Calculation and validation of iron loss in laminated core of power and distribution transformers. (2014) - ,
Abstract : Purpose – The purpose of this paper is to present a simple method to analyze the iron loss in the laminated core of power and distribution transformers.Design/methodology/approach – This paper presents a practical method to calculate the no‐load loss in the transformer cores. Considering the non‐uniformity of the magnetic flux density in the corner areas of the Epstein frames will affect the measurement precision of the Wt‐B curves then further affect the core loss calculation in FEM, a dual‐Epstein frame method is used to measure the Wt‐B curves with the Epstein sample stripes cutting by different angles to the rolling direction. A 2D FEM that considers the type of joints of the core and eddy current effect in the laminations is used to analyze the core loss with multi‐angle Wt‐B curves.Findings – The impact of lamination thickness, size of gaps and type of joint of the core are considered. Considering the no‐load testing conditions, harmonics in the exciting currents are taken into account.Originality/value – Harmonic wave of magnetic flux density in the transformer core is calculated and the core loss in the joint region is calculated by the loss curve measured with dual‐Epstein frame. It makes the calculation result of transformer core loss more exactly. Acknowledgements : The authors acknowledge valuable discussion with senior engineer Qifan Hu (the former Chief Engineer of Baoding Transformer Works) during the preparation of this paper and also acknowledge the help from Lanrong Liu, Yana Fan and Tao Liu (the engineer in R&D Center, Baoding Tianwei Group Co., Ltd).