33kV-grade dry-type transformer

Q: What is a 33kV dry‑type transformer?

A 33kV dry‑type transformer is a medium‑voltage transformer designed to step voltage up or down in power distribution systems up to approximately 35,000 volts , using air cooling instead of oil. It uses solid insulation and does not require oil for heat dissipation.

Q: Where are 33kV dry‑type transformers commonly installed?

They are commonly used in industrial power systems, commercial facilities, buildings, data centers, airports, and urban power distribution , especially where indoor installation, higher safety, and lower fire hazards are required.

Q: Why choose a dry‑type transformer over an oil‑immersed transformer?

Dry‑type transformers are safer for indoor and densely populated environments since there is no oil that could leak or catch fire. They also require less maintenance and are often preferred where high safety standards are needed.

Q: How does a dry‑type transformer dissipate heat?

Dry‑type transformers dissipate heat through natural air circulation (AN) or forced air cooling (AF) via ventilation ducts or fans. This air cooling keeps the transformer core and windings at safe operating temperatures.

Q: What are typical applications for a 33kV dry‑type transformer?

Typical applications include medium‑voltage power distribution , connection between utility grids and industrial loads, renewable energy systems , auxiliary power in substations, and safety‑sensitive indoor installations .

Q: What are the main components of a dry‑type transformer?

Key components include the magnetic core, windings, solid insulation, terminal bushings, cooling ducts , and a protective enclosure designed for safe airflow and insulation.

Q: What insulation class do dry‑type transformers use?

Dry‑type transformers often use Class F (155°C) or Class H (180°C) insulation systems, which allow higher temperature tolerances and better heat resistance under load.

Q: What are the advantages of dry‑type transformers?

Advantages include: • No oil , reducing fire and environmental risk • Lower maintenance needs • Good performance at partial loads • Safe for indoor use and enclosed spaces • Reliable performance in dusty or polluted environments

Q: What maintenance is required for a dry‑type transformer?

Minimal routine maintenance typically includes: • Visual inspection for dust and debris • Testing insulation resistance • Monitoring temperature and loading • Cleaning ventilation paths to ensure proper airflow and cooling

This series of power transformers is designed to directly step down a 33kV power grid to a 400V distribution power supply or a 10kV transmission power supply for end users. With remarkable advantages, these electrical transformers have been widely adopted across various engineering projects, especially in modern power substations. Their key benefits include reduced space requirements, minimized construction costs for multi-stage substations, enhanced economic efficiency, and increased reliability in power supply.

Key Features:

The 33kV dry-type transformer uses epoxy resin vacuum cast insulation, offering high voltage resistance, safety, flame retardancy, and fire and explosion prevention. It features strong short circuit resistance, moisture and dust protection, reliable operation, and easy maintenance. With no oil and no leakage risks, it is environmentally friendly. It can operate stably for long periods in indoor environments, basements, areas with high foot traffic, and places with strict fire safety requirements. This makes it a safe, efficient, and environmentally friendly high-voltage distribution device in the 33kV distribution system.

Why choose a 33KV dry-type transformer?

The 33kV-grade dry-type transformer is designed to minimize energy loss and comply with international quality standards. By transforming the high-voltage low-current transmission system into a low-voltage high-current transmission system, this transformer effectively reduces line losses and operating costs. Furthermore, its ability to bring 33kV power directly into the load center enhances supply reliability, making it an essential choice for modern power substations and other critical power applications.

Product Advantages

High Performance, Low Loss:

The 33kV dry-type transformer is a low-loss product designed in compliance with national standards GB6450 and GB/T10228, as well as IEC726.

Superior Noise Reduction: Premium silicon steel sheets with optimized flux density significantly reduce operational noise caused by magnetic stretching.

Enhanced Overvoltage Resistance: The high-voltage coil structure has been optimized, improving inter-layer voltage and capacitance distribution, thereby enhancing resistance to atmospheric and operational overvoltage impacts while lowering partial discharge.

Advanced Cooling System: Optional temperature control and fan cooling systems automatically activate under heavy load, significantly boosting overload capacity.

Operating Conditions

Ambient Temperature: -25°C to +40°C.

Relative Humidity: Daily average ≤95%, monthly average ≤90%.

Altitude: ≤1,000 meters.

Installation: Suitable for environments free of fire hazards, explosion risks, or intense vibrations.

Application

The 33kV-grade dry-type transformer features reliable high-voltage insulation, fireproof and flame-retardant properties, oil-free environmental friendliness, and safe operation. It is mainly applied in places such as mines, power plants, industrial areas, industrial parks, high-rise buildings, data centers, airports, subways, ports, and overseas 33kV voltage-level power grids where strict fire and safety requirements exist and where load centers need to be installed at close proximity. It is the core safety and stable power distribution equipment in the 33kV power distribution system.

Model meaning

Technical Parameters

Overall and mounting dimensions(mm)（Reference）

Model meaning

SCB14-XXX/33	S:	Three-phase dry-type transformer
	C:	Epoxy resin encapsulated insulation
	B:	Foil winding, strong overload and short-circuit resistance
	14:	Low loss energy-saving level
	XXX:	Rated capacity (kVA)
	33:	Rated voltage 33kV (high-voltage side)

Technical Parameters

Item	Specification
Rated Voltage	HV: 33 kV; LV: 0.4 kV or 0.48 kV
Rated Capacity	500–10,000 kVA
Number of Phases / Frequency	Three-phase, 50 Hz / 60 Hz
Vector Group	Dyn11, YNd11
Insulation Type	Epoxy resin vacuum cast
Winding Material	All copper winding, foil or wire type
Cooling Method	AN / AF (Air Natural / Air Forced)
Tap Changer	Off-circuit tap changer: ±2 × 2.5% or on-load tap changer (OLTC)
Impedance Voltage	6%–8%
Insulation Class	Class F / Class H
Degree of Protection	IP20 / IP23 / IP30 / IP31 / IP42
Operating Environment	Indoor use, fire-resistant, flame-retardant, moisture-proof, dust-proof, oil-free and environmentally friendly
Performance Level	SCB13, SCB14, SCB15 (low-loss series)

Overall and mounting dimensions(mm)（Reference）

Custom 33kV Grade Dry-Type Transformer Solutions

(The values can be customized according to project requirements.)

If you have specific requirements for the 33kV grade dry-type transformer, please contact us. Our team will review your system design and provide a tailored solution.

We can customize rated capacity, voltage class, cooling method, insulation level, winding configuration, and enclosure features to ensure optimal performance and efficiency in your medium-voltage power distribution system. The 33kV dry-type transformer offers high efficiency, low no-load loss, and excellent energy performance, making it ideal for industrial plants, commercial buildings, renewable energy projects, and utility applications.

By choosing a dry-type transformer, you ensure enhanced safety, environmental sustainability, and reduced maintenance costs. With its robust design and high thermal endurance, the 33kV transformer provides reliable operation in even the most demanding environments.

FAQ

What is a 33kV dry‑type transformer?

A 33kV dry‑type transformer is a medium‑voltage transformer designed to step voltage up or down in power distribution systems up to approximately 35,000 volts, using air cooling instead of oil. It uses solid insulation and does not require oil for heat dissipation.

What does “dry‑type” mean?

“Dry‑type” means that the transformer is cooled and insulated by air rather than oil or liquid dielectric. This eliminates the need for transformer oil, reducing fire risk and environmental concerns.

Where are 33kV dry‑type transformers commonly installed?

They are commonly used in industrial power systems, commercial facilities, buildings, data centers, airports, and urban power distribution, especially where indoor installation, higher safety, and lower fire hazards are required.

Why choose a dry‑type transformer over an oil‑immersed transformer?

Dry‑type transformers are safer for indoor and densely populated environments since there is no oil that could leak or catch fire. They also require less maintenance and are often preferred where high safety standards are needed.

How does a dry‑type transformer dissipate heat?

Dry‑type transformers dissipate heat through natural air circulation (AN) or forced air cooling (AF) via ventilation ducts or fans. This air cooling keeps the transformer core and windings at safe operating temperatures.

What are typical applications for a 33kV dry‑type transformer?

Typical applications include medium‑voltage power distribution, connection between utility grids and industrial loads, renewable energy systems, auxiliary power in substations, and safety‑sensitive indoor installations.

What are the main components of a dry‑type transformer?

Key components include the magnetic core, windings, solid insulation, terminal bushings, cooling ducts, and a protective enclosure designed for safe airflow and insulation.

What insulation class do dry‑type transformers use?

Dry‑type transformers often use Class F (155°C) or Class H (180°C) insulation systems, which allow higher temperature tolerances and better heat resistance under load.

What are the advantages of dry‑type transformers?

Advantages include:
• No oil, reducing fire and environmental risk
• Lower maintenance needs
• Good performance at partial loads
• Safe for indoor use and enclosed spaces
• Reliable performance in dusty or polluted environments

What maintenance is required for a dry‑type transformer?

Minimal routine maintenance typically includes:
• Visual inspection for dust and debris
• Testing insulation resistance
• Monitoring temperature and loading
• Cleaning ventilation paths to ensure proper airflow and cooling

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Nearly 20 Years of Industry Experience

10,000⁺ Units/Year Production Capacity

40,000^m²+ Factory Area

500⁺ Power Utility Clients

1 Billion⁺ CNY Annual Sales Revenue