35KV Oil-immersed Transformer — YUANGUANG (YGT) | Uzbekistan EPC 2020

Overview — Industrial & EPC Ready 35 kV Oil-Immersed Transformer
YUANGUANG’s 35KV oil-immersed transformer is a purpose-built transformer for EPC, industrial and heavy rectifier applications. Its autotransformer/toroidal coil architecture and interleaved-continuous HV winding deliver even voltage distribution, low stray loss and improved short-circuit robustness — all essential for sites with limited civil works and demanding electrical duty cycles. The product is skid-mounted for rapid on-site placement and shipped with seaworthy accessory packing for reliable global delivery.

Why buyers choose this model

Low Partial Discharge & High Insulation Reliability. Apparent PD is designed <80 pC at 1.5×Vrated — minimizing insulation aging and improving service life in harsh environments.

Superior Acoustic & Energy Performance. Noise is controlled ≤58 dB(A) for units ≤63 MVA — suitable for community-facing installations. No-load loss is typically ~30% lower than IEC reference, delivering lower lifecycle OPEX.

Thermal & Mechanical Engineering for Real Duty. Zig-zag oil guides inside the winding and radial margin design reduce winding hotspots and improve oil circulation; heavy bracing and epoxy-impregnated glass fiber straps ensure mechanical integrity during transport and short-circuit events.

EPC-Friendly Logistics. Skid-mounted design, certified lifting points and CoG drawings simplify siting and dramatically reduce foundation scope — accelerating commissioning.

3 — Technical highlights (engineer bullets)

Core: High-permeability grain-oriented (CRGO) cold-rolled silicon sheet, automatically sheared (<=0.02 mm burr) and o-upper yoke lapped with 45° full-miter joints; epoxy bonded laminates for low loss and sound.

Winding: Interleaved-continuous HV coil to flatten voltage restraint under impulse; chamfered stays and pads; zig-zag oil guide to cool internal zones and reduce hotspot rise. Radial margin and precise pre-drying assure concentricity.

Insulation & Process: Vacuum drying followed by Vacuum-Pressure Impregnation (VPI) for full varnish penetration and mechanical bonding — improves insulation life & moisture resistance.

OLTC / Tap Options: NLTC (no-load tap changer) as standard; OLTC (on-load tap changer) available for live regulation — endurance & electrical ratings per TDS.

Protection & Instrumentation: Buchholz / PRV / OTI/WTI, PT100 hotspots; optional RS485/Modbus SCADA integration.

Project Proven: Delivered and commissioned on Uzbekistan EPC 2020 with FAT witnessed and documentation.

4 — Applications (where to use)

Grid & Substation step-down: 35kV distribution for industrial parks

Rectifier service for heavy DC loads (steel, electrolysis, smelting)

EPC & Turnkey projects requiring fast deployment and low civil works

Mining, power plant auxiliary supplies, and remote factory electrification

5 — Manufacturing & FAT (detailed)

Design & calculation tools
We use advanced electromagnetic & mechanical analysis (strength analysis, leakage flux distribution, electro-dynamic forces, insulation stress analysis) to optimize core geometry and winding arrangement.

Winding detail

HV coils adopt interleaved-continuous structure to improve voltage distribution under impulse and reduce local stress. Stays and pads chamfered for improved insulation contact.

Zig-zag oil guide structure ensures oil reaches all winding areas to lower hotspot temperatures and extend insulation life. HV and MV regulation windings are independently provided where required to balance ampere-turns and reduce axial electrodynamic forces during short-circuit.

Radial margin design and strict pre-drying assure compactness and concentricity; coils are banded and braced to withstand mechanical stress.

Core details

Cut from premium CRGO silicon sheet; 45° full-miter lapped joints; laminate pressed and epoxy bonded to form a robust core with superior no-load performance and reduced audible noise.

Quality control & traceability

Material certificates (steel, copper, varnish), winding tension logs, VPI cycle logs, oven records, assembly torque logs and instrument calibration certificates are included in the FAT pack.

FAT scope & deliverables

Routine: transformation ratio & polarity, DC winding resistance, no-load loss & current, load loss & impedance, insulation resistance, oil dielectric tests.

Type tests: temperature rise, lightning impulse withstand, short-circuit, noise measurement, partial discharge testing (per project spec).

Deliverables: signed FAT protocol, measured value tables (CSV/PDF), instrument calibration certificates, test photos and witness signatures.

6 — Packaging, logistics & supply

Packaging details

Power transformer main body in nude (oversize) when required; accessories packing in seaworthy standard wooden case. Dry silica-gel, anticorrosion wrapping and secured fastenings for sea transit.

Port of dispatch

Shanghai or Ningbo (or buyer-specified Chinese port)

Selling unit

Single item per order (or according to contract)

Supply capability

YUANGUANG production: 5,000 pieces per year (power transformers series)

On-site guidance

Certified lifting & CoG drawings provided; skid mount recommended to minimize foundation; local commissioning and O&M training available.