不对称短路故障下非故障6kV电动机速断保护动作行为分析  

Analysis of 6 kV no-fault motor instantaneous trip protection action on asymmetrical short-circuit faults

作　　者：高博[1] 罗亚桥[1] 郑国强[1] 宋卓[1] 

机构地区：[1]安徽省电力科学研究院,安徽合肥230601

出　　处：《电力系统保护与控制》2011年第8期104-106,134,共4页Power System Protection and Control

摘　　要：根据对称分量法,分析了单相接地短路和两相接地短路两种不对称短路故障下的电压向量。对6kV电动机在不同序电压下的运行情况进行了分析,表明运行在同一6kV母线上的非故障电动机速断保护在不对称短路情况下,特别是在两相接地短路时,负序电压产生的较大电流可能会导致电动机速断保护误动作。提出在进行电动机速断保护定值整定校核时,不仅需要考虑启动电流,还需要考虑不对称短路故障时的负序电压影响的问题。Based on the symmetrical component method,this paper analyses the voltage vector of two asymmetrical short-circuit faults including single-phase grounding fault and two-phase grounding fault,and also analyses the operation condition of 6 kV system at different sequence voltages.The analysis results show that in the situation of asymmetrical short-circuit faults,especially in the two-phase grounding faults,the instantaneous trip protection of no-fault motors maybe falsely act because of large current which produced by negative voltage.To solve the problem,this paper presents an idea that not only the startup current,but also the negative voltage at asymmetrical short-circuit fault is needed to be considered in motor instantaneous trip protection setting and checking.

关 键 词：对称分量法 电压向量 电动机 速断保护 不对称短路 

分 类 号：TM773[电气工程—电力系统及自动化]