33/11 kV, 33/6.6 kV 15 MVA On-Load Tap Changer Transformer

Medium Voltage Power Transformer for Industrial and Utility Substations

The 15 MVA 33/11 kV and 33/6.6 kV On-Load Tap Changer Transformer (OLTC Transformer) is a medium-capacity power transformer designed for utility substations, industrial power distribution systems, and renewable energy plants.

This oil-immersed power transformer steps down 33 kV medium voltage to 11 kV or 6.6 kV distribution voltage, ensuring stable electricity supply for factories, infrastructure, and grid networks.

With an integrated on-load tap changer, the transformer can automatically regulate voltage under load conditions, maintaining stable output voltage even when grid load changes.

This makes it a reliable solution for modern power distribution networks that require high efficiency, low losses, and long-term operational stability.

Key Technical Specifications

Typical parameters for a 15 MVA OLTC transformer are shown below.

Technical specifications can be custom designed according to project requirements.

Core Engineering Features

On-Load Voltage Regulation

The integrated OLTC transformer system enables automatic voltage adjustment without interrupting power supply.

This function is essential for industrial substations and utility transformers, where voltage stability directly affects equipment performance and grid reliability.

Low Loss Core Design

The transformer core uses high-grade CRGO silicon steel, reducing both no-load loss and load loss.

Benefits include:

• Higher transformer efficiency

• Reduced operating cost

• Improved power system stability

This design makes the transformer suitable for continuous operation in power distribution networks.

High Reliability Insulation System

The transformer adopts a robust insulation structure consisting of:

• Transformer insulation oil

• Electrical insulation paper

• Pressboard insulation components

This ensures high dielectric strength and reliable operation under high-voltage power system conditions.

Efficient Cooling System

The transformer uses standard cooling configurations:

ONAN – Oil Natural Air Natural
Suitable for normal load operation.

ONAF – Oil Natural Air Forced
Provides enhanced cooling for higher load conditions.

The cooling system ensures stable thermal performance and long transformer life.

Heavy-Duty Tank Construction

The transformer tank is designed for outdoor substation installation and long-term operation.

Standard protection devices include:

• Buchholz relay protection

• Oil level indicator

• Winding temperature indicator

• Pressure relief device

• Silica gel breather

These components ensure safe operation of the medium voltage transformer.

Engineering Advantages

Stable Grid Voltage

The on-load tap changer transformer continuously adjusts the voltage ratio, ensuring stable voltage output across varying load conditions.

Reduced Power Loss

Optimized core design and copper windings reduce transformer losses, improving overall energy efficiency.

Long Service Life

With high-quality materials and advanced manufacturing processes, the transformer can operate reliably for 20–30 years under proper maintenance.

Adaptability to Power Systems

The transformer can operate reliably in various power distribution applications, including industrial networks and utility grids.

Typical Applications

The 15 MVA medium voltage transformer is widely used in the following industries.

Utility Substations

Used as a grid power transformer to convert 33 kV transmission voltage to 11 kV distribution voltage.

Industrial Power Systems

Factories, mining plants, and heavy manufacturing facilities require reliable industrial power transformers for stable operation.

Renewable Energy Plants

Solar and wind power projects require step-down transformers to connect generation systems to medium voltage grids.

Infrastructure and Commercial Facilities

Applications include:

• Airports

• Hospitals

• Data centers

• Large commercial complexes

These facilities require reliable distribution transformers for continuous operation.

Custom Transformer Solutions

Professional transformer manufacturers can provide custom power transformer solutions, including:

• Voltage options: 33/11 kV transformer, 33/6.6 kV transformer

• Special design for tropical climate environments

• Corrosion-resistant tanks for coastal regions

• High-efficiency low-loss transformer design

• Customized OLTC configurations

Request Technical Quotation

If you are looking for a reliable 15 MVA OLTC transformer manufacturer, our engineering team can provide:

• Technical consultation

• Custom transformer design

• Competitive transformer pricing

• Global export support

Contact us today to receive a technical proposal and quotation for your power transformer project.