA control sensing from the meter reading with other data traffic from non-critical applications.
o Core Data Transport Function: This function provides secure and efficient network signalling and data transmission planes over a wide geographical area, enabling functionality related to the interaction, and data and information exchange between different function groups.
• Smart Metering Functions: This function group encompasses the interaction with End-User Functions, Network Functions, Management Functions, and Security Functions groups. It performs functions to control and maintain metering equipment and to read meter data. It interacts with Application Functions group for establishing meter data base and billing information and interacts with Network Functions group for meter data aggregation and transportation; it may interact with End-User Functions through gateways and home networks. This function group also enables the real-time monitoring and protection via effective event or alarm reporting and processing.
• Energy Control Functions: This function group performs functions to monitor and manage distributed energy resources and support services such as Plug-in Electric Vehicle (PEV) charging, and to manage energy capacity planning. It interacts with End-User Functions and Application Functions group through Network Functions.
• End-user Functions: This function group consists of energy demand response, home/ building energy management and automation, local energy generation and storage, and PEV charging functions. It interacts with Demand Response (DR) application for dynamic pricing information, controls energy usage of home appliances and in-building equipments. It also interacts with Energy Control Functions for distribution capacity management and two-way energy transmission.
• Application Functions: This function group consists of functions for application system information management (e.g., data syntax, semantic, and storage), customer information management (e.g., billing, user subscription), energy market and dynamic pricing as well as energy DR management and control. This function group interacts with End-User Functions, Smart-Metering Functions, Energy Control Functions, Management Functions, and Security Functions groups. This function may interact with End-User function, Energy control function and Power grid function to manage environmental parameters.
• Management Functions: This function group consists of functions for management of systems in all function blocks. This function group interacts with all other function groups and covers various system management, including application management, device management, and network management, which are described below.
o Application Management Function: This function provides the functions to help the operator to manage the key aspects of applications. It monitors various applications and helps application providers to ensure that their applications meet end-user’s expectations.
o Device Management Function: This function enables the communication with a vast array of devices in the field and substations, whether heterogeneous or homogeneous. The device management provides an efficient way to normalize and transmit data to and from these devices.
o Network Management Function: This function enables the diagnostics solution of network issues before the system actors are affected. It ensures that the network is available and runs as expected, so that the desired performance of network services can be achieved. Network Management Function is also responsible for keeping track of network resources and how they are assigned, configuring resources in the network to support a given service, and adjusting configuration parameters in the network for better quality. Data for network management is collected through a real-time two ways communication between Network Management Function and other functional groups.
• Security Functions: This function group interacts with all other function groups in terms of physical security, system security, and operation security. This function group covers various security aspects and the examples of applications are described below:
o Identification and Authentication Function: This function is the process of verifying the identity of a user, process, or a device, as a prerequisite for granting access to resources in a smart grid system.
o Audit and Accountability Function: This function enables the review and the examination of the information record and activities related to smart grid to determine the adequacy of security requirements and to ensure compliance with the established security policy and procedures.
o Access Control Function: This function ensures that only authorized personnel or users have access to use various utilities and services in the grid system.
o Data Integrity Function: The function is responsible for data integrity in smart grid via cryptography and validation mechanisms.
o Privacy Preserving Function: This function is designed to provide the privacy considerations with respect to the Smart Grid, including the examination of the rights, values, and interests of individuals, the related characteristics, descriptive information and labels, activities, opinions of individuals, and others.
A more detailed requirements and description of Security Functions can be found in NISTIR 7628 - Guidelines for Smart Grid Cyber Security [9].
7.2 Detailed Functional Architecture of Smart Grid
As discussed in the Overview document, there are several representative applications for smart grid, including energy distribution, renewable energy management and storage, electric vehicles-to-grid, grid monitoring and load management, and smart metering. The functional model of smart metering and load management will be presented in Section 7.2.1. This covers functions commonly called the Advanced Metering Infrastructure (AMI) plus additional functions to support PEV charging and energy generations and storages in Customer domain. The functional model of energy distribution and management will be presented in Section 7.2.2. This covers the monitoring, measurement, and control of the grid to ensure the reliability and availability of the grid, and management of energy usage and energy distribution to ensure balanced energy supply and demand. Note that those two are fundamental and have the most interaction in the ICT area.
7.2.1 Functional Architecture of Smart Metering and Load Control
Figure 4 shows the functional model for Smart Metering and Load Control application. Within each function group, a more detailed grouping of functions is shown in this figure. The lines between the function boxes indicate data flows and interactions between them. For example, in order to obtain metering information End-User Functions are invoked. The text box below the figure provides the keys for the notations in the figure.
Note that although there are no explicit data flows and interactions from Management Functions to either End-User Functions or Power Grid Functions, there exist many relevant interactions with Management Functions. Similarly, Security Functions also interact with all other function blocks. Although there should be lines connecting the Security Functions with others, for ease of reading, those are not shown in the figure.
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Figure 4: Functional Model of Smart Metering and Load Control Service
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7.2.1.1 End-User Functions
• DR Function: This function group covers all operations in the Customer domain for the major smart grid application that the customers interact with Service Provider domain and Smart metering.
1. DR Client Function: This function interacts with the DR (Demand Response) Application Function in the Application Functions for subscription to the service and dynamic pricing information. For industrial customers, this function also enables the management of industrial energy consumption per their needs.
2. Home Energy Management (EMS) Function: This function monitors the energy consumption of appliances and the dynamic pricing information, and interacts with homeowner in order to control appliances, and generation and storage devices in the customer premises. This function provides notification of power outage to utility companies, and responds to mitigation and recovery signals during a scheduled or unscheduled energy outage.
3. Metering Information Retrieval: This function retrieves meter reading information either directly from meters, or indirectly through the Smart Metering Application in the Applications Functions. Metering information may also be obtained from sub-meters in the customer premises.
• Home /Business/ Industrial Network Functions: This function set provides communications function in the home/building/industrial through a Home Area Network (HAN), Building Area Network (BAN), and Industrial Area Network (IAN), respectively. The HAN/BAN/IAN interconnects all appliances and equipments, EMS, PEV charging stations, generation and storage facilities, and meters. Major sub-functions include:
1. Configuration: It manages the membership of the HAN/BAN/IAN, as equipment joins and leaves the network. It interacts with the Security Functions to authenticate the members, to authorize the operations they could perform, and the information they could send and receive, and to maintain encryption key information.
2. Bridging: As the HAN/BAN/IAN may consist of multiple transmission mediums and PHY/MAC communications protocols, this bridging function, either at the Link or Network layer, allows the EMS to communicate with all members in the HAN.
3. Energy Service Interface (ESI) Functions: For home ESI, it refers to the interface between the HAN and the Network Functions. It is more than the simple “gateway” logical device in a communications network. It is an “Energy Service Interface” that gates information in/out of HAN like a firewall and performs other functions. For industrial, it provides bi-directional logical interface that supports the communication of information between industrial energy automation and other entities in smart grid.
• PEV Charging Function: This interacts with the Energy Control Functions and Customer Bill Function in the Application Functions to manage the charging rate and billing information.
• Generation & Storage Management Function: This function manages the facilities for local energy source. It interacts with EMS for switching of power for consumption at customer premises or distribution to Power Grid. It also interacts with Energy Control Functions for feeding of power to the grid.
7.2.1.2 Application Functions in Smart Metering and Load Control
• Smart Meter Headend Function: This function pairs with the Meter Reading function to provide the necessary smart metering functions for initiation of meter readings, and then performs further processing of collected data. It may interact with the data aggregation function in the Metering Network Function. It interacts with the Information Storage Function on meter reading database as well as with the Security Functions associated with security and privacy areas.
• DR Application Function: This function pairs with the DR Client in the End-User Functions to effect the Demand Response operations in managing the demand of energy. It interacts with Energy Monitor and Control function and other market functions (not shown in Figure 4) to determine the price of energy dynamically. It interacts with DR Client Function for customer registration/de-registration of clients, and interacts with Customer Subscription/Billing Function.
• Information Handling / Storage Function: The function addresses the syntax, semantics, and storage aspect of all information related to the smart metering and load control application.
• Business Data Transport Function: This function handles the networking function for supporting business related activities. It interacts with all external counter-parts of this application.
• Energy Pricing Function: This function determines the energy price based on energy market operation, power utility’s policy, customer’s demand, and others.
7.2.1.3 Smart Metering Functions
• Meter Reading Function: This function concerns operations of physical smart metering devices; it provides meter readings at the command of Smart Metering application. The data passes through the Metering Network Function and Core Network/Transport Function as well as the Business Network function. The Meters may provide meter readings to End-User Functions through the Energy Service Interface (ESI) that may be a part of meter, or interacts with the Network Function. An alternate path is for the Energy Management Station (EMS) to inquire the meter database in the applications functional group.
• Meter Control and Maintenance Function: This function, interacting with the Smart Meter Headend Function in the application functional group, provides the management and maintenance of meters and metering infrastructure, such as service initiation or termination, testing, fault detection and recovery, firmware update, and others. It also interacts with the Security Functions group for authentication, authorization, accounting, and auditing functions.
• Fault monitoring and protection: This function enables real-time two way communication between customers and utilities (e.g., service providers) for monitoring and control to improve stability of the grid. It provides the exchange of tailored metering data, event or alarm information. The features include voltage and energy use monitoring, identification of faulty meters, verification of restoration after outage, outage detection, isolation and restoration, and others.
7.2.1.4 Energy Control Functions
• Load Monitor and Control Function: This provides the capability to monitor and control the system load. It interacts with the Demand Response Function in the End-User Functions to achieve necessary load reductions. It also interacts with the Load Monitor and Control Function in the Power Grid Functions group to control the distribution of power in response to changing load of PEV charging.
7.2.1.5 Network Functions
• Metering Data Transport Function: This function provides the connectivity for meters in a small geographical area, and data aggregation for meter readings in the area, and connectivity for End-User Functions group in homes or buildings through Gateway function. The network that supports this function is denoted as Neighbourhood Area Network (NAN).
• Core Data Transport Function: This function is described in Section 7.1.
7.2.1.6 Management Functions
The Management Functions are described in Section 7.1.
7.2.1.7 Security Functions
The Security Functions are described in Section 7.1.
7.2.2 Functional Architecture of Energy Distribution and Management
A major goal of smart grid is the development of an energy distribution and management system that is intelligent, reliable, self-repairing, and self-optimizing. There are two major application areas in the Energy Distribution and Management application: (i) monitoring, measurement, and control of the grid to ensure the reliability and availability of the grid, and (ii) management of energy usage and energy distribution to ensure balanced supply and demand.
A way to accomplish this goal is the deployment of ubiquitous networked sensors and measurement devices, and the software system to understand and ultimately optimize the management of grid components, grid behaviour and performance, and to anticipate, prevent, or respond to the problems before disruptions can arise.
The functional models of these two areas are shown in Figures 5 and 6 below. In particular, Figure 5 shows the functional model for power grid monitoring and control, and Figure 6 shows the functional model for energy usage and distribution management. These two figures follow the model shown in Figure 3 in Section 7.1 with eight major function groups – Application, Network, Power Grid, End-User, Energy Control, Smart Metering, Management, and Security Functions. Within each function group, a number of functions are detailed. The lines between function boxes indicate data flows and interactions between them. Note that several functions appear in both figures, some provide common functions to both applications, and some provide unique functions to each application. The Security and Management Functions are referred to Section 7.1.
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Figure 5 Functional Model of Power Grid Monitoring and Control
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Figure 6: Functional Model of Energy Usage and Distribution Management
7.2.2.1 End-User Functions
This function group covers the functions for users of electricity, including home, commercial, and industrial users. Major functions of this group were already discussed in the Demand Response and Energy Control application in Section 7.2.1. Two functions applicable to power grid monitoring and control are repeated here: (i) the local generation and storage function or Distributed Energy Resources (DER) and (ii) the networking function.
• DER (Local Generation & Storage) Function: The generation and storage facilities composing the DER at the customer site may participate in the grid monitoring and control application by providing status information to the grid and allowing the grid operator to control the feeding of power to the grid. The status and control information are transferred from/to the corresponding DER Control Function in the Energy Control Functions group through the premises network and core network functions. Note that the local generation and storage facilities on DER could be autonomous or locally controlled as well as centrally controlled by a grid operator.
• DR Client Function: This function interacts with the DR Application Function in Application Functions group to control the usage of energy using dynamic pricing. During the period of peak demand the utilities raise the price through DR Application Function to reduce demand and at the same time DER Function is used to increase power supply.
• Home/Business/Industrial Network Function: This function is described in Section 7.2.1.1 for Home Network Function.
￮ The HAN transports data between all appliances and equipment (e.g., EMS, PEV charging stations, DER, and others). ESI/LAN provides the secured and effective communication functions that enable the interactions between relevant HAN devices and utility network.
￮ The Business/Industrial Networks transport data between devices in commercial and industrial premises. This function interconnects meters, DER, PEV charging stations, BEMS (Building Energy Management System), and others. BEMS monitors and controls all conventional BAS (Building Automation System) of electric power and HVAC (heating, ventilating, and air conditioning) as well as FMS (facility management system). Business Network Function guaranties secured and effective data transport functions that enable the interactions between relevant systems and BEMS, and the interactions between BEMS and utility network.
7.2.2.2 Power Grid Functions
This function group covers the functions performed within a Power Grid station, which could be a bulk generation site, a substation in the transmission and distribution grid, transmission lines, or a micro-grid of distributed generation and storage facilities. These functions are necessary for efficient and intelligent management of power generation, transmission and distribution, as well as distributed energy resources (DER).
• DER Function: The distributed generation and storage devices associated with DER Function may be embedded in the transmission/distribution systems or in distributed micro-grids. Therefore those DER need to interact with DER Control Function in Energy Control Functions group so that their status are available, and their outputs are fed into the grid as needed. This function also allows industrial customer to integrate their production and storage into the grid.
• Protection and Control Function: This function, either at the command of the Operation Control Function in the Application Functions group or initiated automatically based on local sensing or measurement data, executes necessary protection, recovery, and control operations in a Power Grid station – generation, transmission, or distribution station. Within a station, it interacts with Operation Control Function through Substation LAN/SCADA Network Function.
• Sensing and Measurement Function: This function is provided by sensors and measurement devices located at the power distribution system. New generation of devices, such as Intelligent Electronic Devices (IED) and Phasor Measurement Unit (PMU), could provide more accurate, real-time information Operation Control Function and Energy Control Functions to manage the operations of the power grid.
• Time Synchronization Function: This function maintains and synchronizes high resolution clocks in substations and the power grids. Measurement data (e.g., PMU data) needs to include accurate time stamps before forwarding to the Energy Control Functions group.
• Data Aggregation Function: The measurement data may be aggregated before forwarding to the Energy Control Functions group, which will be de-aggregated for further processing.
• Substation LAN/SCADA Real-time Data Transport Function: This function enables the communications between devices within the Power Grid station, and between these devices and external Functions group through the SCADA Real-time Transport Function and Core Network Transport Function. This function provides the secured and real time delivery and management of data and information to SCADA control centre. Minimum message forwarding delay and delay variation are major requirements in this function.
7.2.2.3 Application Functions
The Application Functions group provides functions performed at the operation centre of utility companies, regional transmission organizations (RTO), or independent systems operators (ISO), and at the offices of energy service providers. This function group performs functions to monitor and control the performance of power distribution systems, analyzes the operation condition, and manages the supply and usage of electricity. It also includes back office functions such as database for subscribers, equipment inventories. It interacts with End-User Functions, Power Grid Functions, Energy Control Functions and Security Functions through Network Functions.
• Operation Control Function: This function is responsible for monitoring the day-to-day operation of the grid. It ensures the reliability, frequency and voltage stability, transient angular stability and small signal angular stability in the power system. This function provides the functionality to monitor the status of processes under control, modify control settings, and manually override automatic control operations in the event of emergency. This function also interacts with the rest of the Application Functions, in particularly with the Energy Usage Management Function to ensure supply meets demand. This function includes simulation and forecasting.
• Asset Management Function: In addition to the normal business operations, this function could be established and used for the correlation of measurement reports, for display, and used by the operators in performing the Operation Control Function, and maintaining and upgrading systems.
• Energy Usage Management Function: This function, in conjunction with Operation Control function and other functions, controls the demand response of electricity. On the supply side, it interacts with the Capacity Planning Function to estimate the short and long term demands, and with the Wholesale Marketing Function to secure supply. On the demand side, it interacts with DR Application Function using dynamic pricing and other means (e.g., capacity) to control the energy usage.
• Wholesale Marketing Function: The open market provides means for efficient distribution between the suppliers and energy distributors. It affects the other functions such as bringing DER online, changing the DR pricing, and others.
• Capacity Planning Function: Capacity planning from the Operations perspective is mainly a short term planning in projecting the available supply so that the Energy Usage Management Function and Wholesale Marketing Function can take appropriate actions.
• Demand Forecast Function: This function projects the short term demand based on usage trend and other information such as weather forecast information.
• DR Application Function: This function manages the Demand Response application discussed in Section 7.1; it receives the energy supply and demand information from Operation Control Function and interacts with Wholesale Marketing Function to dynamically determine the price of energy. It is responsible for managing the demand of energy and supports the utilities to balance the demand and response with the efficient energy delivery and usage.
• Smart Meter Headend Function: This is part of DR application (as described in Section 7.2.1) that obtains the energy usage information for the Energy Usage Management Function.
7.2.2.4 Energy Control Functions
This functional group enables the intelligent, reliable, and effective utilization of energy consumption and distribution and provides the self-repairing and self-optimizing management of power grid.
• DER Control Function: DER pairs with the DER Function in the Power Grid Functions group to monitor the status of distributed energy resources and control the flow of electricity into the grid.
• Load Monitor and Control Function: This function provides the capability to monitor and control the load power transmission and distribution. It either initiates load balancing operation in the power grid, or interacts with the DER Control Function to bring the power sources online or offline. It also interacts with the Energy Usage Management Function for system wide supply and demand management. Note that DER could be autonomous or locally controlled as well as controlled by DER Control Function.
• Fault Location/Isolation/Recovery Function: This function enables the fault detection and recovery of grid infrastructure. It interacts with the Sensing and Measurement Function and the DER Control Function to improve the reliability of energy distribution by identifying the faults quickly, providing quick response to isolate the faults, and taking effective system outage recovery actions such as informing the status of power grid, reacting to the information from others, and predicting and preventing the impact of control function to other grids.
• Wide-Area Situational Awareness (WASA) Function: This function represents the monitoring of the power grid across wide geographic areas. The WASA Function in the group interfaces with the WASA function of other utility’s Smart Gird, exchanges grid status with each other, reacts to status information from others, and project the impact of local control action to other power grids.
• Time Synchronization Function: Just like the Time Synchronization Function in stations of the power grid, the home office for the energy control needs to maintain and synchronize clocks, so that events in the grid could be correlated for other functions to be interpreted as status data and take actions accurately.
• Data Aggregation/De-Aggregation Function: This function interacts with the Sensing and Management Function to de-aggregate data from grid-monitoring devices (e.g., PMU and others) and aggregate control information to be sent downstream.
7.2.2.5 Smart Metering Functions
The Smart Metering Functions group consists of the following function:
• Meter Reading Function: Similar to Smart Metering and Load Control discussed in Section 7.2.1, Meter Reading Function in energy distribution is concerned with the operations of smart metering. The meter reading data are transmitted through the Core Network Transport Function. It interacts with DR Application Function and Energy Usage Management Function. The meters may provide meter readings to End-User Functions through the Energy Service Interface (ESI), which may be a part of meter or, interact with the Network Functions. It also provides the End-User energy consumption information to help Energy Usage Management Function to realize energy consumption management in real time.
7.2.2.6 Network Functions
This function group enables the communication between all function groups. A unique characteristic of this group is that it carries the time sensitive and low delay tolerance real-time information. To accomplish this, the traditional dictated SCADA network can continue to be used. If the shared transport network, such as IP-network, is adopted, a strong Quality of Service (QoS) control is required.
• SCADA Real-time Transport Function: This function supports the real-time communication between the Power Grid Functions group and the Energy Control Functions/the Operation Control Function groups.
• QoS Management Function: The QoS Management Function is described in Section 7.1.
• Core Data Transport Function: This function is described in Section 7.1.
7.2.2.7 Management Functions
The Management Functions are described in Section 7.1.
7.2.2.8 Security Functions
The Security Functions are described in Section 7.1.
8 Deployment Model of Smart Grid
This section focuses on development and implementation models for smart grid network.
8.1 Networks in Smart Grid
In order to describe the architecture of smart grid communication networks, the smart grid network can be categorized into several logical components based on their coverage, such as Home Area Network, Local Area Network, Neighbourhood Area Network, Wide Area Network, and Access Network. This does not imply that physical implementation must divide the network this way, nor that network companies must structure their network in a similar way and limit their services to some specific components. The general meaning of these components is listed in Table 1. Note that the areas covered by these components may overlap, but should be obvious in the context being discussed.
Table 1: Major Components of Smart Grid Networks
|Term |Definition |
|Wide Area Network |A wide area network (WAN) is a communication network that covers a wide geographical area and accommodates |
| |terminals and LANs. This is typically called “Back Haul” network in smart grid environment. |
|Local Area Network |A local area network (LAN) is a network that connects computers and devices in a limited geographical area such |
| |as home, computer laboratory, office building, and closely positioned group of buildings. |
|Home Area Network |In the smart grid applications, Home Area Network (HAN) refers to the networks in the homes that interconnect |
| |energy devices, including appliances, energy management station, plug-in electrical vehicle chargers, energy |
| |sources. |
|Access Network |An access network refers to a network which connects subscribers to their immediate service provider (ISP). It |
| |is contrasted with the core (or transport) network in wide area network. |
|Neighborhood area network|Neighborhood area network (NAN), is an access network that allows smart grid end-device and home area networks |
|(NAN) |to connect to wide area network. |
8.2 Smart Grid Network Architecture
8.2.1 Home Area Network Architecture
This section provides additional descriptions of the Home Network Function group in the End-User Functions group. While in Section 7.2.1.1, the major functions of HAN are discussed, the issues related to the architecture of HAN or the physical connections within a HAN will be focused here.
8.2.1.1 HAN Topology
Within a HAN, there are many ways to interconnect devices in a home, depending on the physical medium and communications protocol to be used. As shown in Figure 7, possible topologies in a HAN include:
• Bus Topology: As shown in Figure 7(a), all devices in a bus topology share a common transmission medium. An example is the use of power lines or coaxial cables.
• Tree Topology: As shown in Figure 7(b), all devices in a tree topology are connected to a central “root” node in a tree fashion. A Wi-Fi access point communicating with IEEE 802.11 devices is an example of a tree topology; and a simple router used in home that connects devices using twisted pair cables is another example. It is possible to cascade stars into hierarchy of stars like tree branches.
• Mesh Topology: As shown in Figure 7(c), devices interconnect in a meshed network. Each node participates in maintaining communications with its neighbours and routing message toward their destinations. This topology is typically used in wireless network when reliability and connectivity is needed.
[pic]
Figure 7: Possible topologies of HAN
In a home environment, one or more of these topologies may be used, as a single transmission medium or communication technology may not provide sufficient coverage, due to wiring constraints and environmental factors. Therefore, interconnecting devices into a network and routing message among these devices with minimum human intervention are major issues in designing HAN architecture.
8.2.1.2 Energy Service Interface (ESI)
The Energy Services Interface (ESI) function block in the End-User Functions provides data transfer for devices in HAN, and interface to the Utility network through the Neighbourhood Area Network that provides the Metering data exchange Function in the Network Functions block. The implementation may consist of one or more physical devices; it could even be an integrated part of smart meters. The ESI satisfies the “gateway” requirement as described in the Requirement Deliverable.
The functions of ESI on the HAN include:
• Provide interfaces to support the transmission medium used in HAN, wired or wireless, in order to provide connectivity to all devices supporting End-User Functions.
• Provide message routing capability to allow exchange of information between devices. This could be implemented as OSI layer 2 bridging or layer 3 routing. This function is essential in enabling the Home Energy Management Function block to communicate, manage, and control energy devices in a home.
• Provide message filtering capability to ensure the integrity of the Utility network. The filtering is carried out in the way that only a certain outgoing messages from HAN are permitted to go across the HAN, NAN, or WAN boundaries.
• Perform HAN device configuration and management. The ESI works with the Home Energy Management Function block and Security Functions block as well as the Customer Subscription and Billing function in the Application Functions block to manage joining and departure of devices in HAN, to authenticate the validity of these devices, and to determine their privileges in exchange of information.
On the NAN side, the ESI provides external connection to rest of Utility network for:
• Access to the metering information,
• Exchange information for the Demand Response Function.
8.2.1.3 Interactions with Other Networks
In the context of this deliverable, the term HAN refers to the home portion that connects with the Utility network, which is defined in Section 7.2.1.1. However, networks in homes very often have many uses, such as residential broadband for PCs or entertainment devices, and may have connections to non-utility networks such as Internet from Telecommunications Companies or Internet Service Providers (ISP) as depicted in Figure 8 below. The diagram on the right is the Customer Domain portion of the reference architecture in Figure 2 of the Smart Grid Overview deliverable; the circled part shows multiple connections from a customer domain to the outside world. The diagram on the left of Figure 8 shows how such home networks, consisting of a utility HAN and a residential broadband network might be configured; the two entities could be physically separate networks, or the utility HAN could be a logical subnet within the home network. Therefore, how one architect the utility portion of a home network, or Utility HAN, has profound impact to the security of the Smart Grid. In both cases, security issues must be addressed to ensure the integrity and reliability of the Smart Grid utility network. Note that the arrow between ESI and Router on the left of Figure 8 implies communication path between ESI and a third party through the router.
[pic]
Figure 8: A Home with Multiple Networks and Connections to
Utility Network and Other External Networks
The architectural design of customer premises networks could address the security issues in the following ways:
- When the utility HAN is physically separate from the residential broadband network, an ESI or a gateway with additional functions of an ESI could be used to interconnect the two networks so that limited information could be exchanged.
- When the two networks are not physically separate from each other, a configuration manager could be used to make the Utility HAN a logically sub-network such that nodes in the sub-network has special privileges in accessing the Utility Network. The privileges may be in multiple classes.
- Detailed security functions of an ESI are described in Section 8.2.1.2 Energy service interface.
- Proper encryption and signature mechanisms are used to maintain the authenticity and integrity of messages transfer end-to-end between Application Functions group and nodes in the Utility HAN.
8.2.2 Neighborhood Area Network Architecture
The Neighborhood Area Network performs the Metering Data Transport Function shown in Figure 4 for Functional Model and provides connectivity for meters in a small geographical area, data aggregation for meter readings, and connectivity for the homes through the ESI function. The metering information are aggregated and forwarded through the Wide Area Network to the Smart Meter Head-Ends. The information for the Demand Response Application Function communicated with the Home Energy Management Function in the End-User Functions block through WAN, NAN, and HAN.
8.2.2.1 NAN Topology
In a neighbourhood area, the environmental factors affecting the performance of communications network such as geographical topology, the density of buildings, and the external signal interference are major considerations for developing the architecture of the NANs. There are potentially two different network topologies as shown in Figure 9.
• Tree Topology: As shown in Figure 9(a), each ESI as a “leaf” node has a point to point link with the upper level Collector as a “root” node.
• Mesh Topology: As shown in Figure 9(b), each ESI has point to point connection with other ESIs or other NAN nodes in the network. This is used in a wireless environment to enhance the reliability and resilience of communication paths, and to extend coverage area that one collector supports.
NAN topologies are described according to the following three functionalities.
– ESI Function: This function is described in Section 8.2.1.2 “Energy service interface (ESI).” In the NAN topology models, ESI function terminates NAN communication link at HAN side. ESI may have routing functions to form a full-mesh topology, or may only have simple forwarding function to communicate with few specific nodes in a tree topology.
– Collector Function: This function is one of an AMI function referred to in IETF RFC6272. In the NAN topology models, Collector function terminates NAN communication link at WAN side. Collector function may aggregate data from underlying Collectors, Relays and ESIs, and de-aggregate data to underlying Collectors, Relays and ESIs.
– Relay Function: This function is a routing function to form a NAN full-mesh topology. Relay function works between Collectors and ESIs to control routing metrics for multi-hop mesh network. Relay function may be implemented separately to construct redundant networks or to cover wider area of neighbourhood. Relay function may also be implemented in ESI or Collector nodes.
[pic] [pic]
(a) NAN Tree Topology (b) NAN Mesh Topology
Figure 9: Possible topology of NAN
In the NAN tree topology model, a collector is connected to one or more ESIs at HAN side, and to AMI Head-end at WAN side. Collector may also connect to other collectors to form a hierarchical tree topology as shown in the lower right side of Figure 9(a). A special case of tree topology is one-hop star topology as shown for the two ESIs on the left of Figure 9(a). Either wired communication or wireless communication is applicable to this model. A variety of link layer technologies can be used; for examples, power line communications, wireless technology such as IEEE family of wireless protocol and cellular network technologies can be used for the communication links between collectors and ESIs.
A type of NAN Mesh network where all possible links between nodes are selected for communication paths is called “Full-Mesh”. Full-Mesh works well but routing metrics and its control traffic become huge as the number of nodes in a network increases to a certain amount. Another routing method is many-to-one routing. Many-to-one routing is optimized to collect data from many points to one single point and is recommended in the large scale networks such as an AMI infrastructure. Figure 9(b) illustrates these two types of NAN mesh topology, where the left side is a Full-Mesh topology and the right side is Many-to-One topology. Note that there are multiple routes between some specific two nodes to form a mesh topology in Figure 9(b). In this case, data are forwarded through one of those routes.
The following two methods could be considered for relaying data in the mesh networks.
• Layer 2 Forwarding: This is a method of multi-hop forwarding on data link layer. It can work effectively using control information and status in the data link layer and it can forward data efficiently without overhead of IP layer. This method is suitable for nodes with less CPU power and strong power-conscious.
• IP Forwarding: This is a method of multi-hop forwarding on IP layer. Data is forwarded as IP datagram hop by hop in the mesh network where a routing protocol runs on the IP layer. This method is more suitable for relatively high-end nodes with enough CPU power and memories for IP router functions.
Note that IETF developed specifications for both methods (L2 forwarding aka mesh-under and IP forwarding aka route-over) while IEEE802 addressed L2 forwarding technologies [2].
Hierarchical mesh network should also be considered, especially where WAN connects to multiple multi-hop networks covering large geographical area like town as well as smaller neighbourhood area as shown in Figure 9(b).
8.2.3 Wide Area Network Architecture
The Wide Area Network (WAN) performs the Core Network Transport Function in the Functional Model shown in Figure 4. There are many different views on where the WAN begins and ends. In some countries, WAN includes all telecom company circuits and ends at the entrance to customers premises. To facilitate discussions of network architectures in this document, any networks beyond the NAN or the last metering information aggregation point belong to WAN.
8.2.3.1 IP-Based Network
A possible WAN architecture is an Internet Network utilizing the Internet Protocol suite, including session control, transport function, message routing, security functions, network management and many others, as described in RFC6272 [2], “Internet Protocols for the Smart Grid.” The following is a general description of Internet in this RFC.
“The Internet is a network of networks in which networks are interconnected in specific ways and are independently operated. It is important to note that the underlying Internet architecture puts no restrictions on the ways that networks are interconnected; interconnection is a business decision. As such, the Internet interconnection architecture can be thought of as a "business structure" for the Internet.
Central to the Internet business structure are the networks that provide connectivity to other networks, called "Transit Networks". These networks sell bulk bandwidth and routing services to each other and to other networks as customers. Around the periphery of the transit network are companies, schools, and other networks that provide services directly to individuals. These might generally be divided into "Enterprise Networks" and "Access Networks"; Enterprise networks provide "free" connectivity to their own employees or members, and also provide them a set of services including electronic mail, web services, and so on. Access Networks sell broadband connectivity (DSL, Cable Modem, 802.11 wireless or 3GPP wireless), or "dial" services including PSTN dial-up and ISDN, to subscribers. The subscribers are typically either residential or small office/home office (SOHO) customers. Residential customers are generally entirely dependent on their access provider for all services, while a SOHO buys some services from the access provider and may provide others for itself. Networks that sell transit services to nobody else - SOHO, residential, and enterprise networks - are generally referred to as "edge networks"; Transit Networks are considered to be part of the "core" of the Internet, and access networks are between the two.”
This general structure is depicted in Figure 10.
[pic]
Figure 10: Conceptual Model of Internet Businesses
It should be noted that the medium layer technologies mentioned above is not an exhaustive list, and there are other technologies and protocols that are equally applicable.
The Internet protocol suite is based on the protocol stack shown in Figure 11. This model is important as IP-based smart grid applications end-to-end exchange of information, is assuming certain services provided by the transport and network layer functions, and is independent of physical communication media used. This allows software designers to focus on application protocol and coding of information, thus simplifies the design task.
|Application |
|Application Protocol |
| |
|Encoding |
|Session Control |
| |
|Transport |
|Transport layer |
| |
|Network |
|Internet Protocol |
| |
|Lower network layers |
| |
|Media layers |
|Data Link Layer |
| |
|Physical Layer |
| |
Figure 11: The Internet Protocol Stack Model
8.2.3.2 Next Generation Network Architecture
NGN services include multimedia services such as conversational services, and content delivery services such as IPTV services. In addition, key features of NGN such as fixed mobile convergence (FMC) support providing QoS and security play an important role in areas of smart grid applications. Figure 12 shows an overview of the NGN functional architecture, which is described in detail in ITU-T Y.2012 [8].
As described in ITU-T Y.2011 [7], the separation of services from transport, allowing them to be offered separately and to evolve independently, is the key cornerstone of NGN characteristics. The separation is represented by two distinct blocks or strata of functionality.
There is a set of transport functions that are solely concerned with conveyance of digital information, of any kind, between any two geographically separate points. A complex set of layer networks may be involved in the transport stratum, constituting layers 1 through 3 of the OSI 7-layer Basic Reference Model. The transport functions provide connectivity.
The services platforms provide the user services, such as a telephone service, a Web service, etc. The service stratum may involve a complex set of geographically distributed services platforms or in the simple case just the service functions in two end-user sites. There is a set of application functions related to the service to be invoked.
Figure 12 shows that the transport functions reside in the transport stratum and the service functions related to applications reside in the service stratum. The delivery of services/applications to the end-user is provided by utilizing the application support functions and service support functions, and related control functions. The transport stratum functions include transport functions and transport control functions. The transport stratum provides the IP connectivity services to the NGN users under the control of transport control functions.
Among interfaces specified in Figure 12, ANI (application network interface) and SNI (service network interface) are distinguished from each other. The ANI is an interface which provides a channel for interactions and exchanges between an NGN and applications. The ANI offers capabilities and resources needed for realization of applications. The ANI supports only a control plane level type of interaction without involving media level (or data plane) interaction. On the other hand, the SNI is an interface which provides a channel for interactions and exchanges between an NGN and other service providers. The SNI supports both a control plane level and media level (or data plane) type of interaction.
8.2.3.2.1 Transport Stratum
The transport functions provide the connectivity for all components and physically separated functions within the NGN. These functions provide support for unicast and/or multicast transfer of media information, as well as the transfer of control and management information. Transport functions include the followings:
• Access Network Functions
• Edge Functions: The Edge Functions are used for media and traffic processing when aggregated traffic coming from different access networks is merged into the core transport network; they include functions related to support for QoS and traffic control.
• Core Transport Functions
• Gateway Functions: The Gateway Functions provide capabilities to interwork with end-user functions and/or other networks.
• Media Handling Functions: The Media Handling Functions provide specialized media resource processing for service provision, such as generation of tone signals and transcoding.
The transport control functions include the followings:
• Resource and Admission Control Functions: The Resource and Admission Control Functions act as the arbitrator between service control functions and transport functions for QoS.
• Network Attachment Control Functions: The Network Attachment Control Functions provide registration at the access level and initialization of End-User functions for accessing NGN services.
• Mobility Management and Control Functions: The Mobility Management and Control Functions provide functions for the support of IP-based mobility in the transport stratum.
8.2.3.2.2 Service Stratum
The Service Stratum functions include Service Control and Content Delivery Functions, and Application Support Functions and Service Support Functions.
• Service Control and Content Delivery Functions: The Service Control Functions include resource control, registration, and authentication and authorization functions at the service level, while the Content Delivery Functions receive content from the Application Support Functions and Service Support Functions, store, process, and deliver it to the End-User Functions using the capabilities of the transport functions, under control of the Service Control Functions.
• Application Support Functions and Service Support Functions: The Application Support Functions and Service Support Functions include functions such as the gateway, registration, authentication and authorization functions at the application level. These functions are available to the "applications" and "end-user" function groups.
8.2.3.2.3 Identity Management (IdM) Functions
ITU-T Y.2012 [8] describes that IdM Functions and its capabilities are used to assure the identity information, assure the identity of an entity and support business and security applications (e.g., access control and authorization), including identity-based services. An entity is considered to be anything that has separate and distinct existence that can be uniquely identified.
In the NGN environment, a single entity may be associated with multiple types of identity information which can be grouped as follows:
- Identifiers: UserID, email addresses, telephone numbers, URI and IP addresses, and others.
- Credentials: Digital certificates, tokens and biometrics, and others.
- Attributes: Roles, claims, privileges, patterns and location, and others.
[pic]
Figure 12: NGN Architecture Overview
8.2.3.3 Consideration of the M2M Service Layer aspects
When considering Smart Grid as one of the various specific M2M applications, telecommunication aspects at the service layer can be addressed in an optimized way by taking benefit of the functional architecture specified by [3] through standardized Service Capabilities (SCs), as shown in Figure 13.
M2M Service Capabilities provide M2M functions that are to be shared by different Applications. These functions, implemented at the Service Layer in M2M Devices / M2M Gateways and in the Network server, are exposed through a set of open interfaces.
[pic]
Figure 13: High Level Architecture with ETSI M2M Service Capabilities Layer
These SCs, using the ETSI M2M terminology, are partly described below for specific use by the Smart Grid applications. For more details on these SCs and how to implement them, refer to ETSI M2M specifications [3, 4].
• The “Generic Communication” SC (in the Device / Gateway / Network) for the communication between Network Service Capability Layer (SCL) and Gateway SCL (or Device SCL) to enable delivery of the M2M Service corresponding to the Power Grid Functions;
• The “Telco Operator Exposure” SC (in the Network) is an optional SC that can be used for interworking purposes with existing telecommunication networks that could be involved in the Power Grid Functions;
• The “Communication Selection” SC (in the Device / Gateway / Network) to ensure that there is a new network selection to exchange information for the Power Grid Functions in case of failure of the one initially used;
• The “Reachability, Addressing and Repository” SC (in the Device / Gateway / Network) to be kept informed on the status of the entities involved in the Power Grid Functions;
• The “Remote Entity Management” SC (in the Device / Gateway / Network) provides the Management functions also involved in the functional model of Smart Grid illustrated in Section 7;
• The “Interworking Proxy” SC (in the Device / Gateway / Network) is an optional SC to provide interworking between non ETSI compliant devices or gateways and the Network SC Layer through an mId compatible reference point; in smart grid applications, this can be used for the smart meter to be M2M-enabled for example;
• The “Compensation Brokerage” SC (in the Device / Gateway / Network) is an optional SC used where a Broker acts to submit compensation tokens (i.e. electronic money) to requesting Customers and to bill the customer of compensation tokens for the amount spent, before redeeming Service Providers for tokens acquired as compensation for services provided to customers;
• The “Application Enablement” SC (in the Device / Gateway / Network) is the single contact point between the SCLs and the M2M Applications;
• The “SECurity” SC (in the Device / Gateway / Network) performs Security Functions also involved in the functional model of Smart Grid as illustrated in Section 7;
• The “History and Data Retention” (in the Device / Gateway / Network) is an optional SC, deployed when needed by the Service Capability Layer provider. It is used to archive relevant information pertaining to messages exchanged over the reference point and also internally to the SCL.
All these Service Capabilities are exposed to the M2M applications (including Smart Grid applications) through the following reference points, and those are specified by [4].
mIa Reference Point: allows a Network Application (NA) to access the M2M Service Capabilities in the Network Domain.
dIa Reference Point: allows a Device Application (DA) residing in an M2M Device to access the different M2M Service Capabilities in the same M2M Device or in an M2M Gateway, and also allows a Gateway Application (GA) residing in an M2M Gateway to access the different M2M Service Capabilities in the same M2M Gateway.
mId Reference Point: allows an M2M Service Capabilities residing in an M2M Device or M2M Gateway to communicate with the M2M Service Capabilities in the Network Domain and vice versa. mId uses core network connectivity functions as an underlying layer.
9 Sample Implementation of Smart Grid Applications
9.1 ITU-T G.9970 Home Network Transport and Application Layer Architecture
ITU-T G.9970 [5] addresses the home network architecture for both the transport layer and the application layer. The physical configuration depicted in Figure 14 shows home networks consisting of multiple networks technologies, including IP-based and non IP-based terminals, and gateway to the IP-based carrier networks. It shows the protocol mapping and how they are interconnected. It also includes the following features:
– The primary terminal contains both the IP terminal function and the Application Layer Device Function (ALDF), while the secondary terminal contains both the non-IP terminal function and the ALDF. The AGW (Access Gateway), which is the aggregated type in this example, contains NT, AGTF (Access Gateway Transport layer Function) and AGAF (Access Gateway Application layer Function).
– The AGW terminates the public IP address and interacts with the IP terminal function by a local IP address, while the IP terminal function interacts with the non-IP terminal function by non-IP (L3) protocol. Both the IP terminal function and the non-IP terminal function lie within the transport layer in the home network.
– On the other hand, the ALDF in the primary terminal interacts with functions in the application layer of the carrier's network via the AGAF in the AGW. It also interacts with ALDF in the secondary terminal at the application level.
– The primary domain is provided over an IP home network, while the secondary domain is provided over a non-IP home network.
[pic]
Figure 14: One Physical Configuration of Generic Home Network Architectures
Figure 15 from ITU-T G.9971 [6] illustrates the functional architecture of the AGW. Note that although management and security functions are related to transport layers 1, 2, and 3 as well as the functions above layer 4, G.9971 handles only layers 2 and 3 aspects. Among functions shown in Figure 15, transport related functions are specified as follows:
– Layer 1 Termination (L1T): Termination functions of physical layer, such as Ethernet PHY.
– Layer 2 Termination (L2T): Termination functions of Ethernet port, such as MAC address assignment.
– Layer 2 Forwarding (L2F): Ethernet bridging functions using MAC forwarding table as well as L2 QoS processing, such as L2/L2 QoS mapping. Note that L2F of Ethernet bridges also contains L2/L2 mapping function between Ethernet and wireless within LAN.
– Layer 3 Termination (L3T): Termination functions of IP port, such as IP address assignment.
– Layer 3 Forwarding (L3F): IP routing functions using IP routing table as well as L3 QoS processing, such as L3/L3 and L3/L2 QoS mappings.
[pic]
Figure 15: Functional Architecture of Separate Type AGW
9.2 Architecture with the HAN and Relevant External Interactions
Figure 16 presents a functional model of Smart Metering and home energy management in a graphical format in which both communication and power flows are depicted. Functions similar to the End-User Functions shown in Figure 4 are presented in the right four columns of Figure 16. These include:
• Energy Service Interface (ESI), which provides an interface for energy management and advanced energy services that enable secure interactions between relevant home area network devices and electric power companies or IP based energy service providers.
• Energy man-machine interface (MMI) devices, which are to provide a customer with home electrical energy service interaction; display, control, selection, management, verification, and so forth.
• Energy devices, which are end devices that consume the electrical energy, control electrical energy usage, monitor energy usage, store electrical power, and recover and supply the electrical energy.
• Advanced energy services, which are to provide new emerging energy services based on IP based home area network to home energy customer.
The Application Functions and Network Functions are shown on the left side of Figure 16. This conveys similar functional structure with more implementation details.
[pic]
Figure 16: Another Functional Model of Smart Metering and HAN
Components inside the functional model shown in Figure 16 correspond to the relevant functions specified in Figure 4, which represents for the Smart Metering and Load Control, and in Figures 5 and 6 representing for the Energy Distribution and Management. To be specific, the Advanced Energy Service and the Energy MMI devices depicted in Figure 16 are closely related to the Power Grid Monitoring and Control in Figure 5, and the Energy Usage and Distribution Management in Figure 6, those of which are two major application areas in the Energy Distribution and Management application.
The next sub-section of 9.3 addresses another example of the necessity of further functional considerations in the functional architecture model in order to deal with more implementation details.
9.3 Architecture Focusing on Interface between HGW and PEV
Figure 17 considers another different configuration model of HAN. Similar to the previous example shown in Figure 16, the End-User Functions shown in Figure 4 will be presented.
There are PEV and home area networks with HGW, which controls whole electricity inside customer premises. In addition to PV, PEV, and HGW, there are components such as a power conditioning system, a femto base-station (BS), a storage battery, home appliance / household equipment, and a power meter/a sensor/a monitor as depicted in Figure 17.
Some of the functionalities related to HGW are listed and explained in the followings:
- Detection of the PEV coming to (or out of) the garage. The HGW authenticates and authorizes the PEV. The PEV sends information such as charge level, miles driven, and driving patterns to the HGW.
- Monitoring power generation of PV and electricity consumption of home appliances/ household equipment, the HGW decides whether to charge or discharge the PEV.
- Information received during processes relevant to the above functionalities is accumulated in the HGW. The HGW analyses the information and learns electricity usage / generation patterns. Based on learned information, the HGW renews its policy for charging / discharging the PEV.
Similar to the previous example described in the sub-section 9.2, the model here explains the detail of the Energy Distribution and Management Application that are specified in 7.2.2. The functionality explained above would be additionally required for the functional model in Figure 6 if more implementation details are considered for this type of application.
[pic]
Figure 17: Another Functional Model of HAN
9.4 Example of Implementation Platforms to Support Energy Management Services
Energy management services such as the one for energy saving applications are provided to enhance electric power usages in homes, offices and shops in the Customer domain. Figure 18 shows the implementation-oriented functional model for such energy management services. Management Platform (PF) and Agent Platform (PF) are specified between the Customer domain and the Service Provider domain. These two PFs provide key functions for service providers to make the use of multi-vendors’ devices available.
Management PF manages Smart Grid devices and sensor devices in home and provides service interface to monitor and control them. Agent PF has analysis engines and analyzes information from devices getting through GW and Management PF. It also notifies analysis results to service providers when they meet conditions with which services have specified. Detailed definitions for devices shown in Figure 18 are described below:
[pic]
Figure 18: Functional Model for Energy Management Services
• Gateway (GW): Gateway relays information between the Smart Grid devices and Management PF.
• Management Platform (PF): This platform has common functions such as communication network device management and the provision of service interfaces. The communication network function provides reliable, efficient and secured transmission of application/service specific data. The device management function manages the Smart Grid devices in Energy domain. The service interfaces provide the syntax and semantics of application related data to the Agent PF and service providers. The interface also provides virtual device management and data conversions to facilitate service offerings with the information collected from sensors.
• Agent Platform (PF): This platform has common additional functions such as temporary storages of data and basic analysis of data. The analysis function encapsulates the detailed analysis algorithm into several analysis engine components and provides reusability of analysis engines and analysis. It also provides analysis results of application related data as a metadata.
There are three reference points indicated in Figure 18 and defined as follows;
- IF-a: Communication interface between Gateway and Management PF;
- IF-b: Communication interface between Management PF and Agent PF or Service providers; and
- IF-c: Communication interface between Agent PF and Service providers.
9.5 Architecture of a Communication Infrastructure to Provide Energy Related Services
Figure 19 shows the functional model of a communication infrastructure that enables provision of Value Added Services based upon information exchange related to energy usage, energy consumption and energy tariffs in the HAN. Based on this functional mode, the following services are considered:
• Customer awareness: This includes visualization of current energy and power data, visualization of historical data, alarm, and other energy information.
• Appliance regulation: This implies both coordinated and self management appliances regulation, examples of which are home domain overload management, energy cost optimization in case of multi-tariff contract, and Demand Response.
• Provisioning and Maintenance: This includes to add a new device and to remove a device as well as general maintenance.
Similar to the examples considered in Sections 9.2 and 9.3, the functional model here explains the details of applications discussed in Section 7.2.1 for Smart Metering and Load Control, and in Section 7.2.2 for Energy Distribution and Management.
[pic]
Figure 19: Functional Model of Communication Infrastructure to support Energy related Services
10 Standards Gap Analysis
10.1 Functions across Reference Points and Applicable Standards
Section 6 Reference Architecture defines five Reference Points for the smart grid domains, and Section 7 examines the functional architectures of two important smart grid applications, smart metering and load control, and energy distribution and management. This section maps the functions to the Reference Points and related them to the operations to be performed and information to be carried across the Reference Points. The results are shown in column 2 of Table 2. Column 3 identifies standards gaps and shows the activities of the SGIP Priority Action Plans in filling the gaps, while column 4 lists some of relevant standards.
Table 3 contains further analysis of communication technologies applicable to Smart Grid.
Table 2: Analysis of Reference Point Functions
|Reference Point |Information/Operations Across the |Gaps being Addressed by SGIP Priority Action Plans and |Partial List of Relevant |
| |Reference Point |Related Standards |Standards in Addition to |
| | | |those in PAP Column |
|Reference Point |This reference point provides connectivity between the power grid domain and service provider, customer, and smart meter |
|1 |domains through communication networks. It supports the functions to efficiently and intelligently distribute energy and |
|(Grid domain |integrate distributed renewable energy generation and distribution. It interacts with application and energy control |
|through Network |functions through networks, and interacts with end-users for energy transmission. |
|to Service | |
|Provider domain)| |
| |Distributed Energy Resources (DER): |PAP07: Energy Storage Interconnection Guidelines: Standards|HD 60634: Electrical |
| |DER inventory, DER status |and implementation guidelines for energy storage devices |installation allowing DER |
| |information, DER management and |(ES), power electronics interconnection of distributed |installation |
| |control messages (DER activation, |energy resources (DER), hybrid generation-storage systems |IEC 61850-7-420: Access DER|
| |deactivation, scheduling, voltage, |(ES-DER), and plug-in electric vehicles (PEV) used as |generation devices and |
| |frequency, power level, etc) |storage. IEC 61850-90-7 Advanced Inverter Functions, IEC |controllers |
| | |61850-7-420 DER Object Modeling, IEEE 1547.x |IEC 61850-7-410: Access |
| | |Interconnection standards. |Hydro generation devices |
| | |PAP 09: Standard Demand Response Signals: Common syntax and|and controllers |
| | |semantics for DR signals, including price, grid integrity |EN 61400-25: Access Wind |
| | |signals, and possibly environmental signals. OASIS Energy |Generation devices and |
| | |Interoperation Version 1.0. |controllers |
| | | |IEC 61968 - 61970-10: |
| | | |Interface to the Energy |
| | | |market: Standard to allow |
| | | |all connected generators |
| | | |associated in VPPs to |
| | | |participate to new ways of |
| | | |operating grid |
| |Protection and Control, Load |PAP 08: CIM for Distribution Grid Management: Define object|EN 61968-11: Distribution |
| |Monitoring and Control: Device, |models for substation automation, integration of |Information Exchange Model |
| |subsystem status, command messages |distributed energy resources, equipment condition |EN 61968-13:2008: CIM RDF |
| |for protection and control commands |monitoring, and geospatial location, enabling the |Model Exchange Format for |
| |Sensing and Measurement, Load |integration of data and information from equipment in the |Distribution |
| |Monitoring: Real-time information |distribution grid with information used for enterprise |IECTS 62351-2: Data and |
| |from sensors and measurement devices |back-office systems. IEC 61850. |communications security |
| |(e.g. RTU, IED, and PMU). |PAP12: DNP3 Mapping to IEC 61850 Objects: Mapping of DNP3 |IEC 61970-301 / 61698: |
| | |data types and services to IEC 61850 Standard to enable |Common Information Model |
| | |transport of Smart Grid data and services over legacy DNP3 |IEEE 1686-2007: Functions |
| | |networks for substations. IEEE1815 (DNP3), IEC 61850. |and features to be provided|
| | |PAP 14: Transmission and Distribution Power Systems Model |in substation intelligent |
| | |Mapping: Integration of standards across different utility |electronic devices (IEDs) |
| | |environments to support real-time grid operations (relay, |to accommodate critical |
| | |circuit breaker, IED, transformer operations) and |infrastructure protection |
| | |back-office applications. IEEE C37.239, IEC 61850, IEC |programs |
| | |61970 | |
| |Sensing and Measurement, Load |PAP 08: CIM for Distribution Grid Management: Define object| |
| |Monitoring: Real-time information |models for substation automation, integration of | |
| |from sensors and measurement devices |distributed energy resources, equipment condition | |
| |(e.g. RTU, IED, and PMU). |monitoring, and geospatial location, enabling the | |
| | |integration of data and information from equipment in the | |
| | |distribution grid with information used for enterprise | |
| | |back-office systems. IEC 61850. | |
| | |PAP12: DNP3 Mapping to IEC 61850 Objects: Mapping of DNP3 | |
| | |data types and services to IEC 61850 Standard to enable | |
| | |transport of Smart Grid data and services over legacy DNP3 | |
| | |networks for substations. IEEE1815, IEC 61850. | |
| | |PAP 14: Transmission and Distribution Power Systems Model | |
| | |Mapping: Integration of standards across different utility | |
| | |environments to support real-time grid operations (relay, | |
| | |circuit breaker, IED, transformer operations) and | |
| | |back-office applications. IEEE C37.239, IEC 61850, IEC | |
| | |61970. | |
| |Time Synchronization: High-resolution|PAP 13: Harmonization of IEEE C37.118 with IEC 61850 and | |
| |clock information |Precision Time Synchronization: Define a common syntax and | |
| | |semantics for time data in synchrophasor measurements used | |
| | |to monitor conditions in the transmission grid. IEC TR | |
| | |61850-90-5, IEEEC37.238 Profile for Use of IEEE 3 Std. 1588| |
| | |Precision Time Protocol in Power System Applications. | |
| |Integration of Renewable Energy and |PAP07: Energy Storage Interconnection Guidelines: Standards|HD 60634 |
| |Plug-in Electric Vehicles: Capability|and implementation guidelines for energy storage devices |IEC 61400-25-2 |
| |and status information, management |(ES), power electronics interconnection of distributed | |
| |information, command and control |energy resources (DER), hybrid generation-storage systems | |
| |message. |(ES-DER), and plug-in electric vehicles (PEV) used as | |
| | |storage. IEC 61850-90-7 Advanced Inverter Functions, IEC | |
| | |61850-7-420 DER Object Modeling, IEEE 1547.x | |
| | |Interconnection standards. | |
| | |PAP11: Common Object Models for Electric Transportation: | |
| | |Standards to enable the charging of plug-in electric | |
| | |vehicles (PEVs). SAE Communication Standards - Vehicle to | |
| | |grid communication interface, J2836 (use case), J2847 | |
| | |(requirements), and J2931 (protocols), PEV charge couplers | |
| | |SAE J1772. | |
| | |PAP 16: Wind Plant Communications: Standards for command | |
| | |and control of wind power plants and site monitoring. IEC | |
| | |61400-25-2 Wind turbines, IEC 61850. | |
|Reference Point |This reference point provides connectivity between Smart metering domain and Communication Network domain. It enables the |
|2 |bi-directional information exchange and interactions between smart metering and service providers, customer, and grid |
|(Smart |domains. It supports functions of billing, load shedding, meter management, and others. |
|Metering domain | |
|through network | |
|to Service | |
|Provider domain)| |
| |Meter Reading: Meter reading |PAP 05: Standard Meter Data Profiles: Profile for data to |NAESB REQ-21: Energy |
| |commands, meter readings. |be reported by meters- ANSI C12, and AEIC Guideline. |Services Provider Interface|
| | |PAP06: Translate ANSI C12.19 to and from a Common Semantic | |
| | |Model: Harmonization of ANSI C12.19 End Device (meter) data|IEC 61400-2 |
| | |model with IEC 61968-9 and other models. | |
| | |PAP 09: Standard Demand Response Signals: Common syntax and| |
| | |semantics for DR signals, including price, grid integrity | |
| | |signals, and possibly environmental signals. OASIS Energy | |
| | |Interoperation Version 1.0. | |
| | |PAP 10: Standards for Energy Usage Information: Data | |
| | |standards for energy usage information. NAESB Business | |
| | |Practices and Information Models REQ 18 (retail), WEQ 19 | |
| | |(wholesale), Green Button Initiative, harmonizing | |
| | |IEC61970/61968, IEC61850, ANSI C12.19/22, ASHRAE SPC201. | |
| |Management of meters: meter |PAP 00 Meter Upgradability Standard: A requirements for |IEC 61850: Substation |
| |management information, meter |meter upgradeability in order to manage meter firmware |Automation Systems and DER |
| |firmware update. |changes to remotely upgraded meters. | |
| |Other functions related to customer | | |
| |energy management, see Reference | | |
| |Point 5 | | |
|Reference Point |This reference provides connectivity between Customer domain and Communication Network domain. It enables bi-directional |
|3 (Customer |information exchange coordination, and interactions with Service Provider and Grid domains to support energy management, load|
|domain through |shedding and storage, billing, demand response, and others. This interface may be in two classes, connection to Internet |
|network to |through public ISPs, and connection to secure smart grid network through ESI and NAN. |
|Service Provider| |
|domain) | |
|3a-Home to |Access to information and initiation of services through open Internet, such as web portal. |
|public ISP | |
| |Demand Response: |Same as Reference Point 4 | |
| |Customer registration information to | | |
| |participate in DR application | | |
| |Pricing and energy usage information | | |
| |for web page access. | | |
| |Customer EMS: Customers access |Same as Reference Point 5 | |
| |pricing and meter reading thru web | | |
| |access, Users control appliances | | |
| |directly or through EMS | | |
|3b-Home to smart|Access to secure smart grid network through ESI |
|grid NAN |Functions same as Reference Point 5 |
|Reference Point |This reference point provides connectivity between Service Provider domain and Communication Network domain. It enables |
|4 (Service |communications between services and applications in the Service Provider domain to actors in others domains to support |
|Provider domain |control operations, data aggregation, customer management, and all other related services. |
|through network | |
|to Service | |
|Provider domain)| |
| |Smart Metering Head-end: It provides |PAP 00 Meter Upgradability Standard: A requirements for |IEC 61850: Substation |
| |the necessary smart metering |meter upgradeability in order to manage meter firmware |Automation Systems and DER |
| |functions for initiation of meter |changes to remotely upgraded meters. |IEC 61968-9: Interface for |
| |readings, and then performs further |PAP 05: Standard Meter Data Profiles: Profile for data to |meter reading and control |
| |processing of collected data. |be reported by meters- ANSI C12, and AEIC Guideline. |IEC 62056: Electricity |
| | | |metering – Data exchange |
| | | |for meter reading, tariff |
| | | |and load control |
| | | |EN 13757: Communication |
| | | |systems for meters and |
| | | |remote reading of meters |
| |Demand Response: |PAP 04: Develop Common Scheduling Communication for Energy | |
| |Customer registration information to |Transactions: OAIS WS-Calendar, Version 1.0 for schedule | |
| |participate in DR application |and event information to be passed between and within | |
| |Pricing and energy usage information |services | |
| |– detailed or aggregated, on web or | | |
| |through ESI | | |
| |Energy Usage Management: It controls |PAP 10: Standards for Energy Usage Information: Data |NAESB REQ-21: Energy |
| |the demand response of electricity |standards for energy usage information. NAESB Business |Services Provider Interface|
| | |Practices and Information Models REQ 18 (retail), WEQ 19 | |
| | |(wholesale), Green Button Initiative, harmonizing |IEC 61970-2: Energy |
| | |IEC61970/61968, IEC61850, ANSI C12.19/22, ASHRAE SPC201 |management system |
| | | |application program |
| | | |interface |
| | | |EN 13757 |
| |Energy Pricing: It determines the |PAP 03 Develop Common Specification for Price and Product |IEC 61970-302: Financial, |
| |energy price based on energy market |Definition: OASIS Energy Market Information eXchange (EMIX)|Energy scheduling and |
| |operation, power utility’s policy, |version 1.0, a common specification for price and product |reservations |
| |customer’s demand, and others. |definition, to be used in demand response applications, | |
| | |market transactions, distributed energy resource | |
| | |integration, meter communications, and many other | |
| | |inter-domain communications | |
| | |PAP 04: Develop Common Scheduling Communication for Energy | |
| | |Transactions: OAIS WS-Calendar, Version 1.0 for schedule | |
| | |and event information to be passed between and within | |
| | |services | |
| |Operations Control: It is responsible|PAP 08: CIM for Distribution Grid Management: Define object|IEC 61968 |
| |for monitoring the day-to-day |models for substation automation, integration of | |
| |operation of the grid |distributed energy resources, equipment condition | |
| | |monitoring, and geospatial location, enabling the | |
| | |integration of data and information from equipment in the | |
| | |distribution grid with information used for enterprise | |
| | |back-office systems. IEC 61850 | |
| | |PAP12: DNP3 Mapping to IEC 61850 Objects: Mapping of DNP3 | |
| | |data types and services to IEC 61850 Standard to enable | |
| | |transport of Smart Grid data and services over legacy DNP3 | |
| | |networks for substations. IEEE1815 (DNP3), IEC 61850. | |
| | |PAP 14: Transmission and Distribution Power Systems Model | |
| | |Mapping: Integration of standards across different utility | |
| | |environments to support real-time grid operations (relay, | |
| | |circuit breaker, IED, transformer operations) and | |
| | |back-office applications. IEEE C37.239, IEC 61850, IEC | |
| | |61970. | |
| | |PAP17: Facility Smart Grid Information Standard: Data | |
| | |standard to enable energy consuming devices and control | |
| | |systems in the customer premises to manage electrical loads| |
| | |and generation sources in response to communication with | |
| | |the Smart Grid. Working on going at ASHRAE SPC 201P. | |
| |Distributed Energy Resources (DER): |PAP07: Energy Storage Interconnection Guidelines: Standards|HD 60634 |
| |DER inventory, DER status |and implementation guidelines for energy storage devices |IEC 61850-7-420 |
| |information, DER management and |(ES), power electronics interconnection of distributed |IEC 61968 |
| |control messages (DER activation, |energy resources (DER), hybrid generation-storage systems | |
| |deactivation, scheduling, voltage, |(ES-DER), and plug-in electric vehicles (PEV) used as | |
| |frequency, power level, etc) |storage. IEC 61850-90-7 Advanced Inverter Functions, IEC | |
| | |61850-7-420 DER Object Modeling, IEEE 1547.x | |
| | |Interconnection standards. | |
| | |PAP 08: CIM for Distribution Grid Management: Define object| |
| | |models for substation automation, integration of | |
| | |distributed energy resources, equipment condition | |
| | |monitoring, and geospatial location, enabling the | |
| | |integration of data and information from equipment in the | |
| | |distribution grid with information used for enterprise | |
| | |back-office systems. IEC 61850. | |
|Reference Point |This reference provides connectivity and interactions between Smart Metering and Customer domain. It enables interactions and|
|5 |information exchange between smart meters and customer appliances and equipment to support meter management, billing, and |
|(Customer Domain|others. |
|to Smart | |
|Metering) | |
| |Energy Usage Management: Energy usage|PAP 04: Develop Common Scheduling Communication for Energy |OASIS WS-Calendar: Web |
| |information, energy pricing, |Transactions. This action plan will develop a standard for |Services Calendar |
| |See also DR functions |how schedule and event information is passed between and |NAESB REQ-21: Energy |
| | |within services. |Services Provider Interface|
| | |PAP 10: Standards for Energy Usage Information: Data | |
| | |standards for energy usage information. NAESB Business | |
| | |Practices and Information Models REQ 18 (retail), WEQ 19 |IEC 62351-3Security Using |
| | |(wholesale), Green Button Initiative, harmonizing |Transport Layer Security |
| | |IEC61970/61968, IEC61850, ANSI C12.19/22, ASHRAE SPC201. |(TLS) |
| | | |IEC 62325: Market |
| | | |Communications using CIM |
| | | |OASIS Energy Market |
| | | |Information Exchange 1.0 |
| |Demand Response: |PAP 03 Develop Common Specification for Price and Product |ISO 16484: Building |
| |Customer registration information to |Definition: OASIS Energy Market Information eXchange (EMIX)|automation and control |
| |participate in DR application |version 1.0, a common specification for price and product |systems |
| |Pricing and energy usage information |definition, to be used in demand response applications, | |
| |for web page access. |market transactions, distributed energy resource |ISO 13584: Industrial |
| |Customer EMS: pricing information, |integration, meter communications, and many other |automation systems and |
| |meter readings, device control |inter-domain communications |integration |
| |commands |PAP 09: Standard Demand Response Signals: Common syntax and| |
| | |semantics for DR signals, including price, grid integrity |EN 15232: Energy |
| | |signals, and possibly environmental signals. OASIS Energy |performance of buildings — |
| | |Interoperation Version 1.0. |Impact of Building |
| | |PAP 10: Standards for Energy Usage Information: Data |Automation, Controls and |
| | |standards for energy usage information. NAESB Business |Building Management |
| | |Practices and Information Models REQ 18 (retail), WEQ 19 | |
| | |(wholesale), Green Button Initiative, harmonizing | |
| | |IEC61970/61968, IEC61850, ANSI C12.19/22, ASHRAE SPC201. | |
| |Energy Services Interface (ESI)/ HAN | | |
| |gateway: Home appliance registration | | |
| |information for entry to HAN, | | |
| |security information and management | | |
| |of ESI from DR head-end | | |
| |HAN and NAN Networks: Smart meters | | |
| |form a metering network to ensure | | |
| |reliable communication to the meter | | |
| |head-end through this Reference | | |
| |point, and interact with the billing | | |
| |in the service provider domain. | | |
| |Distributed Energy Resources (DER): |PAP 08: CIM for Distribution Grid Management: Define object|HD 60634 |
| |DER inventory, DER status |models for substation automation, integration of |IEEE 1379-2000: substation |
| |information, DER management and |distributed energy resources, equipment condition |automation |
| |control information |monitoring, and geospatial location, enabling the | |
| |Local Generation and Storage: |integration of data and information from equipment in the | |
| |monitoring and control information |distribution grid with information used for enterprise | |
| |exchange for distributed generation |back-office systems. IEC 61850. | |
| |and DER at the Customer domain. |PAP07: Energy Storage Interconnection Guidelines: Standards| |
| | |and implementation guidelines for energy storage devices | |
| | |(ES), power electronics interconnection of distributed | |
| | |energy resources (DER), hybrid generation-storage systems | |
| | |(ES-DER), and plug-in electric vehicles (PEV) used as | |
| | |storage. IEC 61850-90-7 Advanced Inverter Functions, IEC | |
| | |61850-7-420 DER Object Modeling, IEEE 1547.x | |
| | |Interconnection standards. | |
| |PEV Charging: This interacts with the|PAP11: Common Object Models for Electric Transportation: |HD 60634 |
| |Energy Control Function and Customer |Standards to enable the charging of plug-in electric |IEC 61850 |
| |Bill Function to manage the capacity |vehicles (PEVs). SAE Communication Standards - Vehicle to | |
| |of power and billing information. |grid communication interface, J2836 (use case), J2847 | |
| | |(requirements), and J2931 (protocols), PEV charge couplers | |
| | |SAE J1772. | |
|Networking & |Transport functions to provide |PAP01: Guidelines for the Use of IP Protocol Suite in the |See Table 3 |
|Communication |end-to-end transport of data and |Smart Grid: RFC 6272 Internet Protocols for the Smart Grid | |
|Functions across|control messages for smart grid |identifies the core set of IETF protocols for establishing | |
|all reference |applications. |Internet based Smart Grid networks | |
|points |Communications technologies to |PAP 02 Guidelines for the Use of Wireless Communications: | |
| |provide interconnections between |NISTIR 7762 Guidelines for Assessing Wireless Standards for| |
| |devices for smart grid applications |Smart Grid Applications provides tools and information for | |
| |and network nodes. |evaluating wireless communications technologies for use by | |
| |Home Area Network (HAN): to |Smart Grid applications. | |
| |interconnects all appliances and |PAP 15: Harmonize Power Line Carrier Standards: Harmonize | |
| |equipment, EMS, PEV charging |broadband and narrowband PLC standards and their | |
| |stations, generation and storage |coexistence mechanisms. IEEE P1901, P1901.2, ITU-T G.9960,| |
| |facilities, and metes. |G.9961, G.9972, G.hnem. | |
| |Neighbourhood Area Network (NAN): |PAP18: SEP 1.x to SEP 2 Transition and Coexistence: The | |
| |Metering networks |coexistence of SEP 1.x and 2.0 and the migration of 1.x | |
| |Wide Area Networks (WAN) |implementations to 2.0. | |
Table 3: Standardization Activities for Smart Grid Networks
|Communications technologies|Standardization activities |Status |Note (related works) |
|IMT |ITU-R IMT-2000 family |Already studied |NIST SGIP PAP02 |
| |ITU-R IMT-Advanced family | | |
| |ITU-T SG13 | | |
| |3GPP | | |
|Wireless Local Area |IEEE 802.11 (Wireless LANs) |Already studied | |
|Networks | | | |
| |IEEE 802.11s (Mesh Wireless LAN) | | |
|Wireless Personal Area |ITU-T SG15 Q4 |Study in progress |G.9959 (G.wnb) |
|Networks | | | |
| |IEEE 802.15.4 |Already studied (may need| Bluetooth SIG, Zigbee |
| | |additional work) |Alliance, etc. |
| |IEEE802.15.4g (Smart Utility Networks) |Study in progress | |
| |IEEE802.15.5 (Mesh networking) |For further study |Best of Practice |
| |IETF 6LoWPAN WG |Already studied |RFC 4919 (Informational), RFC |
| | | |6282 (Proposed Standard) |
| |IETF ROLL WG |Study in progress |Routing requirement has been |
| | | |done. Routing protocol (RPL) is|
| | | |under study. AMI Applicable |
| | | |statement proposed. |
|WiMax |IEEE 802.16 (Wireless Metropolitan Area Networks) |Already studied (may need| |
| | |additional work) | |
| |IEEE802.16j [MMR (Mobile Multi-hop Relay)] |Study in progress | |
|Short distance wireless |IrDA |Already studied (may need|Infrared Data Association |
|communication | |additional work) | |
|Ethernet |IEEE 802.3 (Ethernet) |Already studied | |
|Power Line Communication |ITU-T SG15 |Already studied | |
|(PLC) |G.9960/9961 (G.hn), G.9963 (G.hn-MIMO), G.9972 (G.cx), | | |
| |G.9955/9956 (G.hnem) | | |
| |IEEE 1901 |Already studied |IEEE1901.2 |
| |ISO/IEC |Study in progress |ISO/IEC15118 (V2G CI) |
|Technology over coaxial |ITU-T SG15 |Already studied | |
|cable |G.9954 (HomePNA), G.9960/9961 (G.hn) | | |
| |DOCSIS (Data Over Cable Service Interface |Already studied | |
| |Specifications), | | |
|Technologies over twisted |ITU-T SG15 |Already studied (may need|G.fast (FTTdp) |
|pairs, access network |G.992 series, G.993 series (xDSL), etc. |additional work) | |
| |ITU-T SG9 Q9 (HNW) |Study in progress | |
|Technologies over fibre |ITU-T SG15 |Study in progress |NG-PON2 |
|cable |G.983 series (B-PON), G.984 series (G-PON), G.987 series | | |
| |(XG-PON), G.985/G.986 (point-to-point Ethernet based | | |
| |optical access system), | | |
| |IEEE 802.3ah (1G-EPON), |Study in progress | |
| |IEEE 802.3av (10G-EPON), | | |
|Home Area Network |ITU-T SG15 Q1 (HNW architecture) |Already studied (may need| |
|Architecture |G.9970, G.9971, G.9973 |additional work) | |
| |ITU-T SG13 Q12 |Study in progress |Y.energy-hn |
|Neighborhood Area Network |ITU-T SG15 Q4 |Study in progress | |
|Architecture | | | |
|Wide Area Network |IETF (IP-based network) |Already studied | |
|Architecture |RFC (RFC6272) | | |
| |ITU-T SG15 Q12 (Transport network architecture) |Already studied | |
| |G.803,G.872 | | |
| |ITU-T SG13 (Next Generation Network) |Already studied (may need| |
| | |additional work) | |
From these two tables, several gaps are identified below.
• Many data models and communication protocols applicable to Smart Grid are already studied or study in progress in most areas. Harmonization of existing standards may be necessary.
• There were no formal standards on requirements for the smart grid networks, HAN, NAN, and WAN.
• Network architectures of HAN and WAN are well studied in correspondent SDOs, however, additional work for Smart Grid are necessary. In addition, no activities have been identified in the NAN area.
• Even though there are many communication standards that are applicable to smart grid applications, there is a need to develop integration specifications on how to utilize these standards into a system that best satisfies the requirements of Smart Grid.
10.2 Recommendations for Future Work
Based on the gaps identified, the following work items are recommended.
• Develop generic network architecture models for smart grid networks, including networks for smart meters, home network for home energy management, and networks for power grids.
- Architectures for AMI; Develop architecture models and associated procedures for configuring and managing the metering network, such as
a) procedures for activation, deactivation of meters in the network,
b) procedures for fault isolation and discovery,
c) procedures for meter firmware updates, and
d) procedures for meter reading data aggregation, de-aggregation operations within network nodes.
- Architectures for home energy management networks including
a) procedures for activation, deactivation of meters in the network,
b) procedures for admittance and departure of devices into the home energy network, with special attention to security aspects, such as authentication, authorization of devices with respect to identity and capability,
c) functional specifications of key devices in the home network, home energy management station, energy service interface, and gateways,
d) procedures enabling multiple communication protocols to operate the home energy network.
- Architectures for power grid communications networks, including communication within transmission/distribution substations, and between substations to control centres, as well as quality of service, and security management of such networks.
a) procedures for fault isolation and discovery,
b) procedures for firmware updates.
• Develop system integration specification of smart grid applications enabling end-to-end communications between applications at the utility’s business office and smart grid devices including
a) Procedures for system start up, such as connecting devices to application server at the business office, addressing and end devices (or systems),
b) Message flows of the system.
• Many smart grid applications fit the Machine-to-Machine (M2M) communication model. There are moves by many SDOs working on M2M standards to jointly expand their effort into smart grid area. ITU-T should participate in this activity.
• Coordination is recommended to be taken with other SDOs such as IEC, IEEE, and other regional organizations such as the CEN-CENELEC-ETSI Smart Grid Coordination Group (SGCG) to avoid duplication of efforts, and improve interoperability.
Annex A. Comparisons of Architectures among ITU-T FG-Smart, IEEE P2030 and ETSI M2M
From the architectures of ITU-T FG-Smart, IEEE P2030 and ETSI M2M, Table A-1 shows detailed comparisons of architectures among the respective deliverables of these three organizations in the various perspectives.
Table A-1: Comparisons of architectures among ITU-T FG-Smart, IEEE P2030 and ETSI M2M
|Item |ITU-T FG-Smart |IEEE P2030 |ETSI M2M |
|Goal |Smart Grid in the ICT perspective |Smart Grid interoperability |All M2M applications |
|Domain model |Based on NIST 7 domains |Based on NIST 7 domains |3-level model |
|Reference architecture |Simplified reference architecture |Based on NIST system architecture |End-to-end functional architecture at |
| | | |the “service layer” |
|Detailed architectures |Functional architecture |- Communications architecture |- Set of Service capabilities (SCs) |
| |- Functional model of smart grid |- Power system architecture |- reference points used to expose the |
| |- Functional model of smart metering |- IT architecture |SCs to the M2M applications including |
| |and load control service | |Smart Metering and Smart Grid |
| |- Functional model of energy | | |
| |distribution and management | | |
|Power grid |Grid domain (bulk generation/ |Generation, Transmission, Distribution |M2M Enablers for Distribution (at the |
| |transmission/ distribution) | |border between Utility domain and |
| | | |end-user domain, through the telco |
| | | |domain) |
| |LAN (substation network function) |Transmission substation network | |
| | |(hotspot), Distribution substation | |
| | |network (hotspot), Feeder distribution | |
| | |energy resources microgrid network, Field| |
| | |area network, Feeder network, | |
| | |neighbourhood area network | |
|Networks |Communication network (short |Regional interconnection, Wide area |Agnostic to communication networks (use|
| |descriptions of WAN, AN, NAN, etc) |network, Backhaul, Public Internet, |of the most appropriate) |
| |Premises network (HAN, LAN) |xAN, Customer DER network, workforce | |
| | |mobile network | |
|Services |Markets, Operations, Service Providers |Markets, Operations, Service Providers |Mainly Service Providers |
Annex B. Network Configuration Scenarios for Smart Grid
In Sections 8.2.1 - 8.2.3, where smart grid network architecture for HAN, NAN, and WAN were analyzed, the discussions on potential architectures were purely based on technical aspects, without considering who owns and manages each segment of a smart grid network.
This appendix presents how the ownership issues affect network architecture. A Smart Grid network could be owned and operated by Telecommunication Companies, or by Utility Companies. Since a Smart Grid network consists of several major segments, WAN, NAN, and HAN, each segment could be independently owned and run by different companies (with the exception of HAN which belongs to customers), therefore there are combinations of owners and operators. The issue is further complicated by whether smart grid home area network exists, as it affect how home energy devices are accessed and managed. These various combinations are shown in Table B-1 in six scenarios and discussed in details in sections below.
Table B-1 Summary of Network Scenarios
[pic]
B-1 Scenario 1
Utility Company will manage both Wide Area Network and Neighborhood Area Network. Generally, WAN is composed of dedicated links, and NAN is composed of wireless networks. Note that in this scenario, Customer Premises Network or Home Network does not exist, and therefore the utility has no access to appliances in the home. A Gateway Device is used to represent the HAN and to terminate or originate exchanges with remote end systems on the WAN.
[pic]
Figure B-1: Scenario 1 - WAN(Utility) + NAN(Utility) without HAN
B-2 Scenario 2
Telecommunications Company manages Wide Area Network, and Neighborhood Area Network is managed by Utility Company or Power Company. Generally, WAN and NAN is composed of the wireless networks. Note that in this scenario, Customer Premises Network or Home Network does not exist, and therefore the utility has no access to appliances in the home. A Gateway Device is used to represent the HAN and to terminate or originate exchanges with remote end systems on the WAN.
[pic]
Figure B-2: Scenario 2 - WAN(Telecom) + NAN(Utility) without HAN
B-3 Scenario 3
Wide Area Network is managed by Telecommunications Company; it includes Transport Network and Access Network. WAN is composed of the wireless / wired network. Note that in this scenario, Customer Premises Network or Home Network does not exist, and therefore the utility has no access to appliances in the home. A Gateway Device is used to represent the HAN and to terminate or originate exchanges with remote end systems on the WAN.
[pic]
Figure B-3: Scenario 3 - 7 WAN(Telecom) without HAN
B-4 Scenario 4
Utility Company will manage both Wide Area Network and Neighborhood Area Network. Through the Gateway (GW), the utility can directly access appliances (e.g., washing machine, air conditioner) within the HAN, or indirectly via an energy management station in the customer premises.
[pic]
Figure B-4: Scenario 4 - WAN(Utility) + NAN(Utility) with HAN
B-5 Scenario 5
Telecommunications Company manages Wide Area Network, while the Neighborhood Area Network will be managed by Utility Company. The utility can manage the home appliance through the path WAN NAN Gateway, and collect information through the same path.
[pic]
Figure B-5: Scenario 5 - WAN(Telecom) + NAN(Utility) with HAN
B-6 Scenario 6
Wide Area Network is managed by Telecommunications Company. Wide Area Network consists of Transport Network and Access Network. A Home Area Network exists and connects to the WAN via a Gateway. The Utility can access appliances in the home through WAN and Gateway.
[pic]
Figure B-6: Scenario 6 - WAN(Telecom) with HAN
-----------------------
Keys to Figures 4, 5, and 6:
A rectangular block, referenced as ‘block’, represents a single function; a rounded rectangular area, referenced as ‘group’, represents a particular grouping of functions. The solid lines represent direct relationship between functional groups, either a single function block or a functional group, typical a data path between those boxes. If a line connects to a function block, it means the relationship exists with all functions within the block; if it connects to single function block, it means the relationship exists with that specific function associated with the block. The dotted lines represent an end-to-end relation between two boxes. For example, the dotted line between the DR Client function in the End-User Functions block and DR Application function in the Application Functions block represents end-to-end data exchange of subscriber information and dynamic pricing information between them while the physical data paths are shown in solid lines from Business Network function in Application Functions through Network Functions and ESI in End-User Functions.
Home
SOHO
Access
Service
Provider
Enterprise
Network
Transit
Service
Provider
Management PF
GW
IF-b
IF-a
Agent PF
IF-b
IF-c
Service provider domain
Customer domain
................
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