| 摘要: |
| 由于对供电可靠性的要求越来越高，有必要研究在电流互感器（TA）断线情况下发生故障时，距离保护的动作行为。基于保护安装处测得的故障回路电阻，分析了TA断线对接地距离保护的影响。由分析可知，接地距离保护受潮流方向和故障相别影响：在电源侧，当相位超前于断线相的相别发生区内故障时，接地距离保护容易拒动，当相位滞后于断线相的相别发生区外故障时，接地距离保护容易误动；而负荷侧的接地距离保护动作情况与电源侧相反。结合TA断线识别方法提出了自适应接地距离保护方案，并对方案进行了理论分析和试验验证；针对TA回路和保护配置给出了改进建议。 |
| 关键词: 继电保护 TA断线 接地距离保护 超越动作 拒动 接地 |
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| Improvement of grounding-fault distance protection under CT disconnection |
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CHEN Fufeng
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Guodian Nanjing Automation Co.，Ltd.，Nanjing 210003，China
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| Abstract: |
| The behavior of distance protection under CT（Current Transformer） disconnection is studied and its influence is analyzed based on the fault-circuit resistance measured by the protection，which shows that the influencing factors are the direction of power flow and the position of faulty phase. At the power-source side，the grounding-fault distance protection tends towards the miss operation when the in-zone fault occurs in the leading phase relative to the phase of CT disconnection and towards the improper operation when the out-zone fault occurs in the lagging phase relative to the phase of CT disconnection，while it behaviors on the contrary at the load side. Combined with the method of CT disconnection detection，an adaptive grounding-fault distance protection scheme is proposed，which is theoretically analyzed and verified by the test. Suggestions are given on the CT circuit and protection configuration. |
| Key words: relay protection CT disconnection grounding-fault distance protection overstepped action miss operation electric grounding |
