Assessment of voltage sag in distribution system regarding the uncertainty of wind based distributed generation

This paper presents a new assessment of voltage sag due to faults in distribution system connected with wind based distributed generation (DG) in which some uncertain factors of this DG technology are considered. Voltage sag characteristics depend on the system´s short-circuit power that includes the contribution of DG power injection when faults occur. The output power produced by wind based DGs is a function of the wind speed that is stochastic in nature. By using the probabilistic modeling of wind speed at the DG installation site, the uncertainty of wind regime is built into the problem of stochastic prediction of voltage sag in distribution system with wind energy resources connected. The paper assesses voltage sag performance in IEEE 34 Nodes Test Feeder. DG connected network modeling and fault analysis are done using PSS/ADEPT 5.0. Voltage sag characteristics and frequency are also determined in relation to wind speed for different scenarios of DG sizing and placement, types of wind power generation and the impact of the system source capacity of the distribution system of interest.