The Analysis Of Voltage Sags And Short Interruptions And Reliability Evaluation Of Distribution System

The characteristic quantities of voltage sags and short interruptions and the factors affecting the voltage sags are analyzed first. Then the paper studies the following two questions: 1) A comparison between the critical distance method and the fault positions method, which are two methods for voltage sag estimation, is made and the two methods are extended. Then the idea of the two methods combination is presented and used to calculate the exposed areas of IEEE RBTS (Roy Bilhinton Test System), and more accurate results are got with less calculation. 2) To analyze the influences of voltage sags and short interruptions to distribution reliability, the reliability indexes are calculated by the FMEA (Failure Mode Effects Analysis) method and the Monte-Carlo simulation method on IEEE DRTS (Distribution Reliability Test System) respectively. According to the comparison with the original results, the paper reaches the conclusion that the distribution system reliability is lower when voltage sags and short interruptions are taken into account.