Stochastic Voltage Assessment of Unbalance Radial Feeder

This paper presents voltage assessment indices for unbalance radial feeder in smart grid application. These indices are voltage stability margin, voltage deviation index, voltage profile and voltage unbalance factor. Voltage assessments are based on unique two-bus pi-network model having time varying composite voltage sensitive load for every 15 mintues. Each node of feeder have three different time varying load categories consumers (industrial, commercial and residential), which is more practical to actual feeder. Characteristics and composition of residential, industrial and commercial consumers are accounted through time varying static composite load models. Composite load modelling is combination of constant impedance, constant current and constant power. The load flow solution is based on two port network modeling, load modeling and forward- backward sweep technique. Developed indices were calculated for modified IEEE 37 node test feeder with consideration of 15 minutes characteristics time interval for load modeling to meet out requirement of smart grid implementation. Simulation results demonstrate the validity and effectiveness of proposed indices for smart grid applications.