750 kV系统线路侧断路器取消合闸电阻可行性研究

Study on the Feasibility of Cancelling the Circuit-breaker Pre-inset Resistor at 750 k V Overhead Transmission Line

以榆横—延安750 k V架空输电线路为工程背景,研究取消线路侧断路器合闸电阻的可行性。根据2014年的实际运行数据建立了系统不同运行方式下的ATP-EMTP仿真计算模型,并进行了多种运行方式下不同避雷器配置下的合空线和不同故障状态下的单相重合闸操作。计算结果表明:在80%高抗补偿下仅加装合闸电阻就可将合空线操作及成功重合闸操作时沿线最大2%操作过电压降低到1.8 p.u.以下;在80%高抗补偿下仅采用避雷器配置时,合空线操作、Ⅱ回线路停运两端不接地时成功重合闸操作和无功送端带有永久接地故障不成功重合闸时沿线最大2%操作过电压仍会超过1.8 p.u.;在80%高抗补偿下加装合闸电阻且线路两端配备648MOA时,对于合空线操作、成功重合闸操作和线路中点带有永久接地故障不成功重合闸时可将沿线最大2%操作过电压降至1.8 p.u.以下。因此,为适应系统各种操作方式线路侧断路器合闸电阻不能取消。

Taking the Yuheng -Yan＇an 750 kV electric transmission line for example, different ATP-EMTP models with different operation modes are built based on the actual data in 2014. Closing no-load line operation with different MOA settings and single-phase reclosing operation with different fault conditions are performed. Computation results show that： 1）in the case of equipping a reactor with 80% compensation degree, the application of only a pre-inset resistor can reduce the maximum 2% switching overvohage to under 1.8 p.u. in the operations of closing no-load line and successful reclosing; 2）when only different MOAs are equipped, the maximum 2% switching overvohage is greater than 1.8 p.u. in the operations of closing no-load line, successful reclosing, and unsuccessful reclosing with an earth point at the reactive power sending end when the circuit Ⅱ is in normal operation condition; and 3）when a pre-inset resistor and 648MOA at each end of the line are equipped, the maximum 2% switching overvoltage is under 1.8 p.u. in the operations of closing no-load line, successful reclosing, and unsuccessful reclosing with an earth point in the middle of the line. Consequently, it is concluded that the pre-inset resistor of circuit-breaker cannot be cancelled.