Study on Voltage Stability of Transmission Lines Under Large Reactive Power Burden

In this paper, the results of load flow studies on a fictitious 6-bus system under conditions of large reactive power burden and reactive power mismatch have been presented. With increasing reactive power burden and reactive power mismatch, it has been noted that the voltage profile becomes poorer and poorer eventually leading to voltage collapse. Even before a collapse, the voltage profile becomes unacceptably poor. All bus voltages fall below 0.95 p.u. It has been indicated that the load flow must be planned with a look to this phenomenon. The role of series and shunt compensators has also been highlighted in this context.