Zimbabwe Absurdity

It became evident soon after we installed the solar panels and inverter that we were going to have to do something about the terrible power quality. Most of Zimbabwe has erratic power supplies. Called “load shedding” it’s really just a statement about the government’s ineptitude in supplying power to the nation. The national supplier, ZETDC (Zimbabwe Electricity Transmission and Distribution Company) is a subsidiary of Zimbabwe Electricity Supply Authority (ZESA) and is the sole distributor of power. Other subsidiaries, also government companies, are responsible for sourcing power. It’s a mess and a major driver of the private sector embracing solar power. We have a friend who works for a company that installs industrial sized solar systems and she tells us that they cannot keep up.

Our problem is not power supply per se, but a wildly fluctuating voltage. We have been told that we are on the same part of the power grid as a “person of influence”, i.e. a political fat cat, so we don’t often get intentional power cuts though faults are not uncommon especially during the rainy season.

We installed the voltage protection unit (VPU) pictured above to protect the solar inverter from the voltage which we have seen anywhere from 280 volts down to 160 volts. It simply disconnects the supply outside of the safe range of 190 volts to 240 volts. During the day the supply is often above this range and at night it falls below. We can hear the VPU switching on and off in the evening and the lights flicking as the inverter takes over. Most of the time it is merely tedious but on occasion the voltage goes low for so long that the solar battery goes flat and the lights go off. Especially in cloudy weather when the solar battery never fully charges.

Over the years I have acquired a reasonable collection of woodworking and other power tools. These are in the spare garage next to the cottage in the garden and most can run off the cottage solar system. The planer/thicknesser and it’s accompanying dust collector cannot as they draw too much power so must run off the mains supply and the voltage fluctuations would destroy the motors very quickly. The planer is a very useful machine and because I am so dependent on it very little happens in the woodworking sphere these days.

Whilst I knew that voltage regulation units (VRUs) that supply a constant voltage existed, I had researched them on the internet and found that they tended to be large and very expensive. I asked my friend Barry, who is a professional carpenter, what his solution would be. He has liquidated his company he has no large machines but I thought he might know someone who did. It turned out that he and his partner had just installed a relatively small VRU in a flat that they’d bought and were available locally for less than US$1,000. So I got hold of the company and started asking questions, lots of them.

Having ascertained that I would need a 15kVA regulator and that the warranty would be valid for a year they couldn’t give me a clear answer as to whether it would be valid, or what would happen to the unit, if the voltage went outside the maximum rated supply of 250 volts. Asking around led me to another hardware outlet but they were only interested in selling the VRU and had little backup and simply wouldn’t answer the voltage range issue. A chance conversation with one of my cousins and with an electrician that he knows led me to call Richard of ElectroTronics and he answered all my questions.

ElectroTronics is based in the Southerton industrial area of Harare. Once a bustling hub of industry it’s a lot quieter than I remembered (I had no reason to go there for quite a few years) but was surprisingly clean. The roads were mostly good though the one past ElectroTronics was in very poor shape.

Richard is a very trim man, not looking at all like his 70 years and he assured us that he’d been in the business nearly 50 years. His small warehouse was impressively well stocked, indicating an active business, and he happily gave of his time explaining the principles of VRUs. The one we’d opted for was essentially a variable transformer. “Of course they are made in China” he responded to my inevitable question. “I could sell you that Italian-made one for 18 times the price but these work just fine” he added (we paid $900). He has sold VRUs to all manner of customers including hospitals, laboratories and factories. The biggest was 1,000 kVA. “I back up and repair everything I sell and if it’s a genuine part failure I will honour it outside the warranty”.

Having got the AVR home my brother Duncan noticed some cosmetic damage to the case. I sent in pictures to Richard and asked if it would jeopardize the warranty. He apologized, said no, and the machine was replaced that afternoon. I was VERY impressed!

The AVR is installed in our kitchen (the only place where it can be easily placed to supply regulated/stabilized power to the whole property) and my woodworking machines work just fine! However, a VRU can obviously only work when there’s power and the next day there was none. Fortunately a WhatsApp message to the local faults department led to a prompt replacement of the problem fuse in the nearby sub-station. We’re back in business!