Qu'est-ce qu'un transformateur immergé dans l'huile?

Qu'est-ce qu'un transformateur immergé dans l'huile?

Untransformateur immergé dans l'huile is a power transformer that usesinsulating oil (huile minérale ou ester synthétique) for bothrefroidissement etisolation électrique. Le noyau et les enroulements sont immergés dans l'huile, which dissipates heat and prevents electrical breakdown.

Composants clés

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

2. Enroulements: Copper or aluminum conductors (HV/LV).

3. Réservoir: Sealed steel container filled with oil.

4. Insulating Oil:

• Mineral oil (most common).

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

5. Cooling System:

• Radiateurs/ailettes (ONAN – Oil Natural Air Natural).

• Fans (ONAF – Oil Natural Air Forced).

6. Protection Devices:

• Relais Buchholz (gas detection for internal faults).

• Soupape de surpression.

• Temperature sensors (oil/winding).

Types of Oil-Immersed Transformers

1. Hermetically Sealed

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

• No conservator; peu d'entretien.

2. Conservator-Type

• Expansion tank (conservateur) 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 (conception compacte).

Avantages

✔ Haute efficacité: Oil provides excellent heat dissipation.
✔ Longue durée de vie: Correctement entretenu, lasts 25-30 années.
✔ Rentable: Lower initial cost than dry-type transformers.
✔ Capacité de surcharge: Handles temporary overloads better.

Inconvénients

✖ Risque d'incendie: L'huile est inflammable (requires fireproof barriers).
✖ Entretien: Regular oil testing and leak checks needed.
✖ Préoccupations environnementales: Oil disposal and spill risks.

Applications

• Distribution d'énergie: Step-down 11kV/33kV to 400V.

• Installations industrielles: Aciéries, chemical factories.

• Énergie renouvelable: Wind/solar farm substations.

• Railways: Traction power supply.

Exigences d'entretien

1. Oil Testing:

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

• Acidity (<0.1 mg KOH/g).

• Moisture content (<20 ppm).

2. Leak Inspection: Check gaskets, welds, and valves.

3. Sludge Removal: Clean oil ducts periodically.

Normes & Certifications

• CEI 60076: Normes internationales.

• IEEE C57.12.00: North American standards.

• GB/T 6451: Chinese standards.

Oil-Immersed vs. Transformateurs de type sec

Purchasing Considerations

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

2. Rapport de tension: Input/output voltage levels.

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

4. Environment: Indoor/outdoor, température, humidité.

5. Certifications: Ensure compliance with local regulations.

FAQ

Q: Can oil-immersed transformers be used indoors?
UN: Oui, but require fireproof vaults and ventilation (NFPA 70 règles).

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

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

For acustomized selection, provide:

• Load details (kVA, tension).

• Environnement d'installation.

• Special requirements (par ex., faible bruit, high efficiency).