IEC TC57 Industry Updates

IEC TC 57 WG 17 Update

Flexibility for Power Systems – Definitions and Protocols

b y Tom Berry, Schneider-Electric

IEC TC 57 WG 17 is in charge of power system intelligent electronic device communication and associated data models for microgrids, distributed energy resources and distribution automation. 

As more and more solar panels and EV charging systems are deployed, grid operators are looking at how they can run their existing grids. There have been many research projects looking at flexible control of loads and generation. 

The concepts are not new – there have been demand response programs and virtual power plants for many years. What has changed in the last couple of years is a consensus that these types of programs should be expanded and deployed at scale.

For electricity system balancing, generation is scheduled which is a type of explicit flexibility. Flexibility in loads is much better known as demand response. This could be by explicit instructions, or it could be implicit flexibility based on price.

One of the challenges to define information exchanges to manage flexibility is that it involves many actors who have their own terminology and perspectives. These actors include transmission and distribution grid operators, facility managers and electrical vehicle charging operators. 

One of the first steps in standardization is to agree on definitions. In the case of the term flexibility, although the need is for the grid operators, the terms are more precisely defined in standards related to the devices that provide the services such as electric vehicle charging and building management systems.

Electropedia for market operations doesn’t use the term flexibility. This may be that it is a relatively new term, but perhaps because it is not precise enough for bulk markets. Some standards are providing definitions that describe the concepts and systems.

IEC SRD 62913-2-2 defines the term “flexibility aggregator” as an “entity that buys and aggregates the flexibility of consumption (demand response) and distributed generation in order to value them on the market and through the transportation products (adjustment mechanism, capacity market)”

IEC 63110-1 has defined flexibility as “elasticity of resource use (demand, storage, generation), modification of consumption and/or generation of energy/power, on an individual or aggregated level, in reaction to an external signal (price signal or request) in order to provide a service within the energy system.”

There is a trend that the end devices need to respond to a combination of price incentives together with mandatory or emergency explicit control. 

This overlap in use cases is leading to the extension of standards to provide alternative ways of describing the same things. In IEC 61850 based systems, the automation systems for microgrids, energy community, edge controllers require forecasts and schedules. Work is in progress to add data models for time series including forecasts compatible with the Common Information Model (CIM).

At the same time, information exchange profiles based on CIM, need to describe the physical and control capabilities of individual or aggregated energy resources to allow connection planning and as a pre-requisite for participation in markets for flexibility services. It is planned to extend the CIM models with the equivalents of parts of IEC 61850-7-420 that correspond to the requirements of grid codes.

Biography:

Tom Berry studied Electrical Engineering at Bath University, UK. For the last 25 years he has worked for Schneider Electric in the UK and France. 

Tom has worked on control center projects integrating SCADA systems within dispatch training simulators, transmission and distribution network management systems.  He now works “closer to the edge” as a software architect for feeder automation RTUs. He is a member of several IEC TC57 WGs and the editor of IEC TS 62361-102 technical report on CIM-61850 harmonization.