Distribution Transformer 6kV (Um=7.2kV)

Product Parameters

Product Introduction

Fully Sealed Transformer

In the Research on the Mechanism for Revitalizing Mechanical Industry Products in 2000, approved by the National Economic and Trade Commission, the Ministry of Science and Technology, and the Ministry of Machinery, the development of fully sealed transformers was listed as one of the key national technological development projects in 1990. It was determined that by 1995, fully sealed transformer structures should be promoted for power transformers up to 10-35 kV and below 6300 kVA.

Traditional transformers with oil tanks allow transformer oil to come into contact with the surrounding air, which causes oxygen and moisture in the air to enter the oil tank. This accelerates the aging of transformer oil and insulation materials and reduces insulation strength due to the absorption of moisture. To address these issues, a type of transformer has been developed internationally, which isolates the cooling medium from the air—this is the fully sealed transformer.

Based on years of production experience, our company has adopted new technologies, new processes, and new materials to design the S9-M and S11-M fully sealed transformers. The primary focus is to enhance product functionality, improve product standards, and increase reliability, ensuring that transformer oil does not leak and better meets the needs of petrochemical systems and environments with high humidity and pollution.

This product series has a rated capacity of 20-2000 kVA and voltage combinations of 6-10/0.4 kV. The transformer’s design is optimized through Transformer CAD Expert Systems, with the following main features:

Key Features

1.Vacuum Oil Injection Process
During transformer sealing, a vacuum oil injection process is used to completely eliminate moisture from the transformer. The oil is kept isolated from the surrounding air, effectively preventing the oxygen and moisture in the air from coming into contact with the transformer oil and insulation materials. This process prevents aging due to oxidation, maintains insulation performance, and eliminates the need for regular oil sampling and testing.

2.Wave-shaped Oil Tank
The fully sealed transformer adopts a wave-shaped oil tank and eliminates the traditional oil conservator. When temperature and load changes cause the oil volume to fluctuate, the wave-shaped oil tank adjusts the volume through the elasticity of the corrugated plates. The corrugated oil tank not only has a cooling function but also a "breathing" function, significantly improving operational reliability.

3.Sealing Types
Two sealing types are available:

• Welded Type: The box edge and cover are welded shut after passing all tests.
• Removable Type: The box edge and cover are sealed with sealing strips and bolted together.

4.Reliable Positioning Method
The transformer body and oil tank are positioned using a new, more reliable method, and the body is additionally supported with an upper positioning structure. All fasteners use anti-loosening nuts, ensuring that the transformer can withstand vibrations and bumps during transportation. This ensures that the transformer can operate safely without the need for core lifting after reaching the user.

5.Environmentally Friendly
Since the fully sealed transformer’s oil does not come into contact with air, it does not cause environmental pollution and is safe for human health.

6.Protection Devices

• Pressure Relief Valve: A pressure relief valve with an electrical signal is installed. When the internal pressure of the oil tank reaches 35 Kpa due to overload or faults, the valve activates to release pressure. Once the pressure returns to normal, the valve resets, ensuring reliable operation.
• Temperature Measurement Device: A temperature gauge with high-capacity contacts is installed on the transformer’s cover.

7.Reduced Maintenance Requirements
The fully sealed transformer significantly reduces maintenance workload. Compared to traditional transformers, it does not require:

• Oil sampling, testing, replenishment, filtration, or replacement.
• Replacement of moisture-absorbing silica gel.
• Monitoring of oil levels in the oil conservator.

8.High Economic Benefits

• The fully sealed transformer requires no maintenance and does not need core lifting, saving a significant amount of core lifting and maintenance costs.
• It is absolutely reliable in terms of quality, saving on downtime maintenance costs (including manpower, materials, and funds, as well as the losses in production, output, and profit during downtime).

9.Low Loss, Low Noise
The S11-M series fully sealed transformer offers significant energy savings compared to the S9 series.

• No-load loss is reduced by 30-40%.
• No-load current is reduced by 70-80%.
• Load loss is reduced by 5-10%.
  

This makes it an ideal choice for urban and rural power grid upgrades.

10.Compact Design and Aesthetic Appearance
The fully sealed transformer has a compact design, which reduces the installation footprint, making it an ideal maintenance-free, high-quality product.