混合双馈入系统中VSC-HVDC对LCC-HVDC受端电网强度的影响

Influence of VSC-HVDC on the Strength of LCC-HVDC Receiving Power Grid in Hybrid Dual-infeed HVDC System

在含有LCC-HVDC和VSC-HVDC的混合双馈入系统中,LCC-HVDC受端电网电压支撑能力是影响系统稳定性的重要因素。为对电压支撑能力进行准确评估,该文借鉴单馈入LCC-HVDC系统中有效短路比和临界有效短路比的概念和计算方法,将混合双馈入系统等效为单馈入LCCHVDC系统,分析等效原则以及等效单馈入系统的参数计算方法,并提出混合双馈入系统中等效有效短路比和临界等效有效短路比的定义。机理分析和PSCAD仿真结果表明,所提指标能够准确地反应VSC-HVDC对LCC-HVDC受端电网强度的影响。

The voltage support capability of the LCCHVDC receiving power grid is an important factor affecting the stability of the system in hybrid dual-infeed system containing LCC-HVDC and VSC-HVDC. To evaluate the voltage support capability accurately, this paper referenced the concept and calculation method of the effective short circuit ratio and the critical effective short circuit ratio in a single-infeed LCCHVDC system, equivalent the hybrid dual-infeed system to a single-infeed LCC-HVDC system, analyzed the equivalence principle and the parameter calculation method of the equivalent single-infeed system, and then proposed the definition of equivalent effective short-circuit ratio and critical equivalent effective short-circuit ratio in a hybrid dual-infeed system. The mechanism analysis and PSCAD simulation results show the proposed indicator can reflect the effect of VSC-HVDC on the strength of the LCC-HVDC receiving power grid accurately.