Common Faults Of Oil Filled Self Cooled Type Transformer

The operation of the oil filled self cooled type transformer directly affects the power supply quality of the entire power system. In practical work, due to the constraints of various factors, various faults will inevitably occur during the operation of the transformer. If the fault is minor, the power supply will be interrupted, and even lead to a major power accident. Therefore, it is necessary to scientifically analyze the faults of oil-immersed transformers, and let transformer manufacturers analyze the common faults of oil-immersed transformer circuits.

Influence of discharge fault on insulation of oil filled self cooled type transformer:

1. The discharge particles directly bombard the insulation, so the insulation is destroyed.

2. The ozone and nitrogen oxides produced by the discharge chemically corrode the insulating parts and cause thermal damage.

Partial discharge failure

Under the action of voltage inside the insulating structure, an unsteady discharge phenomenon occurs at the edge of the hole, which is called partial discharge. The reason is that there is gas in the hole or cavity of the transformer oil, the dielectric constant of the gas is small, and the compressive strength of the insulating material will be reduced, resulting in air gap discharge. The energy intensity of partial discharge is not large, but if the long-term partial discharge leads to the destruction or damage of oil-immersed transformer equipment, it will become a serious safety hazard.

Failure due to damaged insulation

1, when the oil-eroded transformer installation pendant is inspected, the gas is exposed to the air and moisture is generated. Fill oil completely so that moisture is concentrated around insulating parts.

2, due to the short manufacturing cycle of the equipment, if the insulation factory is not dry enough before, the insulating paper and cardboard that absorb moisture will remove moisture after running for a period of time, thereby reducing the insulation performance of the transformer's low-voltage winding, thereby increasing the DC leakage current.

3, poor sealing can easily cause moisture in the insulating part of the winding.

4, if the volume of hydrogen and carbon monoxide in the transformer oil in operation is relatively high, the adsorption of gases generated by solid insulating materials or stainless steel must also be considered in the manufacturing process.

Oil filled self cooled type transformer manufacturers share solutions

(1) When a new substation is built, high and low voltage fuses should be installed in time according to the specifications. If the fuse is burned out or stolen during the operation of the transformer, it should be replaced immediately.

(2) Reasonable configuration of high and low voltage fuse components:

Transformers with a capacity of more than 100kVA must be equipped with a fuse of 2.0 to 3.0 times the rated current.

Transformers with a capacity below 100kVA must be equipped with a fuse of 1.5 to 2.0 times the rated current.

(3) Strengthen the power load measurement, temporarily measure the load with a clamp galvanometer during the peak period, adjust the load reasonably, and prevent the three-phase unbalanced operation.

(4) When the low voltage side voltage of 10kV transformer is in the range of 7%~-10%, it is generally impossible to adjust the tap switch. When adjusting the tap switch, the test technician should make a trial adjustment.

(5) Regularly check whether the three-phase current is balanced or exceeds the rated value. If there is a serious imbalance of the three load currents, take timely measures to adjust.

(6) Before the thunderstorm season comes every year, the arresters of all distribution transformers should be sent to the testing department for inspection, and they should be installed in time after passing the test.

(7) The following tests should be done before operation:

Load minutes, switch three times, can not misuse.

Test it three times with the test button and it must work properly.

The test resistance is grounded for 3 times, and it should work normally.

(8) Regularly clean the dirt on the surface of the distribution transformer bushing, whether there are flash marks on the bushing, whether the grounding is good, whether the lead used for grounding has unbroken strands, desoldering, or fractures, and the grounding resistance should be detected at 4 the following.

(9) Analysis of transformer oil leakage