Manufacturer's professional analysis of the reasons for the high temperature of the transformer
Writer： Hengfeng you electric Time：2023-04-24 views：times
Hengfengyou electric engineer thought that there are many reasons why the temperature of a transformer is too high, which may be due to the fault of the transformer itself or external factors.
1、 The reason for the failure of the transformer itself
When the heating and heat dissipation of the transformer reach a balanced state during operation, the temperature of each part tends to stabilize. If, under the same conditions, the oil temperature is higher than usual by more than 10 ℃, or the load remains unchanged but the temperature continues to rise, it can be considered that a fault has occurred inside the transformer.
1. Poor contact of tap changer
Due to insufficient contact pressure or contamination at the contact point of the tap changer during operation, the contact resistance increases. An increase in contact resistance will cause the temperature of the contact point to rise and generate heat. Especially after switching the tap changer and during transformer overload operation, it is more likely to cause poor contact and heating of the tap changer.
Poor contact of the tap changer can be judged by frequent action of light gas, and by taking an oil sample for testing, it can be found that poor contact of the tap changer causes a rapid decrease in the oil flash point; In addition, the contact condition of the tap changer can be determined by measuring the DC resistance value of the coil.
2. Short circuit between turns of winding coils
Due to insulation damage between adjacent turns of the coil, a closed short-circuit current will occur. At the same time, the coil of this phase reduces the number of turns, and the short-circuit circulation generates high heat, causing the temperature rise of the transformer to be too high. In severe cases, the transformer will be burned out.
There are many reasons for inter turn short circuits in coils, such as mechanical damage to insulation caused by rough manufacturing processes during coil manufacturing; High temperature causes insulation aging; Under the action of electric force, the axial displacement of wire turns can cause insulation wear, etc. However, the main reasons for developing inter turn short circuits are overvoltage and overcurrent. The severe inter turn short circuit causes the oil temperature to rise, and the oil at the short circuit turn looks like boiling, and the sound of "guru guru" can be heard. During oil sampling and testing, the oil quality deteriorated and developed from a light gas action to a heavy gas action. At this point, using the method of measuring DC resistance can also detect inter turn short circuits.
3. Short circuit between iron core silicon steel sheets
Due to external force damage or insulation aging, the insulation between silicon steel sheets is damaged, eddy currents increase, and local overheating occurs. In addition, the insulation damage of the piercing screw is also the cause of eddy current, which may cause local heating. Generally, the rise of transformer oil temperature cannot be observed; In severe cases, it causes the iron core to overheat, causing an increase in oil temperature, frequent action of light gas, and a decrease in oil flash point. In severe cases, it causes heavy gas to act.
4. Lack of oil or blockage in the heat dissipation pipe
Transformer oil is the main insulation inside the transformer, which plays the role of insulation, cooling and arc extinguishing. If there is lack of oil or the inside of the radiator pipe is blocked, the circulating cooling speed of the oil will drop, causing the temperature of the transformer to rise during operation.
Hengfengyou is a professional electrical company specializing in the production, manufacturing and sales of electrical distribution products, mainly engaged in the production and global sales of distribution transformers, rectifier transformers, electric furnace transformers, etc. We have provided OEM / ODM services for customers in Europe, America and the Middle East for 20 years. It can provide customized production of transformer core, transformer coil and transformer shell. Hengfengyou Electric will provide you with the best electrical product solutions. https://www.hengfengyou.com ； info@hengfengyou.com WhatsApp：+86158 5325 2696（Jack） +86158 5326 5269（Alisa）
