Determination of error of loss calculations in double wound transformers using L-shaped substitution scheme by conditional method constant coefficients
When calculating the modes of electric networks, an L-shaped circuit is used to replace one phase of the transformer with bringing its parameters to high voltage (HV), neglecting losses in the HV winding. More precisely, they can be taken into account using a T-shaped substitution scheme. In order to determine the error of the use of the L-shaped scheme in comparison with the use of the T-shaped scheme, the method of conditionally constant coefficients (CPC) was used, which was adapted to calculations using the L-shaped substitution scheme. By the method of the CPC, studies of the modes of the module "double-winding transformer - load (DTN)" were carried out in order to determine the error in calculating the total power losses of the transformer when using the L-shaped equivalent circuit in comparison with the T-shaped one. It was shown that the error in calculating losses for a 25 kV×A transformer was 2%. The research results presented in this article are recommended to be applied in existing electrical networks for a more accurate calculation of modes and losses in transformers when using the L-shaped equivalent circuit.