Protection Performance Testing in IEC 61850-Based System

IEC 61850 offers significant advantages when compared against other substation communication protocols; in particular the replacement of analog and binary signals with Ethernet messages reduces the cost of the system and improves flexibility and functionality. However, it also requires a new type of test bench suitable for the functional and performance testing of IEC 61850 compatible protection relays and systems. This presentation reviews methods for testing conventional protection relays and discusses some of the issues that affect how we test the next generation of relays; this includes the use of system configuration information, the GOOSE mechanism, Sampled Values and Client/Server SCADA Communication. Together these open new possibilities for enhanced secondary system testing. The implementation of IEC 61850 in the substation can be defined as partial, hybrid and complete. Test sets used in such applications need to have the functionality to perform coordinated and precisely synchronised tasks as a part of a distributed, system wide test facility. The presentation also investigates new approaches for testing IEC 61850 compatible relays based on the Real Time Digital Simulator (RTDS) and the OMICRON test set. The Giga-Transceiver Network Communication Card (GTNET) adopted in RTDS can provide real time communication to and from the simulator via Ethernet. Different firmware versions are used to accommodate IEC 61850 GSE binary messaging, IEC 61850-9-2 sampled values, playback of large data files stored on a PC hard disk and DNP communication (SCADA protocol commonly used in substations). In IEC 61850 installations, new significantly simplified test scheme based on RTDS can be achieved; more relays and their associated protection schemes can be tested simultaneously due to elimination of voltage and current amplifiers. OMICRON test sets utilise the NetSim Software (Network Simulator),which provides predefined Test Cases and Network Configurations to perform the tests. Standard network configurations with a simple parameter setup allow instant 'click and run' simulations with signal outputs via the test set. The criteria for selecting appropriate test sets are proposed. These take into account factors such as the scope of system under test, the requirement of extensive real time interaction, the ranges of test volts and amps and the number of logical and output signals that need to be monitored. An optimised test scheme layout is able to be delivered by configuring the test sets (separately or jointly) according to the test objectives. Preliminary results obtained when testing IEC 61850 based IEDs are presented and analysed with respect to test data from more conventional relays. With the availability of substation wide configuration data, tests involving multiple devices (e.g. interoperability test) are also facilitated. In addition, tests involving several points of signal injection and the measurement of overall scheme response will become easier to implement in IEC 61850 installations.