Enhancement of Power System Voltage Stability with the Aid of Reactive/Capacitive Power Switching Mechanism (A Case Study of Oweeri Transmission Company of Nigeria)

The focus of this paper is on the application of Static Var Compensator in enhancing voltage stability in power system. In other to achieve this, the Owerri transmission substation is used as a case study. Owerri transmission substation receives its power from Alaoji transmission station at a voltage level of 132kV. This substation is made up of three power transformers, two steady transformers and a mobile transformer with ratings of 60MVA and 40 MVA. ETAP 7.0 was the major tool used in achieving this aim. It was clearly observed that with SVC out of service bus voltage at Owerri was far below regulated value and very high loss occurred along the transmission line leading to high voltage drop. But with the SVC in service the bus voltage experienced a boost in voltage to a regulated value with corresponding reduction in voltage drop, drop in reactive power from the sending end and increase in real power supplied. Also the model was tested with light loads and it was observed that bus voltage was more than the source without the SVC but with the SVC the bus voltage was kept at a regulated value by the reverse flow of reactive power into the SVC. This again showed the dynamic nature of the SVC, absorbing reactive power in period of high voltage and supplying reactive power when low voltage occurs