Research On Temperature Characteristics Of Transformer Short Circuit Based On The Micro Grooves Of Composite Phase Change Cooling Technology

Power transformer is one of the important electrical equipment in the power system and has a very important significance to the power grid in the stability of the power transmission, the rationality of the a llocation, safely use and economical operation using. T he operation of transformer in the system will have the occurrence of a short circuit that people try to avoid and cannot be absolutely avoided, and its ability to withstand short circuit size is direc tly related to the safe and reliable operation of the power grid. Along with the rapid development of China's national economy and continuously expansion and transformation of power grid in our country, more and more large power transformer has been put in to use in the power grid, but in the course of its operation when the transformer is subjected to the impact of short-circuit current, due to lack of the ability to withstand short circuit current caused by the poor thermal stability of transformer insulat ion breakdown and damage accidents happen frequently, which has become a prominent problem in power transformer. T herefore, it's imperative that to find better transformer cooling methods to improve the ability of anti-short circuit.In this paper, combined with domestic and foreign research present situation of electric power equipment cooling technology, based on the application of engineering practice, according to the ba sic principle of heat transfer and the classical experiment heat transfer principles, analyzes the internal heat source and thermal radiation of power transformer. Summarizes the traditional cooling methods of transformer and points out its shortcomings or deficiencies, and analyzes the short-circuit temperature characteristics of transformer winding when using traditional cooling methods. Introduces the micro grooves composite phase change cooling technology( referred to as MGCP) and its application in detail. On this basis, the micro grooves composite phase change cooling technology(MGC P) is applied to transformer, using large-scale finite element analysis software ANSYS to calculate the short-circuit temperature characteristics of large oil immersed power transformer based on MGCP.Firstly, analyzes the feasibility of MGCP applied to t he transformer cooling in detail, discusses the composition and working principle of transformer cooling system using MGCP, obtains the transformer model based on MGCP, and points out the advantages of the cooling system of transformer based on the micro grooves composite phase change cooling technology.Secondly, using ANSYS software to establish the model of transformer, with transformer windings for solving area, calculates and solves the solid winding using traditional cooling methods and the hollow winding based on MGCP. For the adoption of MGCP hollow winding, by controlling the pressure setting of the phase transition temperature of liquid refrigerant in the winding are respectively 60 ?, 70 ? and 80 ?. Calcu lates the temperature field of solid winding using traditional cooling method and hollow winding based on MGCP, when the transformer rated load operating, and the simulation results are analyzed and verified the power transformer based on MGCP has the advantages of high heat radiating efficiency and good temperature control ability; studies the highest temperature of the winding when transformer under different short-circuit current in three seconds, five seconds, ten seconds; compares the longest time of the traditional solid winding and the hollow winding based on MGCP can understand under different short circuit current when transformer is short circuited; A comprehensive analysis of liquid medium with different phase change temperature effect on the temperature of transformer windings based on MGCP.Finally, according to the results of solving comparative analyzes the short-circuit temperature characteristics of the transformer based on MGCP, and the conclusion is given.The research of this subject provides a theoretical basis for the future perfecting the design of transformer cooling system structure and enhance its ability to withstand short-circuit, for the similar research provides a reference, has certain theoretical and engineering application value.