基于混合换流器的多端交直流系统潮流计算

基于电网换相换流器(LCC)和基于电压源换流器(VSC)在稳态模型和工作原理上有本质的不同,当这2种换流器混合运用于同一个多端直流输电系统,系统的稳态数学模型和潮流计算方法也发生了相应的变化。首先描述了该混合多端交直流系统的稳态模型,然后在综合考虑2种换流器工作原理的基础上,导出了该混合系统的潮流计算数学模型。为实现系统的功率平衡和保证各换流器有一定的裕度配合运行,分析了混合系统控制方式的配置原则,利用牛顿法得到了一种适用于该系统的交替求解算法,并给出了算法的具体实现步骤。最后,分别通过两端和多端的混合直流输电系统算例验证了该算法的准确性和有效性。

Power flow calculation of multi terminal AC / DC system based on hybrid converter

LCC and VSC are essentially different in the steady-state model and working principle. When the two converters are mixed and applied to the same multi-terminal HVDC transmission system, the steady-state mathematical model and the power flow calculation method have also changed accordingly. This paper first describes the steady-state model of the hybrid system. Then, based on the comprehensive consideration of the working principle and control mode of the two converters, the mathematical model of the power flow calculation of the hybrid system is derived. Furthermore, an alternating solution algorithm suitable for the hybrid system is proposed. Finally, the effectiveness and accuracy of the proposed algorithm are verified by a hybrid DC transmission system example and a hybrid three-terminal system.