Power cuts or what??!!! Have a UPS

Power cuts or what??!!! Have a UPS

 

We all like living in the countryside, small villages and towns etc. but the drawback is the angry electric pixies that we use to drive our electrical equipment are delivered mainly by overhead cables. All these pylons look to the sky and demand to be hit by lightning. Add to this, the power network providers will think nothing of switching to different parts of the grid system which cause momentary breaks in your mains supply, causing mayhem.

The last couple of months have been quite bad with regards to problems with power cuts and outages. The next few months will see more to come. When it’s very windy, the overhead cables can sway and touch, debris can be blown across conductors, causing the local distribution nodes to shut down and reconnect. Lightning can cause all kinds of problems. At least, a lightning strike on overhead cables will electrically “saturate” power transformers, causing a “brownout” of power. i.e. a second or so of no electric. In the worst case, it can destroy all equipment in your property. Most pylon networks are linked together at the top with a cable called a longitudinal earth. This cable travels the length of pylon routes. The idea here is that should lightning hit a pylon, the energy is discharged to ground via many pylons, over tens of kilometres, minimising local damage.

Almost every electronic piece of kit we have in the home has some very sensitive circuitry with more computing power than the whole of the UK had in the 1960s. All this stuff runs at very low voltages and currents and can be confused or trashed by a power “spike”. This can be generated by a local lightning strike or routine maintenance at its best. I see many a household item needing repair as a result of this. TV sets, satellite boxes, IPTV boxes, PCs, routers, fridges, sound systems….it goes on.

While lightning strikes can destroy equipment, the short power breaks we get can cause real damage to equipment as well. The glitch can cause corruption of the computer-controlled insides, or damage the internal power supplies. A UPS (uninterruptible power supply) can help minimise damage.

What is an uninterruptible power supply, UPS?

 

This is a box that sits between the power supply socket in your house and your equipment to be protected. Two types basically; OFF LINE. This UPS in normal conditions, connects your equipment directly to the power in your house, as if nothing was happening. However, when a short power stoppage occurs, it quickly switches in its internal battery which operates a circuit to provide synthesised mains power to your equipment. The long and short, whatever you have connected to it continues to run without problems. The changeover takes some 10ths of a second. Most electronic equipment, which is designed to meet the CE approval, should tolerate a small break in the electric supply. When normal power is restored, the box reconnects you to the mains and then recharges its battery ready for the next interruption. Jolly good. The other type is an ON LINE. Here we have a unit which provides a synthesised power all the time, irrespective of power cuts. What you are connected to is not a mains power from the network, but locally generated supply. It provides a far greater isolation between you and the outside world of mains supply. These systems are favoured by data centres and communications networks and people on iron lung machines. But seriously, I have clients who use dialysis machines at home. These UPS systems are 4 or 5 times the price of the OFF LINE kit, your choice.

 

Before buying a UPS, there are a few things you must consider. The amount of power you require to use, the amount of time you want the equipment to operate in the event of power cut and lastly, the type of items you need to protect.

The “power requirement” could be small, 150 Watts, for a small TV and a sky Box, IPTV box let’s say. A large OLED TV, older plasma TV and other bits and bobs would draw more power. The “runtime” the UPS indicates how long it will operate for in case of a mains outage and determined by the capacity of the internal batteries required. Another thing is how much power is required when your piece of equipment initially starts up, we call this inrush current. Let’s say that you have a power cut and you want to turn on your equipment. The equipment will demand some 3-6 times more energy than it consumes when operating normally, for a split second. Most standard UPS’s will cope with that. However, some bigger items with bulking power supplies like big home cinema systems will have a massive inrush demand, which may cause the UPS to shut down. Items such as pellet burners should be protected, but these require different amounts of power depending on their working cycle. So, I always suggest a UPS with a higher capacity than normal. Always best call me for advice.

Other things to consider when looking at a UPS, is the type of equipment you want to connect to it and what the equipment has inside it. An example would be your heating system with electric pumps etc. These like to see a nice clean Sine Wave of power (the shape of the supply power you get from the power company). Budget UPSs tend to generate a rather crude rough output and can stress induction motor pumps, making them sad and unhappy. The power rating of a UPS is normally stated in Watts and VA, example being 1000 Watts – 650VA. Now Volts x Amps should equal Watts, but due to the reactive element of the equipment connected, there is a sort of loss. Don’t worry, take the lower figure. I can help with all of the above in guiding you to what you need. Just give me a shout. Or phone call if easier.

A couple of other things I would mention relating to your electric supply.

Solar

A lot of people are having solar energy systems installed. Spain, by law, has good access to the Sun, so that’s good. A few customers have spoken to me regarding what happens during a power cut when they have a solar system. Generally speaking, if you have a system that does not have a physical battery set up and you are using it to feed power into the network supplier to top up your virtual account and save money, should you have a power cut, your house supply will shut down. This is based on regulations that stipulate, quite rightly so, that if the network supply to you house is switched off for maintenance for example, you must not continue to provide that supply. Thus, not frazzling the poor engineer working 200 mtrs down the road. Check with your solar system supplier. If it is important to you to have continuous power supply, then an additional UPS may be required should you wish.

If you have a solar system with local batteries, which are float charged all the time, then just ensure your system will provide you with uninterrupted power during a local power outage. The other thing to consider when specifying your solar system, is the power rating. You have solar panels rated at say, 7 Kilowatts. Most panel’s output will degrade as the temperature rises. On hot days, you may find your capacity is reduce by 30%. Solar panels like cold bright clear days.

Generators

I repair a lot of equipment that has been damaged as a result of being connected to generator sets. This mainly relates to people who are totally “off grid” and use a generator as a backup to solar systems. Your standard generator is fine for supplying lights and basic and other basic equipment. But, most electronic gear can be upset by the poor quality and unstable output of a budget generator or one in poor condition. The power from a generator can fall short in two ways; 1. The output voltage can vary wildly and if excessive will cause damage to electronic power supplies in TVs, etc… 2. The frequency of the power from the generator should be as near as possible to 50Hz, cycles per second, the same as the mains power. However, this is generally a function of the RPM of the generator. As the generator starts up and shuts down, this frequency will go way off target and can damage equipment’s power transformers and switching power supplies. So, it is important to switch on your generators output once it has been started and got to speed and switching off the output prior to shutting the engine down.

Whilst scribbling, you may be well minded to have fitted to your consumer unit, module with over voltage / current safety fuses (ICP, interruptor de control de potencia). These will help protect your household from mains surges, lightning and incorrect voltages when the electric company. It is also worth checking the integrity of your property’s Earth. Any electrician should be able to catty out an Earth Impedance Test which will determine the presence and quality of your safety Earth.  Again, give me a call and I can advise. Stay safe.

Seth, Zeta Services, working hard.…for you.