Assessment of Voltage Distortions in Power Supply Systems of Industrial Enterprises

Deviations of the power quality indicators (PQI) from their standardized values in the power supply systems of industrial enterprises entail the issuance of defective products, complete shutdown of technological processes, and significant damage. At the same time, industrial consumers pose different requirements for PQI, with the most stringent ones posed by especially critical electricity receivers. To ensure their reliable operation, it is necessary to implement devices that automatically monitor PQI by evaluating the extent to which the three-phase system sinusoidal voltage waveform is distorted. This information enables the on-duty personnel of power grid companies and industrial enterprises to promptly make decisions on the implementation of measures in the external and internal power supply networks for bringing the PQI into the range of permissible values. A generalized indicator for evaluating the sinusoidal voltage waveform distortion degree is suggested. The proposed indicator is based on the modulus characterizing the ratio of a spatial vector's positive and negative rotation complex amplitudes. The article presents block diagrams of algorithms and structural diagrams of automatic PQI monitoring devices, in which parametric and nonparametric multi-hypothesis sequential analyses involving the use of the generalized indicator are implemented. In the study, Palmer's algorithm and the nearest neighbor method are used. The computation results have demonstrated that the developed algorithms feature fast operation and highly efficient detection of PQI deviations.