Entropy Based Analysis of Delayed Voltage Recovery

In this work, Fault Induced Delayed Voltage Recovery (FIDVR) phenomenon has been characterized as the loss of Entropy in the voltage time series. The relationship between entropy and the voltage recovery rate has been established. It is shown that, the entropy can be an estimate of the recovery rate. Furthermore, the entropy computation has been done entirely from the statistical properties of the time series, without using any model information. Kullback-Leibler(KL) divergence, an entropy based quantity, has been demonstrated to capture both the rate and the level of recovery. A critical value of the KL divergence is computed, which can indicate possible violations of the WECC voltage performance criterion. The KL divergence is then applied to identify weak buses , and severe contingencies in power network.