Residents of Ntinda, Kiwatule, Najjera, Kungu, Buwatte and Kyanja are always experiencing power outages due to a technical faults— well, that’s according to UMEME the electricity distribution company and as many have noticed these power cuts get worse during rainy seasons. UMEME always ends up their tweets with ” Our teams have already been alerted to resolve this issue at the earliest.” to console the affected residents. But, why does this happen? Why does UMEME always have to switch-off power whenever it rains?
It should be noted that whenever UMEME switches off power during heavy rains, it is actually a good safety practice.
Power outage during rainy storms is one of those third world problems (rarely happens in the first world). There are a number of reasons, but the biggest reason is because our system is utterly outdated and in ruins and we largely use overhead power distribution option rather than underground.
If you look at most of the usual low-tension/low-voltage pole that carries regular household voltage our distribution systems in Uganda, most are in a sorry state and prone to any damage especially from any natural and unavoidable catastrophes.
So, in the case of thunderstorm or heavy winds, there is a high chance of broken wires and short circuits. These broken wires and short circuits can cause tripping in the transformers and even whole feeders. Broken wires also cause high hazard to human lives due to shock. In most cases and areas, the wooden poles are very old and in some cases rotten. These are some of the reasons why, UMEME will deliberately turn the power supply off in order to minimize the damage.
Sometimes its not UMEME’s fault
Power distributions companies like UMEME know that sometimes rains are so heavy that the trees fall and pull down transmission cables transmitting alternating current (AC) on high voltage (69 kV, 115 kV, 230 kV, 500 kV, 765 kV) which could prove fatal if it comes in contact with any human body or animal. Although pure water isn’t a good conductor of electricity, but rain water includes some impurities(ions) which makes it (partially) a good conductor of electricity. Sometimes the broken end of the cable falls into accumulated rain water on the streets which is hazardous.
From the above its clear that sometimes UMEME will not deliberately switch the power off and this can happen in usually two ways –
- During a rainstorm, winds of 72 to 80 Km/h or more sustained can cause brownouts and short-term outages. 80 Km/h winds or higher can cause tree limbs or branches on top of power lines to snap and fall down on power lines which can in turn snap or break leading to power line transformer explosions and resultant outages this has nothing to do with UMEME.
- During a rainstorm where there is lightning (as seen in thunderstorms or thundershowers), a cloud-to-ground lightning hit (or strike) on a power line or the transformer can break or shatter the power line and/or blow up the transformer, causing much more quicker and much longer power outages.
