MID/AN/03

1. Repairs to 2.5MVA Automatic Voltage Regulator-I, by way of isolating various units of AVR from power supply main and controlling supply while following all safety measures pre/during work. It includes visual and close inspection of main transformers (step up/down transformer and Buck-Boost Transformer) for excessive corrosion and oil leakages, if any in chamber, conservator tank, radiator, etc. Checking of bushing for oil leakages, chips and cracks developed if any in the insulator. Checking of winding temperature indicator, Oil temperature Indicator thermometer, pressure relief valves, Buchholz relay. Checking quality and quantity of oil in the chambers, checking Di-electric strength/ BDV of transformer oil, insulation resistance value of transformer windings, earthing connection and its conductivity. Repairs to Voltage Regulator unit by way of draining out oil from the chamber in suitable container, opening top cover and extracting out coils and Roller assembly with the help of suitable mechanical/manual tools & tackles and cleaning of coils by removing carbon chips/deposition using cotton cloth and suitable solvent. Replacing worn out cạrbon rollers-18 nos. tag and tail-18 nos. and refitting coils along with roller assembly in the chamber with the help of appropriate mechanical/manual tools & tackles. Cleaning inside of oil chamber to remove all kind of unwanted deposition and sediments. Checking the existing oil for its specified di-electric strength/BDV and refilling in the chamber. Topping up with fresh transformer oil 200 ltrs in units of AVR. Opening motor control box for inspecting/servicing of Servo motor with control system by replacing defective/damaged components such as Aux. contactor 02 for minimum run down (CLS)- 01no., Limit Switches- 02nos., Time delay relay – 01no. All of reputed make having actual specification as that of damaged ones. Replacing silica gel of breather assembly. Complete job includes cost of material, labour charges, to & fro transportation, loading, unloading charges for all tools & tackles required for execution of job and all applicable taxes. Testing of AVR after repairs for all connected parameters with periodic observations. (QTY- 01 No.) 2. Disconnecting 11KV incoming power supply to 500KVA capacity, 3-phase, 11KV/440V ONAN cooling vector group Dy-11. LT Transformer by disconnecting all the electrical connections and loading the Transformer in the Mechanical vehicle with the help of mobile crane and all the tools and tackles required to execute the job and then shifting to workshop for its repairs and unloading at workshop. The job includes draining out of transformer oil into barrels (380 liters. Approx). Disassembling the transformer at workshop by disassembling of all the fasteners i.e. Nuts, bolts etc. Extracting of transfer coils assemblies out of the main housing, complete disassembling of transformer assembly-core and damaged coils and allied parts at workshop. Providing/Fixing of new HV coil as per sample size of requisite specifications with proper F-class insulation (1-leg@66 kg per leg/limb) in place of damaged coils of the limb/leg. Reconditioning of LT coil (1-leg@56 kg per leg/limb) of transformer. Then assembling & making of connections by proper dehydration of core and winding in heat chamber till specified proper IR value is achieved. Cleaning of transformer tank from inside to make it free from slag, dirt, dust etc. Job also includes welding works of the transformer tank to prevent the leakages of transformer oil by using good quality welding electrodes. The Job involves assembling of Transformer with new and re-conditioned transformer core-coil assembly and complete connected accessories/gaskets/sundry items etc. Filling of oil in transformer 440 ltrs. (old) after proper treatment and topping with requisite quantity of T-Oil. Then testing of Transformer for permissible magnitudes of all connected parameters on full load conditions as per IS.2026 specifications. Then loading of the repaired Transformer from workshop and its unloading at site on its platform with the help of mobile crane. The job includes making of all the requisite electric connections both on HV & LV side and making proper earthing to the Transformer. Job also includes site testing of LT transformer for its proper functioning on no-load and full-load conditions and its proper commissioning. Complete job includes cost of material after deducting rebate on old unserviceable material, charges for skilled & semi-skilled labour, hire charges of machinery/tools & tackles with transportation charges (to & fro) etc. Complete Job. (QTY- 01 No.)

AAR PEE ELECTRICAL ENGINEERING WORKS (BID ID -2375897)

MS SYSK ELECTRICALS (BID ID -2375982)