reconstruction of power transformer

Reconstruction of power transformer– a topic that often causes a lot of controversy and, to be honest, mistrust. It seems to be a time-tested technology, but how many times have I encountered situations where a “overhaul” turned into a “complete disassembly” with the subsequent replacement of most of the components. This often occurs due to insufficient understanding of the actual condition of the transformer and inadequate assessment of the cost of work. I would like to share my experience without claiming the absolute truth, but only to highlight some points that are worth paying attention to.

Transformer condition assessment: the first step to successful reconstruction

Before even thinking about replacing the windings or selecting new insulating materials, it is necessary to conduct a thorough diagnosis. And this is not just a visual inspection! I always start with a comprehensive analysis: measuring insulation resistance, hydrodynamic testing (if possible), checking the mechanical strength of the structure. Without this, you are like a blind man in a dark forest. Many customers, seeing the low cost of reconstruction, try to save on diagnostics, which, as a rule, leads to much larger problems in the future. A recent case with a 33 kV transformer purchased second-hand clearly illustrates this. The initial assessment showed an 'acceptable' condition, but after re-diagnosis after the start-up, it turned out that the problem was hidden under a layer of oil and a significant build-up of oxides on the windings. The repairs cost more than the cost of a new transformer.

Insulation resistance measurement: more than just numbers

Insulation resistance is, of course, an important parameter, but a simple measurement does not give the full picture. It is necessary to take into account temperature, humidity and other factors affecting the results. In addition, do not forget about 'false' values ​​that arise due to contamination or damage to the insulation, which are not always obvious. In such cases, it is necessary to use special diagnostic methods, such as thermography or ultrasound testing. We at Wenzhou Qiaonasen Electrical Equipment Co., Ltd. use thermography to identify hot spots in windings, allowing us to pinpoint areas that require special attention whenreconstruction of power transformer.

Sometimes, especially in older transformers, the problem may not be in the insulation itself, but in its sublayer. This is difficult to detect using traditional methods, but is quite possible using more sophisticated instruments. We often encounter similar situations when working with old transformers that have served for more than 30 years. In these cases, it is necessary to take into account the degree of insulation depletion and decide on further actions based on the actual condition.

Transformer windings: repair or replacement?

The decision to repair or replace windings is one of the most difficult in the process.reconstruction of power transformer. If the windings have minor damage (for example, small breaks or short circuits), they can be repaired by rewinding or insulating the damaged areas. However, if the windings are severely damaged (for example, significant damage to the insulation or physical damage to the conductors), then replacing them is the only possible option. In such cases, it is necessary to use high-quality materials and comply with all technological requirements. We cooperate with winding manufacturers who use modern technologies and materials, which allows us to guarantee the reliability and durability of refurbished transformers. This is especially true for high and low voltage applications.

Rewinding windings: subtleties and nuances

Rewinding windings is a labor-intensive and responsible process that requires high qualifications and experience. It is necessary to comply with accurate calculations and technological requirements in order to avoid errors and ensure that the winding parameters comply with the design values. It is especially important to choose the right material for winding insulation to ensure reliable protection against breakdowns. We must not forget about the quality of soldering and insulation of connections, since they are the most vulnerable points in the winding. Often, when soldering, the integrity of the conductors is violated, which leads to a decrease in performance and subsequently to emergency situations.

When rewinding windings, a problem with material compatibility often arises. Old windings may be made from materials that are no longer used in modern production. In such cases, new materials must be carefully selected to ensure compatibility and avoid problems with electrical and mechanical properties.

Transformer insulation: selection of materials and restoration methods

Insulation is a key element of a transformer, ensuring its reliable and safe operation. Whenreconstruction of power transformerit is necessary to choose the right materials for insulation and use modern restoration methods. Nowadays polymeric materials are used that have increased heat resistance and chemical resistance. In addition, there are special methods for restoring insulation, such as applying epoxy resins or polyurethane coatings. These methods make it possible to restore the insulating properties of windings and extend their service life.

Influence of operating conditions on the service life of insulation

The service life of a transformer insulation depends on many factors such as operating conditions, voltage, temperature, humidity and contamination. In conditions of high humidity and pollution, insulation deteriorates faster. In addition, high temperatures and overloads also negatively affect the service life of the insulation. Therefore, it is necessary to take these factors into account when choosing materials for insulation and develop measures to protect the transformer from adverse influences.

We often encounter problems related to insulation damage due to mechanical stress. It is necessary to ensure reliable protection of the transformer from shock and vibration. In addition, it is important to properly ventilate the transformer to avoid overheating of the insulation.

Experience and mistakes: what practice has taught us

Over the years, we have accumulated rich experience in the fieldreconstruction of power transformer. We have faced a variety of problems and found effective solutions. But, of course, there were also mistakes. One of the most common mistakes is incomplete analysis of the transformer condition. Another is the use of low-quality materials or non-compliance with technological requirements. Another one is insufficient qualifications of personnel. The importance of staff training and development cannot be underestimated. Otherwise, even the most modern tool will be useless.

Prospects for the development of reconstruction technology

Technologyreconstruction of power transformeris constantly evolving. New materials and methods for restoring insulation, as well as new diagnostic methods, are emerging. In the future, automation of renovation processes is likely to be widely used, which will improve the quality and reduce the cost of work. We constantly monitor new developments and implement them in our work. We believe that with continuous advancements in technology, power transformer refurbishment will become even more efficient and accessible.

Wenzhou Qiaonasen Electrical Equipment Co.,Ltd strives to be at the forefront of this industry by constantly improving its technology and improving the skills of its specialists. We are ready to offer comprehensive solutions for the reconstruction of power transformers of any power and voltage, taking into account the individual needs of each customer.