非全线并行架设的交、直流共用输电走廊线路间电磁耦合计算分析

Electromagnetic Coupling Calculation and Analysis of Lines Non-parallelly Erected Entirely in One Common AC/DC Transmission Corridor

为研究非全线并行架设、具有一定长度接近段的高压输电线路的电磁耦合变化规律,提出了适用于非全线并行架设的共用走廊高压输电线路电磁耦合的计算方法。通过算例,对影响共用走廊高压输电线路电磁耦合的主要因素进行了分析,结果表明：接近段长度及位置对非全线并行架设的共用走廊高压输电线路电磁耦合分量有较大影响。随着接近段长度的增加,静电感应电压、电磁感应电压和感应电流会逐渐增大。随着接近段首端与线路起点间距离的增加,线路首端、接近段两端的静电感应电压会逐渐减小,线路末端的静电感应电压则呈现先增大后减小的趋势;同时,线路首端的感应电流逐渐增大,而末端的感应电流逐渐减小,接近段两端的感应电流则先增大后减小。随着接近段与线路接地端间距的增加,电磁感应电压会逐渐减小。并计算了非全线并行架设输电走廊内直流线路接近段两端、线路两端电磁耦合分量及其沿线路的分布情况,进一步分析结果提出：对于非全线并行架设、具有一定长度接近段的交、直流输电线路,应根据线路间的电磁耦合分量水平合理选择接近段长度;接近段应选址靠近直流线路中部区域（即直流线路全长的20%～40%处）,并避免在直流线路两端有多条输电线路共用走廊的情况。

In order to analyze the electromagnetic coupling between high voltage（HV） transmission lines, which are not entirely parallel erected, and their nearby line section of a certain length, we put forward a method to calculate the electromagnetic coupling components of the HV transmission lines in a common corridor. With a case study, we analyzed the main factors affecting the electromagnetic coupling components. The length and location of nearby line section considerably influence the electromagnetic coupling components of HV line. Increasing the length will raise the electrostatic induction voltage, the electromagnetic induction voltage, and the induced current. When the distance between the head ends of the HV line and the nearby line increases, the electrostatic induction voltages at the head end of the HV line and at both terminals of the nearby line decrease gradually, while the electrostatic induction voltage at the end of the HV line firstly increases and then decreases; as for the induced currents, the one at the head ends of the HV line increases gradually, the one at the end of the HV line decreases, and the two at the two ends of the nearby line firstly increases and then decreases. Moreover, the increasing distance also decreases the electromagnetic induction voltage. We also calculated the electromagnetic coupling components at the ends of the HV line and the nearby line, as well as their distributions along the lines. The results indicate that when AC and DC transmission lines which are not in fully parallel erection but with nearby sections share a corridor, it is necessary to determine a reasonable length of the nearby section according to the electromagnetic coupling components among the lines. Furthermore, the nearby section should be close to the central part of the DC line（approximately at 20%～40% length of the DC line）, and multiple lines sharing the corridor with a DC line at its both ends should be avoided.