Wide Area Protection and Control (WAPAC) is an exciting new technology in the power systems industry. As with all new technological developments, it is critical that it is thoroughly tested before being deployed in the power network.
One important device, which is often an essential element of WAPAC studies, is the Phasor Measurement Unit (PMU). PMU’s are typically placed at various locations in the power network to provide real time monitoring of the system frequency as well as the voltage and current phasors (i.e. magnitude and angle). Today PMU’s are found as standalone units and are implemented as features within protection and monitoring equipment. Currently, most PMU data from Wide Area Monitoring Schemes (WAMS) is used for offline analysis, but research is being done to apply the data to protection and control in so called Wide Area Stability and Voltage Control Systems (WACS). Decisions based on the PMU data could be made by WACS schemes to perform many different actions such as the adjustment of generation set points, pick up or drop out transmission lines, shed load, etc. With the use of such actions, these schemes have the potential to be very powerful. At the same time, however, they have the potential to do great harm to the network stability if the wrong action is taken. Therefore an environment for closed-loop, real time testing is essential in developing these schemes so as to ensure they operate in a secure and reliable manner.
This paper will focus on the requirements of a real time electromagnetic transient power system simulator for closed-loop testing of WAPAC schemes. These requirements include simulation models as well as standard industry communication protocols. It is important to have comprehensive libraries of protection and control models in case the functions are not all represented in the equipment under test. Standard industry communication protocols should be available (IEEE C37.118, DNP3, IEC 61850, IEC 60870-5-104). Synchronization of a simulation to an external time reference is also critical to WAPAC testing and will also be discussed.
Finally the paper will present results of testing a Wide Area Protection (WAP) scheme created by EKRA, a Russian manufacturer of protection equipment, using an RTDS® Simulator. The testing conducted by EKRA will also show comparison of the same tests conducted using a hybrid analogue/digital simulator at the JSC “STC UPS” (formerly JSC “NIIPT”) institute in St. Petersburg, Russia.
C. Peters, V. Naumov, P. Forsyth, S. Cayres, Presented at XII Symposium of Specialists in Electric Operational and Expansion Planning, Brazil, 2014, May 18 - 21, 2014, pages 1-7
KEYWORDS - PMU, WAPAC, RTDS, WAP