Individual testing of each protective device and stop/control valve assembly. Automatic functional PRE-TESTING of substitute circuit which protect the turbine during ATT. Monitoring off all programme steps for execution within a pre-defined time. Interruption of the testing programme if the running time of any programme step is exceeded or if the turbine trip is initiated. Automatic resetting of the test programme after a fault. Full protection of the turbine during testing is ensured by special test safety devices.

AUTOMATIC TURBINE TESTINGPROTECTIVE DEVICES Remote trip solenoid-1 Remote trip solenoid-2 Over speed trip device Thrust bearing trip device Low vacuum trip deviceMAIN STOP/CONTROL VALVE HP stop/control valve-1 HP stop/control valve-2 HP stop/control valve-3 HP stop/control valve-4 IP stop/control valve-1 IP stop/control valve-2 IP stop/control valve-3 IP stop/control valve-4

ATT SAFETY DEVICESTEST STARTEnergise the test solenoidsControl oil pr adequateDe-energise the test solenoidsControl oil pr zeroPRE-TESTHYDRAULIC TEST CKT ONTest solenoid onChange over valve in test positionOil pressure in trip oil header O.KMAIN TEST ONTest ckt onSelected protective Device OperatedTurbine trip gear operatedTurbine protection operatedRESETTest ckt OFFReset solenoid energiseTrip gear & protective device resetChange over valve in operating positionTest solenoid de-energiseTEST ENDSFAULTFAULTFAULT

AUX TRIP FLUIDTEST FLUIDCONTROL FLUIDAUX START-UP FLUID

CONTROL OILDRAINTEST OIL

ATMOSHPHERECONDENSERHTT

ATT SV & CVTEST STARTEHG in serviceOne set of SV & CV selectedCV opening < 60 %RELEASEMAIN TEST ONPositioner motor ONControl valve closedTest solenoid ONTrip oil to SV drainsSV closedRESETReset solenoid ONSV spring resetTest solenoid OFFSV opensPositioner motor reverseControl valve opensTEST ENDS