Applied Research On The Port Model Of Transformer Windings Based On Transmission Line Theory

Power transformer plays a very important role in the power system, and it is one of the main components in the power network. Transformer contacts with the power grids of different voltage levels. We know that the power system often encounters the high frequency overvoltage signal such as lightning. etc, which has caused great harm to the operation of equipment. So it is very important to study on the influence for the port of the high frequency voltage signal when we designing the insulation of transformer and the other equipments in power system.In order to study the influence on the transformer port characteristics of voltage or current when encountered the overvoltage signal such as lightning, the port model of the transformer’s whole windings by transmission line theory is established. According to the physical structure of the transformer windings, the basic parameters of the transformer windings are calculated by the analytical method. Through the experimental measurement for the transformer windings and the simulation for the port model, the feasibility and correctness of the port model by transmission lines method is verified. Furthermore, when simulating the transformer encountered the lightning, we use this model to discuss the variational characteristics of terminal current of primary winding by changing the transformer ’s loadings. Some theoretical reference is given through the conclusion of this paper when doing the insulation design of transformer or others’ equipments in power system.