Analytical interval assessment method of voltage sag frequency considering the satisfaction degree of sensitive customer

Meeting customer satisfaction is an essential responsibility of power and utilities companies. Considering the property of customer´s satisfaction degree, an analytical interval assessment method of voltage sag frequency is proposed. The customer satisfaction degree is presented by interval data corresponding to the voltage tolerance of the tested equipment installed at the customer side. Based on the determination function derived from the relationship between the voltage magnitude and the length of fault line in the power supply system, the critical fault positions are determined using an analytical iterative algorithm. By studying the variation in the satisfaction degree within a given interval range, the interval sag frequency is calculated. Moreover, the quantitative sag frequency is determined with the help of the interval sag frequency. After a comprehensive analysis, the proposed method is applied to a five-bus system and IEEE 30-bus reliability test system (RTS). A myriad of experiments based on different methods indicate that the proposed method is very credible and practical for the application.