SAIDI & SAIFI

Reliability Indices


System Average Interruption Frequency Index (SAIFI)

The System Average Interruption Frequency Index (SAIFI) is the average number of interruptions that a customer experiences and is calculated as:
SAIFI = total number of customer interruptions ÷ total number of customers served 
SAIFI is measured in units of interruptions per customer. It is usually measured over the course of a year in accordance to IEEE Standard 1366-2003.

System Average Interruption Duration Index (SAIDI)

The System Average Interruption Duration Index (SAIDI) is the average outage duration for each customer served and is calculated as:
SAIDI = sum of all customer interruptions ÷ total number of customers served
SAIDI is measured in units of time, often minutes or hours. It is usually measured over the course of a year in accordance to IEEE Standard 1366-200

Nairobi County Power Reliability Indices for the period January  to December 2020

County

Sum of Numerator SAIFI

Sum of Numerator SAIDI

No. of Customers

SAIDI

SAIFI

CAIDI

Nairobi North County

4,464,806.22

11,501,220.19

879,437

13.1

5.1

2.6

Nairobi South County

3,569,047.22

10,548,724.07

985,463

10.7

3.6

3.0

Nairobi West County

3,919,018.35

8,760,965.72

817,949

10.7

4.8

2.2

Grand Total

11,952,871.78

30,810,909.98

2,682,849

11.5

4.5

2.6