This unit keeps HV switching, the transformer and the LV connections in separate compartments, and its air-insulated load-break switch opens with a visible isolating gap. A pad-mounted transformer puts the load-break switch and fuses inside the transformer oil tank and takes up little more space than the transformer itself; ETENZ supplies that form as the Pad-Mounted Transformer for Solar and Wind. Choose the compartmented unit when site practice calls for a visible HV isolating point for maintenance, and the pad-mounted unit when footprint comes first.
Wind Turbine Transformer
For wind farm contractors and turbine suppliers — the step-up unit at each turbine, with HV, transformer and LV compartments and visible HV isolation.
Wind Converter Support FacilityRenewable Grid-Connection Power DistributionRenewable Energy Collector Station SupportPackage Substation
Key Metrics
10 / 35kV
High voltage
690–1140V
Low voltage
800–6800kVA
Rated power
3700–14000kg
Total mass
Product Features
Three compartments
HV switchgear, transformer and LV connections sit in separate compartments of one housing, in an in-line or a more compact triangular arrangement.
Three compartments
HV switchgear, transformer and LV connections sit in separate compartments of one housing, in an in-line or a more compact triangular arrangement.
Visible HV isolation
The air-insulated load-break switch opens with a visible isolating gap, so one unit can be isolated for maintenance while the collector line stays energised.
Turbine-matched LV
LV of 0.69 kV, 0.95 kV or 1.14 kV matches the turbine’s AC output, stepped up to a 10 kV or 35 kV collector line.
Up to 6800 kVA
Ratings run from 800 kVA to 6800 kVA in the 35 kV class and to 4000 kVA in the 10 kV class, covering multi-megawatt turbines.
Cold-site oil grades
Oil grades I-10 °C, I-20 °C and I-30 °C set the lowest cold-start energising temperature, so the oil can be chosen for the coldest site conditions.
Product Details
S stands for three-phase, and the position after it is the performance level code. After the hyphen come the rated power and the voltage class, written as kVA/kV. S□-4000/35 therefore identifies a three-phase unit rated 4000 kVA in the 35 kV class; □ is the selected performance level code.
In the in-line layout the HV, transformer and LV compartments stand in a row. In the triangular layout the HV and LV compartments sit side by side along one side of the transformer compartment, which gives a shorter, squarer footprint. The transformer is three-phase and oil-immersed with copper windings, cooled ONAN (oil natural, air natural). Insulation is Class A, with a winding temperature rise of 65 K and a top-oil temperature rise of 60 K.
The HV compartment holds an air-insulated load-break switch–fuse combination on the transformer feeder: the switch makes and breaks load current and the fuses clear faults. The contacts sit in air, so the open position can be checked by eye before work starts on that unit. The 10 kV class has a highest voltage for equipment (Um) of 12 kV, a short-duration power-frequency withstand of 35 kV and a lightning impulse withstand (BIL) of 75 kV full wave and 85 kV chopped wave. For the 35 kV class, these values are 40.5 kV, 85 kV, 200 kV and 220 kV respectively.
The LV winding is set to the turbine’s rated AC output voltage, with 0.69 kV, 0.95 kV and 1.14 kV among the options. Rated frequency is 50 Hz. The vector group is specified with the order: Dy11, with a delta HV winding and a star LV winding, or Yd11, with a star HV winding and a delta LV winding. Tap changing is off-circuit (de-energised), with the tap range agreed for the project.
Delivery Scope Options
Scope 1
Single Unit or Complete Package Supply
Scope 1Single Unit or Complete Package Supply
Transformers are supplied as single units against the order schedule, or as a complete package together with the protective enclosure, the temperature controller and the cooling fans. The active part is wound, assembled and routine-tested at the works and shipped as a complete unit; the assembly interface for the accessories follows the transport conditions. Where the transformer is to arrive together with a prefabricated power module, the E-House line takes on the enclosure, the internal arrangement and the foundation fixing, and the transformer is delivered as equipment housed within it.
Scope Includes:
Single unit or complete package
Complete-unit shipment and assembly interface
Foundation and fixing interface
In-cabin delivery handled by the E-House line
Technical Specifications
Product form
Three-phase oil-immersed step-up transformer, copper windings, in a housing with HV, transformer and LV compartments; in-line or triangular layout
Type designation
S□-□/□ (performance level code-rated power/voltage class)
High-voltage class
10 or 35
kV
Highest voltage for equipment (Um)
12 or 40.5
kV
Rated power, 10 kV class
800 / 1600 / 2000 / 2500 / 3150 / 4000
kVA
Rated power, 35 kV class
800 / 1600 / 2000 / 2500 / 3150 / 4000 / 5000 / 6800
kVA
Low voltage
0.69 / 0.95 / 1.14 kV and other values matched to the turbine’s output
HV switching
Air-insulated load-break switch–fuse combination with a visible isolating gap
Vector group
Dy11 or Yd11, as ordered
Tap changing
Off-circuit (de-energised); tap range agreed for the project
Insulation level (power frequency / lightning impulse full wave / chopped wave)
10 kV class: 35 / 75 / 85; 35 kV class: 85 / 200 / 220
kV
Rated frequency
50
Hz
Cooling
ONAN (oil natural, air natural)
Insulation class and temperature rise
Class A; windings 65 K, top oil 60 K
Insulating oil
I-10 °C, I-20 °C or I-30 °C grade (LCSET), selected for the minimum site temperature
Total mass, 10 kV class
800 kVA: 3700; 1600 kVA: 4950; 2000 kVA: 5300; 2500 kVA: 6200; 3150 kVA: 7000; 4000 kVA: 8500
kg
Total mass, 35 kV class
800 kVA: 4300; 1600 kVA: 6150; 2000 kVA: 7200; 2500 kVA: 7700; 3150 kVA: 8100; 4000 kVA: 9400; 5000 kVA: 9950; 6800 kVA: 14000
kg
Losses, impedance, dimensions, degree of protection
Agreed for the selected rating, loss level and service conditions
| Parameter | Specification |
|---|---|
| Product form | Three-phase oil-immersed step-up transformer, copper windings, in a housing with HV, transformer and LV compartments; in-line or triangular layout |
| Type designation | S□-□/□ (performance level code-rated power/voltage class) |
| High-voltage class | 10 or 35 kV |
| Highest voltage for equipment (Um) | 12 or 40.5 kV |
| Rated power, 10 kV class | 800 / 1600 / 2000 / 2500 / 3150 / 4000 kVA |
| Rated power, 35 kV class | 800 / 1600 / 2000 / 2500 / 3150 / 4000 / 5000 / 6800 kVA |
| Low voltage | 0.69 / 0.95 / 1.14 kV and other values matched to the turbine’s output |
| HV switching | Air-insulated load-break switch–fuse combination with a visible isolating gap |
| Vector group | Dy11 or Yd11, as ordered |
| Tap changing | Off-circuit (de-energised); tap range agreed for the project |
| Insulation level (power frequency / lightning impulse full wave / chopped wave) | 10 kV class: 35 / 75 / 85; 35 kV class: 85 / 200 / 220 kV |
| Rated frequency | 50 Hz |
| Cooling | ONAN (oil natural, air natural) |
| Insulation class and temperature rise | Class A; windings 65 K, top oil 60 K |
| Insulating oil | I-10 °C, I-20 °C or I-30 °C grade (LCSET), selected for the minimum site temperature |
| Total mass, 10 kV class | 800 kVA: 3700; 1600 kVA: 4950; 2000 kVA: 5300; 2500 kVA: 6200; 3150 kVA: 7000; 4000 kVA: 8500 kg |
| Total mass, 35 kV class | 800 kVA: 4300; 1600 kVA: 6150; 2000 kVA: 7200; 2500 kVA: 7700; 3150 kVA: 8100; 4000 kVA: 9400; 5000 kVA: 9950; 6800 kVA: 14000 kg |
| Losses, impedance, dimensions, degree of protection | Agreed for the selected rating, loss level and service conditions |
Product FAQs
Start from the turbine’s rated apparent power and select the next listed rating at or above it, in the voltage class of the collector line. The LV voltage is set to the turbine’s rated AC output voltage, and the oil grade to the lowest temperature expected on site.
The price mainly depends on the voltage class, kVA rating, LV voltage, loss level, compartment layout and accessories. For a quotation, provide the collector-line voltage, the turbine model and rated power, the LV voltage and vector group, the preferred layout, the minimum site temperature and altitude, the grid frequency and the document requirements.
Yes. The transformers stand at the turbines, and the 10 kV or 35 kV collector circuits run back to the wind farm substation. For the collector switchgear there, the ETENZ E-House line supplies the enclosure, internal layout and HVAC and fire-protection systems, for example the Containerized MV Switchgear E-House or the MV Switchgear E-House. Interfaces between the transformers and the E-House are confirmed together before dispatch.
This unit stands on its own foundation beside the turbine tower, normally one per turbine. LV cables from the turbine enter the LV compartment, and the HV compartment connects to the 10 kV or 35 kV collector circuit that runs to the wind farm substation.
Related Solutions
Power & Control
MV/LV Switchgear E-House Integration Solution
For industrial plants, utility infrastructure, data centers, and renewable-energy connection projects, ETENZ integrates MV/LV switchgear layouts, enclosure interfaces, ventilation or cooling, fire and grounding provisions, cable routes, and factory checks into a prefabricated E-House delivery scope, with enclosure supply, pre-installation, complete E-House delivery, and OEM/ODM cooperation options.
Product Application Cases
Related Products
Electrical E-Houses
Containerized MV Switchgear E-House
Electrical E-Houses
MV Switchgear E-House
Electrical E-Houses
Integrated E-House
Power Transformers
Pad-Mounted Transformer for Solar and Wind
New Energy Enclosures
BESS Step-Up Substation Enclosure (20 ft)
Power Transformers
35 kV Oil-Immersed Power Transformer
Have a project in mind?
Message us on WhatsApp or send an inquiry. We reply within 24 hours on working days.