Iney Unit

INEY: unità di refrigerazione olio trasformatore

GlobeCore presents the INEY refrigeration unit for vacuum elimination and vacuum drying of solid insulation of 110- to 1150-kV power transformers during installation, maintenance and repairs.

Three types of units are produced that differ in components, mode of operation and specifications, all of which are equally efficient.

• The first type is a single-module unit consisting of a two-stage refrigerator designed for cold process generation (at 70°C);
• The second type is dual-module units with a vacuum pump where the first module has a two-stage refrigerator designed for cold process generation (to 70°C) and a vacuum pump, while the second module has a pre-vacuum pump and liquid cooling and heating system;
• Finally, the third type is a dual-module unit (UH-70 + BV-2000): the first module is a dual-stage unit for cold process generation (minus 70°), and the second module contains a vacuum pump and three support pumps.

You can select the option that best suits the requirements of your facility.

The refrigeration section can operate in the following modes:

1. COLD ACCUMULATION. The temperature on the surface of the evaporator gradually drops to the -700°С set point.
2. FREEZING. When the preset temperature (-700°С) is reached, the unit automatically switches to cyclic operation mode in the preset temperature range, with occasional component shutdowns.
3. EVAPORATOR DEFROSTING. When a certain amount of moisture is frozen on the evaporator, it should be defrosted. The process takes about thirty minutes.

Since the evaporator cools in the cold trap to -70°, there is a difference in vapor pressure on the surface of the solid insulation and in the trap. (For example, the saturated water vapor pressure at +20 ° C is 2337 Pa, and 18 Pa at -40 ° C.) This difference drives the drying process. Water vapor from the transformer tank moves into the cold trap because of the pressure difference and is frozen in the evaporator. The duration of drying depends on the amount of moisture in the transformer, its temperature, the ambient temperature and the residual pressure in the transformer tank. The unit can operate continuously for 20 days.

There is an indicator light in the side of the insulated cold trap, which ensures visual observation of the freezing process. The lower part of the trap is equipped with a condensate drain to remove condensation after defrosting. On average, the unit can trap at least 7.5 kg of moisture in 24 hours.