Real time simulation and testing using IEC 61850

As the IEC 61850 communication protocol becomes more widely accepted and applied in electrical engineering, it is important that the testing tools keep up with these developments. IEC 61850 presents new challenges to real time simulation and closed-loop testing of protective relays. The electrical interfaces used for binary signaling and the voltage/current amplifiers used in traditional test methods must be replaced by an Ethernet connection and an IEC 61850 protocol stack. The electrical interfaces of a real time simulator are engineered to provide low latency and deterministic performance appropriate for a real time testing. Similar attention must be given to IEC 61850 interfaces. Latency must be minimized so that the IEC 61850 interface does not add unacceptable delays to the operation of the simulator. Also, protocol processing must be deterministic to allow real time simulations to be repeatable and dependable. In addition, IEC 61850 specifies new configuration parameters and a new method for configuration called the Substation Configuration Language (SCL). These must be implemented in such a way that they fit within the typical modes of operation of the simulator. The paper will present a successful implementation for IEC 61850 messaging on a real time simulator using the GTNET card and will discuss the key design criteria. The software required to configure the IEC 61850 will also be introduced along with the advantages of using the IEC 61850 protocol. One of the significant advantages brought about through the realization of the IEC 61850-9-2 sampled value communication is the elimination of complex and expensive amplification equipment traditionally used as the interface between the real time simulator and the physical protective relay(s). Sampled values of the voltage and current signals are sent via Ethernet, making it simpler, more practical and less expensive to perform closed-loop tests. As part of the IEC61850 communication standard the “qual- - ity” of information is contained within the transmitted data. As an example of the effectiveness of the RTDS simulator as a testing tool, tests were run in which the “quality” information contained in the IEC 61850 data was dynamically changed. The purpose of such a test is to show how various IEC 61850 IEDs would react to abnormal (and normal) IEC 61850 data. Understanding how a protection system responds to IEC 61850 data is important and will give engineers confidence that the system will behave in an acceptable manner.