The Study And Development Of Transformer Protection Based On The Equivalent Circuit Equation

Power transformers are amongst the most essential elements in power system. Whether transformers can operate under normal state has a direct influence on the reliability of the entire power grid. In this paper, initially, the current research of transformer protection and its tendency of development are summarized. Further, the most existing methods for discrimination between fault current and magnetizing inrush current are compared and evaluated. Then, a new transformer protection scheme based on transformer equivalent circuit equation is proposed, which theoretically addresses the differential protection problem that has long been a conundrum for many researchers--discriminating fault current from magnetizing inrush current.A novel transformer protection device is developed on MPC555 embedded hardware platform using the novel protection scheme. Firstly, a brief introduction for this hardware platform of the protection device is presented. Secondly, the configuration, algorithm, design scheme, as well as auxiliary function of the protection are introduced in detail. Finally, by conducting dynamic analogy experiment, the feasibility and correctness of the protection scheme are tested.