Electric power system reliability indices: SAIFI, SAIDI, and CAIDI calculations.
1 Answer
Electric power system reliability indices are measures used to assess the performance and reliability of an electric power distribution system. They help utilities and regulators evaluate how well the system is providing continuous and uninterrupted power supply to customers. Three commonly used reliability indices are SAIFI, SAIDI, and CAIDI. Let's take a closer look at each of them:
SAIFI (System Average Interruption Frequency Index):
SAIFI measures the average number of outages a customer experiences over a specified period. It is calculated by dividing the total number of customer interruptions by the total number of customers served during the same period.
Formula: SAIFI = (Total Number of Customer Interruptions) / (Total Number of Customers Served)
SAIFI provides insight into the frequency of interruptions a customer might experience on average.
SAIDI (System Average Interruption Duration Index):
SAIDI measures the average duration of outages that customers experience over a specified period. It is calculated by dividing the total customer outage duration by the total number of customers served during the same period.
Formula: SAIDI = (Total Customer Outage Duration) / (Total Number of Customers Served)
SAIDI gives an indication of the average time a customer is without power due to interruptions.
CAIDI (Customer Average Interruption Duration Index):
CAIDI represents the average time it takes to restore power to customers after an interruption. It is calculated by dividing the total customer outage duration by the total number of customer interruptions during the same period.
Formula: CAIDI = (Total Customer Outage Duration) / (Total Number of Customer Interruptions)
CAIDI provides information about the average response time of the utility in restoring power after an outage.
These indices are useful for utilities to monitor and improve their system reliability, identify areas that require attention, and make informed decisions regarding infrastructure investment, maintenance, and outage management. Lower values for SAIFI, SAIDI, and CAIDI indicate better system reliability and performance, as they reflect fewer interruptions, shorter durations, and quicker restoration times.
SAIFI (System Average Interruption Frequency Index):
SAIFI measures the average number of outages a customer experiences over a specified period. It is calculated by dividing the total number of customer interruptions by the total number of customers served during the same period.
Formula: SAIFI = (Total Number of Customer Interruptions) / (Total Number of Customers Served)
SAIFI provides insight into the frequency of interruptions a customer might experience on average.
SAIDI (System Average Interruption Duration Index):
SAIDI measures the average duration of outages that customers experience over a specified period. It is calculated by dividing the total customer outage duration by the total number of customers served during the same period.
Formula: SAIDI = (Total Customer Outage Duration) / (Total Number of Customers Served)
SAIDI gives an indication of the average time a customer is without power due to interruptions.
CAIDI (Customer Average Interruption Duration Index):
CAIDI represents the average time it takes to restore power to customers after an interruption. It is calculated by dividing the total customer outage duration by the total number of customer interruptions during the same period.
Formula: CAIDI = (Total Customer Outage Duration) / (Total Number of Customer Interruptions)
CAIDI provides information about the average response time of the utility in restoring power after an outage.
These indices are useful for utilities to monitor and improve their system reliability, identify areas that require attention, and make informed decisions regarding infrastructure investment, maintenance, and outage management. Lower values for SAIFI, SAIDI, and CAIDI indicate better system reliability and performance, as they reflect fewer interruptions, shorter durations, and quicker restoration times.