What does SAIDI measure in utility services?

SAIDI, or System Average Interruption Duration Index, measures the average duration of electrical service interruptions that customers experience over a specified period, typically in a year. This metric provides utility companies with crucial insight into the reliability of their service, as it quantifies how long customers are without power due to outages. It is calculated by dividing the total duration of all interruptions (in minutes or hours) by the total number of customers served.

Understanding SAIDI is vital for utilities to identify trends in service reliability, assess the impact of maintenance and improvement efforts, and communicate performance effectively to customers and stakeholders. High SAIDI values indicate frequent or prolonged outages, prompting utilities to take corrective action to enhance service reliability.