Unitised Sub Station (USS)

The USS will comprise of HV 12 KV Load Break Switch Panel, Cast Resin Air Cooled Transformer, with associated protection and Ventilated Housing.The whole assembly is mounted on to a rigid base of steel fabricated section. The units are factory assembled, tested and they will be despatched in dissembled condition. All the dissembled components can be assembled at site.


Load Break Switch is suitable for indoor application and is used to switch ON/OFF the 11 KV supply.
The Load Break switch works on the principle of extinguishing the Arc by a blast of compressed air, produced by the switch itself, while opening. During the switch off operation, the Arcing contact maintains continuity while the main contact travels along with the piston attached with it, compressing the air in the pressure cylinder. After a predetermined length of travel, the arcing contact opens striking on arc. At the same time, a blast of compressed air, extinguishes the arc, through the nozzle surrounding the arcing contact.

The Air Break Switch is provided with HT Fuse and earthing facility. The panel is designed to segregate completely incoming and outgoing termination chambers with Epoxy resin cast seal off bushings. The HRC fuses are easily with drawable type so that fuses can be renewed easily. When the fuse switch operates on fault, the mechanism would give simultaneous break on all three phases and also would go into lock position to prevent closure until the blown fuses are replaced. The busbars will be 630 Amps rating, aluminium or electrolytic copper, tinned, supported by epoxy insulators.

Load Break Switch rating : 12 KV 630 Amps Rating.
System Voltage : 12 KV
Insulation Level : 28/75 KV
Rated Short Time Current : 26.3KA 1 Sec
Rated Peak withstand current : Rated Peak withstand current

Special Features

INTRANS Load break switch panel for indoor use have the following Special Features

» Load break switch and accessories are housed in a vermin and weather proof welded panel. These panels are pretreated with 7 tank phosphating process and stove enamelled.

» Earthing switch and earthing interlocks are provided.

» Cable gland plate is provided at the top/bottom of the panel for entry/exit as required.

» Provisions for sealing by the Electricity Board Authority

» Complete conformation to all the relevant Indian Standard Specifications.

» Electronic Meter with TOD (Time-of-Day) metering facility : The meter is versatile enough to register the maximum demand in separate preset periods of the day. With the present control measures this eliminates the need for additional meters for day and for night demand. This can help in planning operations to increase load and reduce average KWH costs. Similar facility regarding active energy consumption at various times of the day is also provided.