EN
Utility Substation
Transmission and distribution substations where capacity, redundancy, impedance and voltage regulation must be coordinated.
01 · Choose by application
Start with the operating duty—not a catalogue model
Select the closest project profile to see the transformer families and engineering questions that should shape the first technical discussion.
Industrial Plant
Heavy motors, furnaces, rolling mills and harmonic-rich loads that require close review of temperature rise and mechanical strength.
Renewable Energy
Solar, wind and storage projects requiring step-up duty, compact layout and a coordinated grid-connection package.
Commercial & Critical Building
High-rise buildings, hospitals, data centers and confined indoor locations where fire safety and ventilation govern selection.
Residential Distribution
Underground communities and overhead rural feeders where network architecture decides between pad- and pole-mounted equipment.
EPC & Infrastructure
Transport, petrochemical, mining and international EPC packages that require market-specific standards and clear scope boundaries.
02 · Compare transformer types
Match technology to installation conditions
Product type is a consequence of voltage, capacity, network architecture, fire safety, environment and maintenance strategy—not a preference in isolation.
Power transformer
Power Transformer
Grid & large industrial duty
- Published range: 3–400 kV, up to 240 MVA
- Generator step-up and transmission applications
- Configuration defined by system study
Oil-immersed
Oil-Immersed Transformer
Outdoor & high-capacity duty
- Strong heat dissipation and scalable capacity
- ONAN / ONAF cooling options by product
- Oil condition and containment must be planned
Dry-type
Dry-Type Transformer
Indoor & fire-sensitive sites
- Cast-resin or VPI construction
- No insulating-oil containment system
- Ventilation and environment remain critical
Pad-mounted
Pad-Mounted Transformer
Underground distribution
- Single- and three-phase platforms
- Ground-level access in a weatherproof enclosure
- Loop-feed or radial design by utility standard
Pole-mounted
Pole-Mounted Transformer
Overhead & rural networks
- Low civil-work and land-use requirement
- Conventional or self-protected configuration
- Utility clearance and protection rules apply
Integrated substation
Integrated Substation
Fast deployment & compact sites
- Prefabricated or compact arrangement
- Integrated HV, transformer and LV systems
- Footprint and transport access drive the choice
| Decision factor | Oil-immersed | Dry-type | Pad-mounted | Pole-mounted |
|---|---|---|---|---|
| Typical environment | Outdoor, high-capacity, harsh duty | Indoor, fire-sensitive, controlled space | Underground urban or commercial distribution | Overhead rural distribution |
| Primary design focus | Cooling, losses, oil system, containment | Fire safety, ventilation, insulation class | Feed design, enclosure, BIL, public safety | Efficiency, protection, corrosion, access |
| Maintenance focus | Oil, seals, bushings and cooling | Cleaning, ventilation and connections | Enclosure, fluid and cable interfaces | Elevated access, protection and coatings |
| Best comparison basis | Exact rating, site conditions, guaranteed losses, protection philosophy and lifecycle assumptions | |||
03 · Define the configuration
Turn project conditions into an engineering baseline
Use the six decisions below to make supplier responses technically comparable. Final values must be confirmed through the project study and approved datasheet.
Size the unit from the load study—not from connected load alone. Include diversity, motor starting, harmonic content, short-time overload, N-1 requirements and credible future growth.
Buyer providesLoad curve, peak demand, load factor, motor duty and growth horizon.
Supplier confirmsProposed rating, overload basis, thermal margin and applicable loading guide.
State nominal and maximum system voltage, required secondary voltage, frequency and permitted variation. A 33 kV and a 35 kV project can require different winding and insulation coordination.
Buyer providesGrid nominal voltage, operating range, 50/60 Hz and secondary bus voltage.
Supplier confirmsRated voltage, insulation level, ratio and compliance with the local grid basis.
The connection determines phase displacement, neutral availability, zero-sequence behavior and whether units can operate in parallel. Do not leave it to a catalogue default.
Buyer providesSystem grounding, neutral requirement, existing units and parallel-operation plan.
Supplier confirmsVector group, terminal arrangement and compatibility with protection studies.
Impedance affects fault current and voltage regulation. No-load loss is incurred whenever energized; load loss rises approximately with the square of load. Compare guaranteed values at the same reference conditions.
Buyer providesFault-level study, loss capitalization basis and target limits.
Supplier confirmsGuaranteed losses, impedance with tolerance, test basis and short-circuit evidence.
Use an OLTC where continuous regulation under load is required. Use an off-circuit design where voltage is stable and tap changes can be scheduled during an outage. OLTC adds control, maintenance and spares requirements.
Buyer providesVoltage-deviation range, regulation frequency and outage availability.
Supplier confirmsTap type, range, steps, controls, maintenance basis and spare-parts plan.
Cooling must suit rating, ambient temperature, altitude and enclosure conditions. Published YAWEI oil-immersed references include ONAN and ONAF; the selected method remains product- and project-specific.
Buyer providesMaximum ambient, altitude, enclosure, ventilation and overload expectation.
Supplier confirmsCooling stages, temperature-rise limits, derating and measured test values.
04 · Check the site
Environmental conditions are design inputs
Declare these conditions before quotation. They can change insulation, cooling, enclosure, coating, fire protection, derating and civil works.
Ambient temperature
State normal and extreme values. Published limits do not automatically cover exceptional cold or heat.
Altitude
Higher altitude can reduce dielectric and cooling performance; insulation and thermal correction may be required.
Humidity & salt spray
Specify corrosion category, sealing and coating. Coastal duty should not be inferred from a generic enclosure.
Dust & contamination
Mining, industrial and desert sites can require enhanced sealing, filtration, clearance and cleaning access.
Fire-sensitive location
Indoor critical sites may favor dry-type or less-flammable fluid, subject to local building and electrical codes.
Seismic duty
Foundation, anchoring, restraint, bushings and structural verification should follow the site seismic basis.
Space, access & public safety
Confirm footprint, transport route, lifting plan, cable approach, working clearance, public-area barriers and code-required separation.
Ventilation & noise
Indoor dry-type performance depends on airflow; urban and building projects may also require a noise target.
05 · Compare lifecycle value
Evaluate more than equipment price
The lower quotation is not automatically the lower-cost solution. Apply the same assumptions to every option and avoid fixed claims about electricity, tariffs, lead time or service life.
01Procure
Equipment Purchase
Transformer price, specified accessories, controls and the agreed factory documentation package.
02Deliver
Logistics & Insurance
Packing, freight, insurance, port handling, permits and transport from factory to project site.
03Install
Installation & Commissioning
Foundation, lifting, assembly, cabling, testing, energization and project handover activities.
04Operate
Energy Losses
Annual cost of no-load and load losses based on the actual load curve and electricity price.
05Maintain
Maintenance & Spare Parts
Inspection, oil or insulation checks, cleaning, service labor, planned outages and critical spares.
06Retire
Recovery & Disposal
Decommissioning, insulating-fluid treatment, material recovery, recycling and compliant disposal.
Equal-weight framework: card size does not represent cost share. Calculate every category with project-specific inputs.
06 · Select the right supplier
Compare capability, evidence and delivery scope
A fair supplier decision starts with one technical baseline. Ask every bidder to answer the same requirements and support each claim with the evidence appropriate to the offered configuration.
Product fit
Confirm voltage class, capacity, technology, market standard and customization boundary.
Engineering response
Review losses, impedance, tap scheme, cooling, site corrections and short-circuit design.
Evidence
Match certificates, test reports, materials and drawings to the exact offered product.
Complete delivery
Compare packing, logistics, documentation, commissioning, spares and after-sales scope.
Ask the supplier
Can the design meet the required impedance?Request value, tolerance and study basis
How are losses guaranteed?Request guaranteed table and test standard
Is OLTC available?Request range, steps, controls and maintenance basis
Will the site require derating?Request altitude and ambient review
Claim versus evidence
“Complies with IEC”Applicable standard, edition and test record
“Low-loss design”Guaranteed no-load and load losses
“High short-circuit strength”Design calculation or applicable type-test evidence
“Certified product”Certificate subject, scope and validity
From selection to technical review
Have a transformer project to evaluate?
Share the application, voltage, capacity, standards and site conditions. YAWEI’s engineering team can review the requirement before quotation and identify the fields that still need confirmation.