Analysis Of Operating Characteristics And Turn-to-Turn Faults Of The Locomotive Transformer With Split Types Of Multi-Windings

Transformers are widely used in power systems and play the most important role in it.Therefore,it is necessary to conduct a comprehensive and in-depth study for its related issues.In the thesis taking a transformer with 4-split types of windings as an example,an axisymmetric model of field-circuit coupling analysis based on ANSYS is established,and some operation characteristics and turn to turn fault of the working condition are studied by it.The following work is specifically completed:(1)A field-circuit coupling analysis method based on ANSYS is used to study the turn to turn faults of transformer,such as the simulation of turn to turn fault,etc..and of course,the correctness of the analysis model is verified by studying on operation characteristics of transformer under relevant working conditions.(2)The turn to turn faults of a winding are studied in depth,including the current changes of different windings,such as in the faulty or the non-faulty parts of the winding,or in the short-circuit winding or the normal winding.As well as the characteristics of the impedance changes at the entry end of the primary wingdings is also calculated.Furthermore,the following cases are studied respectively that the turn to turn faults with the same turn number is at the different location of a winding,or the turn to turn faults with the different turn number is at the same location of a winding,and the turn to turn faults has a characteristics of metal or non-metal short circuits.Obviously these can provide reference for judging short circuit fault and its degree.(3)At the same time,the electromagnetic force in turn-to-turn fault is also studied,including the whole electromagnetic force of a winding when the turn-to-turn fault occurs,which is compared with that of the normal operation of transformer.Moreover a distribution of the electromagnetic force density along the given path is analyzed.(4)In view of the fact that there are few literatures on the research of split locomotive transformer by the field-circuit coupling analysis method,the work completed in this thesis maybe provide some references to the research of the locomotive transformer or other similar one.At the same time,some suggestions are put forward on how to further improve the field-circuit coupling method to analyze such problems.In a word,a beneficial practice in analyzing transformer problems by using field-circuit coupling method is has been done in the thesis,and the results and conclusions obtained from it have certain engineering application value.At the same time,it also points out the shortcomings in the thesis and the direction of follow-up work.