Power quality monitoring

The power quality subject contains various aspects which have to be included in the quality of service, as perceived by the customer. We have exposed some definitions and notions, used in power quality monitoring, with for instance the planning levels, which are to be monitored as internal power quality objectives of the utilities. The parameters defined in the existing standard are bi-dimensional, introducing a notion of time as well as levels. The trend curve of the harmonics, time related measurement methods and the algorithms are totally defined in the standard, involving mean values, RMS values, peak values with a 95% statistic. The equipment necessary to record these parameters has to be wide spectrum bandwidth and with a great processing capacity, in order to respect the integration time, and the observation period for each parameter. A pragmatic approach has to be followed in order to do the balance between the economical cost of improving the PQ at the source, and the process of limiting the pollution of the disturbing loads and improve the immunity of the devices critical for the continuity of the industrial processes