OIL-IMMERSED EARTHING TRANSFORMERS BTUO TYPE
Application
Earthing transformers are used to obtain an artificial 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 operating conditions, even if the primary winding is overloaded 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 introduce the appropriate reactance for clearing the arc and earth fault currents.
Charakterystyka
Core – cold-rolled steel sheet with inorganic insulation,
Winding – electrolytic copper wire, enamelled round or profiled in paper isolation,
Adjustment – 5-step manual voltage regulation
Tank – made of steel sheets, powder coated or hot dip galvanized, with an underbody equipped with wheels which can be suitably adjusted
Standard equipment:
Manual driving mechanism of the tap changer
HV porcelein bushing
LV porcelein bushing
Oil level indicator
Nomina plate
Earth terminals
Transport lugs
Lifting lugs
Pulling lugs
Bi-directional undercarriage
Thermometer pocket
Additional equipment:
Protection relays DMCR® or DGPT2
Connector bushings,
Connector heads
Surge arresters,
Terminal clamps for bushings
Underbody vibration dampers
Thermometer
Operating conditions:
Max. operating altitude – 1000 m above sea level
Operating temperature range – 25 to + 40 °C
Rated frequency – 50 or 60 Hz
Manufacturing range:
Rated power 250 kVA up to 4 MVA
Rated voltage up to 36 kV
Vector group Znyn11
