基于方波电流的接地阻抗电阻分量的测量方法

Measurement method of resistance component of grounding impedance based on square wave current

目前,接地阻抗测量方法主要基于正弦波电流激励,测量其响应电压的幅值及相位,从而计算得到接地阻抗值。然而,现场互感耦合分量的影响会引起相位测量误差,从而导致接地阻抗阻性分量、感性分量及模值均出现较大误差。基于方波电流提出了一种接地阻抗阻性分量的直接测量方法。从接地阻抗感性分量的理论分析出发,讨论了接地阻抗感性分量的上限值,提出了简化分析方案并列举了相关算例。在此基础上,在理论上分析了方波测量接地阻抗阻性分量的有效性,并开展了实验室和现场的验证。结果表明,方波法可以作为接地阻抗阻性分量的准确测量手段,进一步提高接地阻抗测量的准确性,可作为异频法的良好补充。

At present,the measurement of grounding impedance is mainly based on sine wave current excitation,measuring the amplitude and phase of its response voltage,and calculating the measured value of grounding impedance.However,the influence of field mutual inductance coupling will cause phase measurement error,which will lead to large errors in the resistance component,inductive component and mode value of grounding impedance.Based on square wave current excitation,this paper presents a direct measurement method of the resistance component of grounding impedance.Based on the theoretical analysis of the inductive component of the grounding impedance,the upper limit value of the inductive component of the grounding impedance is discussed,and the simplified analysis scheme and the related calculation examples are proposed.On this basis,the paper theoretically analyzes the effectiveness of square wave measurement of grounding impedance resistance component,and carries out laboratory and field verification.The results show that the square wave current excitation method can be used as an accurate measurement method of the resistance component of the grounding impedance,further improving the accuracy of the grounding impedance measurement,and can be a good supplement of the different-frequency method.