基于不对称参数补偿的同塔六回输电线路不平衡问题抑制

为了解决同塔六回输电线路存在的三相不平衡问题,首先对线路阻抗矩阵进行解耦计算,推导出负序、零序电流表达式,然后提出基于线路不对称参数补偿的不平衡抑制方法,理论计算了补偿电容参数,最后以广东某同塔六回输电线路为例,在PSCAD环境下进行仿真分析。结果表明,对于同塔六回输电线路,优化导线间距、优化相序布置等方法仍无法使不平衡度达到要求时,考虑合理配置补偿电容补偿线路不对称参数能够进一步减小线路不平衡度,该结论对同塔六回或更高回输电线路的不平衡抑制问题有实际指导意义。

Unbalance Suppression of Six-circuit Transmission Lines on Same Tower Based on Asymmetrical Parameters Compensation

In order to solve the problem of three-phase unbalance of six-circuit transmission lines on the same tower, firstly decoupling calculation of the line impedance matrix is carried out and the expressions of the sequence currents are deduced. Then a method of eliminating unbalance based on compensation of asymmetrical line parameters is proposed, with the parameters of compensation capacitors calculated in theory. Finally, based on an actual project of six-circuit transmission lines on the same tower in Guangdong Province, corresponding simulation is done using the software of PSCAD. Results show that unbalance of six-circuit transmission lines on the same tower are still not able to meet the requirements with the methods of optimizing wire spacing, optimal layout of line phase sequences, etc. So the method of allocating compensation capacitors appropriately should be considered to further reduce the line unbalance. This conclusion has a certain practical significance for eliminating the unbalance of six or more circuit transmission lines on the same tower. This work is supported by National Natural Science Foundation of China (No. 51177098), Innovation Program of Shanghai Municipal Education Commission (No. 12YZ138) and Shanghai Natural Science Foundation (No. 15ZR1418000, No. 15ZR1418200).