maintenance work at 220kv sub-station azamgarh - to attend sf-6 gas leakage of 145kv sf-6 cb (cgl make s.no. 16936c type 120 sfm-32b) of 132kv mubarakpur bay at 220kv s/s azamgarh. 2 a:- detect gas leakage by sf-6 gas leakage detector.b:- extract sf-6 gas from pole units by help of sf-6 extraction plant and keep it into empty sf-6 gas cylinder.c:- dismantle all top covers from pole units and opening of fixed contact chamber from pole unit.d:- cleaning of all fixed & moving contacts, polishing the contacts and applying micro carbon grease on contact surface.e:- replace pole top cover o ring p-170, absorbent and re-fitting thesame.f:- apply vacuum in all poles by help of vacuum pump up to specified value and keep it for 4/5 hour & check no loss of vacuum. g:- complete overhauling of spring charging mechanism assembly, cleaning & lubrication.h:- dismantling of close & trip coil assembly, opening its parts, cleaning. lubricating and adjustment of air gap of this plunge. 1. checking electrical connection in the marshalling box and tightening all electrical connection.j:- check close/trip operation of this breaker satisfactory. k. check close/trip timing by digital timer.k:- sf6 gas fling in all poles at desired level for satisfactorily completion of work. 3 replacement of main nrb with pipeline(if required) work consist of dismantling of main nrb with pipeline & replace it with new one & |fitting at its original place in cb.