How does Water or Moisture affect Power Transformer Health?

Water has one of the most significant effects on the aging of paper and insulating oil in a power transformer by reducing the dielectric strength of the oil and physical deterioration of the strength of the paper at working temperature. It also sets up the process of hydrolysis which together with heat and an acidic environment triggers a self-sustaining paper degradation...

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The Importance of Proper Cooling of Power Transformers

The correct design and operation of the cooling system of a power transformer is very important to maintain the health of the transformer. The design and type of cooling is usually governed by the application of the power transformer and is influenced by power output, location and environmental conditions. The cooling system thus in turn affects the design of the transformer. ...

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Duvals Triangle Method

The Duval Triangle Method makes use of the three combustible gases CH4, C2H4 and C2H2 that are transformed for representation in a triangular plot. The triangle is able to differentiate the fault types partial discharges, electrical faults (high and low energy arcing), and thermal faults (hot spots of various temperature ranges). Each point is derived from the percentage...

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Case Study - 390 MVA GSU Transformer [1]

Background [2]  On the 15 May 2005 this 390 MVA GSU transformer failed. During the previous unit outage the transformer oil was purified to remove moisture. The transformer was initially commissioned in October 1971. In 1996 the transformer was involved in a coupling transformer incident with another unit and was sent to the repair facility for refurbishment in...

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Case Study: Investigation into Combustible Gases in Selector of Tap Changer

The following report highlights the problem of the production of combustible gases in the selector of the tap changer of gen/motor transformer 1 at A Pumped Storage Scheme.  This may be caused either by abnormal arcing or a leak between the diverter and selector compartments. INTRODUCTION From the oil results in 2002 it was noticed that there was an increase...

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