This paper is focused on active power consumption and losses in industrial and commercial facilities, depending upon supply voltage quality parameters. The shunt capacitors for power factor correction affect directly supply voltage level and harmonic distortions of supply voltage and current and hence affect power losses in industrial facilities, particularly in induction motors. In the paper practical measurement methods are described for estimating power losses when power factor correction capacitors are used. The impact of capacitors upon supply voltage level and harmonic distortions is discussed. Measurement results of voltage and current harmonics spectrum in industrial 0,4 kV power systems are shown.

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This paper is focused on the measurement and analysis of supply voltage quality in low voltage industrial power systems in Estonia. A practical method for analysis of supply voltage quality parameters, implementing stochastic theory, is discussed. Measurement results of supply voltage quality parameters-voltage magnitude, voltage events, harmonics, flicker and unbalance in industrial 0.4 kV power systems of Estonia-are shown.

High-power industrial spotwelding machines make use of transformers that have very high reactive power consumption. Simple reactive power compensation schemes cannot be used however, because of the cyclic nature of the spot welding transformer operating. This paper describes the development of a simple reactive power compensator solution for the spotwelding machines. Focus is also put on the transformer saturation and current transients that can emerge from deployment of such reactive power compensation methods. Fig. 1. Schematic of a spot welding machine.