Tender Document for Repowering Project of Ghorasal 3rd Unit - BPDB

e kept (without bay equipment) for two (02) nos. of 230 kV line which
will connect Power Plant Sub Station with Ghorasal Grid Sub Station.
2.10.2 Transformers and Associated Equipment (for GT)
1) Two (2) sets of three phase step-up transformers with associated
equipment. Two (2) sets for GT(s) and having capacity to match the power
output of GTG(s) with the following features:
• Type : Oil immersed Three phase, outdoor power
transformer
• Rating : To meet the requirement of the specification
as stated above & Clause-8
• Voltage ratio of :15.75 (or as per Generation Voltage) / 230 kV
transformer at full load
• Connection :Ynd 1 as shown in single
line diagram.
: HV winding LV winding
• Rated insulation level 650 kV (Peak) 75 kV (Peak)
• Lighting impulse Withstand : 650 kV (Peak) 75 kV Peak
Voltage (1.2/50 micro sec.)
• Power frequency withstand : 275 kV 28 kV
Voltage (for 1 min).
• Impedance voltage : Shall be within the range of
15% and 18%
• Tap changer : On load at high tension
winding +8 x 1.25% to -12x1.25%.
• Termination :Outdoor bushing for Cable Pot
High tension side
Head connection
• Low tension side : Isolated & insulated phase copper
bus duct.
2) One (1) lot of associated equipment.
2.10.3 Unit Auxiliary Transformer, Station Transformers and Associated
Equipment (for GT)
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)
Re-Powering Ghorasal 210 MW 3 rd Unit (Vol-2A of 2) 22