I’ve recently read a quite comprehensive report by the Leonardo Energy Power Quality Initiative Team, that put the costs of poor power quality in Europe at €150bn, a quite staggering figure.
Not all the costs are due to obvious power quality issues, such as blackouts, in fact, short term interruptions were the main culprit, followed by transients and surges – then blackouts. A rising phenomenon is flicker, and the costs borne here aren’t equipment damage, but rather the effects on individuals working in an environment that is prone to flicker. It’s interesting I find, as mostly power quality cost are put in the “data lost cost” and “hardware costs”, but seldom are people included in the equations.
Flicker is caused by changes in the supply waveform amplitude and is noticeable particularly with CRT’s and lighting. Workers subject to environments where flicker is a problem, complain of headaches, eyestrain and fatigue. What’s more, a lot of people are completely unaware that they have a problem.
Flicker frequencies are relatively low, but fast enough to mean that a line interactive UPS can do nothing about them. In fact, the transformer in a line interactive system may make flicker even worse. The only way to cure flicker, is either to remove equipment that is causing the flicker, remove the equipment that is showing the flicker, or fit an online double conversion UPS system. This will provide smooth power to the systems, eliminating flicker, and of course, protecting against all other power anomalies along the way.
