Voltage Support Control Strategy for Distributed Synchronous Condenser Based on an Excitation System with Full-Controlled Devices

With the development of large-scale renewable energy connections to the grid and ultra-high voltage direct current transmission, the lack of dynamic reactive power compensation and voltage support capacity has become an important problem for power systems. Equipping with small-capacity distributed synchronous condensers in new energy sites can provide sufficient reactive power backup capacity, which will help to recover fault currents quickly. This paper applies the excitation system with full-controlled devices to the distributed synchronous condenser to improve the dynamic reactive power compensation capacity and achieve strong voltage support. Firstly, a mathematical model of the single machine-infinite bus system with the proposed condenser is established. Secondly, its voltage support control strategy is studied; then, the mathematical modeling and parameter design are carried out for the automatic voltage regulator and reactive power injection controller, respectively. After multi-case simulation, it is verified that the proposed condenser has better dynamic reactive power performance and voltage support capability than the distributed synchronous condenser with a conventional excitation system.