REPAIR / MAINT OF VCBS, RMUS, DISTR TRANSFORMERS, HT ELECTRICAL DISTR SYSTEM INCL REPAIR / CALIBRATION OF RELAYS, METERS AND OTHER ALLIED WKS AT NAD TECHNICAL AND RESIDENTIAL AREA, ABE PARK AREA UNDER AGE E/M NO-II OF GE (U-I) VISAKHAPATNAM

M&L for disconnecting carefully electrical connection from both HT/ LT (primary & secondary) sides of the transformer, keeping them at safe side and taking the transformer out from the plinth with the help of crane, indoor/ outdoor type of capacity 500 KVA to 800 KVA, 11 KV / 0.433 KV, step down any make for carrying out complete overhauling which shall comprise of the following:- a) M&L for lifting, transporting, handling the transformer to workshop and opening top cover of the transformer by unscrewing nuts, bolts, washers etc. including disconnecting core assembly from HT/ LT bushing and lifting the same gently and taking out from the shell (container/ body) of the transformer. b) M&L for draining out transformer oil from the above said transformer in the suitable capacity of container / drums and keeping it in safe custody for reuse. c) M&L for cleaning the transformer body from inside, removing deposited dirt / sludge / foreign particles etc. from the bottom / body of the transformer with appropriate chemical solution and drying up the shell from inside before refilling of the transformer oil. d) M&L for cleaning and washing thoroughly core and windings of the transformer by hosing down with clean dry oil conforming to IS 335/1983, removing deposited dirt / sludge / foreign particles from the windings / core, thorough inspection of windings, providing insulations to leads and terminals, heating / drying / baking complete carefully and thoroughly inside the heating chamber at suitable temperature to obtain required value of insulation resistance etc. all as specified and as directed by Engr-in- charge. (Contd...)

(Contd...) e) Lifting and re-fixing core assembly inside the transformer shell gently and carefully, connecting primary / secondary / Neutral connections to the bushings assembly, fixing of tap change over including tightening of nuts, bolts, washers of the core to reduce humming noise all as directed. f) Refilling the filtered transformer oil in the shell of transformer complete. g) Re-fixing the top cover including replacement of cork sheet / gasket 8mm thick, tightening of nuts / bolts / washers etc. and replacement of breather with silica gel crystal type all as directed by Engr-in charge h) Lifting / shifting to the place from where removed or to any location as directed and re-installing the transformer including connecting primary / secondary / neutral connections etc. all as directed by Engr-in-Charge. j) The inspection of transformer shall involve:- i) Checking of all clamps, nuts, bolts including core bolts & cover fixing bolts. ii) Checking all brazing, joints, tap heads and connection joints. iii) Checking all jumpers, terminations / connections inside the transformer. iv) Checking the Buchholtz relay / conservator MOG if any. v) Painting complete with two coats of synthetic enamel paint externally transformer shell complete all as directed by Engr-in-Charge. vi) Inspection of tap changer, checking the moving and fixed contacts for contact wear and connection to winding. k) Conducting the tests on core and windings as per IS like ratio, magnetic imbalance, short circuit etc. in presence of Engr-in-Charge and test results shall be signed both by the contractor and Engineer -in-Charge and kept on record. Note:- (i) Any damage to insulators / bushes / windings etc. while in the custody of the contractor shall be made good at no extra cost to Department. The serviceability of the transformer shall be checked and confirmed by the contractor before taking into his custody. (ii) M&L for rewinding / re-insulation of HT / LT (primary / secondary) coils, bushes, studs, Transformer oil, cable box, replacement of buchholtz relay / MOG if any etc will be measured and paid separately. (iii) Necessary gate pass duly signed by all concerned i.e JE, Engr-in-Charge & contractor should be taken while lifting / before taken in to costody of contractor foe handling workshop for repair. (iv) Guarentee / warranty of the existing transformer to be verified by the Engr-in-Charge before lifting the equipment for repair. (v) Serviceable transformer Oil shall be duly certified by the Engr-in-Charge. (vi) Engr-in-Charge shall satisfy with serviceability of Transformer. No extra cost will be allowed for rectification of defect till expiry of defect liability period once carryout repairs of the transformer measured under this item.

All as per Item No. 2.00 above but transformer / Voltage stabiliser indoor / outdoor type of capacity up to 250 to 400 KVA

All as per Item No. 2.00 above but transformer / Voltage stabiliser indoor / outdoor type of capacity up to 100 to 200 KVA

Filtration / Dehydration of transformer oil of transformers / FRMUs installed at various locations to achieve di-electric strength not less than 60 KV at 2.5mm gap as per relevant IS with portable filtration plant, testing of the oil for the di-electric strength before filtration and after filtration complete all as directed by the Engineer-in-Charge.

Supply and topping up of transformer oil with di-electric strength not less than 60 KV into the conservator tank / body tank of the transformer / OCB / FRMUs etc at various locations complete all as directed by the Engineer-in-Charge.

M&L for rewinding of distribution (HT/LT) transformers of capacity 500 to 750 KVA type by winding the defective coils with new copper wire as per I.S. of same gauge and existing size together with new insulated materials / bracings before placing in to the transformer and assembling the coil with new insulation and fitting the coils in the chamber, testing and commissioning the transformer and recording the test results complete all as directed. Note: M&L for re-insulation of serviceable coils will be measured & paid separately under relevant items.

All as per Item No. 7.00 above but rewinding of distribution (HT/LT) transformers of capacity 100 to 400 KVA type

M&L for re-insulating windings of HT / LT distribution transformers of capacity 100 to 750 KVA by strip opening of HT / LT coils (i.e. Primary / secondary coils) from core assembly safely, unwinding the HT / LT coils (i.e. Primary / secondary coils) complete, removing the old defective insulation paper and replacing with new DPC insulation to the copper conductor, re-varnishing of the windings with super varnish including heating, drying, backing complete carefully and thoroughly inside the heating chamber at suitable temperature to obtain required value of insulation resistance etc. all as directed by Engr-in- charge.

Disconnection of the distribution transformer of capacity 100 to 800 KVA from HT and LT supply mains, removing of Bus duct and Bus bar, leakage arresting by draining out of oil after arrangement of necessary empty oil drums, buckets etc.,dismantling of top cover and accessories, dismantling of LT bushings by disconnecting leads / jumpers from inside, replacement of gaskets and oil seals and re fixing of the LT bushings, making internal and external connections, replacement of cover gasket and accessories, reassembling of acessories and cover, filling back of existing transformer oil complete and making cable connections and assessing for energising the transformer complete all as specified and as directed. Note: (i) The rate quoted shall include cost of materials like gaskets and oil seals and labour etc. (ii) Bushing and bushing rods shall be measured and paid separately.