考虑参数空间潮流可行域的交直流混合微电网下垂系数选取

孤岛运行模式下,交直流混合微电网中的分布式电源逆变器的下垂系数会影响系统潮流可行域,而传统的下垂系数由逆变器的容量、频率和电压调节范围决定,并未充分考虑这一影响。针对上述问题,首先建立了考虑逆变器控制方式的交直流混合微电网潮流计算模型,基于此提出了参数空间下的潮流可行域快速计算方法,进一步分析了下垂系数对潮流可行域的影响,综合考虑负荷稳定裕度和小信号稳定因素求取下垂系数最优值。最后,针对改进的12节点的交直流混合微电网算例进行仿真计算,验证了所提方法的有效性与适用性,与传统方法相比系统电压稳定裕度显著提升。

Selection of Droop Coefficients for AC/DC Hybrid Microgrid Considering Feasibility Region of Power Flow in Parameter Space

Droop coefficients of inverters for distributed generators in AC/DC hybrid microgrid can have great influences on feasibility region of power flow in island operation mode. While traditional droop coefficients are determined by capacity and frequency of inverters and voltage regulation range, which can not give full consideration of the above influence. To fill the gap, a calculation model for power flow of AC/DC hybrid microgrid considering control modes of inverter is firstly established. Then a fast calculation method of feasibility region of power flow in parameter space is proposed, the impact of droop coefficients on feasibility region of power flow is further considered. The optimal values of droop coefficients are suggested by overall considering both load stability margin and small-signal stability factors. Finally, an improved 12-node AC/DC hybrid microgrid is simulated to verify the effectiveness and applicability of the proposed method. Results show that the voltage stability margin is significantly increased compared with traditional methods.