What does the System Average Interruption Duration Index (SAIDI) measure?

The System Average Interruption Duration Index (SAIDI) is a key reliability metric used in the utility industry that specifically measures the average duration of power outages experienced by customers over a year. It calculates the total duration of interruptions within a defined period, typically a year, divided by the total number of customers served. This metric helps utilities assess their performance regarding the reliability of service and gauge customer satisfaction, as longer outages can lead to greater dissatisfaction among consumers. By focusing on the average duration, SAIDI provides a clear picture of how long customers are typically without power, which is critical for evaluating the performance of the electrical distribution system.