Abstract:

Based on the CVT circuit structure,the circuit equivalent model with the whole circuit distribution parameters was established,and a cascade analysis method based on Y-Δ equivalent transformation was proposed to solve the problem that it is difficult to simplify the equivalent circuit and derive the transfer function when considering the complex distribution parameters.From the perspective of frequency characteristics,the influence of key parameters such as the distributed capacitance of compensation reactor,the distributed capacitance between the primary and secondary sides of the intermediate transformer to the ground and the coupling capacitance between the primary and secondary sides on the harmonic transfer characteristics is analyzed in detail,which provides guidance for optimizing the design of CVT parameters and improving the production process.On this basis,a method of harmonic transfer coefficient correction strategy based on three-layer BP neural network algorithm was proposed to improve the accuracy of CVT harmonic measurement.Finally,the validity of the method was verified by the measured data.

Key words: capacitor voltage transformer (CVT), power quality, distributed parameter, frequency characteristics, neural network