Earthing transformers are used to obtain a neutral point in compensated or resistor grounded networks. These are the three-phase transformers which in normal working conditions,while no ground fault occurs, provide power supply to unit auxiliaries. The coil windings are made in the ZNyn11 arrangement, which enables the division of the current between phases and reduces the current on the line which has been exposed to ground fault or short circuiting. The secondary
winding can permanently operate at rated conditions, even if the primary winding is loaded with compensated current. In the event that the network is grounded using a resistor, the neutral point of these devices is connected to an earthing resistor used to input the active component. In compensated networks it is usually combined with an arc-suppression reactor which is used to ensure the appropriate reactance for clearing the arc and earth fault currents.

Manufacturing range:

Power range:  from 150 kVA up to 4000 kVA
Voltage range: up to 36 kV
Current range: 15 A up to 300 A
Isulation class: F or H
Type of cooling: AN,AF

Standard operating conditions:

Max. operating altitude -1000 m above sea level
Operating temperature range – 25 to + 40 °C or other on request
Rated frequency 50 Hz (60 Hz on request)

Design characteristic:

Core– grain-oriented electrical steel sheets
assembled into core using the “Step-Lap” method
Winding  – electrolytic copper or aluminium wire, enamelled round or profiled
Optional enclosure IP20, IP21,IP23,IP31,IP33,IP54

Standard equipment:

Thermal protection
PT100 or PTC Sensors
The terminals on the connectors HV
The terminals LV – busbar leadouts
Rating plate
Earting Terminals
Lifting lugs
Pulling lugs
Bi-directional wheels

Optional equipment:

Antivibration pads
Surge arresters
Earthing bolts
Cooling fans
Cable boxes
HV plug-in bushings

Making, testing & loss levels, tolerance ranges are in compliance with IEC 60076-1, IEC 60076-11, IEC 60076-6