How the IEC works to integrate electric vehicles into the grid
Frances Cleveland is the lead for cyber security and resilience guidelines in the IEC Systems Committee on Smart Energy. She is also the Convenor of working group (WG) 15, which prepares standards addressing data and communication security aspects in the electricity network, inside IEC TC 57, which prepares core standards for the smart grid. In this article, she explains the role of the various IEC Technical Committees, including SyC Smart Energy, in helping EVs integrate into the grid.
tilities everywhere are concerned that the charging load for EVs will greatly increase the load on power grids. In many places, the charging load could exceed the existing demand from residential consumers during peak hours. As more electric vehicle charging points are deployed, it becomes increasingly important to manage flexibility of both the power levels and the time of charging.
For many years, academic papers have proposed using EV batteries as a form of energy storage that can provide services to the power grid even if only charging. But now there are many research and pilot projects around the world that are deploying some form of bidirectional flow of energy (charging and discharging), either as vehicle-to-grid (V2G) or vehicle-to-home (V2H), with EVs able to sell power to the main grid and even support the energy management of microgrids. One of the driving ideas behind these projects is to provide a means of storing energy in the EV from variable renewable resources, like solar and wind, for use at other times. This implies that EVs can actually be viewed as a type of distributed energy resource (DER).
Many IEC Technical Committees involved
Within the IEC, various committees and working groups are collaborating to define standards and guidance on how these new types of EV-related equipment should be integrated into power systems. There are several technical groups that are concerned with the physical and safety aspects of different types of equipment and others that look at how the different types of EV-related equipment are integrated into the power system.
The purpose of the IEC System Committee for Smart Energy (SyC-SE) is to help coordinate and guide the various efforts across the different IEC Technical Committees and working groups. One of its current projects is to produce a document, IEC 63460, that will describe the "Architecture and use-cases for EVs to provide grid support functions", or more familiarly called "EV-as-DER". Many of the members of the EV-as-DER group are also members of the other EV-related technical groups, thus leading to lively discussions and hopefully good consensus. Most of this standard will be concerned with the identifying of realistic EV charging and discharging configurations, and the communication and control between the various actors, grid system operators, aggregators, premises energy management, and EV charging systems. The results from this document will hopefully help other technical groups to take the grid-support capabilities of EVs into account as they develop their own standards.
Understanding the utility perspective
However, integrating EVs into power systems so that they do not overload the grid and can actually support grid reliability, requires understanding the electric utility perspective. Figure 1 (below) shows the big picture with various types of systems relevant to DERs and EVs. SyC-SE is using this big picture to help the discussions related to the information exchanges between the various actors and systems.
The IEC has many different groups addressing aspects of EVs and their charging from the grid. For the physical aspects, IEC TC 8 and its subcommittees work on the overall system aspects of electricity supply systems. IEC TC 120 is responsible for standardization in the field of grid integrated energy storage systems. IEC TC 69 prepares publications related to electrical power/energy transfer systems for electrically propelled road vehicles, including some physical charger connection standards such as IEC 61851. TC 69 has also worked with ISO to develop charging communication protocols such as ISO/IEC 15118. It has established joint working groups with other IEC TCs to manage the higher-level charging infrastructure with use cases and communication protocols and is currently developing IEC 63110 and IEC 63382.
IEC TC 57 has that utility perspective and has developed sophisticated communication and automation standards for power systems control equipment and control centre systems. These standards include IEC 61850 for substations, distribution automation, and more recently DER. The Common Information Model (CIM), covered in the standards IEC 61968, IEC 61970 and IEC 62325, is focused on grid management applications and market interactions. In addition, IEC TC 65 has developed some standards describing energy management systems for industrial sites and the subcommittee IEC SC 23K is working on standards for energy management within residential and commercial premises. Complementing these energy standards is IEC TC 13 which provides metering standards.
IEC TC 69 originally adopted the principle that EV charging is managed by charging stations similar to gas stations, but today it is clear that EV drivers often use phone applications, cloud-based systems, and remote service providers to manage their charging. This shift is also complicating the design of the EV standards.
Discussions in the SyC-SE "EV as DER" group have so far identified two groups of use cases: those concerned with the market aspects of charging, and those concerned with the grid services related to the impact of charging on the power system. Figure 2 (below) illustrates the IEC standards used for EV grid support and market-related charging management.
Today TC 69 and SC 23K are working with use cases that consider the prices and timing of energy management. Typically, the energy management systems are concerned with optimizing the cost of energy, subject to possible constraints or desired responses determined by the grid operator and will need to manage not just energy flows but also the various commercial contracts. This is an area of rapid development around the world which necessarily involves different business models in different countries and regions and will require sophisticated and flexible information and communication technologies.
From the grid integration perspective, IEC TC 8, TC 57 and TC 120 are providing use cases and information models related to the physical effects of the grid connections, particularly the concept of power system functions to help manage voltage and frequency, and to ride through abnormal conditions. These use cases are based on national grid codes originally developed for the integration of bulk generation resources, and which are now extended to cover smaller distributed energy resources and battery storage. Most of the use cases will equally apply to electric vehicle charging systems and will require transferring control parameters to the power electronics control systems.
This is an exciting time as energy management of EVs address not only the charging aspects but also the V2G and V2H capabilities. The SyC-SE "EV as DER" group is working to challenge the thinking within the different silos of the groups developing EV-related standards to help ensure the "big picture" requirements are indeed met. We welcome support from anyone interested in helping develop and review our IEC 63460 Standard.
Frances Cleveland is a graduate in electrical engineering and applied physics from Harvard University and a post-graduate in electrical engineering and computer science from the University of California at Berkeley.
She has managed and consulted on smart grid information and control system projects in the electric power industry for over 35 years. Her expertise has focused primarily on smart grid information interoperability standards, cyber security issues, resilience of the power grid, smart inverter functionalities for distributed energy resources (DERs) and integration of systems, including DERs, plug-in electric vehicles, advanced metering infrastructures, distribution automation, substation automation and energy market operations.