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Mr Ashok Chavda
Dr. Vivek Pandya


Sweep Frequency Response Analysis has become very popular now – a - days due to its ability to provide comprehensive information regarding mechanical as well as electrical condition of power transformers. The SFRA is a signature test and provides better information when evaluation of Transformer condition is done by comparing actual set of SFRA results with reference results. This field experience refers to 400/220/33KV ICT bank, formed with three single phase units – each with capacity of 167MVA. Heavy fault current was fed through ICT due to failure of LA provided on external delta formation of Tertiary winding. Mechanical defects / deformation occur ostensibly due to short circuit current flowing through transformer winding in case of terminal faults i.e. fault adjacent to / on the power transformer. To ascertain mechanical integrity of power transformer, SFRA test is carried out and is supported by other tests i.e. capacitance and tan delta measurement etc. The test results reveal that SFRA is capable of providing more information about mechanical deformation of active parts of power transformers - compared to other tests

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[1] E .P. Dick and C. C. Erven,, Transformer Diagnostics Testing by Frequency Response Analysis”, IEEE Transaction on Power Apparatus and Systems, Vol.97,pp. 2144 2153,Nov/Dec.1978.
[2] Asif Islam, Shahidul Islam Khan and Dr. Aminul Hoque, Detection of Mechanical Deformation in Old Aged Power Transformer Using Cross Correlation Co-Efficient Analysis Method”, Energy and Power Engineering, Vol.3, pp. 585–591,January 2011.
[3] M. Arul Sathya, Usa Savadamuthu, Prediction of Change in Equivalent Circuit Parameters of Transformer Winding Due to Axial Deformation using Sweep Frequency Response Analysis, Journal of Electrical Engineering and Technology, Vol.10, pp.983–989,May 2015
[4] Hormatollah Firoozi, Nami Mahmoodi, Mohammad Kharrazi and M.I.Ghiyasi,, Frequency response analysis- Low frequency characteristics and fault diagnosis on power transformers”, IEEE International Conferences on Solid Dielectrics,Postdam,Germany,July2010.
[5] K. Ludwikowski, K. Siodla and W. Ziomek, Investigation of transformer model winding deformation using sweep frequency analysis, IEEE transaction on Dielectrics and Electrical Insulation, Vol.19. December 2012