Generation re-dispatch algorithm against voltage collapse in Jeju island system with a frequency control by high-voltage direct current

A new algorithm for the determination of adequate generation re-dispatch as a protective measure against voltage instability is presented in this study. The study applies the method to the Jeju island system in Korea with a frequency control by the current sourced converter (CSC) high-voltage direct current (HVDC) system, which regulates the local system frequency by the active power injection from the mainland system. In order to transfer the active power using the CSC HVDC system, reactive power consumption is essential, and the frequency control of the HVDC is very fast. Therefore voltage instability may occur if the dynamic reactive support is not enough in the local power system at severe contingencies such as generator's outages. The authors suggest generation against voltage curves (g-V curves), constructed by generation continuation power flow, and propose the procedure to determine voltage stability limit of active power generation at each generator using g-V curves. An illustrative example of the proposed algorithm is shown as applied to the Jeju island system.