Analysis of non-symmetrical operating conditions of 0,38 kV rural networks

摘要

Formulae are given for determining approximate values of positive-sequence currents, negative-sequence currents and zero-sequence currents by using the values of three phase currents. Calculations of a typical 0,38 kV rural network withtransformer windings connected in star-star-zero and star-zigzag-zero are carried out. It is shown that in contrast to the negative-sequence coefficient of voltages the values of the zero-sequence coefficient of voltages when transformerwindings are connected in star-star-zero largely exeed the ones established by the State StandardГOCT 13109-87. Power losses are less in a network with transformers connected in star-zigzag-zero.