Class H Non-Encapsulated Dry-Type Power Transformer

Overview

The class H non-encapsulated dry-type power transformer has a sound design and meets Chinese national performance standards. It suits environments with high fire requirements, wide load fluctuation and humidity, such as high-rise buildings, airports, stations, ports, metro systems, hospitals, power plants, metallurgical works, shopping centres, densely populated areas and petrochemical sites.

Safety and fire performance

• Non-combustible and flame-retardant: the transformer contains no combustible resin and is non-combustible, flame-retardant, non-toxic and self-extinguishing, releasing virtually no toxic or harmful gases in an open flame.
• No partial discharge: vacuum pressure impregnation (VPI) and high-temperature curing ensure partial-discharge-free operation with no drop in insulation level over the service life.

Overload and thermal capability

• High thermal class: the winding insulation material (Nomex®) is class C rated, usable continuously at 220℃, while the transformer itself is rated class H (180℃), leaving a wide safety margin.
• Strong overload performance: short-term overload capability is high and the unit can run continuously at 20% overload without forced cooling.

Mechanical and short-circuit strength

• High mechanical strength: the HV coil uses a continuous-disc structure with high mechanical strength and good heat dissipation, the LV coil is foil-wound, and high-strength ceramic supports improve cooling and prevent thermal breakdown.
• Short-circuit withstand: the coil structure has high mechanical strength and withstands sudden short-circuit currents well.