Grid-supporting control strategy in Chongqing-Hubei Back-to-Back HVDC Project of China

Abstract

To resolve the instability problem of the current vector control strategy in the converter station of Shizhou when an N-2 fault occurs during the maintenance of Enshi power grid in Chongqing-Hubei Back-to-Back HVDC project (referred to as “Chongqing-Hubei project”), a new grid-support control strategy is proposed in this research. This strategy simulates the characteristics of the synchronous generator to generate its phase. By adjusting the phase and amplitude of the output voltage, it can flexibly adjust the output of active power and reactive power and realize the frequency and voltage support of the power grid. At the same time, it solves the problem of DC instability when the AC power grid is disturbed and ensures the stable operation of the system. PSCAD/EMTDC simulation test and application in Chongqing-Hubei engineering field verify the effectiveness of this strategy. The grid-supporting control strategy provides technical support for weak system access, inertia compensation and voltage support in the future new energy field.