【作者】 王必平；

【导师】 康忠健；

【作者基本信息】 中国石油大学 ， 控制理论与控制工程， 2010， 硕士

【摘要】 电网中性点接地方式涉及到电网的技术、经济和安全等多个方面,是电力系统实现安全与经济运行的基础之一,对电力系统的安全稳定运行具有重要意义。随着电网容量的日益增大,电压等级的日益提高,原有的中性点接地方式越来越不能满足电力系统发展要求。在各种电压等级的电力系统中,单相接地故障都是最主要的故障形式,一般占据到故障总数的70%以上。小电流接地系统发生单相接地故障时,虽然不形成短路回路,没有量值很大的短路电流,且三相线间电压依然对称,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,断续性电弧接地时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。本文针对这个问题开展研究工作,在深入分析目前国内中压电网所采用的中性点不接地、中性点经消弧线圈接地和中性点经电阻接地三种方式的接地原理和基本运行特性的基础上,研制自动跟踪调谐消弧线圈接地补偿装置,用于补偿电网单相故障时电容电流。现场试运行结果表明:该装置电容电流测量准确,补偿效果好,在发生电网单相接地时能够补偿接地容流。更多还原

【Abstract】 The grounded mode of power system is related to technical, economic, secure and other various aspects and it is one of the foundations of security and stability operation of the power system. It is great significance to the secure and economic operations of the power system. With the growing capacity of grid and increasing voltage levels, the original neutral point grounded mode can not meet the requirements for the development of the power system.In the power system with all sorts of voltage levels, phase-to-ground fault is the main form of the fault, occupied 70% of the total to malfunction. Since no short-circuit loop is formed so that the fault current is small and the three phase line to line voltages are still symmetric when single-phase to earth fault occurs in a non-solidly earthed network, the load can be in normal operation for a period of time. But after the fault, the non-grounded fault phase voltage would increase, discontinuity grounded arc still can produce arc voltage, long-term operation may damage the insulation and serious phase-to-phase fault.Aiming at this problem this thesis thoroughly analyses grounding principles and basic characteristics of three kinds of grounded mode (ungrounded, grounded through a resistance, compensated grounded) used in medium voltage network. An automatic tuning suppression-coil device with on-line tap-changer is developed for the capacitive current compensation and faulted line selection in case of an earth fault. The results from field test show that the measurement of the capacitive current is accurate and the effect of compensation is very good when single-phase grounded fault occurs.更多还原