Evaluation of the PMUs Measurement Channels Availability for Observability Analysis

Phasor measurement units (PMUs) equipped with global positioning system (GPS) receivers are the first devices capable of efficiently performing real-time monitoring of remote electrical power systems. Reliability of the monitoring system that exclusively uses PMUs is directly related to the reliability of each unit allocated on the system. As the failure of measurement channels is more common than PMU's failure, a probabilistic evaluation method of the PMUs measurement channels availability for electrical network observability analysis is proposed. In this method, the Markov process is adopted for estimating the measurement channels availability, as well as for determining an equivalent of the state space diagram of all possible operation states of channels for each unit. With the objective to assess the impact of the failure of measurement channels in the observability and reliability of the system, an algorithm that determines the optimal placement of PMUs using a modified binary search, the measurement channels availability for each unit, the global measurement availability, and the critical measurement channels for power system observability analysis was developed. Numerical results using the IEEE 14-bus, IEEE 30-bus, New England 39-bus, and IEEE 118-bus test systems are presented and discussed.