同相牵引供电系统平衡补偿的最优模型

Optimal Compensation Models in Cophase Power Supply System

为消除同相牵引供电系统中的三相不平衡、滤除谐波、补偿无功,讨论了平衡变换的两种最优补偿模型:以波形质量最优为目标的波形畸变最小模型和以获得最佳负载为目标的最佳负载模型.通过仿真分析了系统电压畸变时两种补偿模型的补偿效果.结果表明,波形畸变最小模型使系统只提供负载所需要的基波有功电流,最佳负载模型将不对称的单相负载变成三相(或两相或四相)对称纯阻性负载.在三相系统电压对称无谐波时,两者补偿特性一致;当三相系统电压不对称有谐波时,两者补偿特性有区别.

To balance the three phases, filter the harmonics and compensate the reactive power in a cophase power supply system, two optimal compensation models were proposed： the minimum waveform distortion model, which can get best waveform quality, and the optimum resistance model, which can get optimum load. Then, the compensation effects of the two models with distortion voltages were analyzed by simulation. The results show that the former can only get fundamental active current, and the latter can transform an unbalanced single phase into a balanced three-（ or two- or four-） phase resistant load. The two models have the same compensation characteristics under voltages without distortion and unbalance, and there are differences under voltages with distortion and unbalance.