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Power play T


Make sure you or your clients aren’t paying the price for poor power quality, says Giuliano Digilio, the ECA’s head of Technical Services


he power you or your clients buy comes in two distinct parts – just like a frothy latte. Think of the coffee body as ‘active power’ that you can use to do work, while the froth on top


is what we call your ‘reactive power’. Some is useful, but too much reactive power is simply a waste – the same as the foam you leave behind in your glass. Your power factor is the relationship between the active


and reactive power in your electrical installation. The good news is that power factor correction (PFC)


equipment manufacturers, like the best coffee shops, can help you get the balance just right – so you can enjoy the very best value from your power supply. Poor power factor may cost you money every time you


pay your electricity bill. Your poor power factor results in extra costs from your electricity supplier, in the form of power factor penalties – you can see these on your electricity bill as the ‘reactive power charge’ or ‘exceeded capacity charges’. If your electrical installation was 100 per cent effi cient


in its use of electric power, then your power factor would be 1 – which is very unlikely! All UK electricity suppliers impose an excess reactive


penalty charge where the average PFC is lower than 0.95 lag.


About the author


Giuliano Digilio Giuliano Digilio is the head of ECA Technical Services. He has extensive experience in the electrical and electronic engineering building services industry, and sits on numerous technical committees for the ECA in the UK and Europe.


What causes poor power factor? Equipment such as AC motors, arc welders, furnaces, fl uorescent lighting and air conditioning can cause a poor power factor. The more inductive loads you have in your installation, then the more likely it is that you will have a poor power factor.


How do you know if you have a power factor problem? A simple check on your electricity bill will tell you. It must state clearly what your reactive power charge is and will probably indicate your power factor. If it is below 0.95, then you need to consider taking action.


What should you do? Most PFC equipment manufacturers offer a free, no- obligation, survey. They will then often work with you to design and install the ideal PFC solution for your installation or site.


What will it cost? The beauty of a PFC installation is that it delivers real savings on your electricity bills from day one. Typically, payback periods are less than two years. On the right, above, is a typical example of an


electricity bill, highlighting key data and actual charges for:


Latte glass = Capacity = kVA Coffee = Useful energy = kW Froth = Waste capacity


A frothy latte = Poor power factor correction


A perfect body = Good power factor correction


Power factor correction equipment is any easy and cost effective solution to install


52


ECA Today May 2011


ABB


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