A novel fault location for distribution systems with high penetration of distributed generation

With the recent trend of adopting and integrating renewable resources and microgrids with distribution systems, it is probable that distribution systems will have significant and arbitrary penetration of distributed generation (DG) in the near future. The fault location in this type of system will be a challenge. This paper describes a general method to locate faults in this type of system. The method uses synchronized voltage measurements at the interconnection of DG units where the injected current at a fault point can be calculated by using the voltage change and its relevant transfer impedance on any bus. A two-stage fault-location optimization model is proposed, along with defining a matching degree index. The first stage is the fault region identification stage, which uses the matching degree index to determine the suspicious fault region in order to reduce the search area. The second stage is used to identify the exact fault section and fault distance. The method has been extensively tested on a 60-bus distribution system for all types of faults with various fault resistances on all sections of the system, with very encouraging results. Results showed that proposed method is more effective in distribution system with more DG connection nodes.