【作者】 金雪芬；

【导师】 武守远； 戴朝波；

【作者基本信息】 中国电力科学研究院 ， 电力系统及其自动化， 2009， 硕士

【摘要】 随着电网迅速发展,短路电流超标已经成为突出的问题。从根本上讲,合理的网络结构是降低短路电流水平最有效、最基本的方法。故障电流限制器(FCL)作为一种新的故障电流限制措施,在不改变电网潮流分布的同时起到限制故障电流的目的,具有很好的应用前景。本文依托华东500kV超高压电网故障电流限制器示范工程,研究了故障电流限制器的故障信号快速识别方法和装置本体保护与系统保护的配合的问题,提出了BOD启动晶闸管阀旁路的后备保护,并将此技术申请了发明专利；提出了线路电流斜率与线路电流瞬时值配合方式,此配合方式是对线路电流斜率判据的有益补充,有利于故障电流限制器更快速地识别出故障信号；提出了改善装置对系统保护影响的方法；对装置本体保护与系统保护的配合提出了合理的建议。本文的研究成果为华东500kV超高压电网故障电流限制器示范工程提供参考。本文主要的工作如下：首先用PSCAD-EMTDC搭建了华东500kV故障电流限制器等值系统,在该系统上对现有的可用于故障电流限制器的基于移相器和基于线路电流定积分的故障识别快速算法、BOD启动晶闸管阀旁路的后备保护方法进行了仿真分析。对线路电流瞬时值、线路电流斜率、MOV电流和MOV能耗这四个故障快速识别判据进行了检验,尤其重点研究分析了线路电流斜率和线路电流瞬时值在时间上的4种配合方式。仿真结果表明最佳配合方式是只要线路电流瞬时值和线路电流斜率相继达到整定值(不区分先后顺序),线路电流斜率保护就动作,二者相继时间为5ms。之后对基于线路电流斜率的故障信号快速识别判据用伊敏-冯屯串补工程和东明-三堡串补工程的现场暂态故障录波数据进行有意义的分析。在FCL等值系统上对FCL对零序电流保护的影响；线路重合闸对FCL的影响及FCL断路器合闸失灵保护与线路保护的配合、线路联动保护等问题进行了理论研究和仿真分析。仿真结果表明：FCL的投入会使线路零序电流保护灵敏性降低甚至产生拒动。采用保护定值切换的方法可以保证零序电流保护正确动作；线路重合闸会对电容器组产生冲击,线路重合闸时宜保证FCL的旁路断路器在合位；FCL的旁路断路器合闸失灵保护能在旁路断路器没有正常合闸时通过跳开本条线路开关来保证晶闸管和GAP等FCL主设备的安全；线路联动保护能在线路远端故障,其他保护都不会动作的时候确保旁路断路器处于合闸位置。最后在华东电力试验研究院数字动模试验室进行FCL本体保护RTDS实验,实验结果证明线路电流斜率能够快速的识别出故障信号；FCL的断路器合闸失灵保护能在断路器没有正常合闸时通过跳开本条线路断路器来保证晶闸管等FCL主设备的安全；线路联动保护能在其他保护都不会动作的时候通过闭合旁路断路器来保证电容器组的安全。更多还原

【Abstract】 With the fast development of grid, short-circuit current will be a serious problem. A reasonable network structure is the most effective and the most fundamental solution. Alternatively the fault current limiter (FCL) can limit the short-circuit current without changing the normal power flow. It is prospective.Based on the fault current limiter demonstration project in East China 500kV power grid, the fast identification of fault signal of FCL and co-operation of FCL protection and system protection are studied. BOD triggering thyristor bypass as back-up protection was proposed in the dissertation and applied for a patent. The co-operation between the slope set value and the instantaneous set value of the line current was proposed, which is the supplement to line current slope criterion. Based on a new approach improving the effect of FCL on system protection, several reasonable proposals of co-operation between FCL protection and system protection were given. All the works provide reference for the fault current limiter demonstration project in East China 500kV power grid. The main works of the dissertation are as follows:First, the equivalent system of the fault current limiter demonstration project in East China 500kV power grid is established using PSCAD-EMTDC. The existing fast identification method which can be used in FCL and other two new fast identification methods were simulated in the equivalent system. The identification criteria of fault signal based on the line current, the line current slope, the MOV current and the MOV energy are studied in details. The co-operation between the slope set value and the instantaneous set value of the line current are detailed with the aid of PSCAD simulation results. Simulation results show the best co-operation, i.e. the line current slope and the instantaneous value of the line current reach the setting values successively(without regard to sequence), and the interval is 5ms. After that, the criterion based on the line current slope is examined with the transient fault recorder data from Yimin-Fengtun series compensation project and Dongming-SanBao series compensation project.Then, the effect of FCL on the zero-sequence current protection, the effect of circuit re-switching on FCL and the co-operation between FCL protection and line protection are studied theoretically and simulated on the equivalent system. Simulation results show that, the insert of FCL will reduce the sensitivity of zero-sequence current protection even make the protection fail to operate. The problem can be solved by switching the protection fixed value freely. Re-switching of circuit breaker will impact on the capacitor bank, and the FCL by-pass breaker must be closed when the circuit breaker re-switched. The FCL breaker closing failure protection can reclose the by-pass breaker and open the line breaker at the same time to protect the thyristors and other main equipments of FCL when the by-pass breaker fails to close. The line coupled protection can close the by-pass breaker to protect the capacitor banks when a remote fault occurs and other protections fail to operate. Finally, the dynamic simulation experiments of FCL protections were conducted in the Digital Dynamic Simulation Room of East China Electric Power Test Research Institute to inspect the operation characteristics of the FCL breaker failure protection and the line coupled protection in various operating conditions.更多还原