The Research Of Loss In Power Transformers And Optimize Design

The main object of this research is concerned with the loss of power transformer, which makes important effect on the cost of the manufacturing and operating. Based on many literatures of China and foreign countries, comprehensive and thorough research has been made. Some results in theories and practical engineering are given.First, it studied no-load loss of power transformer. Three important parameters, which are core technology coefficient, loss per kilogram and weight of core, are compared and analyzed. Core technology coefficient is given. Some main factors to affect core technology coefficient are discussed, and some measures to reduce no-load loss are presented.Second, it studied deeply on-load loss of power transformer. Several main factors, such as eddy current loss and stray loss, which affect the safe operation and cause partial overheat, are analyzed in details. Measures to reduce the eddy loss and the stray loss are given. Reliability and economic of transformer are improved availably.Third, based on the example of over proof on-load loss in 180MVA/220kV power transformer, the eddy loss in winding is analyzed with the leakage flux element software. Some conclusions with practical use are given. In order to reduce the load loss, primarily we should reduce radial leakage flux of transformer possibily. Through which, we can not only reduce the eddy loss and the stray loss availably, but also reduce latent endanger on transformer that caused by partial overheat. Meanwhile it can reduce short circuit mechanical force and improve reliability and economics of transformer significantly. The methods to reduce radial leakage flux are given detailed.Forth, 150MVA/220kV high impedance transformer is calculated by finite element software of leakage field. The short-circuit impedance, winding eddy loss, structural part stray loss and short-circuit electrodynamics are analyzed. It made beneficial conclusions: It is effective to analyze the short circuit impedance, winding eddy loss, structural part stray loss and short-circuit electro-dynamics of high impedance transformer by using finite element software of leakage field. It draws lessons for enhancing reliability and economics of that type of high impedance transformer. It is necessary to adopt perfect shielding measure at tank cover, wall and bottom on high impedance transformer.Finally, the model of optimize design is established. The function and characteristics of the software of optimum electromagnetic design of 35kV, 110kVpower transformers are introduced, some practical examples and results to optimize design are given.