METHOD FOR ASSESSING AND ESTIMATING VOLTAGE STABILITY

摘要

A method for assessing and estimating voltage stability is provided to take preventive steps for stability of a power system by previously checking the voltage stability of the system. A method for assessing and estimating voltage stability includes the steps of: calculating Thevenin equivalent voltage and Thevenin equivalent impedance of a power system terminal by using time series measurement data(S10); calculating changed Thevenin equivalent impedance through a predetermined equation by using the Thevenin equivalent voltage(S20); comparing ratios of the changed Thevenin equivalent impedance and the impedance of the power system terminal, evaluating a voltage stability index by using a Z-index, and estimating the voltage stability(S30); determining whether the voltage stability index corresponds to predetermined time or whether voltage and current of the power system terminal are changed at more than a predetermined reference value(S40); and returning to the first step when the voltage stability index corresponds to predetermined time or when the voltage and the current of the power system terminal are changed at more than the predetermined reference value.