摘要
对平行双回线路内部发生接地故障时反时限零序电流保护的选择性进行了分析。研究表明,对于平行双回线路两侧的相邻线路而言,其零序电流不一定小于故障线路中的零序电流,相邻线路上的反时限零序电流保护有可能无选择性动作;对于故障线路本身,离故障点远的一端的零序电流可能大于离故障点近的一端的零序电流,离故障点远的一端保护可能先动作;对于平行双回线中的非故障支路,其保护不会先于故障支路上保护动作,其选择性可以保证。误动的可能性取决于双回线两侧系统的零序参数和故障点位置,与双回线路本身的零序参数及零序互感大小无关。同时提出一种基于广域信息的反时限零序电流保护算法,在改善保护选择性的同时,提高了保护的速动性。最后通过PSCAD仿真验证了分析的正确性。
The selectivity of inverse-time zero-sequence current protection during earth fault occurred within parallel double-circuit transmission lines is analyzed.Research result shows that as for other transmission lines adjacent to both sides of the parallel double-circuit transmission lines the zero-sequence current in the formers is not always less than that in the parallel double-circuit transmission lines,so that the non-selective action of inverse-time zero-sequence current protections for the adjacent transmission lines may occur.For the faulty line itself the zero-sequence current at the end that is more distant to the fault point end may be larger than that at the opposite end nearer to the fault point,so the protection equipped at the more distant end may act earlier than the protection equipped at the nearer end;the protection equipped for the non-faulty line of the double-circuit lines will not act earlier that that equipped for the faulty line,so its selectivity can be ensured.Therefore,the possibility of misoperation of the protection is dependent upon zero-sequence parameters of transmission lines adjacent to both sides of the double-circuit transmission lines and the position of fault point,and is not dependent upon the zero-sequence parameters and zero-sequence mutual inductance of double-circuit transmission line themselves.Meanwhile,a wide area information-based inverse-time zero-sequence current protection algorithm is put forward,which can improve the speed of the protection while the selectivity of the protection is enhanced.The correctness of above-mentioned analysis is verified by simulation results.
出处
《电网技术》
EI
CSCD
北大核心
2013年第3期707-712,共6页
Power System Technology
基金
国家自然科学基金资助项目(50837002)~~
关键词
继电保护
零序电流
反时限
平行双回线
选择性
广域测量系统
relay protection
zero-sequence current
inverse-time
parallel double-circuit transmission lines
selectivity
wide area measurement system
