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。 接地故障的自动选线，快速地找出故障线路，有利于减小系统带故障运行的时间， 也是减小接地故障损失的重要技术措施。为实现配电网电容电流的自动补偿，本文以调 容式自动跟踪补偿系统为研究对象，对自动跟踪消弧补偿的原理及选线技术进行了研 究。 首先分析了调容式消弧线圈补偿接地电容电流的原理及其补偿特性.其次分析了自动跟踪补偿控制系统的工作原理，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及故障 选线，并设计了基于DSP2812 的自动跟踪消弧补偿控制器。 最后针对2.2kVar／220V 的调容式消弧线圈及其2kVar 的电容调节柜，设计了调容 式自动跟踪消弧补偿系统，并在实验室进行实验验证。结果表明，调容式自动跟踪消弧 补偿系统能实现电容电流的在线测量，电网运行状态的自动识别和对地电容电流的完全 补偿等功能，达到了电网电容电流自动补偿的要求。同时设计了基于双向晶闸管投切电 容器的2kVar 的电容调节柜，在实验中同时完成了LCD240*128 显示模块实时参数的人机交互界面。试验结果表明可控硅投切电容器回路设计合理，投切速度快、冲击小。

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． The automatic fault line selection of single-phase to earth fault which could find the fault line quickly could be good for the reduction of the running time of systemwith fault and also be an critical technical measure of reduction of the grounding damage．Under this circumstance the auto-turning ASC equipment is expected to be installed in the distributions network which can automatically take variation value in zero sequence capacitance in the wake of network changes of topology to compensate fault current when single phase to ground fault occurs．Out of all auto-turning ASC equipment concepts，the method of arc suppression coil that inductance value is changed by switching corporated connected capacitors distinguishes itself as a very attractive option with grounding capacitive current compensating demand．The fundamental effect of novel ASC is no noise，fast， flexible and no rash．In this paper the working principles of the auto-turning novel ASC as well as implementation of the prototype are described． Fistly，the principles of ASC that inductance changes by switching parallel connected capacitors and its compensating characteristic are specified．It is sharply different for switching frequency of each of capacitors of ASC that inductance changes by switching parallel connected capacitors when each capacity is arranged in the past binary manlier．To solve this problem，a new manner is proposed that each parallel capacitor of ASC is arranged in nearly equal capacity．Secondly to ensure ASC automatically to follow the earth capacitive current，there are two key problems which is automatically measurement of capacitive current flowing to ground and identifying occurrence of single phase to ground fault innetwork．According to two problems，the new method identifying single phase to ground fault is proposed that the equipment monitors zero sequence current directions of very load line in the single source supply distributions under the maximum and minimum rum of arc suppression coil by automatically switching parallel connected capacitors．Following this theory, the novel controller based on DSP2812 is designed to fulfill the job of compensation control． At last, the system module is established and proved according to the practice case of 2kv,2.2kVar and 2kVar capacitors auto—turning ASC that inductance is changed by switching parallel connected capacitors in the lab, And also the sample equipment of the 2kVar capacitors is designed and implemented，as well as its each circuit Triode AC Switch is tested in the lab．According to the results，the system can automatically turning arc suppression coil which is used to generate the switching pulses for thyristors to regulate the inductive current of ASC by switching parallel connected capacitors following the value of automatically measurement ， as well as real-time interactive interface parameters based on LCD240*128． The test result has been proved that its design of capacitors based on TSC technique is reasonable and the process of switching capacitors is rapid and surgeless 。