Rated/Full Load Current at HT/LT of 33/11 kV Power Transformer
| Sr. | Transformer Rating | HT Voltage | HT Rated Phase Current* | LT Voltage | LT Rated Phase Current* |
| 1 | 3 MVA | 33 kV | ≈ 52.5 A | 11 kV | ≈ 157.5 A |
| 2 | 5 MVA | 33 kV | ≈ 87.5 A | 11 kV | ≈ 262.5 A |
| 3 | 8 MVA | 33 kV | ≈ 140 A | 11 kV | ≈ 419.9 A (≈ 420 A) |
| 4 | 10 MVA | 33 kV | ≈ 175 A | 11 kV | ≈ 524.9 A (≈ 525 A) |
| 5 | 20 MVA | 33 kV | ≈ 349.9 A (≈ 350 A) | 11 kV | ≈ 1049.7 A (≈ 1050 A) |
Rated/Full Load Current at HT/LT of 11/0.440kV Distribution Transformer
| Sr. | Rating (kVA) | HT Voltage (kV) | HT Rated Current (A) | LT Voltage (kV) | LT Rated Current (A) |
| 1 | 16 | 11 | ≈ 0.84 | 0.44 | ≈ 21.0 |
| 2 | 25 | 11 | ≈ 1.31 | 0.44 | ≈ 32.8 |
| 3 | 63 | 11 | ≈ 3.31 | 0.44 | ≈ 82.7 |
| 4 | 100 | 11 | ≈ 5.25 | 0.44 | ≈ 131.2 |
| 5 | 160 | 11 | ≈ 8.40 | 0.44 | ≈ 209.9 |
| 6 | 250 | 11 | ≈ 13.12 | 0.44 | ≈ 328.0 |
| 7 | 400 | 11 | ≈ 20.99 | 0.44 | ≈ 524.9 |
| 8 | 630 | 11 | ≈ 33.07 | 0.44 | ≈ 826.7 |
| 9 | 1000 | 11 | ≈ 52.49 | 0.44 | ≈ 1312.2 |
Note- For Single Phase 11/0.230kV 10 KVA Distribution Transformer Rated Current at HT side = 0.91A and at LT side =43.5A
Types of Transformers
| S.No. | Transformer Category | Type | Key Features / Short Notes | Common Applications / Where Used |
| 1 | Voltage Level Based | Power Transformer | High-voltage operation (33 kV–220 kV) | Grid Substations, Transmission lines, Large Power Plants |
| Distribution Transformer | 11/0.433 kV supply to consumers | Residential colonies, Commercial areas, Small industries | ||
| Instrument Transformer (CT/PT) | Accurate metering & protection | Substations, Control Rooms, Protection Panels, Labs | ||
| 2 | Function Based | Step-Up Transformer | Voltage increase | Power Plants, Solar/Wind Farms, Transmission systems |
| Step-Down Transformer | Voltage reduction | Distribution networks, Industrial plants, Buildings | ||
| 3 | Construction Based | Core-Type Transformer | Two-limb design | Power Transformers, Outdoor substations |
| Shell-Type Transformer | Three-limb, high mechanical strength | Furnace transformers, Traction, High-fault areas | ||
| 4 | Phase Based | Single-Phase Transformer | Small load supply | Rural feeders, Poles, Lighting circuits, Agriculture pumps |
| Three-Phase Transformer | Bulk load supply | Substations, Industries, Factories, Commercial complexes | ||
| 5 | Cooling Method Based | Dry Type (AN/AF) | Air-cooled, safe indoors | Hospitals, High-rise buildings, Underground substations, Malls |
| Oil Immersed (ONAN/ONAF/OFAF) | Oil-cooled heavy duty | 33/11 kV substations, Power stations, Industrial estates | ||
| 6 | Winding Connection Based | Delta–Star (Δ–Y) | LT neutral available | Distribution networks, Commercial loads, Domestic supply |
| Star–Delta (Y–Δ) | Motor applications | Large industries, Motor-driven plants, Mills | ||
| Delta–Delta (Δ–Δ) | Unbalanced load tolerance | Stone crushers, Welding shops, Small industries | ||
| Star–Star (Y–Y) | Neutral grounding applications | HV transmission lines, Export transformers, Grids | ||
| Zig-Zag Transformer | Neutral creation + Harmonic reduction | Earthing systems, UPS plants, Data centers | ||
| 7 | Application Based | Auto-Transformer | Tap change, voltage control | Railway traction, Testing labs, HV startup, Industries |
| Isolation Transformer | Electrical isolation | Medical equipment, Labs, IT Offices, Data Centers | ||
| Earthing Transformer | Neutral availability | 33/11 kV substations, Industrial networks | ||
| Furnace Transformer | High-current duty | Steel plants, Arc furnaces, Foundries | ||
| Rectifier Transformer | AC → DC conversion | Electroplating, Battery charging plants, HVDC systems | ||
| 8 | Special Purpose | OLTC Transformer | On-load voltage control | 33/11 kV substations, Transmission networks |
| HVDC Converter Transformer | DC link applications | HVDC terminals, Grid interconnections | ||
| Traction Transformer | Railway electrification | 25 kV AC railway substations, Metro rail systems |
