混合双馈入直流输电系统的交互作用机理研究(二):小干扰稳定裕度分析

Research on Interaction Mechanism of Hybrid Dual-infeed HVDC System(Part Ⅱ):Small-signal Stability Margin Analysis

针对由电网换相换流器型高压直流输电(line commutated converter based high voltage direct current,LCC-HVDC)系统和电压源换流器型高压直流输电(voltage source converter based high voltage direct current,VSC-HVDC)系统构成的混合双馈入直流输电系统,基于推导建立的等值单馈入直流输电模型,采用增益裕度(gain margin,GM)指标、相位裕度(phase margin,PM)指标和灵敏度函数最大峰值指标Ms,定量评估交流系统强度、LCC-HVDC子系统的定关断角和锁相环,以及VSC-HVDC子系统的外环功率控制器、内环电流控制器和锁相环对混合双馈入直流输电系统稳定裕度的影响规律;最后,通过PSCAD/EMTDC下的详细电磁暂态详细仿真,验证所建立单馈入直流输电模型的有效性及理论分析结果的正确性。

The equivalent single-infeed HVDC model of the hybrid dual-infeed HVDC system which consists of line commutated converter based high voltage direct current(LCC-HVDC) and voltage source converter based high voltage direct current(VSC-HVDC) was deduced. Then, the influence of stability margin for the hybrid dual-infeed HVDC system with different AC system strength, different control parameters of constant extinction angle controller and phase locked loop(PLL) of LCC-HVDC subsystem and different control parameters of outer-loop power controller, inner-loop current controller and PLL of VSC-HVDC subsystem was quantitatively evaluated by gain margin(GM) index, phase margin(PM) index and maximum peak index of sensitivity function. Finally, the effectiveness of the theoretical analysis results was validated by a detailed dual-infeed hybrid HVDC electromagnetism transient model in PSCAD/EMTDC.