Multi-Type FACTS Controllers for Power System Compensation: A Case Study of the Nigerian 48-Bus, 330 kV System

Flexible alternating current transmission system (FACTS) devices have provided proficient answers to power system instabilities faced in the systems operations today with very little infrastructural investment fund. This paper investigates the effects of the installation of the combination of two kinds of FACTS controllers; static VAR compensator (SVC) and thyristor controlled series compensator (TCSC) compared with the installation of SVC or TCSC alone in the system. Voltage magnitude profile, active and reactive power losses of the three scenarios were achieved in the Nigerian 48-bus power system network using power system analysis toolbox (PSAT) in MATLAB environment. Simulation results obtained without and with FACTS devices optimally placed using voltage stability sensitivity factor (VSSF), revealed that the percentage decrease of the net real and reactive power losses of the combined SVC and TCSC was the highest at 31.917% whereas that of the standalone SVC and TCSC stood at 19.769% and 30.863% respectively. This shows that in addition to their capabilities to maintain acceptable voltage profile, the combination of SVC and TCSC has better compensating effect as they mitigate against power losses which was observed in their high percentage decrease in power losses compared to the standalone FACTS devices. Keywords: FACTS, optimum location, PSAT, SVC, TCSC, VSS