KPLC explains power failure

The following is a simplified version of the cause of the power blackout as explained by the Kenya Power and Lighting Company.

6.34 p.m.- A temporary fault occurs in the transmission line between the two major substations at Kamburu Dam and the substation at Dandora, which is one of the biggest substations in Kenya. Nairobi and surrounding towns- Kiambu, Nyeri, Thika Machakos and Athi River go dark.

The fault is described as transient/temporary, meaning that it would not be easy to tell what it is since it is not evident from looking at the line itself.

The equivalent is lightning striking a line or an animal causing a short circuit and then dropping to the ground as compared to a tree falling on a line, which would have to be removed physically.

The fault causes equipment that protects the line from damage to shut down the system automatically. It senses that the fault was temporary and switches on again.

The disturbance in the system has however been felt by the generation system, which is connected to that of transmission, and the protective equipment for the emergency power generators at Embakasi, Nairobi South and Gitaru shut them down.

The rest of the power generators cannot handle the increased load and they too shut down in quick succession.

KPLC engineers at the National Control Centre in Nairobi have been on the job, trying to restart the system, and in the meantime have to depend on power from Uganda to restart the machines.

Some parts of Kenya get electricity back in one hour due to the Uganda connection but it takes four hours for everyone to be back on line.