A Study on Zero Sequence Impedance of 3-limb Core Transformer

Abstract

As the penetration of the distributed generation gradually increases, the influence by the distributed generation to the power system also increases. Most of the distributed generations is interconnected with the power system through 3-limb core transformers due to relatively cheap price. However, 3-limb core transformers are different with transformers which have another core structure in terms of zero sequence impedance, especially zero magnetizing inductance. However, many 3-limb core transformer manufacturers do not provide zero sequence impedance test data for the 3-limb core transformer. Therefore, a method of estimating the zero sequence impedance of the 3-limb core transformer is needed without testing data. So, this paper proposes a novel method for estimating the zero sequence magnetizing inductance.