矿井供电线路主要采用电缆供电方式。近年来，随着矿井生产能力的扩大，矿井供电电压等级的提升，矿井供电网络不断扩大，电缆长度随之增加，电缆对地的分布电容效应增大，矿井电网分布电容电流也随之增加，因单相接地故障，引起弧光过电压导致设备绝缘损伤，瓦斯爆炸等事故的时有发生，为了减少煤矿安全事故的发生，保护矿井供电系统的安全运行，对矿井电网单相接地电容电流的测量与治理补偿就十分的重要，本文就如何测量系统对地电容电流展开了分析与研究。 首先，在分析电容电流形成的基础上，讨论了传统的电容电流测量方法，对其中的偏置电容法和外加电容中性点法进行了仿真实验，并指出了各种传统测量方法的适用范围、优点及其局限性。其次，深入研究了基于信号注入法测量电容电流的方法，对现有的信号注入法，三频法、分频法和扫频法等方法进行了仿真实验，并指出了各种方法的优缺点以及适用范围。 最后，在分析电容电流测量方法的基础上，对信号注入法进行了改进，改进的信号注入法可以分别测量出系统对地电容和绝缘电阻值，进而准确的计算出系统的电容电流值。通过理论分析和仿真实验，证明了该方法有较高的测量精度，并能够在系统接地故障发生前对系统的绝缘水平做出预测，提高了系统的安全性。

In the mine power supply system, the power is supplied by cable. In recent years, with the expansion of production capacity and upgrade supply voltage level in mine, the range of mine power supply network is widening, and the length of cable is increasing at the same time, therefore, distribution capacitance effects between ground and cable is increasing, so as the capacitive current of mine power grid. The equipment insulation damage caused by arc over-voltage, gas explosion and other accidents has occurred because of single-phase grounded fault. In order to reduce the accidents in coal mines and ensure the safety of the mine power supply system, it is very important to measure and compensate single-phase grounded capacitive current in the mine power supply system. This paper analyzes and researches that how to measure capacitance current. Firstly, the traditional methods of measuring capacitive current are analyzed based on the research capacitive current formation, offset capacitance method and artificial neutral method are simulated, and their advantages and limitations are indicated. Then research the injecting signals method of measuring capacitive current in detail, and complete many simulation experiments, such as three-frequency method, two-frequency method and sweeping frequency method. Their advantages and limitations are also indicated in this paper. Finally, on the basis of analyzing capacitive current measurement, an improved injecting signals method is proposed in this paper. This method can accurately calculate capacitance current by respectively measure the capacitance to ground and insulation resistance. According to the principle analysis and the results of simulation, this method can accurately measure capacitive current, predict the insulation level before ground fault occurs, and improve the security of the system.