Research on electromagnetic field optimization of a 35 kV transformer

Abstract

Under long-term high-load operating conditions, electric field concentration and magnetic flux leakage in transformers can adversely affect operational stability. To address the insufficient attention paid to the coordinated optimization of electric and magnetic fields in existing studies, this paper investigates the electromagnetic field distribution characteristics of a 35 kV laminated-core transformer. First, a three-dimensional electromagnetic field model is established. Subsequently, based on the finite element method, the electric and magnetic field distribution characteristics under rated and load operating conditions are analyzed. The results show that the electric field is mainly concentrated at winding ends, while most magnetic flux forms closed loops along the iron core. On this basis, coordinated optimization of electric field concentration and leakage magnetic flux is carried out by moving the windings closer to the transformer core to improve magnetic flux distribution, while increasing the insulation thickness between the high-voltage and low-voltage windings to reduce local electric field intensity. After optimization, the maximum electric field intensity decreases from 9.257 kV/mm to 5.834 kV/mm, while the peak magnetic flux density is reduced from 2.57 T to 2.27 T. The study confirms that increasing the insulation spacing can effectively suppress local electric field concentration and reduce electric field intensity. Optimizing the winding structure can reduce local magnetic flux concentration in the transformer core. This study can provide reliable references for the electromagnetic design and insulation optimization of medium- and high-voltage transformers.