单相接地故障是电力系统中最主要的故障形式，占据到故障总数的70％以上。小电流接地系统发生单相接地故障时，短路电流小，三相线电压依然对称，不影响负载的正常工作，可以继续运行一定时间，但是在发生单相接地后，非接地相对地的电压会升高，间隙性电弧接地还会产生弧光过电压，长期运行可能会损坏其绝缘，引发严重的相间故障。所以，在系统出现单相接地故障后，应立即找出故障线路，设法使接地设备从系统中切除。 电网对地分布电容的存在是接地点产生故障电流的主要原因，在电网的中性点与大地之间加装消弧线圈，可使容性电流得到补偿，从而使接地点的电流减小。特别是消弧线圈跟踪补偿，根据实际电网电容电流的大小，自动调节消弧线圈产生的感性电流，使两者处于平衡状态，从而使接地电流减小为量值很小的有功电流，使电弧不能维持、自动熄灭。跟踪补偿能使瞬时性接地故障自动消除，也能使永久性接地故障的危害程度大为降低，是减小故障损失的主要技术措施。 首先分析了调容式消弧线圈本体的阻抗变换及调谐原理，并对电容电流在线测量和单相接地故障自动识别两个难点问题进行了分析，提出了采用消弧线圈自动调谐实现准确识别单相接地故障；其次基于matlab仿真软件进行了消弧线圈的阻抗变换及系统接地补偿分析，特别的验证了系统正常情况下系统电容电流的在线测量及基于TSC投切电流的仿真。再次，根据系统要求，详细设计了系统的硬件设计电路；最后，给出了系统的软件流程。

Single-phase to earth fault is the most frequently happened fault form in power system．The probability is up to 70 percents in all forms of faults。 The fault current is small and the three phase line to fine voltages are still symmetric while single-phase to earth fault occurs in a non-solidly earthed network, the load can be in normal process for a period of time．But after the fault，the no—faulted phase voltage would increase and intermittent arc grounding would lead arc over voltage，so the insulation would be damaged in long time running leading more serious phase-to-phase voltage fault．So single-phase to earth fault should be removed as soon as possible and the fault line should be found immediately． For the distributed capacitance of the network is the main cause of the fault current，it can be compensated and reduced by installing arc suppression coil(ASC)．Especially to the ASC is auto-tuning，the capacitive current of the power system can be totally compensated by automatically regulating ASC’s inductive current．Using the function of tracking compensation, the fault current could be reduced to a small active current and the arc can’t maintain and will go out soon．Tracking compensation, which could remove the transient grounding fault automatically and greatly reduce the damage of the permanent grounding fault, is a kind of chief technical measures to reduce the loss caused by ground fault． Firstly, the principle of impedance conversion and tuning tune-contained Petersen coil body, and capacitive current on-line measurement and automatic identification of single-phase ground fault two difficult problems were analyzed, and the use of arc suppression coil automatic tuning to achieve accurate identification of single phase to ground fault; secondly matlab-based simulation software and system grounding impedance transformation compensation Arc analysis, particularly to verify the measurement system under normal circumstances, and the online system capacitive current switching current TSC-based simulation. Again, according to the system requirements, detailed design of the system's hardware circuit design; Finally, the software flow system.