单回800kV直流线路与双回500kV交流线路同塔架设的电磁暂态仿真研究

Simulation Study on Electromagnetic Transient of Single Circuit ±800 kV DC Transmission Line and Double Circuit of 500kV AC Transmission Lines Erected on Same Tower

针对单回800 kV直流线路与双回500 kV交流线路同塔架设的具体工况,通过模拟交直流系统各种严重故障,对交直流系统的相互影响进行了详细的电磁暂态仿真,分别考虑了不同的同塔位置及长度,主要研究了单回800kV直流线路与双回500 kV交流线路同塔架设对交直流线路过电压水平的影响以及对交流线路潜供电流和恢复电压的影响。研究结果表明,交直流同塔架设对交直流系统过电压水平影响较小,可以与单独架设选用相同的绝缘配合方案。当单端挂高抗且不换位的交流线路与直流线路同塔架设时,其潜供电流将有很难熄灭的可能,需在设计中考虑相应解决措施。

Based on concrete operational condition of single circuit ±800 kV DC transmission line and double circuit 500 kV AC transmission lines erected on the same tower,by means of simulating various serious faults occurred in AC and DC transmission systems the detailed electromagnetic transient simulation is performed to research the interaction between AC and DC transmission systems.Considering different positions on the tower where the transmission lines are erected and the lengths of transmission lines,the impacts of such a erection mode,namely single circuit ±800 kV DC transmission line and double circuit 500kV AC transmission lines on the same tower, on overvoltage levels of DC and AC transmission lines as well as the impacts on the secondary arc current and the recovery voltage of AC transmission lines are respectively studied. Simulation results show that such a erection mode of transmission lines slightly affects respective overvoltage levels of UHVDC and EHVAC transmission lines,thus the insulation coordination schemes for separately erected UHVDC transmission line and EHVAC transmission line can be continually utilized.When non-transposed EHVAC transmission line,configured with high voltage reactor at one terminal,is erected on the same tower with UHVDC transmission line,the EHVAC transmission line has to be faced with such a situation that the secondary arc current is difficult to be extinguished,thus it is necessary to consider countermeasure during the design.