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Detection of Near Failure Winding due to Deformation in 33/11kV Power Transformer by using Low Voltage Impulse (LVI) Test Method and Validated through Untanking
Abstract:Power transformer consists of components which are under consistent thermal and electrical stresses. The major component which degrades under these stresses is the paper insulation of the power transformer. At site, lightning impulses and cable faults may cause the winding deformation. In addition, the winding may deform due to impact during transportation. A deformed winding will excite more stress to its insulating paper thus will degrade it. Insulation degradation will shorten the life-span of the transformer. Currently there are two methods of detecting the winding deformation which are Sweep Frequency Response Analysis (SFRA) and Low Voltage Impulse Test (LVI). The latter injects current pulses to the winding and capture the admittance plot. In this paper, a transformer which experienced overheating and arcing was identified, and both SFRA and LVI were performed. Next, the transformer was brought to the factory for untanking. The untanking results revealed that the LVI is more accurate than the SFRA method for this case study.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1061655Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2684
 R. C. Degeneff, M. Loose, "Overview of the Transient Performance of Coils & Windings as a Function of their Impedance Versus Frequency Characteristic," Proceedings EPRI Substation Equipment Diagnostics Conference X, San Antonio, 2002
 K. Feser, J. Christian, C. Neumann, U Sundermann, T. Liebfried, et.al, "The Transfer Function Method for Detection of Winding Displacements on Power Transformers After Transport, Short Circuit or 30 Years of Service", CIGRE Paris, paper no. 12/33-04, 2000
 L. Coffeen, J. Hildreth, "A New Development in Power Transformer Frequency Response Analysis to Determine Winding Deformation WITHOUT the Need for Comparison to Historical Data
[The Objective Winding Asymmetry Test]" Proceedings EPRI Substation Equipment Diagnostics Conference X,San Antonio, 2002,
 L. Coffeen, J. Hildreth, "A New Development in Power Transformer Off-Line & On-Line Frequency Response Analysis," Proceedings EPRI Substation Equipment Diagnostics Conference IX, New Orleans, 2001
 L. Coffeen, U.S. Patent 6369582, "System and Method for Off-Line Impulse Frequency Response Analysis Test"
 Julius S. Bendat, and Allan G. Piersol, Engineering Applications of Correlation and Spectral Analysis, Second Edition. John Wiley & Sons, Inc. 1993.
 James E. McBride, and Larry T. Coffeen, "The Application of Spectral Density Based Estimates in Processing Digital Records from High Voltage Measurements", International Symposium on Digital Techniques in High-Voltage Measurements, Toronto, 1991
 L. Coffeen, J. Britton, J. Rickmann, E. Gockenbach "A New Objective Technique to Detect Winding Displacements in Power Transformers Using Frequency Response Analysis, Without the Need for Historical Data" accepted paper for the ISH 2003 in Delft, Netherlands
 L. Coffeen, J. Britton, J. Rickmann " A New Technique to Detect Winding Displacements in Power Transformers Using Frequency Response Analysis", accepted paper for the Bologna Power Tech ÔÇÿ2003 conference