High-Quality Energy-Efficient 10KVA~63000KVA/3KV~220KV Dry-type Transformer
Winding Temperature Rise: e.g., 100K.
Insulation Resistance: ≥2MΩ (tested with ZC25B-4 megohmmeter, <1000V).
A dry-type transformer is a transformer in which the core and windings are not immersed in insulating liquid, with the insulating medium typically being dry air or other gases. Due to its unique advantages, it is widely used in various applications, effectively meeting diverse power demands.
Based on the principle of electromagnetic induction, two or more mutually insulated coils are wound around a common core leg (three-phase transformers have three core legs). When the rated three-phase power frequency voltage is applied to the high-voltage side, the coil current generates an alternating magnetic field in the core. According to Faraday's law of electromagnetic induction, this magnetic field induces an electromotive force of the same frequency in both the high- and low-voltage windings, enabling the low-voltage winding to supply power to the load.
Some dry-type transformers are equipped with emergency stop buttons and cover-opening power-off devices. The emergency stop button uses a micro switch—when pressed, the normally open contact closes, short-circuiting the terminal element and tripping the upstream circuit breaker to cut off the high-voltage power supply. The cover-opening power-off device operates such that, under normal conditions, the button is pressed by the guard frame, keeping the normally closed contact open. When the terminal box cover is opened, the button resets, closing the normally closed contact and short-circuiting the terminal element to cut off the power. Additionally, the upstream circuit breaker cannot be closed if the guard frame is not installed, ensuring maintenance safety.
Furthermore, the temperature relay has a normally open contact. When the internal temperature rise exceeds the allowable limit, the contact closes, activating an external explosion-proof alarm. In this case, the power supply must be disconnected to resolve the fault, and the transformer can be restarted only after the temperature drops.
Performance Characteristics
Self-extinguishing, with minimal smoke or toxic emissions under high temperatures.
Some models feature smart controls (e.g., cooling, thermal protection, real-time monitoring).
High thermal class (e.g., Class H withstands 180°C–220°C).
Noise reduction measures (e.g., silicone rubber damping elements) minimize operational noise.
Limited performance in extreme temperatures/humidity.
Can be installed near load centers without special foundations.
Easily recyclable materials (e.g., copper) after end-of-life.
Made of high-quality cold-rolled grain-oriented silicon steel sheets, typically with a 45-degree fully staggered joint to allow magnetic flux to pass along the joint direction, effectively reducing no-load loss, no-load current, and core noise. The core legs are usually bound with Class F non-woven tape and encapsulated with epoxy resin.
Windings
• Epoxy resin filled with quartz sand
• Glass fiber-reinforced epoxy resin casting (thin insulation structure, widely used to prevent resin cracking and improve reliability)
• Multi-strand glass fiber epoxy-impregnated wound type
• Layer insulation is provided by insulating paper, and the winding is solidified into a robust whole through VPI.
• High mechanical strength and strong short-circuit resistance.
• Uses a continuous winding structure with high mechanical strength and excellent heat dissipation, wound on a molded insulating cylinder.
• Conductor consists of insulated paper-wrapped flat copper wire, with interlayer insulation provided by insulating paper.
• The winding is solidified into a robust whole through Vacuum Pressure Impregnation (VPI), avoiding the drawbacks of multi-layer cylindrical windings and improving operational reliability, moisture resistance, and thermal shock resistance.
• Partial discharge <5 PC, easy to disassemble and recycle after end-of-life.
Forced Air Cooling (AF)
Natural Air Cooling (AN)
Cooling Methods
Enclosure & Protection
Enclosure
Materials include cold-rolled steel plates or stainless steel plates.
Protection Function
Effectively blocks dust, moisture, and other contaminants, ensuring stable operation in different environments.
Temperature Control System
The safe operation and lifespan of dry-type transformers largely depend on winding insulation reliability. They are often equipped with an intelligent temperature control system that:
● Automatically detects and displays the operating temperature of each phase winding.
● Automatically starts/stops cooling fans.
● Provides alarm and tripping functions.
● Activates a temperature relay when the internal temperature exceeds the allowable limit, triggering an alarm and prompting corrective action.
Applications
● High-Density Areas
High-rise buildings, underground facilities, airports, theaters, metros, transport hubs, commercial/residential areas (fire-safe).
● High Fire/Explosion Risk Sites
Power plants (thermal, hydro, nuclear), industrial zones (ensuring safety).
● Harsh Environments
Humid, dusty, or chemically corrosive areas (moisture/pollution resistant).
● Space-Constrained Locations
Compact substations, retrofits in old buildings (lightweight and space-saving).