Transformer Oil
Transformer oils are insulating oils with excellent electrical insulating and anti-oxidative properties. It is used in Power and Distribution Transformers, high-voltage capacitors as well as high-voltage circuit breakers.
In the case of Transformers, transformer oil preserves the transformer core and windings at high temperatures by suppressing corona discharge and arcing between the winding, transformer core, and surrounding environment.
Transformer Oil must have high dielectric strength, thermal conductivity and chemical stability to perform its primary function as an insulator and coolant in transformer, and should hold these properties at high temperatures for extended period of time.
Transformer Oil as an Insulator
It acts as an insulator by maintaining the supply of electrical current at a constant voltage and protects against damage due to voltage fluctuations.
Transformer Oil as a Coolant
It acts as a coolant in oil-cooled transformers where copper coils get heated at high voltages.
Tech Specifications
Sr. No. |
Characteristics |
Test Method |
Limits |
| I. |
FUNCTION |
||
| 1 | Viscosity at -40 °C | IS 1448 (Part 25) | 12 mm2/s. max. |
| 2 | Viscosity at 0 °C | IS 1448 (Part 25) | – |
| 3 | Viscosity at -30 °C | IS 1448 (Part 25) | 1800 mm2/s. max. |
| Viscosity at -40 °C | I S 16084 | ||
| 4 | Pour point | IS 1448 (Part 10/Sec 2) | -40 °C max |
| 5 | Water content | IEC 60814 | 1) 30 mg/kg max. for bulk supply |
| 2) 40 mg/kg max. for drum supply | |||
| 6 | Breakdown voltage | IS 6792 | i) 30 KV min. delivered |
| ii) 70 KV after treatment | |||
| 7 | Density at 20 °C | IS 1448 (Part 16) | 0.895 g/ml max. |
| 8 | DDF at 90 °C | IS 16086/ IEC 60247 | 0.005, max. |
| 9 | Particle content | IS 13236 | No general requirement |
II. |
REFINING/STABILITY |
||
| 10 | Appearance | – | Clear, free from sediment and suspected matter |
| 11 | Acidity (Neutralization Value) | IEC 62021 – 1 | 0.01 mg KOH/g max. |
| 12 | Interfacial tension mN/m | ASTM D 971 | 40 mN/M Min |
| 13 | Total sulphur content | ISO 14596/ ASTM D 4294 | Max 0.05% before Oxidation Stability test. |
| 14 | Corrosive sulphur | DIN 51353 | Not corrosive |
| 15 | Potentially corrosive sulphur | IS 16310 | Not corrosive |
| 16 | DBDS | IS 16497 (Part 1) | Not detectable (< 5 mg/kg) |
| 17 | Inhibitors of IEC 60666 | IS 13631 | (U) Uninhibited oil; Not detectable (< 0.01%) |
| 18 | Metal passivator additives of IEC 60666 to IS 13631 | IS 13631 | Not detectable (< 5 mg/kg) or as agreed upon with the purchaser |
| 19 | Other additives | – | |
| 20 | 2-Furfural and related comp, content | IS 15668 | Not detectable (< 0.05 mg/kg) for each individual compound |
III. |
PERFORMANCE |
||
| 21 | Oxidation stability | IS 12422 (method C) | |
| Test duration (U) Uninhibited Oil: 164 hrs | |||
| a) | Total acidity | 1.9.4 of IS 12422 | 1.2 mg KOH/g max. |
| b) | Sludge | 1.9.4 of IS 12422 | 0.8% max. |
| c) | DDF at 90 C | 1.9.4 of IS 12422 | 0.500 max. |
| 22 | Gassing tendency | IEC 60628:1985, Method A | No general requirement |
| 23 | ECT | No general requirement | |
IV. |
HEALTH, SAFETY AND ENVIRONMENT |
||
| 24 | Flash Point | IS 1448 (Part 21) | 135 °C, min. |
| 25 | PCA content | IP 346 | 3.0%, max. |
| 26 | PCB content | I S 16082 / ASTM-D-4059 | Not detectable (< 2 mg/kg) |