Publication: Analysis of OLTC condition in distribution transformers using dynamic winding resistance measurement
Date
2015
Authors
Nik Nazrin Nik Azhari
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Abstract
Studies on power transformers have proven that the number one cause of power transformers breakdown is the On Load Tap Changer (OLTC). Faulty OLTC usually due to the insulation degradation and contact failure inside it. Besides that, the OLTC performance is influence by contact wear and this type of fault has not been research thoroughly in Malaysia especially by the main energy provider, Tenaga Nasional Berhad (TNB). Worn contacts of OLTC will result hotspots in the OLTC tank and causing the insulation oil to degrade at a higher rate. Ultimately, this will lead to the breakdown of a complete power transformer unit. Thus, it is essential to to find a new and better ways of detecting an OLTC fault as it may lead to a more costly fault of a complete transformer. Therefore, this research work has been carried out to distinguish the difference of a good and faulty OLTC operation to provide early indication of OLTC fault. On top of that, this dissertation introduced the new way of analysis of OLTC using Dynamic Winding Resistance Measurement (DWRM) by using MATLAB software to figure out the types and locations of the faults inside of the OLTC. The analysis in this dissertation revealed that the results obtained is accurate and the software were able to detect a faulty OLTC and give out warning. Moreover, this research work was based on the real data from TNB in- service distribution power transformer. Hence, the techniques that have been applied in this dissertation were found to be useful for TNB during the OLTC condition assessment of their in-service power transformer.
Description
TK2792 .N54 2015
Keywords
Electric transformer