Research on Harmonic Restoration Method Based on CVT Circuit Model
Capacitive voltage transformer(CVT)is an important equipment for voltage state monitoring of power sys-tem and has higher accuracy in the measurement of power frequency voltage.However,the core of intermediate trans-former of the CVT will be saturated in case of sub-synchronous resonance in power system.The voltage transfer char-acteristic of CVT can change with variation of inductance of core,resulting in the increase of measurement error of the CVT in the measurement of the harmonics.The existing harmonic measurement method based on voltage transfer characteristic has no way to dynamically calculate harmonic components of CVT in the course of variation of voltage transfer characteristic.Therefore,the CVT circuit model taking into account the core saturation characteristics and stray capacitance is set up in this paper.The accurate restoration of the harmonic is achieved by reversely solving the model.Finally,the harmonic simulation verification of 35 kV CVT is performed.The result shows that compared with the traditional voltage transfer coefficient method,the harmonic restoration method proposed in this paper can make the harmonic component error be reduced from 94.6%to 7.1%,which can accurately calculate the actual harmonic components of the primary side voltage when the core of intermediate transformer is at nonlinear state
capacitive voltage transformerharmonic measurementinversion calculationstray capacitance
万方数据
维普
