10kV, 20kV Series Oil-immersed (Special) power transformers, as a common power equipment, are widely used in residential areas, industrial parks, commercial facilities, and other occasions. It has different advantages, but at the same time, there are also some disadvantages. Understanding the advantages and disadvantages of dry-type transformer can help users make more rational decisions when choosing them.

Three phase dry-type isolation transformer are usually small in size and compact in structure, making them suitable for installation in spaces with limited space. This has made it widely used in high-density areas of cities, especially in residential and commercial areas.

The installation of dry-type transformer is relatively simple, without the need to build large substations or power equipment rooms. It can be installed directly at the user's required location, shortening the installation cycle and saving construction costs.

10kV and 20kV Series Oil-Immersed (Special) Power Transformers: Design, Applications, and Technical Considerations

Power transformers are critical components in electrical power systems, enabling efficient voltage transformation for transmission and distribution. Among these, 10kV and 20kV series oil-immersed (special) power transformers are widely used in industrial, commercial, and utility applications due to their reliability, durability, and adaptability to demanding environments. This article explores the design features, operational principles, applications, and maintenance considerations for these transformers.

1. Overview of Oil-Immersed Power Transformers

oil-immersed transformers utilize mineral oil or synthetic esters as both insulating and cooling mediums. The oil enhances dielectric strength, dissipates heat, and protects the core and windings from moisture and oxidation. The 10kV and 20kV series refers to transformers designed for medium-voltage applications, typically serving distribution networks, factories, and renewable energy systems.

Key Advantages:

High Efficiency: Low losses due to advanced core materials (e.g., grain-oriented silicon steel).

Robust Cooling: Oil circulation ensures effective heat dissipation.

Long Service Life: Proper maintenance can extend operational life beyond 25 years.

Adaptability: Customizable for special conditions (e.g., high humidity, corrosive environments).

2. Design and Construction

2.1 Core and Windings

The core is laminated to minimize eddy current losses.

Windings are made of copper or aluminum, with layered insulation to withstand voltage stresses.

10kV transformers typically use cylindrical windings, while 20kV models may employ disc-type windings for higher voltage endurance.

2.2 Insulation System

Kraft paper and pressboard provide insulation between windings.

Oil ducts facilitate cooling and prevent hotspots.

2.3 Tank and Accessories

Tank: Sealed or conservator-type, with radiators for heat exchange.

Buchholz Relay: Detects internal faults (e.g., gas accumulation).

Tap Changer: Adjusts output voltage (±5% to ±10%).

3. Special Features of 10kV/20kV Series

These transformers are often customized for unique applications:

3.1 Flame-Retardant Oil

For installations in high-risk areas (e.g., tunnels, substations), less-flammable oils (e.g., silicone-based) replace mineral oil.

3.2 Corrosion Resistance

Stainless steel tanks or epoxy-coated surfaces protect against salt spray (coastal areas) or chemical exposure.

3.3 Low Noise Design

Amorphous metal cores or noise-damping pads reduce audible noise (<65 dB) for urban installations.

3.4 Overload Capacity

Special cooling systems (e.g., forced oil circulation) allow temporary overloads without damage.

4. Applications

4.1 Industrial Plants

Step-down voltage for machinery (e.g., 20kV to 480V).

Special transformers may include harmonic filtering for variable-frequency drives.

4.2 Renewable Energy

Integrate solar/wind farms into 10kV/20kV grids.

Oil-immersed designs withstand outdoor conditions better than dry-types.

4.3 Mining and Offshore

Explosion-proof variants are used in hazardous zones.

4.4 Urban Distribution

Compact designs fit in underground substations.

5. Installation and Maintenance

5.1 Installation Guidelines

Foundation: Vibration-isolated pads to reduce noise.

Clearance: Minimum 1m from walls for cooling.

Oil Testing: Dielectric strength >30kV before commissioning.

5.2 Routine Maintenance

Oil Sampling: Annual tests for moisture, acidity, and dissolved gases.

Winding Resistance: Check for loose connections.

Bushing Inspection: Clean contaminants to prevent flashovers.

5.3 Fault Diagnosis

Gas Analysis (DGA): Detects incipient faults (e.g., arcing, overheating).

Infrared Thermography: Identifies hotspots in windings.

6. Environmental and Safety Considerations

Oil Containment: Secondary containment pits prevent soil contamination.

Recycling: Used oil must be processed by licensed facilities.

Fire Safety: Install firewalls or automatic suppression systems.

7. Future Trends

Eco-Friendly Oils: Biodegradable esters gain popularity.

Smart Monitoring: IoT sensors predict failures via real-time data.

Higher Efficiency: Amorphous cores and nanotechnology reduce losses.

10kV and 20kV series oil-immersed (special) power transformers are versatile solutions for medium-voltage networks, offering reliability and customization for harsh environments. Proper design, installation, and maintenance ensure optimal performance, while emerging technologies promise greener and smarter transformers for future grids.

This content avoids brand-specific references while covering technical details, applications, and trends. Let me know if you'd like to expand on any section!