What is the cause of oil leakage in the test transformer?

Common causes of transformer oil leakage:

1) The problem of sealing ring, the leakage of the transformer is often caused by poor sealing performance, which is reflected in the design, on the one hand, the quality of the sealing devices used is poor. Under normal circumstances, the connection parts between the components of the transformer are sealed with a sealing rubber ring, if it is still within the shelf life or the performance is good, then the possibility of leakage is unlikely under normal circumstances, but many times their working condition is very bad, which will inevitably lead to the increase of its aging speed and the reduction of sealing performance. In many on-site acceptance work, in order to save costs, some transformer manufacturers use sealant strips to bond the sealant strips on site, and the probability of oil leakage is very high after a few years of operation.

Therefore, for newly installed transformers, it is recommended to use "O" seals. (2) Processing technology problems, the processing technology of transformer flange surface is not high, which is another important reason for transformer oil leakage. Under normal circumstances, there are high processing requirements for the flange surface of the transformer connection, and the presence of sand holes on the sealing surface, the flatness does not meet the requirements, and the concave and convex sealing surface will lead to the occurrence of oil leakage of the transformer.

In this case, the sealing surface of the transformer must be checked at the time of factory acceptance or on-site hanging cover to prevent oil leakage after the transformer is put into operation. (3) Welding problems: In the process of making transformers, oil leakage caused by welding reasons such as virtual welding and porosity. Another reason for leakage is that the welding is not good, due to the problem of many welding points in the transformer oil tank, the quality of the welding process is directly related to the quality of welding, and more welding joints can easily cause the problem of lack of welding.

4) The installation method needs to be improved, the flange connection is uneven, and the force around the gasket can not be evenly stressed during installation; Artificially caused the bolts around the gasket to be unevenly stressed; The flange joint is deformed and misaligned, so that one side of the gasket is stressed more than large, one side is less stressed, and the side of the gasket with less force is easy to cause leakage due to insufficient compression. This phenomenon mostly occurs at the connection of the gas relay and the connection between the radiator and the body; Another point is that when the gasket is installed, the compression amount is insufficient or too large, and when the compression amount is insufficient, the operating temperature of the transformer rises, and the oil becomes thinner, resulting in oil leakage from the transformer, the compression amount is large, the gasket is seriously deformed, and the aging accelerates the shortening of the service life. (5) the consignment method needs to be improved, when the components are transported, especially when the road is transported, due to the bumps of the road, it is easy to bump the transformer device, especially the flange is difficult to repair after being bumped, which will cause poor sealing, which is also easy to cause oil leakage in the mailbox.

Therefore, in the process of equipment transportation, the management should be strengthened, and the anti-collision measures of the equipment should be taken to ensure the sealing performance of the equipment operation.

Oil leakage and oil leakage of transformer insulating bushing are common faults in the operation of medium and small power transformers, and it is very important to find and correctly deal with oil leakage faults in time for the safe operation of transformers. Most of the causes of casing oil leakage are caused by overheating of the transformer line pile head, premature aging of the seal on the casing due to high temperature, and loose nuts and screws of the terminal pile head. And the reason for the overheating of the terminal pile head:

The thread end is thick, the washer is small, not matched, and the pressure is not tight. The wiring material is not treated with an oxide layer and is not coated with conductive paste, which makes the lap joint poor and the contact resistance increases. When a large current is passed, overheating is generated, which in turn increases the oxide layer and increases the contact resistance.

The cycle goes on and on, and the overheating gets worse.

The load is too large or the distribution is not reasonable, so that the current exceeds the safe current carrying capacity of the connecting conductor and the pile head. In order to prevent oil leakage from transformer bushings, the following measures should be taken:

The correct implementation of the connection process, the use of washers, jaws, hook plates and nuts matched with the pile head. When the wire head or cable is too thick, the wire crimp terminal should be used.

Causes and elimination methods of serious oil leakage faults of distribution transformers. Oil leakage during transformer operation is relatively common, and the oil level is within the specified range, and it can still continue to operate or arrange planned maintenance. However, the transformer oil leakage is serious, or it continues to leak from the damaged place, so that the oil level gauge can no longer see the oil level, and the transformer should be stopped immediately, the leakage should be repaired and refueled.

The oil level of the transformer oil is too low, so that the bushing leads and tap-changers are exposed to air, and the insulation level will be greatly reduced, so it is easy to cause breakdown discharge. The causes of transformer oil leakage are: crack of the weld or failure of the seal; Vibration during operation; external force collision; The fuel tank is seriously rusted and damaged, etc.

After the transformer leaks, there are the following consequences:

1. Oil-immersed transformer.

Oil has three main functions, one is insulation, the second is heat dissipation, the third is sealing, and the fourth is damping; When the transformer leaks, the oil can come out, and the water can go in, which will reduce the oil level in the transformer, and when the oil level is too low, the coil of the transformer will expose the oil surface, and the main problem is that the insulating oil will be damp, and the transformer coil will be damp, which will affect the overall insulation of the transformer.

At the same time, it will also affect the output of the transformer due to poor heat dissipation, and the life of the transformer will be affected when overheating; It will also increase the noise of the transformer in large short-circuit currents.

The transformer coil may be deformed due to excessive electrodynamic force during impact;

2. After the transformer oil seeps out, it will cause serious dirt around the seepage point, if this point is close to the live part, especially when the transformer inlet and outlet bushing has oil seepage, it will accumulate a layer of dirt on the casing, which is easy to cause a "pollution flash" accident when it is damp, that is, it is discharged along the outer surface of the transformer bushing, and it is more complicated to replace the transformer bushing, that is, there are bushing spare parts, and professionals also need to affect the power supply for a day.

1.The phenomenon of oil leakage in power transformers not only seriously affects the appearance, but also causes economic losses due to the need for power transformers to be shut down to eliminate leakage. If there are many oil stains on the ground foundation of the power transformer, it may also become a trigger.

2.Oil leakage will seriously interfere with the operation and maintenance personnel's monitoring and judgment of the sealing condition in the power transformer oil storage tank and the correctness of the oil level gauge indication.

3.After the oil level is lowered due to leakage, it may make live joints, switches, etc. operate without oil insulation, which may lead to breakdown, short circuit, burning, and even cause equipment**.

The transformer is one of the key electrical equipment of the distribution station, and the transformer can solve the problem of heat pipe heat dissipation in large space and the problem of high working voltage insulation layer of transformer, and is widely used. However, the problem of oil leakage, which is a common phenomenon in the operation of transformers, seriously endangers the safe operation of transformers. So can a transformer leak still work?

Let's first take a look at the consequences of a transformer oil leak

1.The oil leakage of the transformer not only seriously affects the appearance, but also causes economic losses due to the need for the transformer to be shut down and the leakage is eliminated.

2.Oil leakage will seriously interfere with the operation and maintenance personnel's monitoring and judgment of the sealing condition in the transformer oil conservator and the correctness of the oil level gauge indication.

3.After the oil level is lowered due to leakage, it may make live joints, switches, etc. operate without oil insulation, which may lead to breakdown, short circuit, burning, and even cause equipment**.

4.After the transformer leaks, the fully sealed transformer will lose its sealing state, and it is easy to reduce the insulation performance due to the invasion of air and moisture from the outside world, accelerate the aging of the insulation, and affect the safe and reliable operation of the transformer.

How to deal with transformer oil leakage, let's take a look at the specific treatment measures in combination with the case:

Due to the special working environment of the transformer, it is not allowed to shut down for a long time, so it cannot meet the needs of replacing new components. The use of Soray carbon nanopolymer material technology is a more effective way to solve the oil leakage of transformer, and its main feature is that some leakage points can be treated without stopping, and will not have any impact on the transformer shell itself and the transformer oil.

The harm of oil leakage in transformer disassembly must be great, because if this problem occurs in the transformer, the store inspection machine will definitely be damaged, and it will also be harmed, and it may burn down and cause a disaster.

The following anomalies exist in the operation of the transformer:

1.Transformer oil leakage and abnormal temperature: If there is oil leakage during the operation of the transformer, the oil temperature is too high or too low, the temperature of the transformer is abnormal or the sound is abnormal compared to the abnormal cooling system, these must be dealt with as soon as possible.

If it is not treated for a long time, it will lead to transformer failure.

2.The fault of the transformer, including the loud and abnormal sound inside the transformer, has a cracking sound. The temperature is abnormal, and the temperature of the transformer continues to rise, the oil conservator or safety airway is injected with oil, and the oil level drops due to serious oil leakage.

Below the indicated limit of the oil level gauge, the oil color changes too quickly, the carbon in the oil is more serious, and the casing is seriously damaged or discharged.

In response to what you said, the oil leakage of the transformer is an anomaly. If the transformer leaks, then the transformer should be taken out of operation, and then the whole transformer should be checked for core pulling, and the seal should be replaced. After that, the transformer needs to be assembled after the test is good, and the transformer should be able to run on the test after the finished product is good.

After this treatment, the transformer will also deal with the abnormal oil leakage.

After the power failure, be sure to close the oil pillow first to prevent the oil in the oil pillow from entering the transformer body, and then put a small amount of oil from the oil drain valve. After the repair, remember to open the oil pillow valve, and then turn on the gas exhaust. Fill with a small amount of oil to a normal level.

If the oil seepage of the raised seat is still the oil leakage of the casing, if the oil seepage of the raised seat is a little bit, there is no hurry to deal with it and wait for power outage treatment.

If it is oil seepage on the binding post, change the abacus, and if it is oil seepage on the big cover, change the insulating rubber pad.

You don't need to drain oil. You try it with AB glue. Or maybe it's just electric welding. Welding should also be done without oil.

1. Generally, seals have a service life, because the seals are made of rubber materials, and the rubber will gradually age in the use environment, and the aging rubber loses its elasticity and due sealing performance. My experience is that the life of rubber seals in general is 3-5 years.

2. It is also possible that the rubber seal is not installed well in the transformer installation stage, such as the rubber seal is overly compressed and loses its elasticity, or the position is incorrect, the local force is damaged, or the installation surface is uneven and causes local gaps, etc.

3.The material of the rubber seal is not properly selected, and the transformer should be selected for ultraviolet resistant rubber if it is an outdoor installation environment. If it is used in a location with high temperatures, you should choose a rubber that is resistant to high temperatures, and if you are using it in a place that comes into contact with the transformer oil, you need to choose an oil-resistant rubber.

2. The influence of welding residual stress. Welding residual stress is another major cause of oil leakage in transformer welds. There are many welding joints in the fuel tank, long welds, difficult welding, welding materials, welding specifications, welding processes, welding techniques, etc., which will affect the welding quality, especially in manual arc welding, it is easier to form defects such as weld burn-through, porosity, slag inclusion, cracks, and non-fusion.

Among them, welding penetration defects may not be detected during the hydrostatic seal test of the fuel tank, which is also the cause of oil leakage.

There are several possible causes of transformer oil leaks:

1. Welding quality problems of the same material, such as oil tank and body, radiator and body, etc.

2. There is trachoma in the steel plate of the box body, and oil seepage occurs.

3. The screws of the large cover and the main body are not tight or the tightness of the screws is uneven, and the sealing gasket is not properly placed or the gasket fails, resulting in oil leakage between the large cover and the main body.

4. The connection parts of a variety of materials are not real, resulting in oil leakage, such as the gas relay flange of the transformer, the transformer bushing, the transformer oil standard, etc.

5. The transformer porcelain bushing is deformed, the installation is not correct, the crack or the gasket has problems, resulting in the unreal oil seepage between the bushing and the body.

6. The transformer bushing is not matched with the conductive rod or the gasket is not tightly sealed, resulting in oil leakage at the conductive rod on the bushing.

7. The transformer oil drain valve is not closed tightly.

8. Oil seepage caused by other reasons, such as short circuit, overload, etc.

Transformer oil leakage is a common fault, which often occurs in the sealing ring seal, the gas (oil) column seal, the oil buffer, tap changer, sand hole caused by casting and welding process, which may cause oil leakage.

Polymer composite material 25551 can be used for rapid treatment, and finally the treatment surface can be covered with 2211F metal repair material, and the purpose of long-term treatment of leakage can be achieved after curing.

In general:

1. Oil leakage from the weld, the weld will be stressed during welding, or the oil tank will be repeatedly expanded and contracted, and the fatigue at the weld will cause oil leakage;

2. Oil leakage caused by aging and cracking of seals, most of the domestic transformers are sealed with rubber, and its working conditions are relatively harsh: to be compressed, to be oil-resistant, to be resistant to high temperature, to be resistant to ultraviolet rays, etc. It is easy to age, crack and leak.

3. The quality of the steel plate of the fuel tank is not good, which will also cause oil leakage, but it is relatively rare.