On-Line Diagnosis of Power Transformer Insulation System: Experience of CPRI, India


H. N. Nagamani
T. Bhavani Shanker


Power transformers play a vital role in handling large amount of power from generating stations [through Generating Station Units(GSU] to transmitting stations (through power transformers) and to end user through distribution transformers. Power transformers involve large amount of capital investment and the failure of transformers causes severe fi nancial loss to the utility and inconvenience to the end users. Periodic maintenance and condition monitoring are the key factors for successful operation of power transformers. A number of diagnostic tools are in vogue. Most of these tests are conventionaloff-line techniques and require power shut down and disconnection of transformer from the circuit. Several alternate nonconventional on-line techniques are being adopted and Acoustic Emission (AE) technique is one among them. Central Power Research Institute (CPRI), India, is employing AE technique for on-line diagnosis of power transformers. Nearly 200 transformers have been tested and investigated covering rating up to 315 MVA, 400 kV.>p/p


How to Cite
Nagamani, H. N., & Bhavani Shanker, T. (2012). On-Line Diagnosis of Power Transformer Insulation System: Experience of CPRI, India. Power Research - A Journal of CPRI, 17–24. Retrieved from https://cprijournal.in/index.php/pr/article/view/657


  1. Adrian A Pollock. “Acoustic emission inspection”, Physical Acoustics Corporation, TR 03-96-12/89.
  2. Harrold R T. “Acoustical techniques for detecting and locating electrical discharges”.
  3. “Engineering dielectrics, Vol. 1-Corona measurements”, ASTM Publication, pp. 327–408, 1979.
  4. Kawada H, et al. “Partial discharge automatic monitor for oil fi lled power transformers”, IEEE, Transactions on Power Apparatus and Systems, Vol. PAS 103, No. 2, February 1984.
  5. Nagamani H N, et al. “Detection and location of partial discharges in power capacitors using acoustic technique”, SixthInternational Seminar on Electrical and Electronic Insulating materials-INSULEC2000, Hyderabad, India, pp. 23–24, November 2000.
  6. Nagamani H N. “A study on detection and location of PD in power capacitors employing acoustic emission technique”, A thesis submitted for the degree of Doctor of Philosophy in the faculty of Engineering, 2004.
  7. Nagamani H N, et al. “3D location of multiple partial discharge sources”, International Conference of Doble Clients, USA, Boston, pp. 21–26, March 2004.
  8. IEEE Std C57.127-2000, “IEEE trialuse guide for the detection of acoustic emissions from partial discharges in oil immersed power transformers”.
  9. Nagamani H N, Bhavani Shanker T, Vaidhyanathan V and Neelakantan S. “Acoustic emission technique for detection and location of simulated defects in power transformers”, Presented at IEEE, Powertech 2005, at St. Petersburg, Russia, pp. 27–30, June 2005.
  10. Nagamani H N and Bhavani Shanker T. “Detection and location (3D) of multiple PD sources employing acoustic emission technique”, presented at 7th INSULEC 2005, Mumbai, pp. 20–21, January 2005.
  11. Ramu T S and Nagamani H N. “Partial discharges based condition monitoring of high voltage equipment”, New Age International Publishers, New Delhi, India, January 2010.