Transient Control Optimization of SVG in Renewable Power Collection System

The unbalance between reactive power and voltage in renewable energy collection system restricts sending capability and becomes one of the most concerned problems. However, many Static Var Generators (SVGs) installed in renewable energy stations is difficult to meet the expected demand in application, especially during the fault period. They usually couldn't offer the rated capacity of the reactive power to support voltage during the fault, and might increase the system overvoltage after the clearance of earth fault. In this paper, the SVG controller hardware-in-loop simulation platform is built first. And based on the simulation analysis, the reactive power response characteristics of SVG under different control modes during fault and after the clearance of the fault are explored. Then the standard mathematical model of SVG is established to build SVG electromagnetic transient simulation model whose reactive power characteristics is consistent with the hardware controller. Finally, an optimized control strategy of reactive power compensation is proposed. With the optimized strategy, SVG can do best to support voltage during the fault and will not be locked because of the overvoltage at DC side. At the same time, the overvoltage after clearance of fault will be inhibited. The effectiveness of the proposed control strategy is verified by the simulation.