turbine -1 tripp why-whyWhy-Why Analysis ReportDOC. No. :Initiated by: Rajendra Singh SongaraDept.:- SP (Electrical)Date :- 21.05.2014Shift :- GAreaEquipmentAssemblySub-assy.PartLocationGPP-4GeneratorHT PanelAuxillary TransformerCT TerminationMCC ROOMFailure / Physical phenomenon: -Turbine tripped on generator differential protection at the time of Auxillary transformer switch off in off Load condition.What is your final action: -Immediately turbine roll and generator synchronisedAfter above action, Is it OK (Yes / No):-YesWhyWhy did you take above actionAnswer (Due to)Action TakenWhy-1Why turbine-1 Tripped?.Due to Differential relay operatedSince only GR-1 relay was operated at differential protection hence after resetting the differential relay, immediately clearance was given to Process department for rollingWhy-2Why differential relay operatedMay be due to Differential CT loose connection at the time of breaker operation of Auxillary TR-1 in off load condition, wiring/connection bobbling due toVibration transfered in near by TG incomer breaker (Auto change over of aux transformer was going on to lower the Tap of transformer, the reason behind lowering of transformer Tap was to reduce the system voltage to 425 V from 440V. Changeover was done successfully arroung 14:43, During switching off of Tr-1 breaker from 11 KV side for tap changing, TG incomer got tripped in differential protection)Checked Differential CT connection found OK and tightness done. Change over of Auxillary transformer-1 done again to find out root cause so Auxillary transformer switched off again in off load condition after TG synchronized, Now TG did not tripROOT CAUSE ( tick to correct root cause)Jishu HozenCan check-Y/NPlanned MaintenanceEducation & Training- Lack of lubrication- Poor design- Poor know. (Operator)- Lack of inspection- MTBF not established- Poor skill (Operator)- Lack of tightening/Looseness- Not checked in P.M.- Poor know. (Maint. Man)- Lack of cleaning- Not included in P.M.- Poor skill (Maint. man)- Lack of operation- Poor quality of spares- Lack of adjustment- Not identifiedFailure mode :-Real root cause:-Tightness of CT terminals and shorting linksKaizen Idea:-Kaizen action / Counter measure :-ResponsibleDead lineAll protective CT terminal tightness in shutdown being plannedSection InchargeShutdown opportunityOccurrence (Write Yes / No)Production code (Write Yes / No)RepeatedNoFirst timeYesProdn. StoppedYesProdn. Not stoppedJob attended byJob startJob finishTotal B/D time (in min.)Total man hourRajendra singh songara14:4715:1225 MinutesAnalyzed by :Rajendra singh songaraApproved by:Rahul sharmaIs countermeasure / kaizen idea Horizontally applicable (Yes / No ): -YesIf yes, please make a plan in the following table.AreaEquipmentPlan DateComp. DateResponsibleShree Power RasGPP-4HOD/section incharge

What actually happened, write exactly, do not guess or assumeWrite Action after taking that problem has been rectifiedPlease check page set up before taking print out

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