Tender Document for Construction of Ghorasal 300-450 MW ... - BPDB

us duct.
2) One (1) lot of associated equipment.
2.8.3 Unit Auxiliary Transformer, Station Transformers and Associated
Equipment
1) Two (2) sets of unit auxiliary transformer (2 x 110% of total aux. power
requirement but each capacity not less than 25 MVA) and associated
equipment with the following features:
• Type : Oil immerse, three phase and
two windings, outdoor power
transformer.
• Rating : 25 MVA
• Rated high voltage :15.75 kV (or as per Generation Voltage)
• Rated low voltage : 6.6 kV
• Connection : DYn 11
• Rated insulation
level : HV Winding LV Winding
• Lighting impulse
Withstand voltage
(1.2/50 micro sec) : 95 kV (Peak) 60 kV(Peak)
• Power frequency
Withstand voltage
(For 1 mm). : 36 kV 22 kV
• Impedance voltage : shall be within the range of 5% and 7.5%
• Tap changer : Off-current on high tension winding ±10%
• Neutral grounded : Solidify grounded
2) Four (4) sets of station transformer (4 x 55% of total 0.4 kV aux. power
requirement but each capacity not less than 2 MVA) and associated
equipment with the following features:
• Type : Oil immersed, three phase and
two windings, outdoor power
transformer
• Rating : 2 MVA
• Rated high voltage : 6.6 kV
• Rated low voltage : 415 V
• Connection : Dyn11
• Rated insulation : HV Winding LV Winding
• Lighting impulse : 60 kV(peak)
Withstand voltage
(1.2/50 micro sec.)
Ghorasal 300-450 MW CCPP Project (Vol-2A of 2) 16