A Static Voltage Stability Enhancement Method for Power Systems With a High Proportion of Voltage Source Converters

One of the main characteristics of power systems with a high proportion of renewable energy is that the power system is becoming a power system with a high proportion of voltage source converters (VSCs). Owing to the current limitation of VSCs, the reactive power regulation range is limited, thus greatly weakening the effective reactive power reserve and reducing the static voltage stability. In this paper, the PQ regulation characteristics of the VSC are first analyzed considering the current limitation. By establishing the PQ characteristic analytical model of a single grid-connected VSC system, the changes in the system reactive power reserve and system static voltage stability evolution law under different penetration ratios of VSCs are analyzed. On this basis, according to the proposed reactive power support sensitivity of each source bus, it is proposed to optimally determine the voltage and effective reactive power reserve of each source bus to realize effective enhancement of the static voltage stability margin of the power system with a high proportion of VSCs. Simulation analyses are carried out in a system with multiple grid-connected VSCs and an extended IEEE-39 bus system, which validate the effectiveness and accuracy of the proposed method.