绝缘在线监测中电容式电压互感器的误差校正

对引起电容式电压互感器（CVT）稳态误差的相关因素进行了分析。根据CVT结构及参数建立了用于校正CVT稳态误差的参数模型。将该模型输出电压的误差仿真结果与准确级试验结果进行对比，验证了该模型的有效性。基于该模型提出一种绝缘在线监测中实时校正CVT稳态误差的新方法:通过采集测量绕组的输出电压和各二次绕组的负载电流信号，利用基于Levenberg-Marquardt算法的非线性最小二乘拟合算法提取信号中的基波分量，结合CVT参数模型的数学方程确定CVT的一次电压。分析结果表明，该方法能够有效减小因系统频率、CVT二次负载大小及功率因数的变化对CVT比差及角差的影响，为二次监测设备提供高精度的电压信号。

Error Correction of Capacitor Voltage Transformers for Insulation On-line Monitoring

The relevant factors causing the steady-state error of capacitor voltage transformers(CVTs)are analyzed.A parametric model is developed according to the structure and parameters of CVT.The effectiveness of the model is verified by comparing the error simulation results with experimental data of the accuracy test.For the insulation on-line monitoring,a new method based on this model is developed to correct the steady-state error of CVT,in which the voltage signals of the measuring winding and current signals of the secondary winding with load are collected and the nonlinear least-squares fitting algorithm based on Levenberg-Marquardt algorithm is adopted to obtain the fundamental components.The equations of the model are utilized to determine the primary voltage of CVT.The analysis results indicate that the errors in ratio and phase due to the changes in the frequency,size of load and power factor can be markedly reduced,providing secondary monitoring facilities with high precision voltage signals.