Development Of Single-Phase Double Split Set-up Transformer

With the development of the global power industry and the humanity to the more high material civilization pursuit,the energy demand from human is obviously increasing.At the same time,in order to improve the efficiency of generator,the unit capacity of generator is increasing day by day.The unit capacity for thermal power has been developed from 300MW,600MW to 1000MW,and the unit capacity for hydropower has been developed from 150MW,300MW to 700MW for Three Gorges project.Nevertheless,the hydropower station is normally located in the remote mountain,the withstand ability of the road and the bridge is limited,and the condition of transportation is difficult.So,the large capacity,three-phase transformer can not be transported because of weight and size,and the weight and the size of transformer need to be decreased.For decreasing the weight and the size of transformer,we may think that the three phase transformer can be designed to three single phase transformers,but the quantity of accessories for three single phase transformers is three times of one three phase transformer’s,and the quantity of silicon steel sheet and oil for three single phase transformers is 1.25 times of one three phase transformer’s.Currently,the marketing competition of transfomer industry is very intense,the low losses,the low weight and the low cost has been the main requirements for entering the transformer market.Considering the cost and the requirement of transportation,the double split transformer will be a developing direction.This thesis analysed and calculated the working principle of the double split transformer under the background of generator set-up transformer(Single phase 147MVA,400kV double split transformer)for the GIBE III project in Ethiopia.There is modeling and simulation optimization for the design,and the design was demonstrated by the test data.Firstly,the comparsion for User requirements and operating conditions,Through multiple argument analysis to reach single phase double split transformer It can meet the needs of users.Discusses in detail the operating principle and structure characteristics of double splitting single-phase step-up transformer.single-phase four-limb,there are two core limbs and two side linbs,and the structure of oil ducts is cross type.The HV winding is parallel of two limbs,and the two LV windings are individual,the winding type of two limbs is same and the direction is opposite.It is the key of double split transformer.Secondly,on the base that the core and winding structure of split transformer was understood,the scheme was calculated and designed according to the structure feature and the requirement of consumer.And the best scheme was confirmed through modeling and simulation calculation for electric field,magnatic field,temperature field and mechanical force etc by professional software.The manufacturing drawings were drawn in accordance with the best scheme.Last,through the rationality verified by the factory test and the accuracy of the modeling and the simulation calculation,and the modification of the no load loss factor and the stray loss factor etc,the most reasonable formula can be confirmed.