谐波条件下电容式电压互感器测量影响因素分析

Analysis about Influencing Factors of Capacitor Voltage Transformer Measurement in the Harmonic Conditions

电容式电压互感器(CVT)测量的准确度影响着电能计量的准确性和继电保护动作的可靠性。为了研究在谐波条件下CVT测量的准确性,为提高CVT的测量精度提供参考依据,文章基于CVT的等效电路模型,推导出了谐波条件下CVT变比的表达式,研究了谐波条件下CVT的励磁阻抗和电容分压比对测量精度的影响规律,并通过仿真分析对其进行了验证。

The measurement accuracy of capacitor voltage transformer（ CVT） affect the accuracy of electric energy measuring and reliability of relay protection action. In order to study the accuracy of CVT measurements under the harmonic conditions,and to improve the measurement accuracy of the CVT to provide reference,this paper has obtained some conclusions based on the equivalent circuit model of CVT. The expression of CVT measurement ratio under the harmonic conditions is derived,and the effect of excitation impedance and capacitance divider ratio of the measurement accuracy under harmonic conditions has been researched and been verified by simulation analysis.