变压器低压侧小区差动保护的思考  

Thoughts on the low voltage side transformer differential protection

作　　者：冯国东 

机构地区：[1]上海思弘瑞电力控制技术有限公司,上海201108

出　　处：《电力系统保护与控制》2016年第10期79-83,共5页Power System Protection and Control

摘　　要：根据变压器低压侧小区差动保护原理和动作方程,推导出低压侧不同故障类型时该保护的动作行为。由推导发现,当低压侧绕组内部特定处相间短路时,非故障相差动会动作。同时详细分析了不同故障类型时,流经变压器各侧短路电流的幅值和相位。综合分析得出:由于变压器低压侧绕组采用三角形接法,其绕组内相间短路时各相相互影响,三角形绕组内短路电流会形成环流,从而导致了非故障相差动动作。该结论对于工程事故分析具有一定的指导意义。According to principle and equation of low voltage side differential protection, this paper deduces its behavior when different type faults occurred at low side. It is discovered that the non fault phase differential protection acted when phase-to-phase fault occurred at specific place inside low side winding. Meanwhile, it analyzes in detail amplitude and phase when short circuit current went through transformer under different type faults occurred at low side. In summary, due to low voltage side winding adopting delta connection, each phase influences others when phase-to-phase fault occurred inside the winding, the short circuit current will go through the delta winding which leads to the non fault phase differential action. This conclusion has certain directive significance to the engineering accident analysis.

关 键 词：低压侧小区差动 分相差动 相间短路 绕组TA 环流 三角形接法 

分 类 号：TM774[电气工程—电力系统及自动化]