Maintaining a balanced power key to stability of electricity

By Victor Wanyama

Yesterday when the country experienced national blackout which spilled over to Uganda, Kenyans were in awe as they saw Kenya Power personnel rectify electricity lines in Limuru using a helicopter. It showed dedication for their often criticized trade due to constant power black outs in the country, especially during this COVID-19 pandemic times where people are working from home.

Maintaining a balanced power system in any country is critical to the proper functioning of the electrical grid. In many countries like Kenya the reference point is the frequency which is maintained at 50 Hz. In other countries like the US this is 60 Hz. This means power oscillates between supplier and consumer 50 times every second.

Electrical energy in the form of alternating current is not stored. It is produced and transmitted over large distances at high voltages, to a station where it is measured, stepped down to lower voltages and distributed to various substations where it is further stepped down then supplied to customers all over the country. This constitutes a country’s power grid.

In Kenya, we have one control station at Dandora called Juja Control Station that connects electricity consumption to energy production.  A fault along a transmission line leading to the control station caused a nationwide power blackout early today morning.

The fault was caused by a high voltage conductor falling off its support and coming into contact with a support pylon which led to a ground fault that shut down the whole system. Such occurrences are not strange in developing countries, bearing in mind that many countries are dealing with aging energy infrastructure.

Power grids are also interconnected between neighboring countries so that a surplus production or deficit can be sorted with help from a neighbor and this helps balance the systems. Therefore a fault in our system could and as noted yesterday morning did lead to a black out in our neighboring Uganda.

During these rainy seasons blackouts are a common occurrence in many developing nations. These are partly caused by the regulator switching off power when it is raining heavily in certain areas or other faults such as trees and branches falling on power lines and shutting down the system, lightning causing system faults, falling power lines, sagging power lines swinging  and coming into contact with each other, thieves taking advantage of the time and stealing oil from transformers and transformers themselves, etc.

Kenya Power and Lighting Company (KPLC) engineers using helicopter and a trained team managed to reconnect the broken conductor although the KPLC Chief Pilot Major (Rtd) Alex Koech had difficulty in balancing the engineers on a rope when there were high wind speeds. These shows how our teams have come of age professionally.

 


Bringing the grid back to life does not just happen by a click of a button after the conductor is reconnected. The regulator has to meticulously monitor the power system and switch on in such a way that it does not disturb the balance of power production and consumption.

If the power produced is more than the consumption the frequency will rise above 50 Hz this will risk the system getting disconnected as it is designed to work at a 50 Hz frequency. Too much demand and less production will lead to a drop in frequency and will initiate an automatic load shedding plan, and this might cause power plants to shut down one after the other. This is part of the reason nationwide power blackouts last for hours.

Trained as an electrical engineer, the writer is a plant engineer.

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