Distribution transformers
1600 kVA distribution transformer
A 1600 kVA transformer delivers 2,309 A at 400 V on the low voltage side. At this rating it typically supplies large industrial loads, data halls, campuses and distribution centres.
1600 kVA at a glance
- Rated power
- 1600 kVAthree phase
- Rated current at 400 V
- 2,309 Acalculated
- Rated current at 433 V
- 2,133 Acalculated
- Primary current at 11 kV
- 84 Acalculated
- EU load loss limit, liquid
- ≤ 12,000 WTier 2, class Ak
- EU no load loss limit, liquid
- ≤ 1,080 WTier 2, Ao − 10 %
- Dimensions and weight
- with the quotationthey differ between units of the same rating
Where a 1600 kVA unit is used
A 1600 kVA distribution transformer typically supplies large industrial loads, data halls, campuses and distribution centres. The rating is chosen from the connected load after diversity, the power factor and the starting behaviour of the largest motor, with headroom only for growth that is actually planned.
The low voltage current exceeds two thousand amperes, so the connection between transformer and board is normally busbar trunking, and the room layout is designed around it.
Common voltage configurations
| Primary | Secondary | Frequency | Primary current | Secondary current | Context |
|---|---|---|---|---|---|
| 11 kV | 400 V | 50 Hz | 84 A | 2,309 A | 11 kV, listed as a standard voltage in IEC 60038 |
| 11 kV | 433 V | 50 Hz | 84 A | 2,133 A | 433 V secondary, documented in UK distribution specifications |
| 10 kV | 400 V | 50 Hz | 92 A | 2,309 A | 10 kV networks, common in continental Europe |
| 20 kV | 400 V | 50 Hz | 46 A | 2,309 A | 20 kV networks, common in continental Europe |
| 22 kV | 400 V | 50 Hz | 42 A | 2,309 A | 22 kV networks |
| 33 kV | 400 V | 50 Hz | 28 A | 2,309 A | 33 kV networks. The EU loss limit is corrected under Table I.3a |
| 13.8 kV | 480 V | 60 Hz | 67 A | 1,925 A | 60 Hz networks with a 480 V secondary |
Rated currents calculated as S / (√3 × U) for 1600 kVA, three phase. Configurations are the ones most often requested and are not a list of what is available. The network operator sets the primary voltage; IEC 60038 lists 230/400 V and 11 kV among standard voltages and notes that older 240/415 V systems remain in use.
What load a 1600 kVA transformer can carry, in kW
| Load power factor | Real power at full rating |
|---|---|
| 0.80 | 1,280 kW |
| 0.90 | 1,440 kW |
| 0.95 | 1,520 kW |
| 1.00 | 1,600 kW |
Calculated as kW = kVA × power factor, at rated current and continuous duty. Diversity, planned growth, harmonic loads, ambient temperature, altitude and the largest motor start change the answer, which is why a load in kW does not fix the rating by itself. The sizing guide works through the method.
Construction and cooling
| Construction | Cooling | Typical placement |
|---|---|---|
| Liquid immersed, mineral oil | Natural oil and air, commonly ONAN | Outdoors, or a dedicated transformer room |
| Liquid immersed, ester | Natural liquid and air, commonly KNAN | Where fire point or biodegradability matters |
| Dry type, cast resin | Natural air, with fans as an option | Indoors, including occupied buildings |
Windings are copper or aluminium depending on the specification and the manufacturer's design. Insulation is the insulating liquid with solid insulation for liquid immersed units, and cast resin for dry type units.
Maximum losses on the EU market
| Construction | Load losses Pk | No load losses P0 | Basis |
|---|---|---|---|
| Liquid immersed | ≤ 12,000 W | ≤ 1,080 W | table value, class Ak and Ao − 10 % |
| Dry type | ≤ 13,000 W | ≤ 1,980 W | table value, class Ak and Ao − 10 % |
Commission Regulation (EU) No 548/2014 as amended by (EU) 2019/1783, Annex I, Tables I.1 and I.2, Tier 2, applying from 1 July 2021. These limits apply to three phase medium power transformers with one winding at Um up to 24 kV and the other at Um up to 3.6 kV, and the regulation is still applied in Great Britain. A specific unit declares losses at or below them on its datasheet. Other markets set their own rules, which are confirmed for the destination in each quotation.
Indicative fault level at the low voltage terminals
| Secondary | Rated current | At uk 6 % |
|---|---|---|
| 400 V | 2,309 A | 38.5 kA |
| 433 V | 2,133 A | 35.6 kA |
Calculated as rated current divided by the short circuit impedance, assuming an infinite upstream source, so it is an upper bound for the transformer's contribution. The impedance of the unit offered is on its datasheet, and the design fault level is set by the designer's study, not by this table.
Standards commonly applied
| Standard | What it covers |
|---|---|
| IEC 60076-1 | Power transformers, general requirements |
| IEC 60076-11 | Dry type transformers, where the unit is cast resin |
| Regulation (EU) No 548/2014, as amended | Maximum losses on the EU market and in Great Britain |
| IEEE C57.12.00 | Liquid immersed transformers on North American specifications |
Phase: three. Frequency: 50 Hz on IEC networks, 60 Hz on North American and some other networks.
Enclosure and protection options
| Construction | Arrangement | What decides it |
|---|---|---|
| Liquid immersed | Outdoor tank with bushings, or with cable boxes on the high and low voltage sides | Whether connections are by overhead line, bare busbar or cable |
| Liquid immersed | Inside a compact substation enclosure | Whether the transformer is bought alone or as part of a station |
| Dry type | No enclosure, in a dedicated electrical room | Whether the room itself provides the protection |
| Dry type | Ventilated housing to a stated IP rating | Access by unauthorised people, dust and dripping water at the installed position |
Degrees of protection are expressed with the IP code of IEC 60529. The rating required follows from the installed position, not from the transformer.
Accessories commonly specified
| Accessory | Construction | Purpose |
|---|---|---|
| Off circuit tap changer | Both | Adjusts the ratio to the network voltage at the connection point |
| Temperature indication with alarm and trip contacts | Both | Protects the unit against overtemperature |
| Pressure relief device | Liquid immersed | Relieves internal pressure in a fault |
| Gas and oil actuated relay | Liquid immersed with conservator | Detects internal faults and loss of liquid |
| Liquid level indicator and dehydrating breather | Liquid immersed with conservator | Monitors the liquid and keeps moisture out |
| Winding temperature sensors and relay | Dry type | Alarm and trip on winding temperature |
| Cooling fans | Dry type | Increases output above the natural air rating |
| Cable boxes | Both | Encloses cable terminations |
| Rollers, lifting and haulage lugs | Both | Handling on arrival and positioning |
Accessories vary by manufacturer and specification. Those included are listed in the quotation for the unit offered.
Dimensions and weight
Dimensions and weight are not published for a rating, because two units of the same rating can differ considerably. The construction, the loss level the core and windings are designed to, the cooling arrangement, the enclosure, the cable boxes and the conductor material all change the footprint and the mass.
They come from the outline drawing of the specific unit offered, which is provided with the quotation. That drawing is what the foundation, the room and the delivery are designed around, so it is worth having before those are fixed.
Documents normally requested
| Document | What it evidences | When it is normally provided |
|---|---|---|
| Technical datasheet | Rating, voltages, losses, impedance, dimensions and weight of the unit offered | With the quotation |
| Outline drawing | Footprint, lifting points and cable connection positions | With the quotation or at order |
| Routine test report | The individual unit's tests to its standard | With the delivered unit |
| Type test report | The design has passed the type tests of its standard | On request, where a type test exists for the design |
| Rating plate details | The declared values carried on the unit itself | With the delivered unit |
| Declaration of conformity | Conformity with the legislation of the destination market | Where the destination market requires one |
| Operating and maintenance manual | Installation, operation and maintenance instructions | With the delivered unit |
Which documents apply depends on the destination market, the standard and the manufacturer. Documents are confirmed in the quotation for the specific unit offered.
What we need to quote a 1600 kVA transformer
| 01 | Rated power in kVA, or the connected load and the largest motor if the rating is not fixed yet |
| 02 | Primary and secondary voltage, and the tapping range if the network operator sets one |
| 03 | Phase, frequency and the vector group, or the earthing arrangement it has to suit |
| 04 | Construction: liquid immersed or dry type, and whether oil is acceptable where the unit will stand |
| 05 | Indoor or outdoor, ambient temperature, altitude and any corrosive or dusty exposure |
| 06 | The standard and the loss requirement the destination market applies |
| 07 | Quantity, destination and the date the equipment has to be on site |
| 08 | Whether surplus or refurbished units are acceptable, or new only |
Delivery and logistics
Distribution equipment is heavy, and a delivery date is only real once the site is ready for it. The dimensions and weight of the unit offered decide the vehicle, the lifting equipment and the route to the foundation, and they come from the manufacturer's drawing rather than from the rating.
Liquid immersed transformers are usually shipped filled, which affects transport rules and the handling on arrival. Anything crossing a border also carries customs documentation, and where the destination applies its own conformity or energy efficiency rules the paperwork has to match that market rather than the country of manufacture.
Lead times vary widely with rating, specification and manufacturer loading. We state a delivery basis in each quotation for the specific unit offered and do not publish a general lead time we cannot hold.
Common questions
What size of low voltage incomer does a 1600 kVA transformer need?
The rated current at 400 V is 2,309 A, and 2,133 A at 433 V. The incoming device is normally selected at the next standard rating above that current, commonly 2,500 A. The designer confirms the rating against the actual loading, the ambient and the discrimination study.
Does a 1600 kVA transformer have to meet the EU loss limits?
Where it is placed on the EU market, or in Great Britain, and falls within the regulation's scope, yes. For a three phase unit with one winding up to 24 kV Um and the other up to 3.6 kV Um, the liquid immersed limits at 1600 kVA are 12,000 W load losses and 1,080 W no load losses. A 36 kV Um primary and dual voltage windings are corrected under separate tables.
Related
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