多换流器并联的交直流配电网潮流计算方法

Power flow calculation method for AC-DC hybrid distribution network with multi-converter in parallel

针对多换流器并联的交直流配电网潮流计算展开研究,提出了基于虚拟主从策略的潮流计算方法。将多换流器并联的直流母线视为平衡节点,利用该节点上的功率平衡方程以及Udc=f(P)下垂特性方程,将首编号换流器定义为虚拟主换流器,推导得到其功率与其他换流器下垂特性曲线的关系式,实现该换流器功率与母线直流电压的求解;将其他换流器定位为虚拟从换流器,按照P=f(Udc)下垂曲线进行功率更新,解决了多换流器同时控制平衡节点电压的潮流计算难题。通过算例测试验证了所提算法的有效性和正确性。

The power flow calculation for AC-DC hybrid distribution network with multi-converter in parallel is stu- died, and a power flow calculation method based on virtual master-slave strategy is proposed. The DC bus with multi- converter in parallel is regarded as the balance node, whose power balance equation and the droop characteristic equation of Udc=f（P） are used to define the converter with the first numbered node as the virtual master converter. The relational expression between the power of virtual master converter and droop characteristic curves of other con- verters is derived and the power of virtual master converter and DC voltage of the bus are solved. The other conver- ters are defined as the virtual slave converters ,whose power are updated according to the droop characteristic equa- tion of P =f（ Udc）. Then, the power flow calculation problem that the voltage of balance node is controlled by multi- ple converters at the same time is solved. The validity and correctness of the proposed calculation method are verified by the case study.