A unified power quality conditioner for the fault ride-through operation of photovoltaic power station

This paper presents a unified power quality conditioner (UPQC) and its control strategy for assisting the fault ride-through operation of large-scale photovoltaic (PV) power station. The output voltage of PV station can be controlled to its rated value with UPQC under high grid voltage fault condition. Moreover, it can absorb reactive power from the grid under high voltage condition to support the grid voltage recovery without reducing the injected real power from PV station. The UPQC could also compensate the grid harmonic voltages under various operation conditions, which in consequence can minimize the response time of phase-locked-loops (PLL) embedded in the control loop of grid-tied PV inverters. The UPQC helps the PV station output the required reactive power for enhancing the low voltage ride through performance. Furthermore, the performance of proposed UPQC system with a 100MW grid-tied PV station has been verified by MATLAB/SIMULINK.