Understanding SAIDI and SAIFI: Key Metrics for Power Grid Reliability

Electric utilities worldwide monitor reliability using quantitative indices that reflect both the duration and frequency of service interruptions. Two of the most widely recognised metrics are the System Average Interruption Duration Index (SAIDI) and the System Average Interruption Frequency Index (SAIFI).

SAIDI represents the total outage duration experienced by the average customer over a specified period. It is computed by summing the duration of all interruptions and dividing by the total number of customers served. This index is typically expressed in minutes or hours and provides a measure of the cumulative burden of outages on customers. A lower SAIDI value indicates that, on average, customers are without power for less time.

SAIFI measures how often the average customer experiences a service interruption. It is calculated by dividing the total number of customer interruptions by the total number of customers served. SAIFI is expressed as interruptions per customer per year. A lower SAIFI value denotes fewer outage events and, consequently, higher service continuity.

These indices are standardised metrics used by regulators, system operators, and researchers to benchmark utility performance, compare grid reliability across regions, and evaluate the effectiveness of maintenance and investment strategies. They are often reported both including and excluding major event days to distinguish normal operational performance from the effects of extreme weather or other external factors.

How AI Fault Prediction Contributes to Reducing SAIDI and SAIFI

SAIDI and SAIFI values can be improved through utilizing advanced analytics and fault prediction, Eneryield Intelliview®, using AI based on machine learning algorithms to analyze voltage and current data from existing protection relays and other measuring units detecting and localizing faults with a 95-97% precision.

By detecting subtle anomalies and patterns indicative of incipient faults, our system can forecast potential failures days or even weeks before they result in service interruptions, reducing downtime with 60-80%.

In terms of SAIDI and SAIFI a proactive approach offers several operational benefits:

• Maintenance can be scheduled before faults occur, reducing the number of interruptions (SAIFI).
• When interruptions are unavoidable, early warnings enable more efficient resource allocation and faster response, shortening restoration times and thus lowering SAIDI.

Furthermore, the platform provides transparent insights into the underlying causes of predicted events, allowing engineering teams to address root issues and enhance asset health. Lowering costs of O&M with 15-30% and reducing SAIDI and SAIFI.

With proactive data-driven, preventive strategies, utilities are able to transition from reactive fault management causing higher SAIDI and SAIFI costs, and the result is a more resilient grid, improved service continuity for customers, and a demonstrable reduction in key reliability metrics.