Vx接线组合式同相供电系统建模与分析

作为新一代牵引供电系统的关键技术，同相供电系统设计需要匹配牵引变压器接线方式，优化电能质量综合补偿策略，降低潮流控制器（PFC）容量及其造价。针对高速和重载铁路推广采用的自耦变压器（AT）供电方式和Vx接线牵引变压器，设计了一种组合式同相供电系统。首先，基于该系统各端口接线角关系，建立了三相电网与单相牵引负荷之间的电气量变换模型；其次，利用三相电压不平衡与无功功率综合补偿理论，将相关电能质量限值为约束条件，给出了组合式同相供电系统各端口补偿电流计算方法，提出了潮流控制器动态跟踪补偿控制方案，与已有补偿方案相比，在达到相同补偿目标时所需补偿容量可以减少10%~58%；最后，通过对多种牵引负荷工况下系统运行特性的仿真模拟，验证了上述补偿模型的正确性和控制策略的有效性。 

Modelling and Analysis of Combined Co-phase Traction Power Supply System Based on Vx Connection Traction Transformer

As the key technology of new generation traction power supply system,the design of co-phase traction power supply system should match different connection traction transformers to optimize the comprehensive compensation strategy of power quality and reduce the capacity and cost of power flow controller (PFC) . A new scheme of combined co-phase traction power supply system was developed for high-speed and heavy-haul railways, which adopts auto-transformer (AT)traction mode and Vx connection transformer. First, based on the relationship of the connection angles of different ports, the model for the electrical parameter transformation between three-phase power grid and single-phase traction load was built. Second, according to the principle of comprehensive compensation of three-phase unbalanced voltage and reactive power, the operation current calculation formula for each port was deduced with the limited power quality as a constraint. Further, the dynamic compensation control scheme of PFC was presented. Compared with the current compensation schemes, it can ensure the compensation targets with the decrease of 10%-58% in the compensation capacity. Finally, the compensation model and control strategy are verified by the simulation on the operating characteristics of the proposed system under different loads verified .