Repairing the faulty 1000 kVA transformer in Kerala Books and Publications Society

Disconnecting the transformer from the site- disconnecting the HT cable, LV bus duct terminations, lifting of the transformer using crane hoist and transportation to the factory works for repairs. Rewinding complete HV and LV windings (3 Nos. HV and 3 Nos. LV) using suitable winding material matching the existing specifications of the transformer. (Scrap value of old faulty winding, Oil is absorbed in this price estimate). Un-tanking the transformer, removing core-winding assembly from the tank, disassembling and re-assembling with new windings, replacing all insulation materials with new ones, oven heating the re-assembled job to attain sufficient IR value, cleaning the transformer tank insides to remove sludge and contaminations, re-tanking the core-winding assembly into the transformer tank, replacing the cork-sheet gaskets with new of RC 70 grade, replacing complete transformer oil and re-filling with brand new oil (770 liters as per R&D plate) as per IS 335, replacing all rusted and worn out hardware including fasteners. Testing of the transformer using routine tests strictly as per IS 1180 and IS 2026 through the following tests: a) Winding Turns ratio, vector group and polarity check, b) Measurement of Winding resistance’, c) Insulation Resistance d) Measurement of No-load loss and magnetizing current at principal tap, e) Measurement of Load loss and percentage impedance at principal tap f) Induced over-voltage test (DVDF test) and Separate source voltage test (High Voltage test) using NABL laboratory calibrated Test equipment. Painting of the transformer using suitable colour epoxy paint, replacing 1 No. Replacing the old OTI with a new one.1000g silica gel dehydrating unit with a brand new one. Transportation of the transformer to the site after repairs, unloading at the site using crane hoist, re-connection of HV and LV terminations and earth connections. Pre-commissioning tests of the transformer at the site and commissioning assistance during EB energisation.