BANGLADESH POWER DEVELOPMENT BOARD TENDER ... - BPDB

(peak)- lightning impulse withstand test voltage : Relevant IEC Standard KV(1.2/ 50 micro sec.)- Power frequency test voltage : Relevant IEC Standard kV for oneminute.b. 11 KV circuit- lightning impulse withstand test voltage : 75 KV (peak)(1.2/ 50 micro sec.)- Power frequency test voltage :28 kV for oneminutec. 6.6 KV circuit- lighting impulse withstand test voltage :75 kV(Peak)(1.2 / 50 micro sec.)- Power frequency test voltage :28 kV for oneminuted. 415 V circuit- lighting impulse withstand test voltage : Not applicable(1.2 / 50 micro sec.)- Power frequency test voltage : 4.0 KV for oneminute4) No Load Excitation Current : The no load excitationcurrent under the rated voltage and frequency shall be as small aspossible.5) Mechanical and Thermal Strength for Short CircuitThe transformers shall be designed and constructed to withstand for threeseconds without damage the thermal and dynamic effects of external shortcircuits under the most severe conditions.(6) TolerancesThe tolerances on the guarantee values shall be in accordance with IEC 76-1.(7) NoiseVibration and noise levels of transformers shall be in accordance with the bestcommercial practice.5.1.2 REQUIREMENTS FOR CONSTRUCTION(1) Tank and Interior Structurea. The power transformer shall be of such structure to permit installation atthe Site to be simple.Assembling work at the Site such as staking of core and insertion of coil shall notbe allowed.Ghorasal 200 MW to 300 MW Gas Turbine Peaking Power Plant Project (Vol-2 of 3)47