A new operational approach to minimize open unified power quality conditioner rating: OUPQC-VAmin

Abstract

Distribution Network (DNs) are always face with low quality of voltage and current which their corresponding indices have to be improved by the network operator. Custom power devices (CPDs) are compensating these voltage and current deficiencies. Lately, in smart DNs which are equipped by communication infrastructure, open unified power quality conditioner (OUPQC) is attracted by DN area academics and distribution network utilities. Hence, OUPQC is being applied in DNs to improve V & I related indices take advantage of its series and shunt units (SEU and SHUs) performance, respectively. Effectiveness of OUPQC performance in voltage sag (VS) condition is affected by ratio of active/ reactive power injection of SEU. In OUPQCs which their SEU are equipped with storage system (SS), active power injection is also provided for compensation of VS. Operational approach of OUPQC which decides the amount of (re)active power injection in each VS magnitude, determines required rating of SEU and SHUs. In this paper, the amount of (re)active power injection is tuned in such way that minimize the SEU rating. Moreover, the proposed method takes advantage of charging the SS in healthy condition so as to makes the SEU capable of maximum compensation in VS condition. Therefore, in healthy condition, reactive power injection compensating the small voltage drop while active power injects into the SS to charge it. In this paper, first a precise modeling of OUPQC-VAmin is proposed. Then, its integration method in backward/forward sweep based load flow (BFSLF) is suggested. The suggested model is applied in two DNs: 69-bus IEEE and real Iranian 95-bus DN. Achieved outcomes confirm the effectiveness of OUPQC in steady state healthy condition and particularly in VS condition is intensely enhanced considering the minimization of SEU rating. The proposed method may be applied in design of the operational approach of OUPQC.