Research on Characteristics of ECVT for Power Quality Detection and Optimum Design of Its Parameter

Abstract

Electronic Capacitive Voltage Transformer (ECVT), connecting the transmission system and measuring device, is the key equipment of digital substation in the distribution network. Its frequency characteristics and the rapid transient response performance exert decisive effects on whether it is in keeping with the power quality requirements for wide frequency domain and high precision detection. Many detection methods that require special testing equipment have limitations of high-cost and complexity in project implementation. We establish the mathematical model of ECVT, which is utilized to study its integrative characteristics based on the definitions of frequency response and transient voltage error. Besides, the harmonic and transient disturbance detection performances are analyzed comprehensively with the model by simulation. Then, we propose a multi-objective parameter optimization design model with minimization of transient voltage decay duration, maximization of frequency bandwidth and minimization of transient impulse voltage, which is solved through the entropy weighting method and genetic algorithm. The analysis and optimization results indicate that selecting resistor divider through the proposed method can achieve data transmission results with acceptable accuracy. Further, its superior performance on transforming transient disturbances conforms to the distribution network’s electric energy quality requirements.