Contingency analysis and weakest bus ranking by reactive power reserve margin

This paper shows effect of contingency on system voltage stability. Here voltage stability is derived through V-Q curve and computing reactive power reserve margin of load buses. According the value of reactive power reserve, buses can be ranked. Weakest bus and severe contingency has been decided through V-Q curve. The reactive power reserve margin is obtained through repeated N-R load flow. Voltage control areas are also determined. Matlab programming is used to obtained result.