Two Custom 34 MVA Substation Transformers Ready for North America Project in 84 Days

At a large industrial facility in North America, the 11 kV substation powers critical continuous process loads, including high-power motors, pumps, and ventilation systems. To isolate the incoming supply and guarantee uninterrupted plant operations, the customer required two 34 MVA, three-phase, liquid-filled transformers for outdoor installation. Operating in severe winter conditions with minimal maintenance downtime, the units required exceptional environmental resilience and long-term reliability.

• Extreme Cold & Corrosive Environment: Operating in outdoor ambient temperatures down to -40°C with high moisture and potential atmospheric corrosion.

• Specialized Electrical Configuration: Dual-rating capacity (26 MVA KNAN / 34 MVA KNAF), 11 kV Delta primary to 11 kVY/6.351 kV Grounded-Wye secondary with a Dyn1 vector group.

• Strict Environmental & Control Specs: Non-PCB biodegradable natural ester fluid, combined with remote telemetry integration for oil level, temperature, pressure, and gas relay status.

• Tight Project Timeline: Engineering drawing approval, dual-unit synchronized manufacturing, factory testing (FAT), and documentation needed to be completed on an aggressive schedule.

During technical review, WINLEY systematically addressed every customer requirement, translating all confirmed structural details, dimensions, interfaces, and accessories into formal project drawings. The finalized 41-page engineering package detailed general arrangements, installation dimensions, bill of materials, terminal layouts, control schematics, accessory specifications, and warranty terms.

The general arrangement drawings allowed the site team to verify orientation and physical clearances, while terminal layouts and wiring diagrams facilitated early field routing of power cables, control lines, and alarm loops. All design adjustments finalized during initial technical reviews were fully reflected in the engineering drawings, providing a unified basis for manufacturing and acceptance testing.

Following drawing approval, both transformers entered production under a coordinated dual-unit schedule. Core winding assemblies were completed in March, followed in April by 304 stainless steel tank fabrication, active-part assembly, accessory installation, and final assembly. Manufacturing workflows and material allocations were synchronized to keep progress across both units tightly aligned.

By late April, Unit 1 reached final assembly and entered the testing bay, with Unit 2 completing assembly shortly after to undergo the identical testing sequence. This seamless production flow enabled both transformers to pass complete factory testing within a one-week window, maintaining the total 84-day timeline.

Unit 1 completed factory acceptance testing on April 30, and Unit 2 finished the identical testing program on May 7. The test program encompassed winding resistance, insulation resistance, voltage ratio, no-load loss, load loss, short-circuit impedance, dielectric withstand, fluid quality, and pressure integrity, thoroughly verifying performance prior to release.

Key Test Outcome: Both units passed all dielectric, fluid, and pressure integrity tests on the first attempt. The measured impedance values (5.70% vs 5.69%) demonstrated an exceptional deviation of just 0.01%, assuring optimal current balance during future parallel operation.

On July 30, both transformers were loaded separately, with the engineering team documenting the entire process via photographic records—from physical positioning to tie-downs, cross-lashing, and weatherproofing. Given the substantial weight and external accessories of large power units, loading protocols were reviewed individually to eliminate transit shift and damage risks.

Factory test reports, final documentation, and shipping photographs were archived unit-by-unit for seamless handover with logistics providers and site teams. With final tie-downs secured and weather protection fitted, both units completed all factory-phase milestones and were released for transport.

Through tight engineering alignment and synchronized production scheduling, WINLEY successfully overcame three major challenges—extreme-cold corrosive environment compatibility, non-standard dual-rating electrical configuration, and an aggressive delivery schedule—completing the manufacturing and FAT verification of both custom 34 MVA transformers in just 84 days. Factory tests revealed an exceptional impedance deviation of just 0.01% (5.70% vs. 5.69%), demonstrating superior electrical consistency and product reliability.

• On-Time Site Commissioning Without Delays: The 84-day fast-track delivery secured the project's critical path, preventing costly site downtime and delays in energization.

• Substantially Lower Total Cost of Ownership (TCO): The NEMA 4X 304 stainless steel corrosion protection combined with high-fire-point, biodegradable natural ester fluid minimizes annual maintenance expenses and environmental compliance risks.

• Plug-and-Play Installation with Zero Field Rework: High-current terminal orientation, bushing enclosures, and remote SCADA control interfaces were fully aligned with site drawings prior to dispatch, enabling rapid installation and seamless integration into the station's control network.

• Long-Term Operational Confidence: Exceptional test consistency backed by a 24-month factory warranty provides complete peace of mind for continuous operation under heavy loads and harsh operating conditions.

For projects facing complex technical challenges—such as large capacities (up to 100 MVA / 145 kV), dual-rating or specialized vector configurations, severe cold/outdoor environments, or strict project schedules—WINLEY delivers tailored equipment designs, precise drawing approval packages, and transparent delivery milestones aligned with your site conditions.

• Clear, Capacity-Based Lead Times: Fast-track execution with defined schedules (e.g., 10–12 weeks for 10–40 MVA units post-approval), complete with real-time manufacturing photo updates and production tracking.

• Full Compliance & Testing Oversight: Complete English documentation packages (approval drawings, routine test reports, and operating manuals) backed by 100% FAT verification and third-party inspection (SGS) readiness.

• Long-Term Operational Confidence: Backed by a 24-month warranty, 24/7 technical response, and lifetime documentation archiving derived from extensive North American industrial and utility project experience.

Contact the WINLEY engineering team today for customized technical proposals and rapid 1–3 day quotation support (MOQ: 1 unit).

Email:steven@winley-electric.com