3-Phase Oil Immersed Type Power Transformer

If you are looking for a reliable supplier of 3-Phase Oil Immersed Type Power Transformer, and want to develop long-term cooperation, please choose TAILI, as we have rich experience and can offer advanced products together with comprehensive services.

Standard specification  

1. Applicable specification: IEC 60076 / IEEE

2. Rated capacity : up to3150kVA

3. Primary voltage: up to 66kV

4. Secondary voltage: 0.4/6.3/10.5/35kV or customized

5, Winding materials: Copper/ Aluminum

6.Temperature rise: 65 °C

7. Cooling method: ONAN/ONAF

8.Frequency: 50Hz/60Hz

9.Taps voltage: ±2x2.5% / ±3x2.5% / ±8x1.5% or customized

10.vector group: Yd11 / YNd11 / Dyn11 / YN

Video

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The maintenance of 3-phase oil immersed type power transformers is a systematic task, aiming to ensure the safe, reliable and efficient operation of the transformers and to extend their service life.

Daily inspection and monitoring

1. Oil level check

Check whether the oil level of the transformer body and the oil reservoir (oil tank) is within the standard temperature scale range.

Abnormalities and Handling:

Excess oil level: This may be due to internal faults generating gas or high environmental temperature causing oil expansion. Check if the breather is blocked and analyze the cause.

Insufficient oil level: This may be caused by oil leakage or abnormal internal faults. Immediately locate and address the leak point, and promptly replenish qualified insulating oil of the same brand and model.

2.  Oil Temperature Inspection

Monitor the temperature indicator and check whether the upper oil temperature is normal (generally not exceeding 85℃), and compare it with historical operation data.

Abnormalities and Handling: If the oil temperature abnormally rises, it may be due to overload, cooling device failure, internal overheating (such as poor contact of iron core, winding, or tap changer), etc. The cause must be immediately identified and addressed.

3. Oil leakage inspection

Carefully inspect all sealing surfaces, welds, bushings, valves, gas relays and other parts of the transformer for any traces of oil leakage.

Treatment: If leakage is detected, it should be dealt with immediately. Minor leakage can be resolved by tightening the bolts. Severe oil leakage requires power outage for replacement of sealing components or welding.

4. Insulating oil color and condition

Observe the color of the oil through the oil level gauge.

Normal: Transparent, light yellow.

Abnormal: If the color becomes darker or black, it may indicate oil deterioration or internal faults such as arcs or overheating.

5. Sound (Noise) Inspection

Content: When the transformer is operating normally, it emits a uniform "buzzing" electromagnetic sound.

Abnormalities and Handling:

Increased and uniform sound: This may indicate overload or excessive voltage.

Uneven crackling or popping sounds: There is local discharge or insulation breakdown inside.

Uneven noisy sound: This may be due to loose iron core fasteners.

If abnormal sounds are detected, enhanced monitoring should be conducted. In case of necessity, power should be cut off for inspection.

6. Inspection of bushings

Check whether the surfaces of high and low voltage bushings are clean, and look for any cracks, damages, or discharge marks.

Treatment: If the surfaces are dirty, they need to be cleaned. If there are cracks or severe discharges, the bushings need to be replaced.

7. Respirator (moisture absorber) inspection

Content: Check the color of the silica gel. Dry silica gel is blue, and it turns pink when saturated with moisture.

Procedure: When more than 2/3 of the silica gel turns pink, it should be replaced. If there is oil in the oil cup, check if the oil level is normal.

8. Cooling system inspection

Content: For air-cooled transformers, check if the fans are operating normally; for oil-cooled/ water-cooled transformers, check the working conditions of the oil pumps, water pumps, fans, and for any leakage in the coolers.

Handling: Address any faults promptly to ensure proper heat dissipation.

9. Gas relay inspection

Check if there is any accumulation of gas inside the relay and whether the observation window is clear.

Treatment: If there is a small amount of gas, it should be recorded and sampled for analysis; if the amount of gas is large, the relay will issue a signal or trip, and immediate handling is required.

10. Grounding device inspection

Check whether the enclosure and the neutral point grounding wire are securely connected and free from rust.