Analysis of transformer oil, which is in operation, is quite important. In addition to information on the current state of insulating oil, it also allows you to detect other problems: aging of paper insulation, the presence of partial discharges, etc. Depending on the amount of testing performed, a complete and abbreviated analysis of transformer oil is distinguished.
The process of transformer maintenance has been developing intensively over the past 20 years. This was a consequence of the need for high reliability of energy transmission through power grids, reduction of failures of oil-filled equipment and reduction of costs for repairs. The high price of new transformers does not allow for the replacement of equipment every time it fails. Therefore, maintenance is exactly the tool that increases the life span of power transformers.
For example, monitoring the current status of transformer oil can detect developing defects, which in the future may lead to unplanned outages. If the maintenance approach correctly, you can determine when it is better to bring the power equipment in for repair.
Note that some components of the test of power transformers do not pose great difficulties in their implementation. We are talking about checking the operation of the gas relay, the on-load tap-changer, as well as checking the leakage. To determine the state of the paper insulation, it is necessary to analyze the transformer oil.
Transformer oil performs several functions. One of the most important is the provision of electrical insulation. If the moisture content in the oil exceeds the normalized value, then this leads to a sharp deterioration in the insulating properties, which ultimately result in dielectric breakdown.
Moisture can get into the oil, for example, with a sharp temperature drop. It is not only oil that suffers from it, but also cellulose insulation, which wets out more intensively when wet.
Transformer oil is not much different from other oils in terms of oxidation. Both temperature and oxygen of the air are the factors that accelerate this process. The situation is aggravated by the presence of metal particles that can act as catalysts and contribute to the formation of carboxylic acids. The greater their number, the greater the total acid number of transformer oil. Over time, possible loss of sludge and oil sediment.
In order not to get into a vicious circle and not to engage in regular purchases of transformer oil for the replacement, it is necessary to consider the possibility of regeneration. Oil restoration allows you to restore its performance to normalized values, which makes possible the further operation of the insulating liquid for its intended purpose. Conducting regeneration each time when the acid number of the oil approaches a certain critical value, it is possible to significantly prolong its service life. At the same time, money is saved, the reliability of power supply increases, and the service life of transformer equipment is extended.