耦合地线对交直流同塔输电线路电气特性的影响及规律分析

Analysis on Influences and Regularity of Coupling Ground Wires on Electrical Characteristics of HVAC and HVDC Transmission Lines on Same Tower

为充分利用架空线路走廊,交直流同塔输电将是电网未来发展的趋势,开展同塔交直流线路间电磁耦合干扰研究具有重要意义。建立了双回交流与单回直流同塔输电线路耦合模型,计算分析了在直流线路下方架设耦合地线时,耦合地线根数、耦合地线与直流线路垂直间距、耦合地线横向位置、耦合地线横向间距以及耦合地线排列方式等因素对直流线路上感应电压的影响。研究结果表明:耦合地线根数越多,屏蔽效果越好,耦合地线根数达到一定数量时,屏蔽效果将趋于饱和;耦合地线距离直流线路越近,屏蔽效果越好;耦合地线水平排列时,屏蔽效果最好。

To fully utilize the corridor for overhead transmission lines, the erection of HVAC and HVDC transmission lines on the same tower will be widely adopted in future, so the research on interference due to electromagnetic coupling between HVAC and HVDC transmission lines erected on the same tower is of significance. Using PSCAD/EMTDC, a coupling model containing two circuits of HVAC transmission lines and single circuit of HVDC transmission lines erected on the same tower is established. When coupling ground wires are erected beneath HVDC transmission line, the influences of the number of coupling ground wires, the vertical interval between coupling ground wires and HVDC line, the lateral position of coupling ground wires, the lateral spacing among coupling ground wires and the arrangement of coupling ground wires on the voltage induced on HVDC transmission line are simulated and analyzed. Research results show that the more the number of coupling ground wires, the better the shielding effect will be, and when the number of coupling ground wires reaches a certain amount the shielding effect tends to be saturated; the nearer the coupling ground wires to HVDC line, the better the shielding effect will be; when coupling ground wires are arranged horizontally, the best shielding effect can be attained.