Power Transformer

High-Voltage Power Transformer for Utility Substations and Industrial Grids

Industrial power transformers convert voltage levels across 35kV to 220kV power networks. These units step down high transmission voltages to distribution levels or step up generator output for the grid. Built for continuous operation, each unit uses cold-rolled grain-oriented silicon steel cores and oxygen-free copper windings to reduce energy loss, manage heat, and withstand mechanical stress during grid faults.

Product Types and Configurations

35kV to 66kV Substation Transformers
Used in regional power grids and heavy industrial plants. Available in two-winding or three-winding setups with on-load or off-circuit tap changers.

110kV to 220kV Transmission Transformers
Used in major transmission substations. Features low electrical discharge, high short-circuit strength, and sealed oil preservation systems.

Three-Dimensional Symmetrical Core Transformers
Uses a three-phase symmetrical core layout with zero air gaps in the magnetic circuit, lowering no-load current and operating noise.

On-Load Voltage Regulator Transformers
Built with motorized switches to adjust voltage under load without cutting off power delivery.

Technical Specifications

Parameter	35kV to 66kV Series	110kV to 220kV Series
Rated Voltage	35kV, 66kV / 10kV, 0.4kV	110kV, 220kV / 10kV, 35kV, 110kV
Rated Capacity	5,000 kVA to 31,500 kVA	31,500 kVA to 120,000 kVA plus
Vector Group	Dyn11, Yyn0 (Customizable)	YNd11, YNyn0
Cooling Method	ONAN / ONAF	ONAN, ONAF, ODAF
Impedance Voltage	6.5 percent to 8.0 percent	10.5 percent to 12.0 percent
Tap Changer Range	Plus or minus 2 times 2.5 percent	Plus or minus 8 times 1.25 percent
Design Standard	IEC 60076, GB 1094	IEC 60076, IEEE C57.12.00

Design and Construction

Core Assembly

Built from high-permeability silicon steel sheets stacked using automated lines to reduce eddy current loss and noise.

Winding Setup

Wound with high-purity oxygen-free copper conductors. Uses epoxy-bonded paper and rigid pressing rings to handle mechanical forces during short circuits.

Tank and Structure

Made from heavy steel plates checked by computer simulation to withstand pressure tests. Includes modular radiators and pressure relief valves.

Insulation System

Uses electrical insulating paper and mineral oil treated in high-vacuum drying ovens to remove moisture and ensure electrical strength.

Applications

Utility Substations

Connecting high-voltage transmission lines to local distribution networks.

Heavy Industry

Steel mills, chemical plants, and mines that need large, stable power blocks.

Renewable Energy

Collector substations for large solar farms and wind power projects.

City Infrastructure

Urban power supply hubs that require low noise and compact sizes.

Manufacturing and Quality Control

Automated Core Cutting

CNC laser cutting lines make precise steel layers with smooth edges to keep power loss low.

Vapor Phase Drying

Coils go through sealed vacuum drying chambers to remove moisture down to very low levels, securing high electrical insulation.

Clean Workshop

Coil winding takes place in climate-controlled rooms to keep dust away from insulation materials.

Winding Pressing

Hydraulic machines apply steady pressure to coils to stop movement during electrical faults.

Custom Transformer Solutions

Electrical Changes

Custom voltage ratios, special vector groups, specific impedance values, and dual-voltage options.

Size Limits

Custom tank dimensions, specific cable box locations, and removable radiators to fit tight substation spaces.

Environmental Protection

Coastal anti-corrosion paint, high-temperature cooling arrays, and earthquake-resistant structures.

Testing and Documentation

Factory Acceptance Tests:
Checking winding resistance, voltage ratio, and vector group.
Measuring impedance voltage, load loss, and no-load loss.
Electrical tests including high-voltage withstand tests and partial discharge checks.

Type Tests:
Lightning impulse voltage tests.
Temperature rise tests to check thermal limits under full load.
Short-circuit mechanical strength tests.

Documentation: Every transformer ships with certified test reports, oil analysis data, maintenance manuals, and calibration certificates.

Packaging and Delivery

Transport Prep

Larger units ship filled with oil under a sealed nitrogen blanket, or drained of oil with dry air inside, depending on shipping routes.

Accessory Protection

Bushings, conservator tanks, and control boxes are packed in fumigated wooden crates to prevent damage.

Logistics Handling

Heavy lifting brackets and shock monitors are attached to the main frame to track transit movement during ocean and road freight.

Report on Product Qualifications

FAQ

Q: What standards do your power transformers meet?

A: Our transformers are designed and tested according to IEC 60076 and GB 1094 standards. We can also build units to meet IEEE C57 series or specific local grid rules.

Q: How do you control core losses?

A: We use high-grade silicon steel processed through CNC cutting machines. This reduces joint gaps and magnetic leakage, lowering no-load losses and noise.

Q: What is the production lead time for a custom 110kV transformer?

A: Production and factory testing for a custom 110kV power transformer usually take 10 to 14 weeks, depending on material supply and testing requirements.

Q: What tests are done before shipping?

A: Every unit goes through full routine tests under IEC 60076, including loss measurement, resistance checks, impulse tests, and partial discharge testing. Complete test reports are included.

Q: How is the transformer protected from moisture during shipping?

A: For units shipped without bulk oil, internal parts are kept under dry nitrogen or dry air pressure, tracked with a pressure gauge. Fragile parts are packed in sealed, moisture-proof crates.

Q: Can you match specific space limits for substation upgrades?

A: Yes. We offer custom mechanical layouts, including changed cable box positions, side-mounted radiators, and base sizes to fit existing concrete pads.

As one of the most experienced power transformer manufacturers and suppliers in China, we also support customized service. Please rest assured to wholesale bulk high quality power transformer in stock here from our factory. Contact us for more details.

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