Research on Control Strategy of Back-to-back VSC and Its Isolation Ability to Power Quality Problems

With the application of power electronic equipment in the distribution network, it has brought many benefits to the safe and reliable operation of the traditional distribution network and promoted the development of the intelligent distribution network. Soft normally open point(SNOP) is a new type of power electronic equipment that replaces traditional mechanical switches. As a kind of SNOP, back-to-back voltage source converter (B2B VSC), may replace some interconnection switches or section switches in the traditional distribution network in the future, improving the flexibility of the distribution network operation. The operation mode of B2B VSC and the control strategy under different working conditions are described in detail. In view of the typical power quality problems in distribution network, the isolation ability of B2B VSC to typical power quality problems is discussed, and finally verified by simulation and experiment.