A novel method for distributed real time voltage stability monitoring using synchrophasor measurements

With the advent of synchrophasor technology, real time voltage stability analysis using synchrophasor data has been the focus of many researchers resulting in the development of several new algorithms. These developed algorithms have several advantages as well as limitations. This paper discusses briefly about the shortcomings of some existing synchrophasor measurement based voltage stability indicators. Most of the existing model-free algorithms are iterative in approach, thus making them computationally slow as well as making non-convergence a possibility. Some of these algorithms also have accuracy issues when the system conditions change fast by large amounts. Thus a new algorithm is necessary that is devoid of these limitations. A new algorithm for distributed real time voltage stability monitoring based on local phasor measurements has been presented in this paper. The newly developed algorithm to compute the Voltage Stability Assessment Index (VSAI) can be used for normal operation as well as for contingency cases to monitor dynamic security of a system. Results of the new algorithm tested on different IEEE test cases under different system conditions show its satisfactory performance.