MODELLING & SIMULATION OF PROTECTION RELAY OF POWER TRANSFORMER

Abstract

In the power system network, the transformer is an essential component. When a distribution or transmission substation is out of operation due to a breakdown, they are more expensive. The transformer's protection is a crucial element in ensuring the system's correct operation. As a result, it is required to investigate the operation of the transformer's protections. We are attempting to mimic the main and backup protection of a transformer in this project. In the study of the impacts of different faults and configurations on the operation of these relays, modelling and investigation of various protection relays is critical. The first part of this dissertation presents a method to simulate the Overcurrent relay for a transformer. Overcurrent relay is also used to protect transmission and distribution feeders, and bus couplers, among other things. Overcurrent protection can be utilised as the primary or secondary protection. The second part presents the simulation of differential relay which is used as the main protection of the power transformer. Differential relays are also used to protect bus-bars, generators, small transmission lines and other electrical equipment. Although it can only be used to defend against internal defects and not exterior faults, this relay is the most significant protection. The current project is about a three-phase transformer with a 250MVA rating and a voltage rating of 735kV/315kV. For the sake of avoiding erroneous results, both relays are modelled individually using generally used MATLAB/SIMULINK software. The simulation is run under a variety of faulty circumstances. Many issues, such as Tap altering, inherent phase-shift of currents in transformer, CT ratio, and non-identical CT, were encountered while simulating the differential and overcurrent relay model. The information comes from a research paper. The settings will then be simulated in MATLAB/Simulink, and the various relays will be simulated according to the accessible panel.