500kV同杆并架线路感应电压和电流的计算分析

Calculation of Inductive Voltage and Current for 500 kV Double Circuits Transmission Lines on Single Tower

鉴于同杆并架双回线路线间耦合性很强,当一回运行,另一回停运线路上会有较高感应电压和感应电流,为保证线路检修人员的安全工作,通过理论分析计算分析了同杆双回停运线路上的感应电压和感应电流。分析表明:电磁感应电流与运行线路输送的功率基本呈正比例关系,与线路长度无关,电磁感应电压与运行线路输送的功率及线路长度基本呈正比例关系;静电感应电流与线路长度基本呈正比例关系,与运行线路输送的功率无关,静电感应电压与运行线路输送的功率及线路长度的关系不大;通过在停运线路首末端接地及中间点挂接地线,可有效减小停运线路上沿线的感应电压,在检修点加接地线对减小该点的感应电压尤为有效;流过接地线的电流与接地线的位置关系不大,换位对感应电压的改善效果不明显,但换位后对流过接地开关的电流改善显著,而且完全换位次数越多,改善效果越好。

Coupling between phase lines is strong in 500 kV double circuits on single tower. There are higher inductive voltages and inductive currents on the non-energized lines while another line is energized. On the basis of theoretical analysis, inductive voltage and inductive current are calculated by the EMTP programme. According to simulation results, conclusion can he drawn as follows： both electromagnetic inductive current and electromagnetic indue tive current are directly proportional to power which is transmitted on energized line; both electromagnetic inductive voltage and electrostatic inductive current are directly proportional to length of transmission lines; Electrostatic in ductive current has no connection with power which is transmitted in energized line; Electrostatic inductive voltage has no connection with power and length. Current on earth lines has no connection with location of earth lines. Transposed lines can not reduce inductive voltage over non-energized lines, but can reduce inductive current on non-energized lines greatly.