Microgrids and planning IEC 61850 “Edition 2027”
by 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.
A second committee draft for a technical report describing the use of IEC 61850 for microgrid systems was circulated to National Committees earlier this year. IEC TC 57 WG 17 hopes to get some constructive comments on some modelling suggestions.
One of the topics is related to load management and if necessary, load curtailment. The report proposes some data objects for tracking which loads were disconnected and for how long. This can be used by clients as part of round-robin or other schemes to monitor fairness in allocating curtailment. These models may also be relevant to use cases where a local management system is required to respond to a load reduction request from a demand response program. Similar modelling concepts may apply to load-shedding as part of substation automation.
One of the other new model ideas is a logical node to hold information about forecasts of load, generation or storage power and energy. This has a few data objects in common with the scheduling logical nodes of IEC 61850-7-4, but the data format is simpler as it is intended to allow client devices or systems to manage a microgrid system.
Later this year IEC TC 57 WG17 plans to start the process for publication of a new document IEC TR 61850-7-520 to describe applications of IEC 61850-7-420. This document will include explanatory use cases and modelling examples.
A set of seven documents that describe the data model for “IEC 61850 Edition 2025” has been distributed for review by National Committees. This document set will supersede IEC 61850-7-4:2020 Ed 2.1. There are no technical changes to the definitions of the logical nodes, but they have been distributed amongst several documents to allow easier maintenance.
This has been an essential step before incorporating proposed extensions into the “IEC 61850 Edition 2027.” Work has started within WG17 on planning this “Edition 2027” to include new documents dedicated to the data models for Distribution Automation, as well as a revision of part 7-420 to split it into three more manageable documents to describe “Energy Resources,” “Power Management Functions” and “Solar and other local Energy Production.”
The existing report on using IEC 61850 for Distribution Automation, part 90-6, will be re-issued to preserve the use case descriptions but without defining new models.
Several working groups define models for different types of generation. WG 17 defines models for inverter-based resources typically DER, WG18 defines models for hydro and thermal bulk generation and JWG25 defines models for wind power. The different groups have different architectural concepts for decomposition (WG18) or aggregation (WG17).
For some control functions e.g. active power, voltage, there is clearly some overlap. There is scope to define some common abstract classes for control functions, but it is difficult to complete the discussions before 2027. A first step is expected to be a simple list of key data objects (aligned with the Common Information Model) to check alignment of names and data types.
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.
