Abstract
This paper deals with the fault diagnosis methodology for the V/x-type traction transformer in railway passenger-dedicated lines. A kind of the protection methodology to combine empirical mode decomposition (EMD), energy weight, and information entropy is proposed. This method can sensitively reflect the dynamic information changes of traction transformer differential current, so it can not only effectively identify internal short-circuit fault current from magnetizing inrush but also better identify fault current accompanied with magnetizing inrush. In this method, the differential current is decomposed by EMD and the energy weight of each intrinsic mode function (IMF) is calculated, and the feature vector of the fault pattern recognition is obtained by constructing IMF energy entropy. The field-measured data illustrate that the new method not only has the advantages of high sensitivity, faster identification speed, and clear concept but also is available for the diagnosis of the complicated dynamic system.
Highlights
V/x-type traction transformer is one of the key equipments in the power distributing system of high speed train way
This paper focuses on this new methodology; the differential current signals are first decomposed into a number of IMF components under different time scales using empirical mode decomposition (EMD) algorithm and the energy weight of each intrinsic mode function (IMF) and differential current signal is calculated in a power cycle
The IMF energy entropy is constructed based on energy weight which is sensitive to variation of differential current information, and this entropy value is defined as the feature vector of distinguishing between magnetizing inrush and internal short-circuit fault current
Summary
V/x-type traction transformer is one of the key equipments in the power distributing system of high speed train way. Model-based identification methods have flux linkages increment method [1], combined method of magnetizing inductance and loop equilibrium equation [2], equivalent circuit parameters method [3], magnetic flux symmetry property method [4], dynamic impedance characteristics [5], and so forth Advantages of this type of methods is that it is able to distinguish magnetizing inrush from internal short-circuit fault current on the presupposition that the related electric parameters can accurately be acquired, but some main electrical parameters cannot be accurately measured in the practical applications. The IMF energy entropy is constructed based on energy weight which is sensitive to variation of differential current information, and this entropy value is defined as the feature vector of distinguishing between magnetizing inrush and internal short-circuit fault current
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