Station-initiated outages in composite-system adequacy evaluation

Failure events originating in terminal stations can result in multiple outages of generators and/or lines or loads in a power system. Failures of breakers, transformers and busbar sections are major causes of these multiple outages. The effect of these outages in composite-system reliability evaluation can be quite significant. The effect of station-related multiple outages can be quite dominant and may, therefore, obviate the need to consider higher-order independent outages of major components such as generating units, transmission lines and transformers. In this paper, models are presented and discussed for various possible failure events originating in the stations. Expressions in terms of probability and frequency of appropriate states are developed for each of the failure events. These expressions are then utilised in the adequacy assessment of a composite 6 busbar test system.