Neutral Earthing Transformers

Neutral Earthing transformers are normally provided in 3-phase system, which is without neutral and earth fault protection. We provide Earthing transformer up to 2MVA current rating and voltage class of 33kV. Other higher specifications are manufactured on demand basis against specification.

Neutral Earthing transformer is having zig-zag (inters tar) winding to achieve the required zero phase impedance. In addition an auxiliary winding can also be provided to meet the requirement of auxiliary power supply in these electrical Earthing transformers.

Grounding transformer is used to provide a ground path to either an ungrounded “Y” or a delta connected system & serves to

• limit the magnitude of transient over voltages when re-striking ground faults occur.
• provide relatively low impedance path to ground, thereby maintaining the system neutral at or near ground potential
• Provide a source of ground fault current during line to ground faults.
• Permit the connection of phase to neutral loads is desired.

Technical Specifications

• Manufactured under specification of IS:3151
• Current rating up to 2 MVA.
• High voltage up to 36 kV.
• Low voltage up to 0.69 kV.
• Classes E2, E3, C2, F1.
• Frequencies: 50 Hz, 60 Hz and 16 2/3 Hz.
• Cooling: ONAN/ONAF/AN / ANAN / ANAF.
• Insulation system temperature: F and H.
• Partial discharges
• Protection degree: IP00 – IP54.

Features:

• capable of withstanding a fault current at rated voltage and frequency through the neutral for a time duration of 30 seconds without using neutral grounding resistor and without exceeding the temperature.
• withstanding the mechanical and thermal stresses caused by the rated short time current flowing in the windings under fault conditions.

Standard Fittings:

• Prime Bushings
• Secondary Bushings
• Conservator
• Silica Gel Breather
• Cable Terminations
• Oil Level Indicator
• Filling Device
• Thermometer pocket
• Marshalling Box
• Earthing Terminal
• Rating & Diagram Plate
• Lifting Lugs
• Drain Plug
• Buchholz Relay
• Inspection Cover

Optional Fittings:

• HV / LV Cable Box
• Magnetic Oil Level Gauge
• Winding Temperature Indicator
• Off circuit Tap Switch
• Siphon Thermo filter
• Rollers (Uni-Directional / Bi-Directional)
• Drain Valve
• Conservator and Silica gel Breather
• Pressure Relief Device
• Off Circuit Tap changer / OLTC