The Research And Optimization Of10kV/1MVA Unified Power Flow Controller With Solid-state Fault Current Limitter

Unified Power Flow Controller (UPFC) is currently the most powerful flexible AC transmission system device, which can adjust the line voltage, impedance and phase angle, flexibly control the power flow, voltage and reactive power in power system, increase the transmission capability, improve the operation quality of power system, causing widespread concern in academic circles. In order to effectively solve the problem that short-circuit current brings to power electronic devices in UPFC, a novel flexible AC transmission system is put forward:unified power flow controller with fault current limitting(referred to as current limiting type UPFC, or UPFC-FCL), which integrates the function of UPFC and bridge fault current limiter, can operate in the mode of UPFC in normal situation, and effectively deal with the system fault in short circuit.In this paper, on the basis of existing research, the main parameters of UPFC-FCL are optimized, the selection and design principles of the current limit inductor according to different occasions are put forward, the design and verification of DC capacitor is presented, the selection criteria of the series transformer is carried out, and on the foundation of reliability, this paper improves the economy of UPFC; the10kV testing program is made out, a variety of DC side overvoltage protection scheme are optimized, and on this basis the medium voltage test is operated, lying the foundation of the10kV prototype test and engineering application; in view of the existing problems, put forward a new thought of improvement of UPFC-FCL, and carry out the simulation and verification, providing an idea for current limiting type series FACTS devices in power system.