Electric power quality

Good power quality can be defined as a steady supply voltage that stays within the prescribed range, steady AC frequency close to the rated value, and smooth voltage curve waveform (which resembles a sine wave).

Without the proper power, an electrical device (or load) may malfunction, fail prematurely or not operate at all.

Compatibility problems always have at least two solutions: in this case, either clean up the power, or make the equipment more resilient.

[3] Ideally, AC voltage is supplied by a utility as sinusoidal having an amplitude and frequency given by national standards (in the case of mains) or system specifications (in the case of a power feed not directly attached to the mains) with an impedance of zero ohms at all frequencies.

Harmonic problems can be dealt with by a combination of good design practice and well proven reduction equipment.

Modern systems use sensors called phasor measurement units (PMU) distributed throughout their network to monitor power quality and in some cases respond automatically to them.

Electrical utilities carefully monitor waveforms and currents at various network locations constantly, to understand what lead up to any unforeseen events such as a power outage and blackouts.

This is particularly critical at sites where the environment and public safety are at risk (institutions such as hospitals, sewage treatment plants, mines, etc.).

They measure, for example: In order to sufficiently monitor unforeseen events, Ribeiro et al.[7] explains that it is not enough to display these parameters, but to also capture voltage waveform data at all times.

Nisenblat et al.[9] proposes the idea of power quality compression algorithm (similar to lossy compression methods) that enables meters to continuously store the waveform of one or more power signals, regardless whether or not an event of interest was identified.

By using prediction and modeling on the stored time series in the actual power quality archive the efficiency of post processing compression is usually further improved.

The quality of electricity supplied is set forth in international standards and their local derivatives, adopted by different countries: EN50160 is the European standard for power quality, setting the acceptable limits of distortion for the different parameters defining voltage in AC power.