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35kV Oil Immersed Distribution Transformer

35kV Oil Immersed Distribution Transformer

Basic information

Type: Oil Immersed Transformer

Phase: Three

Service Voltage: up to 35KV

Rated Capacity: up to 31500kVA

Vector group: Dyn11

Cooling type: ONAN

Core material: CRGO

Winding material: Copper/aluminum

Available fluids: mineral oil and ester fluids

Purpose:Three-phase oil filled pad mounted electrical transformers are intended for transforming of electric energy in networks of power systems and in energy consumer networks.

Product Overview

35KV Oil Lmmersed Transformers can be customized to meet specific customer requirements, making them suitable for 35kV power distribution and conversion applications. Standard capacities range from 630kVA to 31,500kVA, including increments of 800kVA, 1,000kVA, 1,250kVA, 1,600kVA, 2,000kVA, 2,500kVA, 3,150kVA, 4,000kVA, 5,000kVA, 6,300kVA, 8,000kVA, 10,000kVA, 12,500kVA, 16,000kVA, 20,000kVA, 25,000kVA, and 31,500kVA. These transformers comply with IEC 60076, GB1094 and GB/T6451. The on-load voltage regulation range is 35±2×2.5%kV, 38.5±2×2.5%kV, 35+3×2.5%kV, and 38.5+3×2.5% kV. Within this range, the output voltage stability is ensured through manual, electrical, or automatic adjustments using an on-load voltage regulator on the primary side. For transformers rated above 6,300kVA, a folding oil tank design is employed, which significantly enhances the mechanical strength of the tank, reduces welds, and improves the overall appearance quality of the transformer. This product serves as an upgraded alternative, offering improved operational economic benefits.

Product Structure

The full inclined step joint design optimizes the flux path, eliminating local flux saturation at the core joints, thereby reducing no-load losses and currents while minimizing transformer noise. To enhance short-circuit resistance, pressure nails are strategically placed around the pressure plates, and support beams connect the upper and lower high and low voltage clips, ensuring the core remains structurally intact. Additionally, the core column surface is coated with specialized end face adhesive for silicon steel sheet , bonding the sheets together and solidifying the core into a single unit after curing. High-strength electrical laminated wood supports are used between the lower part of the body and the tank wall, ensuring reliable positioning of the lower section.

Standards:

● GB1094.1-1996

● GB1094.3-2003

● GB/T6451-200

Parameters

35kV Oil-immersed Three-phase Doubl- winding Non-excited Voltage Regulation Distribution Transformer Parameters
Rated Power   (kVA)Vector groupEfficiency Level 1Efficiency Level 2Efficiency Level 3Short Circuit Resistance%
No-load Loss  (kW)On-load Loss  (75℃  kW)No-load Loss   (kW)On-load Loss  (75℃  kW)No-load Loss  (kW)On-load Loss  (75℃  kW)
3150YNd11       1.7 20.7 2.0 20.7 2.4 21.9 7
40002.0 24.6 2.3 24.6 2.9 25.9 
50002.4 28.2 2.8 28.2 3.5 29.7 
63002.9 31.5 3.4 31.5 4.2 33.3 8
80004.0 34.6 4.7 34.6 5.8 36.5 
100004.8 40.8 5.7 40.8 7.0 43.0 
125005.5 48.4 6.5 48.4 8.0 51.1 
160006.7 59.2 7.9 59.2 9.7 62.5 
200007.9 71.6 9.4 71.6 11.5 75.5 
250009.4 84.6 11.1 84.6 13.6 89.3 10
3150011.1 100.8 13.1 100.8 16.2 106.4 


Product Advantages

● Energy Efficiency

The 35kV oil-immersed transformer incorporates advanced energy-saving technology, effectively reducing energy consumption and improving efficiency. The core is constructed from high-quality cold-rolled silicon steel sheets, characterized by low loss, low noise, and high efficiency.

● Low Noise

 Utilizing high-quality windings and high-performance materials, the transformer operates with minimal noise. Its robust insulation system and reliable structural design ensure stable long-term operation, further reducing possibility of generating noise.

●High Reliability

The core is made from specially treated, low-loss, low-noise steel, providing excellent corrosion and heat resistance. This allows for reliable operation under harsh environmental conditions. High-quality materials and precise manufacturing ensure the transformer's reliability and longevity.

● Ease of Maintenance

The transformer's design facilitates easy maintenance and repair. An automatic protection system automatically disconnects the power supply in case of faults, preventing potential short circuits and fires caused by damaged components. Simple operations allow maintenance personnel to efficiently service the transformer, enhancing its usability.


Product Characteristics

● The transformer core is made of high magnetic conductivity, grain-oriented cold-rolled silicon steel sheets, ensuring low no-load loss.

● The three-phase windings use concentric coils with corrugated oil ducts. A non-dipping paint process and tight band binding enhance mechanical strength, ensure balanced ampere-turn distribution, and provide excellent short-circuit resistance.

● To prevent displacement during transportation, a positioning structure is added to the core assembly. All fasteners are secured with locking nuts to avoid loosening during long-term operation.

● The transformer adopts a fully sealed design. Vacuum oil filling completely removes internal moisture, isolates the oil from ambient air, prevents oil aging, and improves operational reliability. Pressure relief valves are installed across all capacity sections, and optional gas relays with alarm and trip functions are available for enhanced safety.

● A corrugated oil tank design offers simple manufacturing, high strength, excellent welding performance, and no leakage. The strong oil fluidity also improves heat dissipation.

● Compact, aesthetically pleasing, and space-saving, this transformer is an ideal maintenance-free solution.


Typical Applications

● Utility & Substation Distribution – Heavy-duty service for 35 kV grid distribution.

● Industrial & Mining Facilities – Ideal for onsite 35 kV to low-voltage stepping in industrial loads.

● Renewable Energy Integration – Supports wind farms or solar parks with stable power delivery.

● Urban Infrastructure Projects – Underground or pad-mounted installations for city/regional distribution.

● Oil & Gas or Petrochemical Sites – Delivers robust performance in harsh, high-integration environments.


Why Choose Tianya Electric?

  1. Rich Manufacturing Legacy
    Operating since 2007 with a full end-to-end production setup and 6,000 m² facility.

  2. Strict Quality Governance
    Multi-stage QC—from supplier approval to pre-shipment testing—ensures 100% defect-free deliveries.

  3. Deep Technical Expertise
    A team of 30+ seasoned engineers deliver tailored engineering, site support, and seamless product integration.

  4. Comprehensive Manufacturing Process
    In‑house iron core, coils, oil tanks, assembly, vacuum-drying, testing, and packaging—all under one roof for maximal control.

  5. Lifetime Support & After‑Sales
    24/7 customer service, technical assistance, rapid spares, renovation, and maintenance available internationally.

Company Services

  • Custom Solution Design – Voltage, power ratings, cooling methods, accessories, oil types tailored per project.

  • Technical & Project Consulting – EMC assessments, tap changer planning, loading optimization.

  • Factory Acceptance Tests – Witnessed dry and wet tests to international ANSI/IEC standards.

  • International Logistics & Support – Global delivery, customs clearance, and on-site commissioning.

  • After‑Sales Maintenance – Spare parts supply, oil analysis, refurbishment, and comprehensive troubleshooting.


35KV Oil Lmmersed Transformer Purpose

Three-phase oil filled pad mounted electrical transformers are intended for transforming of electric energy in networks of power systems and in energy consumer networks.

  • 35kv Oil Lmmersed Transformer

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