Effect of Generator Outage Contingency on Distance Relay Operation

This paper presents simulation study of distance protection in electric power transmission systems with a renewable energy plant. In many developing countries where renewable energy power plants are typically located in rural remote areas, they can be connected to electric power transmission systems for a case of small power producers (SPP) with their power rating in between 10 - 90 MW. To secure the system operation, distance protection is assigned to protect transmission lines. An in-feed generator of SPP can be taken into account. In this paper, the distance mho relay is placed in the line and is designed according to protection the multi-source system. This study considered the system consisting of a renewable energy plant of 50 MW. The test system was simplified to be an equivalent 6-bus test system for relaying purpose. Fault analysis and distance relay setting in this paper were performed by using DIgSILENT™ software. The test was considered a situation that the renewable power plant is out-of-service due to either an unexpected event or a maintenance schedule. This generator outage can cause some mis-operation in tripping order as a successive fault occurs inevitably.