CREATION OF 250 KVA HT TRANSFORMER ALUMINUM WOUND (LEVEL-II) SUB-STATION INCLUDING MS TUBULAR POLES and TRANSMISSION LINES AT DW STATION JUMANDUB CHANDERGEER OF MISD HAJIN.

Manufacture , providing , installation and Commissioning of 250 KVA (level-II) capacity HT transformer at D/W Jumandub chandergeer . The job comprises of the following specifications , process of fabrication and involvement of material :- Core :- The core of the HT transformer shall be made with laminated and low loss electrical steel sheet that is cold rolled and of high grade steel , the core shall be assembled in a manner that it reduces the noise caused by vibration , individual stamping shall be coated with insulation varnish which shall be resisted to heat and oil on both sides . The core shall be connected to the clamp which ensures that if efficiency earthed. The core legs shall be bounded with heavy duty insulating tape and the yokes shall be rigidly/securely clamped between the folded steel channels , clamps on the top and bottom shall be firmly attached to each other by means of tie rod . The tie rod shall serve the dual purpose of transferring the load from the bottom to the top clamps and securing the winding in the piece to prevent tensile stress being setup in the core legs which shall otherwise will lead to iron loses . Winding :- The coils of the transformer shall be precisely designed to meet the three basic requirements . thermal , mechanical and electrical . The coils shall be wound using the fresh aluminum winding material of specific grade and size and shape , both H.V & L.V type winding shall be wound with adequate securing and brazing tapers in order to get a sturdy , robustic and self supporting structure and shall be provided with inter layer duct ensuring low temperature gradient between windings and oil to that spot temperature shall be kept to minimum . Winding connection :- Tapping and phase leads shall run in paper covered conductors and adequate barriers shall be used to separate the phase leads from the tapping , Brazed tubes shall be used to maintain the required clearance between coil and tank . Tank:- The tank of the HT transformer shall be made from mild steel of adequate thickness with corruged wall panel type radiators of pressed steel fin coils and sufficient quantity of transformer for effective cooling The job includes providing and fill in T–oil upto required level of high grade quality . Specifications :- Capacity ------- 250 KVA No of phases ----------three Supply frequency -------- 50 Hz Type of cooling -------- oil cooled Output voltage --------- 433 V Mounting ------- on wheels Earthing ----- Earthening terminals provided

Providing and installation of 09 Mtrs. long steel tubular poles fabricated as per relevant ISI code/specifications ( SP 33) including their painting with red oxide primer & the two coats of steel primer. The job includes excavation of earth pit & then errection of tubular pole.

providing and laying of plum concrete in the ratio of 1:3:6 underground and rating the jacketing above ground level 1.5’

Providing and fitting of GI V-cross and F-top for HT poles. The job includes providing of nuts bolts and other accessories.

Providing and installation of 11 KV Polymer Insulators

Fabrication/Providing and installation of channel X arm75 x 40 x 6mm and 8’ long to be erected upon the HT Tubular poles for fitting of link set, drop out set, lightening arrestor etc. The channel shall be duly drilled for accommodating bolts for fitting on two pole structure including nuts/bolts

Fabrication/Providing and installed of channel X arm100 x 50 x 6mm and 8’ long to be erected upon the HT Tubular poles for resting of HT Transformer. The channel shall be duly drilled for accommodating bolts for fitting on two pole structure including nuts/bolts

Providing and installation of 11 KV heavy duty lightening arrestor

Providing and fitting of MS Angle of size 65 x65 x 5 mm (ISA 65) with nut and bolts

Providing and installation of 11 KV fuse dropout (heavy duty)