Stability Analysis of VSC back-to-back link taking into consideration adjacent AC systems of arbitrary configuration

Abstract

The VSC back-to-back HVDC link control system stability analysis technique using D-decomposition method is proposed. Linearized mathematical model, including VSC back-to-back model, control system and adjacent power systems models is developed. The equation for calculating the frequency response and the natural frequency of VSC back-to-back, taking into account adjacent AC networks configurations were obtained. The calculations of VSC back-to-back control system stability region using the developed methodology were performed. It is shown that resonance phenomena inherent in circuits contacting VSC with PWM have the most important influence on the of the stability region limits. A good agreement between the results of analytical calculations and digital simulation confirms the correctness of the developed stability analysis method. The developed technique is suitable for analyzing the stability of VSC – as a basis element of HVDC power transmission and STATCOMs.