How is reliability measured in an electrical distribution system?

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Reliability in an electrical distribution system is typically measured using several key indices that quantify the frequency and duration of power interruptions. 

Here are some of the most commonly used indices:

• SAIFI (System Average Interruption Frequency Index): this measures the average number of interruptions that a customer experiences over a specific period. It is calculated as the total number of customer interruptions divided by the total number of customers served.
• SAIDI (System Average Interruption Duration Index): this measures the total duration of interruptions for the average customer over a specific period. It is calculated as the sum of all customer interruption durations divided by the total number of customers served.
• CAIDI (Customer Average Interruption Duration Index): this measures the average time required to restore service to customers per interruption. It is calculated as the total duration of all interruptions divided by the total number of interruptions.
• MAIFI (Momentary Average Interruption Frequency Index): this measures the average frequency of momentary interruptions (typically less than 5 minutes) experienced by customers.

These indices help utilities assess and improve the reliability of their distribution systems by identifying areas that need maintenance or upgrades. They also provide valuable information for regulatory compliance and customer satisfaction.

👉 SAIFI / SAIDI Report

👉An Alternative Approach to Improving SAIDI and SAIFI Indicators