How to PROLONG a life of a transformer
I wouldn't need to write about how transformers are working or how to use transformer oil, because all clients or potential clients are already aware of this information. I'm just gonna say it is really important to treat transformer oil and regenerate it on time.
Here You will see what could happen if You ignore the process of aging of transformer oil.
The main types of oil analysis:
Through DGA (Dissolved Gas Analysis) we can detect slowly developing problems in a transformer.
The increase in gas concentrations over time allows an analysis of possible problems, which also makes it possible to predict the service life of the transformer.
DGA makes it possible to identify the following problems:
- Discharges and partial discharge
- the formation of alien layers of contact layers
- abnormal degradation of cellulose
- local overheating of metal parts
2. Color and appearance (according to ISO 2049)
Although color and appearance are not basic properties and do not serve as criteria for action, they help in comparative assessment:
A quick darkening or dark oil indicates that the oil is aging.
Even when the color changes from 2 on the color scale to 3, sedimentation begins in the oil.
3. Breakdown voltage indicates how well the insulating oil can withstand the electrical load, and is crucial for the maintenance of the transformer.
Breakdown voltage thresholds - depend on the type of transformer
4. Water appears in the process of aging of cellulose - an insulating material, and also to a lesser extent in the process of aging oil, and mainly in the process of absorbing atmospheric moisture, due to poor maintenance of air dryers or defects in the sealing system.
Water is formed even in the expansion tank, although there is a desiccant upstream, these values have not been evaluated in the past.
This is due to temperature fluctuations in the transformer.
Water in oil is in equilibrium with water in solid insulation and reduces breakdown voltage and accelerates the aging process. However, this equilibrium depends on temperature and time.
Temperature, humidity and oxygen: these are the three most important causes of transformer aging and breakdowns.
Effect of temperature and humidity:
The rate of aging is very dependent on temperature, oxygen and water in isolation. High concentration of water in the transformer and high temperature accelerates can accelerate aging by 20 times.
The reasons:
Temperature: overload or poor cooling of transformers, moisture, oxygen through leaky gaskets and poor air dryers.
Anti-aging actions:
- Regular trend analysis (DGA) and oil index determination
- Reducing moisture by drying
- Degassing with a high content of gas in the oil
- Change of oil
My years of experience in transformer maintenance have shown that if you intervene in time, the life of the transformer can be extended. Already when the color changes from 2 to 3 on the color scale, the deposition of sludge begins.
Head engineer of GlobeCore, Mr. Eugene Svyryd.
Change of oil:
The cost of changing the oil is very high and very high. The best and optimal decision is oil regeneration process.
110 KV Transformer Explosion
As a result of aging (accumulation of water and suspended particles, the formation of acids), the oil loses its insulating properties.
There comes a moment when the arc discharge occurs. The arc evaporates the oil, which in the gaseous state has a much larger volume than in the liquid state, shock waves arise. The waves intersect, creating a high static pressure that the transformer tank cannot withstand - it explodes. Only a few milliseconds pass between the impact of the first pressure peak and the explosion. Buchholz relays and pressure relief valve react too slowly and cannot prevent the transformer tank from exploding.
I hope it was useful for You to know about this things and what could happen if You not regenerate old transformer oil on time.
For more information on Transformer oil purification/regeneration equipment please contact me at:
- email: [email protected]
- skype: Annaaa820