Modeling analysis and design of series injection transformer in UPQC

In order to get rid of the blindness in series injection transformer design because of lacking of national standards, this paper, based on the analysis of the work principle of injection transformer, establishes equivalent circuit and deduces transfer function and analyses the effect of parameters of injection transformer on the compensation characteristic of the unified power quality conditioner(UPQC). The selection principle of parameters including injection transformer capacity, ratio, loss and impedance voltage drop based on minimum energy provided by series side is proposed, which provides reference and theoretic basis for UPQC researchers and transformer manufacturer. Finally, product cost analysis and experimental results verify the feasibility and rationality of the principle.