高压电缆外护套故障测距误差分析及改进措施

为了提高直流电阻法故障测距的抗干扰能力和测距精度,分析了直流电阻法高压电缆外护套故障测距误差产生的原因,给出了减小故障测距误差的改进措施。从原理入手分析了直流电阻法故障测距的误差源,推导了电压测量和电流测量函数表达式以及故障测距结果函数表达式,在此基础上分析了大地杂散电流等干扰对电压测量和电流测量的影响,分析了直流电阻法故障测距过程中误差传递与合成的规律,论证了故障测距误差因子与测量电路元件参数、干扰信号频率、压频转换器计数时间以及注入直流测量电流的关系,针对误差分析结果,给出了减小故障测距误差的改进措施。计算和实验结果验证了改进措施的有效性。

Error Analysis and Improvement Measures of the HV Cable Jacket Fault Location

In order to increase the anti-interference ability and fault location accuracy of DC resistance fault location method,the error causes of the DC resistance method using in high voltage cable jacket fault location is analyzed,the measures of reducing errors of cable jacket fault location are given.According to the principle of DC resistance method,fault location error sources are analyzed.Functional expressions of voltage measurement and current measurement as well as result of cable jacket fault location are derived.On this basis,ground stray current interference effect for voltage measurement and current measurement is analyzed,the law of propagation and combination of the cable fault location error in DC resistance method are also analyzed.An error factor of cable fault location relative to circuit components parameters,frequency of interference signal,counting time of voltage-to-frequency converter,as well as injection DC current is also analyzed.Some measures aiming at reducing errors of cable jacket fault location are proposed.Calculation results and experiment data verify the proposed measures.