Real-Time Simulation of Static VAR Compensator and Static Synchronous Compensator

Abstract

In recent years, deregulation, open access, and co-generation in electrical power system are creating transmission voltage sags, swells, forced outages, and frequently followed by black-outs, congestion scenario, and many such problems. Reactive power limit is one of the major causes of voltage instability in the power system, and improving the system's reactive power handling capacity via Flexible AC transmission System (FACTS) devices is one of the remedies for prevention of voltage instability. The typical representatives of parallel FACTS devices for its avoidance are Static Synchronous Compensator (STATCOM) and Static VAR Compensator (SVC). Real-Time Simulator facilitates a physically large and spatially diverse or distributed power system to be accurately simulated in laboratory, and physical devices, like controllers or protection equipment can be tested in real time, even with introduction of faults, overloads, loss of generation condition, and with many more conditions for stability analysis purpose. This paper presents comparison of power flow parameter and the performance characteristic of the controllers on Real-Time Simulator OPAL-RT-OP4510 with SVC, and STATCOM. The waveforms of voltage, current, active and reactive power during the Real-Time execution are taken from the simulation environment to the outside world, using input/output devices, and seen on Digital Storage Oscilloscope (DSO). The validation is done on multi-machine-9-bus system. The results of Real-Time Simulation during LLLG fault indicate that STATCOM supplies reactive power independent of line voltage, whereas SVC behaves as constant susceptance when the reactive power required by the system is above its rated capacity. The power flow parameters with both the controllers are comparable during steady state operation.