Two Winding Three Phase High Voltage Transformer

The Two Winding Three Phase High Voltage Transformer manufactured by Lugao Power Co., Ltd. is a high-performance power transformer designed specifically for high voltage transmission and distribution networks. Unlike three-winding designs, this transformer features only high voltage and low voltage windings, significantly simplifying the structure while enhancing operational reliability. This design reduces failure points and improves fault tolerance, making it especially suitable for generator step-up applications and grid interconnection.

Built with a low-loss grain-oriented silicon steel core and high-conductivity oxygen-free copper windings, the transformer achieves exceptionally low no-load and load losses. The robust oil-immersed cooling system ensures efficient heat dissipation, while the fully sealed tank structure prevents oil oxidation and moisture ingress. With multiple regulation and cooling configurations available, this product delivers long-term stable performance under demanding operating conditions.

Product Feature And Application

Features

1. Meets or exceeds IEC, ANSI, GB, and other international standards

2. Two-winding design for simplified structure and enhanced reliability

3. Flexible voltage regulation with off-circuit or on-load tap changers

4. Multiple cooling methods: oil-immersed self-cooling, forced air cooling, forced oil circulation

5. High overload capacity and excellent short-circuit withstand capability

6. Fully sealed corrugated tank design prevents oil oxidation and moisture ingress

7. Low noise operation and high energy efficiency

8. Robust construction suitable for harsh outdoor environments

9. Standardized dimensions for easy installation and maintenance

Q&A: Key Insights About Two Winding Three Phase High Voltage Transformer

Q: What is a two winding three phase high voltage transformer?

A: A two winding three phase high voltage transformer consists of two separate windings—a high voltage primary winding and a low voltage secondary winding—wound around a common magnetic core. It is used to step up or step down voltage in three-phase power systems, offering a simpler and more reliable alternative to three-winding or auto transformer designs. This structure is widely adopted in power plants, substations, and industrial applications where only two voltage levels are required. 

Q: What makes this transformer flexible in application?

A: Flexibility is achieved through two key aspects. First,voltage regulation options allow users to select either off-circuit tap changers for applications with stable voltage requirements, or on-load tap changers for grids with significant voltage fluctuations—enabling regulation without interrupting power supply. Second,cooling method flexibility includes oil-immersed self-cooling for standard applications, forced air cooling for increased capacity, and forced oil circulation for high-load or high-temperature environments, ensuring adaptability to diverse installation conditions.

Q: How does the two-winding design improve reliability?

A: With fewer windings and simpler internal connections compared to three-winding transformers, the two-winding structure reduces potential failure points and simplifies manufacturing and maintenance. This results in higher operational reliability, lower risk of internal faults, and easier troubleshooting, making it ideal for critical applications such as generator step-up or main grid substations.

Q: What are the advantages of high overload capacity and short-circuit withstand capability?

A: High overload capacity ensures the transformer can handle temporary load surges without overheating or performance degradation, which is crucial in industrial or grid environments with fluctuating demand. Excellent short-circuit withstand capability—achieved through optimized winding structures, robust clamping systems, and high-strength insulating materials—protects the transformer from mechanical and thermal stresses during grid faults, significantly extending service life.

Main Application Scenarios

● Power Generation Plants:Used as generator step-up transformers to connect generators to high voltage transmission grids.

● Grid Substations:Ideal for voltage transformation between two grid levels, such as 110kV to 35kV or 220kV to 110kV.

● Industrial Power Systems:Provides high voltage to low voltage conversion for large industrial facilities requiring reliable power supply.

● Renewable Energy Integration:Suitable for wind farms and solar power plants where voltage is stepped up for grid connection under challenging environmental conditions.

● Infrastructure Projects:Deployed in airports, railways, data centers, and hospitals requiring high reliability and flexible installation options.

Product Parameter (Specification)

Production Details

Core Material and Manufacturing Process

The two winding three phase high voltage transformer core is manufactured using high-permeability cold-rolled grain-oriented silicon steel with a stepped lap joint design, minimizing no-load losses and reducing magnetizing current. Core laminations are precision-cut and automatically stacked to ensure tight joints and uniform magnetic paths. The core is securely bound with semi-dry glass tape to maintain structural integrity and low noise operation.

Winding Structure

Both high voltage and low voltage windings are constructed using oxygen-free copper conductors, offering high conductivity and low resistive losses. The low voltage winding adopts a foil or helical structure with longitudinal oil ducts, significantly enhancing mechanical strength and short-circuit withstand capability. The high voltage winding is designed with interleaved or continuous disc configurations to optimize voltage distribution and impulse strength.

Insulation and Cooling System

High-quality mineral insulating oil or environmentally friendly high-fire-point insulating fluid is used to provide excellent dielectric strength and chemical stability. The oil-paper insulation system undergoes vacuum drying and oil-filling processes to eliminate residual moisture and air, ensuring high partial discharge inception voltage and long-term operational reliability. Cooling options include oil-immersed self-cooling (ONAN), forced air cooling (ONAF), and forced oil circulation (OFAF) to meet varied application requirements.

Tank and Sealing Structure

The two-winding three-phase high-voltage transformer adopts a corrugated tank design.The corrugated tank design provides thermal expansion compensation without the need for a conservator. The fully sealed structure prevents oil oxidation and moisture ingress, reducing maintenance frequency and extending oil life. Pressure relief valves and oil level gauges with low-level alarms are standard to ensure safe operation under abnormal conditions.

Protection and Control Configuration

Standard equipment includes an oil temperature gauge with alarm contacts, a winding temperature indicator, and a pressure relief valve. For applications requiring enhanced monitoring, optional gas relays and fiber-optic temperature measurement systems are available to enable dynamic load management and early fault detection.

Quality and Testing Assurance

Two-winding three-phase high-voltage transformers must undergo comprehensive type testing and routine testing before delivery, including no-load loss and load loss tests, short-circuit impedance tests, induced over-voltage withstand tests, partial discharge tests, and lightning impulse tests. All key performance indicators exceed the requirements of both national standards and IEC specifications, ensuring long-term stable operation under complex field conditions.

Product After-Sales Service

1. All products are covered by a five-year warranty against manufacturing defects under normal use, with a guaranteed leak-free and paint-peel-free operation.

2. Lifetime service support ensures the availability of spare parts and technical assistance throughout the product life cycle.

3. Designed for a service life of no less than 30 years under proper maintenance conditions.

4. In the event of equipment failure, the supplier will respond within one hour of notification and dispatch technical personnel to the site within 24 hours domestically.

Service Commitment

Lugao Power Co., Ltd. operates under an ISO 9001-2008 Quality Management System, ensuring that all Two Winding Three Phase High Voltage Transformers meet 100% quality standards before leaving the factory. Comprehensive pre-sales, sales, and after-sales services are provided to ensure complete customer satisfaction.

Standards Compliance:

GB1094.1~2-1996, GB1094.3-2003, GB1094.5-2008, GB/T6451-2015, JB/T3837-2010, GB/T311.1-3.11-97, IEC 60076 series, and other applicable international standards.