Instability in a power system can be manifested during fault conditions in different ways. To ensure system stability, satisfactory performance of protection systems such as a protective relay is of great importance. Development of more reliable digital protection devices is possible with modeling, simulation and testing. This paper describes a detailed software model of an overcurrent relay developed in the Laboratory Virtual Instrumentation Engineering Workbench (LabVIEW) graphical programming language. The performance of the relay model is tested under different fault scenarios with both the relay model and power system model running in real time. The results obtained are validated against hardware in the loop (HIL) tests conducted with a Schweitzer Engineering Laboratories (SEL)-351S overcurrent relay and power system model in Real Time Digital Simulator (RTDS) to modify the software model to best represent the hardware functionality.
S. Palla, A. Srivastava, N. Schulz, Grand Challenges in Modeling & Simulation, Summer Simulation Conference (SummerSim), June 16-19, 2008 Edinburgh, Scotland.
KEYWORDS: Real time digital simulation, hardware in the loop, overcurrent relay, digital filter, power system protection.