小电阻接地系统中接地变压器零序电流保护改进  

Improvement of zero-sequence over-current protection for grounding transformer in low-resistance grounding power system

作　　者：宁国丽[1] 房亚囡[2] 邢立功[2] 高亮[3] 王广领[3] 宗洪良[3] 

机构地区：[1]天津市电力公司城南供电分公司,天津300201 [2]天津市电力公司,天津300010 [3]江苏金智科技股份有限公司,江苏南京211100

出　　处：《电力自动化设备》2011年第5期141-144,共4页Electric Power Automation Equipment

摘　　要：配网中性点经小电阻接地方式下发生单相接地故障时,传统的主变低压侧接地变压器的零序电流保护方案在保护动作时可能会不必要地跳开变压器低压侧2个分支断路器,导致事故停电范围扩大。现提出一种改进方案:利用故障发生时变压器低压侧两分支中流过的零序故障电流分布特征识别变压器低压侧故障分支,优先切除故障分支,避免停电范围扩大,当无法确定故障分支时,同时切除2个分支,避免故障发展。该方案可在仅对现场设备进行软件改造的基础上实现,且不需要在传统方案基础上增加额外整定值。该保护方案已经在iPACS-5941变压器成套保护装置上成功应用。When single-phase grounding fault occurs in low-resistance grounding power system,the traditional zero-sequence over-current protection of grounding transformer may unnecessarily trip two branch breakers at the low-voltage side of main transformer,for which,an improved scheme is presented：the distribution of zero-sequence currents in two branches is identified,only the breaker of faulty branch is tripped to limit the scope of outage;when none of them can be identified as faulty one,both breakers are tripped to avoid fault spreading.The improvement can be implemented easily by software modification,no additional setting needed.It has been applied in iPACS-5941 transformer protection.

关 键 词：小电阻接地 接地变压器 零序电流保护 iPACS-5941 

分 类 号：TM772[电气工程—电力系统及自动化]