Reliability assessment tool for radial and loop distribution systems using DIgSILENT PowerFactory

This paper presents a simple and practical method for determining reliability indices of radial and loop electrical distribution systems by using an automatic tool. This tool is developed by writing DIgSILENT Programing Language (DPL) script for determining reliability indices of each load point and the whole systems. By using this tool, a large existing distribution system can be easily analyzed. Moreover, it can decrease time to configure components in the system. The developed tool is tested by using Roy Billinton Test System (RBTS) Bus 2 and Bus 4 as case study. The test results demonstrate the correctness of reliability assessment process. In addition, the practical rearrangement from a radial to a closed loop of the 115 kV distribution system in Chiang Mai province is used as another case study to show the effect of installing protective devices for reliability improvement.