|
 |
|
 |
UQ Innovation Expo 2003 |
|
ITEE Innovation Expo 2002 |
|
ITEE Innovation Expo 2001 |
|
ITEE Public Web |
|
ITEE School Alumni |
| UQ Innovation Expo 2003 » Exhibits - by Industry Sector » Benjamin Silec |
Transformer diagnostics by polarisation measurements
Exhibitor: Benjamin Silec
Supervisor: Tapan Saha
Research Group: Complex and Intelligent Systems
Industry Sector: Energy and Utilities
The question to be answered is whether or not polarisation measurements, including polarisation - depolarisation current measurements and recovery voltage measurement, can be used as a reliable tool for diagnosing the extent of degradation of the electrical insulation in power transformers, and whether or not these measurements can distinguish between the different types of insulation degradation that are present (i.e. moisture content and effective age). The study of this question is worthwhile because polarisation measurements are non-invasive, that is, the transformer does not need to be opened and no samples have to be taken from the transformer, unlike methods currently in use. Being able to use polarisation measurements as the diagnostic tool for transformer insulation would therefore mean that diagnosis is easier and cheaper. This is becoming more and more relevant as the transformers currently in use in our power systems become older.
The results presented confirm some previously held beliefs, such as the dependence of polarisation current on the moisture content of the insulation, and the decrease in RVM central time constant with increased insulation moisture content. Evidence of some previous theories, for example the increase in the peak of the RVM spectrum with insulation age, was seen in some instances but not in others. New findings include the extent of the dependence of the parameters of the insulation equivalent circuit on the condition of the insulation. The results also confirm the fact that separating the effects of ageing and moisture content on the polarisation measurements is indeed a difficult task, as the moisture content seems to have an over-bearing effect on the results, as well as the fact that the age of the insulation and the moisture content are often not independent of each other.