Voltage profile and loss assessment of distribution systems with fixed speed wind generators

Abstract

Wind generators are increasingly being integrated into high voltage transmission systems as well as low or medium voltage distribution systems. The increased penetration of wind generators into power grid may significantly change the system voltage profile, losses and other operating characteristics. This paper investigates the effects of wind generators on voltage profile and losses of a distribution system. To make the investigation more realistic, time varying system load and historical wind speed data are used. Randomly generated wind speeds through Weibull probability density function are also used. For a given wind speed, the turbine power is determined through a polynomial obtained from power data supplied by the manufacturer. The system voltage profile and losses are obtained through repetitive power flow solutions with varying load and wind speed data. The exact equivalent circuit of a wind generator is directly incorporated in power flow calculations. The above technique is then applied to two distribution systems consisting of 33 and 69 buses with a number of embedded wind generators. The results obtained are carefully analyzed and discussed.