Patent ID: 8024076

Claim:
A voltage collapse diagnostic method for an electrical power system, comprising: A) defining a network of a plurality of interconnected busses and sources of reactive reserves; B) defining groups of busses within said network such that when a reactive load is applied to any bus within a first group of said groups of busses, a same at least one source generally completely exhausts its reactive reserves: C) establishing each group of busses defined in step B) as a respective voltage instability region, each of which is represented by a respective agent; D) performing simulation of a plurality of single contingencies using equations that define the network; E) selecting a count N of a number of agents to be considered; F) determining a variable threshold value for a reactive remaining exhaustion Factor; G) identifying each single contingency that results in the reactive remaining exhaustion factor for N number of agents being less than the threshold value, wherein the reactive remaining exhaustion factor is a value representing an amount of reactive power available in the respective agent in response to a contingency; H) performing a multiple contingency analysis by combining single contingencies identified in step G); and I) using results of the single contingencies and multiple contingency analysis to analyze a voltage response of at least a portion of the network.