Application of Back-to-Back VSC-HVDC in Power Grids Synchronization Parallel Operation

This paper introduces present situation of power grid synchronization parallel operation, and analyzes the principle and characteristics of back-to-back commutation mode and VSC-HVDC. Back-to-back VSC-HVDC is proposed in this paper, which can be used in the power grid synchronization parallel operation. Its working principle is that the difference of frequency and voltage can be regulated by means of respectively controlling the direction and magnitude of active power and reactive power which are exchanged between the two power grids. The method can be used to achieve differential-frequency paralleling and same-frequency paralleling operation between two power grids. Under normal operating condition, it can be used for reactive power compensation. Simulation results demonstrate the validity of the method.