摘要
针对煤矿电网并联供电线路发生单相接地故障时保护易误动、拒动,并难以断定是并联线路中的哪一条发生故障,提出了基于相间电流差的选线方法。该方法利用以故障相为基准的故障线路相间电流差等于单相接地电流,而非故障线路的相间电流差为零作为判断依据,通过计算比较选出相间电流差最大的线路,亦即故障线路。PSCAD仿真及动模实验表明,该方法能准确判断出故障线路,且在并联线路某支路发生单相接地故障时也能准确选出,保护差值大,不受故障相接地相位及接地方式影响,抗干扰能力强。
In mine power systems,protection false operation and failure operation in parallel supply lines often take place when single-phase-to-earth faults occur and the fault line is difficult to select.A novel method based on phase-to-phase current difference is proposed as line selection criterion.The method builds on that the phase-to-phase current difference based on fault phase of fault line is equal to the grounding fault current while the phase-to-phase current difference of normal line is equal to zero.Thus the fault line which has the biggest phase-to-phase current difference is selected. The results of PSCAD simulation and dynamic experiment show that the method can accurately select fault line and is quite effective when single-phase-to-earth fault occurs in one of the parallel supply lines,and it won’t be affected by grounding patterns and grounding phase of fault phase, and has large protection difference value and strong anti-interference ability.
出处
《电力系统保护与控制》
EI
CSCD
北大核心
2011年第9期108-113,共6页
Power System Protection and Control
基金
江苏省产学研联合创新资金项目(XJ09032)