Accurate Estimation of Frequency-Dependent Losses in High Voltage Test Transformers for the Assessment of Electric Discharge Powers

Abstract

The work presented in this paper is related to the project GEMUDE (Genérateur Multifonction de Décharge Electrique) which aims to design a universal high-voltage generator for electrical discharge studies. To design this variable high voltage source that operates in the frequency range of 0 to 1 kHz, the assessment of transformer losses represents a crucial phase during the design process. These losses in the coils and iron core of the transformer are closely related to the frequency and nature of the materials used. This paper presents a comparative study of transformer losses using analytical methods and experimental calorimetry measurements. Steinmetz empirical formula is used to estimate magnetic core losses whereas coil losses are evaluated by solving Maxwell equations. The main goal is to control these losses to limit the internal temperature rise in the transformer through the implementation of an efficient cooling solution. The results obtained by the analytical method were satisfactory which confirm the feasibility of measuring the power absorbed by the various electrical discharge devices upstream of the high-voltage transformer. This is because it turns out that the power of the generator in charge is the total power of the electric discharge and the transformer losses. This method, termed Power Disparity Method (PDM). In this paper, it is an easy and reliable way as compared with high voltage measurement methods.