drying power transformers

Everyone often talks aboutdrying power transformersas about simple removal of moisture. But this is rather the tip of the iceberg. Many novice specialists, or even experienced engineers, underestimate the complexity of this process and the possible consequences of the wrong approach. The challenge is not only achieving target humidity, but also maintaining insulation integrity, preventing gas formation, and ensuring long-term transformer reliability. Personally, I started out with rather naive ideas, and this taught me some valuable lessons. Today I want to share my experience, which I hope will be useful to others.

Review: from theory to practice - what you need to know

The essencedrying power transformers, of course, in removing moisture. But this removal is not a single process, but a set of measures, including physical drying, degassing and, often, degassing. Ideally, of course, it would be to achieve a humidity level that meets GOST requirements, but often real conditions and customer requirements dictate their own adjustments. It is important to understand that the drying process should not cause thermal stress, which could lead to insulation failure. And this is where the fun begins - choosing a method and adapting it to a specific transformer. There is no one-size-fits-all solution. You will have to take into account the type of oil, the design of the transformer, the degree of contamination and many other factors.

Drying methods: pros and cons

There are several basic methodsdrying power transformers. The classic one is heating the oil at a certain temperature and holding it under vacuum. The vacuum helps to effectively remove dissolved gases and moisture. However, this method can lead to the formation of vapor locks, especially in transformers with a complex design. Another common method is to use a centrifuge, which separates the moisture and gases from the oil. This is a faster method, but requires special equipment. There are also methods based on the use of special absorbents that absorb moisture. The choice of method depends on the specific task and available resources.

Vacuum drying: nuances and possible problems

Vacuumdrying power transformers, in my opinion, is the most effective method if organized correctly. It is important to provide sufficient vacuum so that the oil boils at drying temperature, but does not overheat. Overheating can lead to insulation degradation. The use of high pressure vacuum pumps and temperature control is critical. I remember one time when we were drying out a transformer and the vacuum was too strong. As a result, the oil began to actively boil, and we almost damaged the internal components of the transformer. We had to urgently reduce the vacuum and add an anti-emulsifying agent to stabilize the oil. This experience taught me to carefully control the drying process and not to neglect even minor details.

Analysis of real situations: mistakes and their consequences

I often encounter situations whendrying power transformersis not carried out carefully enough. For example, the transformer is not pre-cleaned from contamination. Contaminants can prevent moisture and gases from being removed effectively. Or, conversely, cleaning too aggressively can damage the insulation. Another common mistake is choosing the wrong anti-emulsifying agent. The anti-emulsifying agent must be compatible with the type of oil and not affect its dielectric properties. Sometimes you see transformers that have dried too quickly, not allowing the gases to escape from the oil. This can lead to the formation of vapor locks and subsequent destruction of the insulation.

Vapor lock problem: how to avoid it

Vapor locks are a serious problem whendrying power transformers. They occur when gases dissolved in the oil are unable to escape, forming a barrier between insulated parts of the transformer. This leads to a decrease in the dielectric strength of the insulation and can cause a short circuit. To avoid vapor locks, it is necessary to ensure sufficient vacuum and controlled drying temperature. Sometimes it helps to add special degassers that help remove gases from the oil. In our practice, we use the method of preliminary degassing of the oil before drying the transformer. This helps to significantly reduce the risk of vapor locks. This step, although it increases drying time, is justified by increased reliability.

Oil degassing: an integral part of the process

Oil degassing is not just a preliminary procedure, it is an important step in the processdrying power transformers. Even after drying the transformer, dissolved gases may remain in the oil, which can reduce its dielectric strength. Oil degassing can be carried out in different ways: vacuum, thermal degassing or by passing gas through the oil. The choice of method depends on the type of oil and the degree of contamination. It is important to monitor the gas content of the oil before and after degassing to ensure the effectiveness of the process. In our case, we use vacuum oil degassing, as it allows us to effectively remove even the smallest gases. Sometimes we apply additional degassing immediately before adding oil to the transformer. This guarantees maximum reliability of the transformer.

Conclusion: Learn from mistakes and be careful

Drying power transformersis a responsible process that requires care, experience and knowledge. No step should be neglected and every parameter must be carefully monitored. Errors can lead to serious consequences, including failure of the transformer. Studying the experience of other specialists, analyzing your own mistakes and constantly improving your skills is the key to successful work in this field. And remember, it is better to spend a little more time and effort drying the transformer than to repair or replace it later. We, at Wenzhou Qiaonasen Electrical Equipment Co., Ltd., always try to approach this task with maximum responsibility, using modern technologies and carefully monitoring every stage of the process. Our experience allows us to successfully cope with the most difficult tasks in the field of drying power transformers.