A POWER STABILITY BASED ON DSTATCOM

This paper presents a cascaded multilevel converter (CMC)-based distribution-typeSTATCOM integrated with distribution transformer for medium voltage application. The star-connected, n-level CMC is connected to the winding taps on the primary windings of the transformer to achieve voltage stress reduction and maintain a flexible connection voltage level.Taking full use of the spare capacity of distribution transformer, a compromise between cascaded cells count and the voltage stress is achieved. The CMC-based DSTATCOM is controlled as a controlled current source to inject compensation current to the primary windings through the taps. A modified decoupled current control is proposed to control the system. Simulation model and scale-down prototype are developed to verify the performance of the proposed integrated structure. Simulation and experimental results demonstrate the good performance of the proposed structure for reactive power compensation. Keywords— Custom power, Distribution Static Compensator (DSTATCOM), Unified Power Quality compensator(UPQC), Dynamic Voltage Restorer (DVR), PowerQuality (PQ).