Research on Compensation Strategies for DFACTS with Insufficient Capacity

DFACTS device is used in the distribution network to compensate for reactive power, harmonics and negative sequence currents. If simple current limiting measures are adopted in the condition of DFACTS with insufficient capacity, the compensation current waveform will be distorted, which will have adverse effects on the system. In order to solve this problem, this paper proposes three kinds of compensation strategies: reactive power priority, harmonic priority and adaptive comprehensive compensation strategies. The reactive power priority or harmonic priority compensation strategy uses the limited capacity of DFACTS to compensate reactive power or harmonics, the residual capacity of DFACTS compensates the specified harmonics or reactive power. The adaptive comprehensive compensation strategy is to set firstly the compensation weight coefficients of reactive power, harmonics and negative sequence current, and to consider comprehensively the deviation of the compensation quantity, finely to allocate adaptively the three kinds of compensation quantity. Simulation results verify the feasibility and effectiveness of the proposed compensation strategies and control algorithms.