Isolation/Normalisation of CEP in 500 MW

Isolation Procedure of CEP

• Stop CEP after Unloading. De-select it from Standby. Close Discharge & its IBV(also isolate them electrically). Breaker Racked out , DC control supply OFF. Press EPB.
• Close Suction Valve fully. Close strainer Relief line valve. Close Recirculation control valve its Manual valve. Close Canister Vent to LPFT
• Close thrust bearing cooling ECW inlet & outlet( depends on Requiremnet).
• Close gland seal Water supply valves from CEP Discharge Header as well as CST( Monitor Vacuum -Coordiante with CCR). In case of Deterioration, charge seal water immediately.
• Open strainer vent(Monitor Condenser Vacuum -Coordiante with CCR).Open strainer drain.Observe Pump draining completed.
• Now CEP ready for PTW to TMD and EMD.

Normalisation Procedure of CEP:

• Close Drain of strainer. Crack OPEN the strainer Vent.
• Charge Gland seal water from both sources (CEP Dicharge Header & CST).
• Open thrust bearing cooling ECW inlet & outlet.
• Close strainer Vent when water comes out of it.
• Open strainer Reief line valve. (Monitor Vacuum -Coordiante with CCR). Open Canister Vent to LPFT
• Open Recircualtion line manual valve.
• Slowly Open suction valve ( Monitor Vacuum -Coordiante with CCR). If any abnormality Close it immediately.
• Electrical normalisation of Discharge and its IBV. Electrically normalise CEP. Release EPB. Select pump as standby. discharge Opens in
• Standby condition.

Checks Before starting CEP:

• Check hotwell level >-250. Thrust Bearing Oil level is normal more than 40%.
• Pump can be started in Standby with discharge Open OR in normal with discharge valve CLOSED. Pump Recirculation valve >60% and in Manual.
• Start CEP. Maintain Minimum Recirculation Flow by OPEN Recirculation valve. Check Current, Vibration, Bearing Temp, Winding Temp.
• When we charge Condensate line from Hotwell to Deaerator during intial period of start-up, we run only one CEP with its Recirculation Full
• Open and Proper Venting of all lines will be done slowly by just opening IBV of its dicharge valve.

Protection of CEP:

• Hotwell l evel very low =-1810 mm(2 out of 3 Level Switch, TD 5 sec)
• Suction valve NOT open(Limit Switch)
• CEP ON and Dis Pr very Low( Pr switch 18 ksc and TD=5 Sec)
• CEP ON and dis Flow very low(Xmtr=300 TPH and TD=120 sec)
• Pump/ Motor thrust Brg Temp High =90 Deg (TD=10sec)
• Motor Electrical Protection operated.

Other Interlocks Relted to CEP:

• At Discharge Header Pr of 22 ksc, further Upward command to D/A level control valve blocked.
• When Dis Hdr Pr drops below 20 ksc, Standby Pump AUTOstart and force closing command will go to D/A control valve to keep it at 25%