A software design technique for differential protection of power transformers

This paper presents design software for Fourier Transform based logic technique for protection of transformer. This software is designed to simulate the operation of the digital differential relay for electrical power transformers. It improves and enhances the sensitivity of operation of the digital differential relay that protects power transformers by discriminating between inrush current and fault current without blocking the relay during the energization of power transformers, as well as avoiding tripping during the normal operation of tap changer. The digital differential relay is designed using a simulation technique in Matlab Simulink environment. The different tests are selected to simulate different cases of operation and faults.