630kVA Oil Immersed Transformer Technical Specifications: Key Parameters Engineers Must Understand

In modern industrial and power distribution networks, selecting the right transformer requires a deep understanding of performance parameters and operational conditions. The 630kVA Oil Immersed Transformer Technical Specifications determine how efficiently the transformer operates, how stable the voltage output remains, and how long the equipment can serve in demanding environments.

 

GNEE Electric is a professional transformer manufacturer and exporter, supplying high-quality oil immersed transformers for industrial plants, renewable energy projects, mining operations, and infrastructure developments worldwide. With advanced manufacturing equipment, strict quality control systems, and international export experience, GNEE provides reliable 630kVA oil immersed transformers that meet international standards such as IEC, ANSI, and GB.

 

Understanding the key specifications of a 630kVA oil immersed transformer helps engineers design safer power systems, optimize energy efficiency, and ensure long-term operational stability.

 

 

One of the most critical aspects of 630kVA oil immersed transformer technical specifications is the rated capacity and voltage configuration. These parameters determine the transformer's compatibility with the local grid and its ability to support electrical loads.

 

A 630kVA transformer means the transformer can safely handle an apparent power load of 630 kilovolt-amperes. It is widely used in medium-voltage distribution networks supplying factories, residential areas, commercial buildings, and renewable energy stations.

 

Typical voltage combinations include:

• Primary Voltage: 6kV, 10kV, 11kV, 13.8kV, 20kV, 33kV
• Secondary Voltage: 0.4kV / 415V / 480V
• Frequency: 50Hz or 60Hz depending on regional power standards

 

Voltage regulation and tap changing mechanisms allow the transformer to adjust output voltage when grid fluctuations occur. Most 630kVA oil immersed transformers are equipped with off-circuit tap changers (OCTC) that enable ±5% voltage adjustment.

 

This flexibility ensures stable voltage supply even in areas where the power grid experiences fluctuations.

 

Transformer winding and core assembly inside the factory workshop

 

 

Energy efficiency is another key factor engineers must evaluate when reviewing 630kVA oil immersed transformer technical specifications. Transformer losses directly influence operational costs and environmental impact.

 

There are two main types of losses:

 

No-Load Loss (Core Loss)

No-load loss occurs when the transformer is energized but not supplying load. It mainly depends on the core material and manufacturing technology.

 

Modern transformers typically use:

• High-grade cold rolled grain oriented (CRGO) silicon steel
• Step-lap core design
• Low magnetic flux density

These technologies significantly reduce core losses and improve energy efficiency.

 

Load Loss (Copper Loss)

Load loss occurs when current flows through the transformer windings.

 

It is influenced by:

• Winding conductor material (copper or aluminum)
• Current magnitude
• Operating temperature

High-quality 630kVA oil immersed transformers typically adopt copper windings to minimize resistance and improve reliability.

Low-loss transformers help industries reduce electricity consumption and comply with global energy efficiency standards such as IEC EcoDesign.

 

 

The cooling and insulation system is a vital component of 630kVA oil immersed transformer technical specifications because it directly affects the equipment's service life and operational safety.

 

Most distribution transformers of this capacity use the ONAN cooling method (Oil Natural Air Natural).

 

ONAN Cooling System

In this system:

• Transformer oil absorbs heat generated by the windings.
• Heated oil rises naturally through the tank.
• Heat dissipates through the radiator fins.
• Air cools the external surface.

This natural circulation system ensures reliable heat dissipation without requiring pumps or fans.

 

Insulation System

A typical 630kVA oil immersed transformer insulation system includes:

• High-temperature insulating paper
• Transformer mineral oil
• Pressboard insulation structures

The insulation class usually supports temperatures up to 98°C oil rise and 120°C winding hot spot, ensuring safe long-term operation.

 

Close-up of transformer radiator fins and oil tank structure.

 

 

Reliable protection features are essential in 630kVA oil immersed transformer technical specifications to prevent damage from electrical faults and environmental conditions.

 

Key protection components often include:

• Oil level indicator
• Winding temperature indicator
• Pressure relief device
• Conservator with oil level gauge
• Silica gel breather
• Buchholz relay (for larger transformers)

These components help detect internal faults such as winding insulation failure, oil leakage, or overheating.

 

630kVA Oil Immersed Transformer Structural Design

 

In terms of mechanical design, transformers must withstand:

• Short-circuit mechanical forces
• Transportation vibrations
• Outdoor weather exposure

GNEE transformers are designed with reinforced tanks, anti-corrosion coatings, and high-quality sealing systems to ensure durability in harsh environments such as coastal areas, deserts, and industrial zones.

 

Transformer packing and shipment ready for overseas delivery.

 

 

Below is a typical reference specification for a 630kVA oil immersed transformer used in medium-voltage distribution networks.

Parameter	Specification
Rated Capacity	630 kVA
Phase	Three Phase
Primary Voltage	10kV / 11kV / 13.8kV
Secondary Voltage	0.4kV / 415V
Frequency	50Hz / 60Hz
Cooling Method	ONAN (Oil Natural Air Natural)
Vector Group	Dyn11 / Yyn0
Tap Changer	±2×2.5% or ±5% Off-Circuit
No Load Loss	≤ 980 W
Load Loss	≤ 6200 W
Impedance Voltage	4% – 6%
Insulation Level	LI75 AC35
Winding Material	Copper / Aluminum
Insulation Class	A / F
Protection Class	IP00 / Outdoor

These specifications can be customized depending on project requirements, local standards, and environmental conditions.

 

 

Understanding 630kVA Oil Immersed Transformer Technical Specifications is essential for engineers, procurement managers, and project developers who want to build reliable and energy-efficient power distribution systems.

 

Key parameters such as voltage rating, energy losses, cooling method, and protection systems determine how safely and efficiently a transformer performs in real-world operating conditions.

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As a trusted transformer manufacturer, GNEE Electric provides high-quality 630kVA oil immersed transformers designed for long service life, low losses, and reliable performance in industrial, commercial, and renewable energy projects worldwide.

 

If you are planning a power distribution project and need professional support, contact GNEE today to get detailed technical specifications, expert selection advice, and a fast quotation for your 630kVA oil immersed transformer.