A system and method are provided to calculate a real time voltage stability risk index in a power system. The method includes calculating an RMS voltage by using bus voltage measured and calculating an N moving average voltage for the RMS voltages. A percentage diversity between the bus voltage measured and the N moving average voltages is calculated. A voltage stability in that risk index is calculated by dividing the area constructed by the percent diversity by the number of sections. The voltage stability risk index is transferred from a real time phasor measurement device to an upper voltage stability monitoring system. The transferred voltage stability risk indexes are acquired and sequenced and the sequence voltage stability risk indexes are output.