Simulation and Evaluation of Voltage Sag in Distribution Network with High Permeability Renewable Energy

Voltage sag simulation and evaluation results is a very necessary scientific basis for electric power department and users of quantitative investment cost / benefit analysis, scheme comparison and reducing power quality hazards measures in the stage of planning and operation. In this paper, the simulation and evaluation of voltage sags in distribution networks with distributed generations is presented. The influence of different types of distributed generations on voltage sags is studied. A novel voltage sag simulation and evaluation method in smart distribution network with distributed generations has been proposed based on Point Estimation Method (PEM). By establishing the stochastic model of fault information and the power stochastic model of distributed generations outputting, the random probability problem in voltage sag simulation is transformed into multiple deterministic problems. Through computing the mean, the standard deviation and the third central moment of each node in distribution network, the voltage sag System Average Root Mean Square Variation Frequency Index (SARFI) can be computed. The simulation and evaluation of voltage sags are also completed. Experiments have been made on a test case with two different types of distributed generations, and the validity of the algorithm is proved.