Dry Type Transformer

TOONICE’s Dry-type transformer is a power transformer that uses air or gas for cooling and requires no insulating oil. Its windings and iron core are encapsulated with solid insulating materials (such as epoxy resin, Nomex paper, etc.), and it boasts significant advantages including fire resistance, minimal maintenance needs, and environmental friendliness. Therefore, it is widely applied in scenarios with high requirements for safety and the environment.

With its characteristics of safety, high efficiency, and environmental friendliness, the dry-type transformers produced by TOONICE have become indispensable key equipment in modern power systems, and play a crucial role especially in urban power grid renovation, green building, and new energy development.

I. Structure and Working Principle

1. Core Components:

① Iron Core: Cold-rolled grain-oriented silicon steel sheets with high magnetic conductivity and low loss are adopted. The full oblique 45° joint and five-step lamination process are used to reduce no-load loss and noise.
② Windings: High-voltage windings mostly adopt epoxy resin vacuum casting or glass fiber reinforced resin encapsulation, while low-voltage windings often use a foil-type structure to improve short-circuit resistance. For example, the high-voltage winding of the SCB13 dry-type transformer adopts a copper foil and silica fume epoxy resin system, which has high mechanical strength and partial discharge less than 5 pC.
③ Insulation System: Classified into class F (155°C) and class H (180°C) according to thermal endurance classes. The temperature rise limit of class F windings is 100K, and that of class H is 125K.

2. Cooling Methods:

① Natural Air Cooling (AN): Heat is dissipated through air convection. It is suitable for well-ventilated environments and can operate at full load for a long time.
② Forced Air Cooling (AF): Equipped with low-noise fans, which are started during overload. It can increase the capacity by 40%-50%, but attention should be paid to the energy consumption in the non-economic operation state.

II. Core Advantages

1. High Safety:

① Fire and Explosion Proof: The oil-free design eliminates the risks of oil leakage and fire. Insulation materials have passed the UL94 V-0 flame retardant test and release no toxic gases during combustion. For example, dry-type transformers are adopted in data centers to meet strict fire protection requirements.
② Reliable Protection: The protection class can reach IP20 (protection against solid objects larger than 12mm) or IP23 (protection against splashing water), making it suitable for humid and dusty environments.

2. Low Operation and Maintenance Cost:

① Maintenance-free Feature: There is no need for regular oil replacement or oil quality detection. Only daily cleaning and fastening inspections are required. The average annual maintenance cost is over 50% lower than that of oil-immersed transformers. The cumulative maintenance cost over 20 years is only 30% of the original equipment value, while that of oil-immersed transformers is as high as 80%.
② Intelligent Monitoring: Equipped with built-in temperature sensors and intelligent temperature controllers (such as the WSK-200 series), it can monitor winding temperature in real time, automatically start and stop fans, and send over-temperature alarms. It supports the Modbus-RTU protocol to access building automation systems.

3. Energy Conservation and Environmental Protection:

① Low Loss: The no-load loss of SCB13 three-level energy-efficient dry-type transformers is 15% lower than that of SCB10, and the load loss is 5% lower. The annual power saving can reach 12,000 kWh (for a 500kVA unit).
② Recyclable Materials: The recovery rate of metal materials exceeds 90%, complying with the requirements of the RoHS directive on prohibiting hazardous substances.

4. Strong Adaptability:

① Environmental Tolerance: It can operate stably at -25°C to +40°C and 100% humidity, and has passed the C2-level damp-heat cycle test.
② Short-circuit Resistance: With windings adopting a foil structure and ampere-turn balance design, it can withstand an impact of 25 times the rated current for 2 seconds without damage.