Transformers Magazine, Vol. 9 No. 2, 2022.
Original scientific paper
Online refurbishment of old transformers
K. K. Murty
D. C. Jain
R. K. Agrawal
J. J. L. Kapil
Abstract
This article focuses on refurbishment / reconditioning for extension of life-expectancy of old transformers of EHV (extra high voltage 66 kV class and above) class, which were continuously in service for more than 20 years in the State Transmission Utility of Madhya Pradesh in India.
The salient feature of this article for moisture refurbishment of old transformers was by adopting the criterion “% relative saturation of water in oil.” This selection criterion is different from the conventional practice in vogue of observing the deterioration trend of IR (Insulation Resistance) and PI (Polarization Index) values and the DGA (Dissolved Gas Analysis), etc. The reconditioning of all such old EHV transformers, precisely 205 units, was taken up “online” in a big way, avoiding long downtimes and frequent load shedding, etc., keeping in view dissatisfaction amongst the consumers at large. This project was completed over a period of five years.
Keywords
moisture content, Karl Fischer titration, oil filter plant / machine, IR and PI
Hrčak ID:
275179
URI
Publication date:
6.4.2022.
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