Supply voltage quality in low voltage industrial networks of Estonia

Abstract

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.

Influence of supply voltage and frequency variations on the electrical equipment and power consumption in LV and MV distribution networks

“…Supply voltage quality is a complex term concerning voltage deviations from its ideal characteristics. A practical approach for the analysis of supply voltage quality parameters by means of stochastic theory is discussed in [3]. The main problem for consumers is often supposed to be too low voltage in the feeder.…”

“…As the network's impedance varies slightly, the voltage variation is mainly due to load current variations. Therefore, the voltage on the transformer's secondary side is often stepped up to ensure the rated voltage level during peak loads [3]. The other issue influencing PQ is the rising penetration level of distributed generation (DG) in LV distribution networks.…”

“…Although under normal operating conditions the voltage variations at the customer's side are considered to be of a stochastic character and can be described by a normal distribution [3], this may not be the rule for all consumers and for all points in the LV/MV distribution power grid. For the example discussed in the previous sections, the null hypothesizes of Gaussian distribution of voltage and frequency were validated and accepted.…”