EMTP TRANSIENT MODELING OF A DISTANCE RELAY AND A COMPARISON WITH EMTP LABORATORY TESTING

This paper reports on a method to test the transient performance of a sampled-data relay. A model of one measuring unit of a digital relay w as created on a personal computer. The simulations are compared with l aboratory results obtained by applying digitally generated waveforms t o the actual relay. Computer modelling of the digital relay is done wi thin the Models version of the Transient Analysis of Control System (T ACS) subsection of the ElectroMagnetics Transient Program (EMTP). The input filter, analog to digital converter, Fourier fundamental frequen cy detector, and the relay measuring principle of one digital micropro cessor based relay are modeled. The modeling of these components withi n an EMTP environment represents new work. An actual 115 Kv 150 mile l ong transmission line was simulated using the EMTP. The faults simulat ed on the transmission line were applied both to the digital model of the relay and the actuaL relay. The physical testing used the Bonnevil le Power Administration (BPA) Relay Evaluation System (RES). Results f rom the digital relay simulation are compared with results from an act ual relay. The educational value of observing relay waveforms at vario us stages within the simulation is discussed.