Title :
Denoising of the neutral current using wavelet for diagnosis of the transformer
Author :
Rao, P. V Kanaka ; Jaya Krishna, B. ; Bhoomaiah, A. ; Singh, B.P. ; Shekar, Chandra M. ; Naidu, Appala P.
Author_Institution :
VNR-Vignana Jyothi Inst. of Eng. & Technol., Hyderabad
Abstract :
Insulation failure within transformer winding is considered to be one of the most important causes of failure of the power transformer. Comparison of neutral currents at reduced and full voltages is an important criterion for detection of fault in the power transformer winding during impulse test. Any difference in wave shape of the recorded current and voltage signal shows the failure of transformer. In this paper, identification and separation of a noise signal from the main neutral current are carried out using wavelet technique. In order to carry out analysis faults are created in discs of the windings of a 61 MVA, 11.5/230 kV generator transformer at different locations. Neutral currents are recorded by applying low impulse voltage. Contribution of each frequency in time domain signal is calculated by Daubechies wavelet. The proposed method can be used for isolating the contribution due to any noise frequency in the waveform.
Keywords :
fault diagnosis; frequency-domain analysis; power transformer insulation; time-domain analysis; transformer windings; wavelet transforms; Daubechies wavelet; apparent power 61 MVA; generator transformer; insulation failure; neutral current denoising; noise signals; time domain signal; transformer diagnosis; transformer winding; voltage 11.5 kV; voltage 230 kV; wavelet techniques; Fault detection; Impulse testing; Low voltage; Noise reduction; Noise shaping; Power transformer insulation; Power transformers; Shape; Signal processing; Windings;
Conference_Titel :
Electrical Insulation Conference and Electrical Manufacturing Expo, 2007
Conference_Location :
Nashville, TN
Print_ISBN :
978-1-4244-0446-9
Electronic_ISBN :
978-1-4244-0447-6
DOI :
10.1109/EEIC.2007.4562577
