| 引用本文: | 郝后堂,史泽兵,江卫良.重合于故障时TA饱和对差动保护的影响及对策[J].电力自动化设备,2013,33(4): |
| HAO Houtang,SHI Zebing,JIANG Weiliang.Influence of CT saturation on differential protection during faulty line reclose and countermeasure[J].Electric Power Automation Equipment,2013,33(4): |
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| 摘要: |
| 结合现场数据对传统的TA饱和判别方法——时差法（从故障发生到TA饱和，TA至少有3~5 ms的时间能正确传变一次电流）进行了理论分析，发现当线路重合于故障时，由于TA中强剩磁的极性与下次故障时短路电流产生的磁通极性相同，造成TA立即饱和，几乎没有时差，一些快速差动保护可能会误动。针对该问题，增设了一个快速差动整组复归时间T。在整组复归时间T内，快速差动保护只动作一次。理论分析表明，所提策略不会影响区内故障时差动保护快速性，同时提高了线路重合于故障、TA直接饱和时差动保护的可靠性。所提策略已成功应用于实际的保护装置中。 |
| 关键词: TA饱和 时差法 差动保护 重合闸 继电保护 |
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| Influence of CT saturation on differential protection during faulty line reclose and countermeasure |
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HAO Houtang, SHI Zebing, JIANG Weiliang
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State Grid Electric Power Research Institute，Nanjing 210003，China
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| Abstract: |
| The time difference method，a traditional way to identify CT saturation since CT may exactly transfer the primary current within 3 to 5 ms after fault，is theoretically analyzed based on site data. It shows that，in case of faulty line reclose，the polarity of CT strong remanence and that of the magnetic flux generated by following fault current are same and CT saturation occurs without time difference，which may result in the misoperation of fast differential protection. A complete-set resetting time T is proposed，within which，the fast differential protection operates only once. Theoretical analysis shows that，the rapidity of the differential protection for the faults inside the protection zone is not influenced by the resetting time while its reliability is enhanced in case of faulty line reclose or CT saturation. The proposed strategy is successfully applied in actual protection devices. |
| Key words: CT saturation time difference method differential protection reclose relay protection |
