Voltage Stability Assessment with Multi-infeed High-voltage DC Based on Voltage/Power Characteristics of Dynamic Reactive Power Sources

Abstract

Voltage security is extensively concerned with the development of power systems, especially in multi-infeed high-voltage DC systems. For predicting voltage stability robustness of a power system, various voltage stability assessments have been proposed to search for weak buses and areas. However, these assessments are only related to network topology, time-consuming, or suitable only for high-voltage DC voltage stability analysis. Therefore, the extended voltage sensitivity factor, an improved voltage stability assessment that considers voltage/power characteristics of dynamic reactive power sources, is proposed and formulated based on a matrix elimination method in this article. Sensitivities of high-voltage DC and dynamic reactive power sources, are derived in detail. And a generalized algorithm of the extended voltage sensitivity factor is proposed for all buses in different grid scales with rapid solution. Afterward, some examples are illustrated and analyzed at different conditions that are related to AC system effective short capacity, high-voltage DC current, or system loads. In addition, compared with voltage sensitivity factor and L-index, the extended voltage sensitivity factor is more accurate and sensitive in identifying weak buses. The extended voltage sensitivity factor indicator is proved as an effective assessment for voltage stability analysis and weak bus identification.