Finite Element Analysis of Thermal Performance Behavior in Medium Voltage Current Transformer

Abstract

Current transformers reduce large current values to measurable current values in electrical systems and provide isolation of various measuring instruments and relays from the main electrical system. Voltage current transformers are produced according to the tests defined in national and international standards during the production phase. In order for the relays used for protection in electrical systems to work correctly, medium voltage current transformers must be within the verified operating range. For this reason, it becomes very important for current transformers to work correctly. In case the main current has a harmonic structure, the operating range of the protection type medium voltage current transformers can change significantly. In this paper, it the steady-state thermal performance behaviour in a medium voltage current transformer is studied and analysed. The study was carried out considering four different loads. The numerical results of the temperature distribution were obtained using a 2D finite element software package. The iron losses in the core region were calculated using the maximum flux density that was obtained with a 2D finite element software package. The numerical solutions were compared with measured experimental results that were obtained in tests. Some conclusions are remarked.