Integrated methods for voltage stability analysis of the NGC system

To address the problem of how close is the system to voltage instability, a voltage collapse margin (VCM) calculation technique has been developed. The function of the VCM is to determine the limit of active power transmission across defined boundaries before voltage collapse would occur. This paper presents an integrated approach for voltage stability analysis based on calculations carried out on the NGC system. It describes improvements on the accuracy of the VCM method as well as enhancements such as the incorporation of synchronous compensators and on-load tap changers. The paper also shows how the problem of what the contributing factors are as well as what the voltage weak areas are when voltage instability can occur, has been addressed using a singular value decomposition method.