Wat is een in olie ondergedompelde transformator?

Wat is een in olie ondergedompelde transformator?

Eenolie-ondergedompelde transformator is a power transformer that usesinsulating oil (mineral oil or synthetic ester) for bothkoeling Enelektrische isolatie. The core and windings are submerged in oil, which dissipates heat and prevents electrical breakdown.

Key Components

1. Kern: Laminated silicon steel to reduce eddy current losses.

2. Wikkelingen: Koperen of aluminium geleiders (HV/LV).

3. Tank: Sealed steel container filled with oil.

4. Insulating Oil:

• Mineral oil (most common).

• Bio-based or synthetic ester (eco-friendly alternatives).

5. Cooling System:

• Radiatoren/vinnen (ONAN – Oil Natural Air Natural).

• Fans (ONAF – Oil Natural Air Forced).

6. Protection Devices:

• Buchholz-relais (gas detection for internal faults).

• Overdrukventiel.

• Temperatuur sensoren (oil/winding).

Types of Oil-Immersed Transformers

1. Hermetically Sealed

• Fully sealed tank (no oil exposure to air).

• No conservator; weinig onderhoud.

2. Conservator-type

• Expansion tank (conservator) with breather to absorb moisture.

• Common in large transformers.

3. Step-Lap Core Design

• Reduced no-load losses and noise.

4. Specialty Types:

• Fire-resistant (less-flammable oil).

• Underground (compact ontwerp).

Voordelen

✔ Hoge efficiëntie: Oil provides excellent heat dissipation.
✔ Long Lifespan: Goed onderhouden, lasts 25-30 jaren.
✔ Kosteneffectief: Lower initial cost than dry-type transformers.
✔ Overbelastingscapaciteit: Handles temporary overloads better.

Nadelen

✖ Brandrisico: Olie is brandbaar (requires fireproof barriers).
✖ Onderhoud: Regular oil testing and leak checks needed.
✖ Environmental Concerns: Oil disposal and spill risks.

Toepassingen

• Power Distribution: Step-down 11kV/33kV to 400V.

• Industriële installaties: Staalfabrieken, chemical factories.

• Hernieuwbare energie: Wind/solar farm substations.

• Railways: Traction power supply.

Onderhoudsvereisten

1. Oil Testing:

• Dielectric strength (>30 kV for mineral oil).

• Acidity (<0.1 mg KOH/g).

• Moisture content (<20 ppm).

2. Lekkage-inspectie: Check gaskets, welds, and valves.

3. Slibverwijdering: Clean oil ducts periodically.

Normen & Certificeringen

• IEC 60076: Internationale normen.

• IEEE C57.12.00: North American standards.

• GB/T 6451: Chinese standards.

Oil-Immersed vs. Droge transformatoren

Purchasing Considerations

1. Capaciteit (kVA): Match to load requirements.

2. Spanningsverhouding: Input/output voltage levels.

3. Impedantie: Typically 4–10% for distribution transformers.

4. Environment: Indoor/outdoor, temperatuur, vochtigheid.

5. Certificeringen: Ensure compliance with local regulations.

Veelgestelde vragen

Q: Can oil-immersed transformers be used indoors?
A: Ja, but require fireproof vaults and ventilation (NFPA 70 regels).

Q: How often should oil be tested?
A: Annually for routine checks; after overloads or faults.

Q: Are biodegradable oils reliable?
A: Ja, synthetic esters offer similar performance with lower fire risk.

For acustomized selection, provide:

• Load details (kVA, spanning).

• Installation environment.

• Special requirements (bijv., laag geluidsniveau, high efficiency).