The end-consumers need high quality of electrical energy like safe, continuous voltage supply with the required current at constant rms values and at constant frequency, then pure sinusoid waveform of voltage. If the rated voltage of computers will be dropping down to its 75% the disturbance in their operation appears and at 50% they will loose their ability for work, then the acquired data, the envisaged commands will be lost. Flicker occurs when high power is fluctuating providing changes in voltage that makes the human eyes fatigue. Long-term flicker severity index must be less than unity otherwise it jeopardizes the smooth operation of other consumers In the vicinity of huge arc furnaces in urban area networks a basic flicker index ranging between 0.2 and 0.25 was recorded. Harmonic spectrum is different if computers working only in a room, then the total harmonic distortion was 3.47%. When luminescent light sources were also working the distortion increased up to 4.71% and when welding equipment were added in a workshop the total harmonic distortion went up to 10.98%. If it reaches 10% then the acquired data, commands, control signals will be lost, the operation of consumers and manufacturing process will be out of order, thus re-installation or even repair is needed for the computers.

http://ieeexplore.ieee.org/iel5/4492963/4510466/04510491.pdf

Black Africa

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Electrical Energy Quality Role on the Globe