Research on harmonic transmission characteristics of capacitor voltage transformer

Abstract

Synthetically considering the effects of such factors as stray capacitances and so on, an equivalent model of capacitor voltage transformer (CVT) is established and, based on this model the harmonic transmission characteristic of CVT is thoroughly calculated and analyzed using the equivalent impedance and the transfer function. Simulation studies and field tests are performed for harmonic transmission characteristic of CVT as well as measurement error. A very good consistency was observed between the experimental results and theoretical analysis. The results show that not only the working point deviation of series resonant circuit is the factor impacting the harmonic transmission characteristic of CVT, but the stray capacitance at primary side of the intermediate transformer and that of compensation reactor greatly affect the harmonic transmission characteristic of CVT. They make the amplitude-frequency curve of the transfer function present striking peak-valley effect and lead to a larger measurement error.