Reliability evaluation of transmission and distribution configurations with duration-dependent effects

On an interruption of transmission or distribution supply, the actions taken to restore customer service and/or the impact on customers are often dependent on the interruption duration of the normal supply paths. An example is the interruption of supply to a load due to transformer failure. If the interruption duration is expected to be long, a mobile transformer may be used to provide a temporary supply. System failure ends when the mobile transformer is connected. The author gives methods of calculating the reliability indices, taking into account duration-dependent effects. Transmission or distribution component down times are allowed to be distributed arbitrarily, in accordance with recently reported data analysis. It is shown that nonexponential down times give significantly different results compared with exponential down times. The methods are simple and easy to implement on a computer