Two-Level Control Method for DPFC Series Units Based on PLC Communication

摘要

Distributed Power Flow Controller (DPFC) is expected to be used for improving the performance of power flow control in AC transmission power system. In this paper, a two-level control scheme for DPFC series units is proposed. The two-level control system consists of an upper-level controller, multiple lower-level series unit controllers and unidirectional power line carrier (PLC) communication link. The reference value of series compensated voltage is calculated by the top-level controller according to the power flow ordered by dispatch center and transferred to series units via PLC communication link. A corresponding compensated voltage will then be generated in series units. Comparing the reference value of the compensated voltage with actual value, the modulation signal of converter in series unit will be modified through PI control. The model of an AC transmission system at high-level voltage involved with DPFC is built in PSCAD/EMTDC. The simulation results indicate that the proposed two-level control method for DPFC series units is flexible and effective.