| 引用本文: | 陈 俊,王昀帆,严 伟,沈全荣.励磁变压器低压侧单相接地故障在线识别方法[J].电力自动化设备,2014,34(11): |
| CHEN Jun,WANG Yunfan,YAN Wei,SHEN Quanrong.Online identification of single-phase grounding fault at low-voltage side of excitation transformer[J].Electric Power Automation Equipment,2014,34(11): |
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| 摘要: |
| 励磁变压器低压侧单相接地故障时，乒乓式转子接地保护原理也能检测到对地绝缘电阻下降，并且计算的励磁绕组一点接地位置百分比为50 %，可能会误导故障排查的方向。因此提出了一种励磁变压器低压侧单相接地故障在线识别方法，当励磁绕组一点接地电阻计算值小于定值，接地故障位置计算值在50 % 左右，且励磁绕组正、负端对地电压的基波有效值中的较大值与励磁电压的比值超过设定值时，则认为励磁变压器低压侧发生了单相接地故障。理论分析和现场录波数据验证了所提方法的正确性。 |
| 关键词: 励磁变压器 单相接地故障 在线识别 故障定位 继电保护 乒乓式转子接地保护 |
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| Online identification of single-phase grounding fault at low-voltage side of excitation transformer |
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CHEN Jun, WANG Yunfan, YAN Wei, SHEN Quanrong
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Nari-Relays Electric Co.，Ltd.，Nanjing 211102，China
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| Abstract: |
| When single-phase grounding fault occurs at the low-voltage side of excitation transformer，the ping-pong type rotor grounding fault protection may detect the reduction of grounding insulation resistance and misconstrue it as the single-point grounding fault of excitation winding with location percentage of 50 %. A method to online identify the single-phase grounding fault at the low-voltage side of excitation transformer is proposed. The criteria are：the calculated rotor winding grounding resistance is smaller than the setting value；the grounding location percentage is about 50 %；and the ratio of the fundamental voltage at any terminal of excitation winding to the excitation voltage is larger than the setting value. Theoretical analysis and field waveform records prove its correctness. |
| Key words: excitation transformer single-phase grounding fault online identification electric fault location relay protection ping-pong type rotor grounding fault protection |
