82726 REPAIR AND MAINT OF HT INSTALLATION AT AVADI UNDER GE (NAVY) CHENNAI

SCHEDULE 'A' PART-I [ E/M WORKS]

Material and labour for On site oil dehydration- filtration for Transformer/Oil Cooled Servo Voltage Stabiliser at the substation .The dehydration - filtration of transformer oil by employing online filtration plant as per IS 1866 : 2000 for the reconditioning & reclamation of mineral insulating oil & making them suitable for reuse as insulating fluids. Transformer oil testing/checking for BDV (before and after filtrations) BDV shall be improved to a minimum value of 50 kV at 2.5mm gap between contactors of testing kit, withstand for 1 minute and top up the transformer oil level & Replacing of transformer oil if the oil strength is not as per the IEEE/IS standard. Note : (i) Contractor shall use the vehicle mounted filtration plant with new suitable size heavy duty hose pipe. (ii) The transformer oil required for replacing/top up shall be measured and paid separately . (iii) Rate quoted shall be inclusive of conducting field testing of di-electric strength of the transformer oil before and after filtration (iv) The Process of Dehydration - Filteration shall include Pre-heating , Coarse filtration , Fine Filteration , Degassing & dehydration , Recirculation / delivery (including Topup of Oil , if required) . (v) The quoted rate shall be inclusive of Transportation Charges of Oil Filteration Machine.

Supply and fill unused Mineral Insulating Oil / transformer oil as per IS 335 : 2018, including dehydration, filteration and testing. Note : 1. The Unused Mineral Insulating oil shall be supplied in standard packing of 200 liters nominal capacity, non-returnable Brand New Steel Barrels (Drums) `A’ grade type-2 conforming to IS-1783 (Part-I) 1993 as amended upto date . 2. Sealed container only will be brought at site with minimum BDV 60 KV complete all as specified and directed.

Material and labour for Mineral Insulating Oil / transformer oil testing for the following parameters : Breakdown Voltage , water content , Tan Delta , Resistivity , Acidity , Interfacial Tension, Sludge , flashpoint , density , Viscosity , Dissolved Gas Analysis, Colour & Appearance, Dielectric Strength (BDV) , Water Content complete all as specified and directed. Note: Quoted rate shall be inclusive of sample collection charges for collecting samples at concerned substation.

Material and labour for preventive maintainance check for 11 kV/433V , 160 kVA Transformer comprising of following works: 1.Mechanical & Visual Maintenance: 1.1. Complete external cleaning of the transformer tank, radiator fins, and Conservator tank to remove dirt, salt deposits, and bird droppings - 1Job , 1.2. Inspection of the main tank, valves, and radiators for oil seepage. Tightening of all gasketed joints and valves - 1Job. 1.3. Surface preparation and touch-up painting of any rusted areas on the tank or radiator using marine-grade epoxy paint.-1 Job 2. Electrical Diagnostic Testing: 3.1. Insulation Resistance (IR) / Megger Test: Testing the insulation strength between HT-LT, HT-Earth, and LT-Earth using a 5kV digital Megger- 1 Set, 3.2,Winding Resistance Test (WRT): Measuring the DC resistance of all HT and LT windings using a micro-ohm meter to detect loose internal connections or winding stress-1 Set, 3.3. Earth Resistance Test: Measuring the resistance of the two Neutral earth pits and two Body earth pits to ensure values are <2.0 Ω.,- 4 Pits. 3.Terminal & Bushing Maintenance: 4.1,De-greasing and thorough cleaning of all porcelain HT and LT bushings using approved anti-tracking solvents- 1 Job, 4.2. Torque-tightening of all HT (11kV) and LT (433V) cable terminations. Application of conductive bimetallic grease on the LT busbar connections to prevent hotspots - 1 Job 5.Consumables & Reporting: 5.1. Supply of required consumables (silica gel, CRC/WD-40, cotton waste, bimetallic grease, touch-up paint -1 Job 5.2. Submission of a Megger values, and a health summary certificate - 1 Job. complete all as specified and directed.

Material and Labour for replacement of silica gel indicating type as per IS: 3401-1992 with minimum 97% SiO2 including removal of old, saturated silica gel from the breather, cleaning the breather cup, refilling with fresh blue/orange indicating gel, and replacing the oil seal at the bottom.complete all as specified and directed.

Supplyand fix new Silica Gel Breather assembly for a 160 kVA (11kV/433V) Distribution Transformer. The scope encompasses the dismantling and environmentally safe disposal of the existing defective breather, thorough cleaning of the conservator tank’s connecting pipe flange, and the installation of a new UV-resistant clear polycarbonate or toughened glass breather unit (0.25 kg to 0.5 kg capacity). The new assembly shall be supplied complete with premium indicating-type silica gel, a heavy-duty metallic or polycarbonate bottom oil seal cup, high-grade neoprene or nitrile mounting gaskets, and SS-304 or Hot Dip Galvanized (HDG) hardware to guarantee a strictly airtight flange connection complete all as specified and directed.

Supply and erect stay set complete Galvanised with 19/20 mm dia x1.8 meter long stay rod, anchor plate size 45 cm x45 cm x7.5 mm thick, thimble, stay clamp,turn buckle,(20 mm x60 mm) /bow tightener, 7/4.00 mm dia. GI stay wire and strain insulator, clamps , hardware etc. as required complete all as specified and as directed by Engr in charge.

Supply and fix 11 KV Pin type, porcelain, vitreous, white, brown or green insulator including one galvanised mild steel spindle, two galvanised iron washers and one galvanised iron nut, 150mm height, 150mm dia for 11000 volts grade complete all as specified and as directed by Engr in charge.

Supply of 11 KV disc insulators(70KN) for 11 KV overhead line as per relevant IS :731 , IS: 3188, IS:2486(Part-I) as per specification with galvanised insulator fitting, ball and socket type and complete with galvanised strain clamps, bolts, nuts, washers etc. as required complete all as specified and as directed by Engr in charge.