Analysis of loss of receiving transformer caused by harmonic current and voltage for loss reduction

Recently, harmonic current flowing into power system is increasing due to power electronics equipments. In addition, harmonic voltage is also increasing according to the increase of harmonic current. Harmonic current and voltage may cause increase of loss in receiving power transformers. However, systematic analysis of the loss of receiving power transformers has not been studied. The authors has been tried to analyze the relationship between loss in receiving transformers and harmonics. A 20kVA power system simulator was developed in order to achieve this study. There are however several problems to be solved to get enough date to establish the equation between loss and harmonics. In this paper, experimental results of loss of receiving transformer after some improvements will be reported. The obtained data is accurate enough to analyze loss caused by harmonics. In addition, the reduction effect of the losses using a power-factor improving capacitor at low-voltage side will be discussed through theoretical analysis and experiments.