基于相角差的发电机定子接地保护方向元件  

Directional Element Based on Phase-angle Difference for Generator Stator Grounding Protection

作　　者：涂崎[1,2] 邰能灵[1] 

机构地区：[1]上海交通大学电子信息与电气工程学院,上海市200240 [2]上海市电力调度通信中心,上海市200122

出　　处：《电力系统自动化》2009年第14期61-65,共5页Automation of Electric Power Systems

基　　金：国家自然科学基金资助项目(50577042);上海市教委曙光计划资助项目(07SG11);新世纪优秀人才支持计划资助项目(NCET-08-0356)~~

摘　　要：分析了发电机发生内外部单相接地故障后,机端和中性点侧3次谐波电压、基波零序电压和零序电流之间相角的变化关系。在此基础上,提出基于相角判别的新型发电机定子接地保护方向元件。该方向元件由2部分组成:对距中性点50%以内的定子绕组故障,利用机端和中性点两侧故障分量3次谐波电压的相角值相等且为负值的特点构成;对50%以上范围的定子绕组故障,由于零序故障电压和电流均相对较大,采用零序电压和零序电流相位的关系来识别故障方向。该方向元件构成原理简单,可以与目前现场应用的各种单相接地保护方案配合使用,具有较强的工程应用前景。The third-harmonic voltages at the generator neutral and the terminals, and the phase angle relationship between fundamental frequency zero-sequence voltage and zero-sequence current under different single-phase grounding faults are analyzed. According to that, a phase-angle difference direction element for generator stator grounding fault protection is presented. It consists of two parts： for fault location less than 50% of stator winding from neutral point, the direction function is based on the phase comparison of the third-harmonic voltages at the generator neutral with that at the terminals. But it cannot detect the ground fault direction near the generator terminal （for fault location larger than 50% of stator winding from neutral point）, which can be determined by the phase comparison of the fundamental frequency zero-sequence voltage with fundamental frequency zero-sequence current. Research results show the direction element can detect stator grounding faults with high sensitivity and accuracy.

关 键 词：3次谐波零序电压 基波零序电压 零序电流 定子接地保护 方向元件 故障分量 

分 类 号：TM31[电气工程—电机]