Hybrid Reactive Power Compensator Based On Voltage Regulation

Reactive power compensation is critical to the economic operation of the power grid. In recent years, with the continuous development of technology and the increasing utilization of new energy sources, the pattern of the power system is rapidly changing, such as the increasing penetration of solar energy, wind power and other distributed power sources, as well as the widespread of electrified railways and other applications. These changes will bring new challenges to the reliability and stability of power grid, thus yeilding higher functions for reactive power compensation technology.In this thesis, a newly designed Inductive Reactive Power Compensator (IRPC) is proposed based on voltage source inverter in order to achieve low-cost high-capacity reactive power compensation. Comparing to the topology of traditional STATCOM, inductance of the reactor in IRPC between the inverter and the bus is designed to be larger. Indirect current control is used as control strategy of IRPC enabling fast compensation, lower voltage stress, and simplified control. Furthermore, a Hybrid Var Compensator (HVC) is proposed in this paper, which featuring the coordinate operation of IRPC and multi-level thyristor switched capacitor sets. And the proposed compensation system takes into account the characteristics of IRPC and TSC, making it present fast response, obvious conpensation effect and economic efficiency.Finally, based on PSCAD/EMTDC, similations on IRPC,TSC sets and hybrid reactive power compensation system are carried out. The output characteristics of IRPC and the operation of TSC sets are analyzed respectively. Moreover, simulations on HVC based on coordinate control is also carried out.The feasibility of the proposed HVC is verified according to satisfying outcome of the simulations.