An Integrated Harmonic-Filtering Transformer for Low-Voltage Distribution Systems

Abstract

In order to deal with the increasingly harmonic problems caused by nonlinear loads and the consequent distribution transformer noise problems in low-voltage distribution systems, a harmonic-filtering distribution transformer applied in the 10/0.38kV box-type substations is designed and fabricated. As a result, the passive harmonic filters are contained and installed in the substations to work together with the existing distribution transformers. However, due to the space and size physically confined in the substations, it is unsuitable to use air-core reactor based filters because of the large volume and electromagnetic interference. Therefore, PPFs with iron-core reactors are generally taken into account. However, there are undesired impacts on the filtering performance of them, affected by magnetic saturation in iron-core inductors, and serious noise pollution, caused by vibration, as the iron-core inductors operate in various conditions. In this paper, a new-type distribution transformer with filtering inductors integrated is presented, attempting to improve the situations described above.