Research on control technology for AC filters based on voltage follow strategy

The AC filter in the converter station is equipped with energy storage components such as capacitors. When the capacitors are charged and put into operation, they will generate high surge currents, endangering equipment safety. After cutting them off, the capacitors need to be discharged to the threshold before they can be put back into operation. Studying the technology of live input control for AC filters has positive significance for improving the efficiency of AC filter usage. In the article, the research object was first determined based on the type of AC filter in the converter station. According to the influence of different closing times on the electrical impact of filter components, a live input control technology for AC filters was proposed. It can record the voltage amplitude of the capacitor at the time of filter opening, calculate the voltage amplitude for closing again based on the discharge time curve, and control the circuit breaker to close at the phase corresponding to this voltage amplitude, which can effectively reduce the closing current of the capacitor. And the effectiveness of the strategy was verified through modeling and simulation.