IEC 61850 & Smart Grids

Author:Christoph Brunner, it4power, Switzerland

Since about five years ago, everybody has been talking about Smart Grids and every organization that wants to be significant for the electric power industry has published its Smart Grid roadmap. While initially many definitions of a Smart Grid existed, it is now a common understanding, that a key element of a Smart Grid is the usage of advanced communication and information technologies to maintain a stable electricity supply while supporting the integration of renewable energy and reducing the overall energy consumption.
Obviously, IEC 61850 is one of the advanced communication technologies that can support a Smart Grid. Already in 2004 the WG17 of IEC TC57 has been created with the initial scope to define a standard for the monitoring and control of Distributed Energy Resources (DER).

The working groups decided to use IEC 61850 as a basis for that work, and in 2009 a first draft of IEC 61850-7-420 – Distributed energy resources logical nodes, was published. In this first version of the standard, the focus was mainly on local control and monitoring between DER units and the plant management system. DER types covered by this first version included reciprocating engines, fuel cells, photovoltaic and combined heat and power systems.

With the push to integrate larger amounts of renewable energy there is as well a requirement for a standard based interface to manage the grid integration of these devices. Currently, a task force of IEC TC57, WG17 is preparing a technical report "IEC 61850-90-15 – DER Grid Integration" that describes the requirements on the data interface for the integration and that defines the IEC 61850 data models for that interface.

The concept is to create a generic data model that describes the electrical characteristics of any DER unit or DER system independent of its type. One of the advantages of that concept is that it can be easily applied to new DER technologies in the future. The interface can not only be used to integrate generation devices, it can also be applied to controllable loads or to energy storage devices and systems.

A possible application of that interface is a virtual power plant (VPP), where the VPP management system has to integrate various DER systems to provide the required power to the electrical network. For this, the VPP management system needs to know the typical and the actual characteristics of the connected DER systems, for example, what is the active and reactive power that can be supplied or what is the amount of energy that can be stored. Based on the power requirements, the VPP management system shall then be able to set the produced power for each DER system through set-points.

But the interface shall also support other modes of operation of a DER system – a scenario may be a large energy storage system that is connected to the grid and operates in a frequency – watt control mode supplying primary regulation energy. In such a mode, the DER system would operate autonomously based on parameter settings and measurements. For an example of the frequency – watt control mode, the DER system would measure the frequency and if the frequency deviates from the nominal value it would supply or consume energy based on the parameter settings.

The report IEC 61850-90-15 is only one example of the activities of WG17 to support the usage of IEC 61850 for Smart Grids.

A technical report describing models for inverter based DER systems has already been published. Models for pluggable electrical vehicles as well as models for energy storage systems are in preparation.
Other works include the creation of new models for components of a distribution network like models for fault indicators supporting a self-healing grid.

Biography:

Christoph Brunner is the President of his own independent consulting company it4power LLC based in Switzerland. He has over 25 years of experience with knowledge across several areas within the Utility Industry and of technologies from the Automation Industry. He has worked as a project manager at ABB Switzerland Ltd in the area of Power Technology Products in Zurich / Switzerland where he was responsible for the process close communication architecture of the automation system. He is Convener of WG 10 of the IEC TC57 and is a member of WG 17, 18 and 19 of IEC TC57. He is senior member of IEEE-PES and IEEE-SA. He is an IEEE Fellow and he is active in several working groups of the IEEE-PSRC and a member of the PSRC main committee and the subcommittee H. He is international advisor to the board of the UCA international users group.

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