Line Loss Minimization Control in a Loop Distribution System Using Circulating Current Compensation and Reactive Current Suppression by a Unified Power Flow Controller

This paper describes line loss minimization control using the shunt and series converters of a UPFC (unified power flow controller) in a loop distribution system. The line losses in a loop distribution system are caused by the circulating current flowing in the loop and the mesh currents flowing to the loads. The authors have previously proposed a compensation method for circulating current using a series converter. In this paper, the authors propose a suppression method for reactive currents using a shunt converter. In the prototype model of a loop distribution system, a theoretical loss reduction ratio of 92% without line loss caused by active currents is obtained. Similar line loss reduction characteristics are obtained in experiments using the prototype distribution system.