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قديم 12-26-2010, 12:43 PM
الصورة الرمزية Khaled Hamza
Khaled Hamza Khaled Hamza غير متواجد حالياً
عضو فعال
 
تاريخ التسجيل: Aug 2010
الدولة: Egypt
المشاركات: 68
معدل تقييم المستوى: 14
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Lightbulb Load Rejecti** Test (Governor Test)

Load Rejecti** Test (Governor Test)


The purpose of Turbine Load Rejecti** Test is to verify and dem**strate the governor functi** to sustain a load rejecti** in order to prevent the turbine from overspeed tripping, steady speed c**trol at no-load operati** and remain in service without any adverse effect to the turbine.
The test requires skillful and appropriate operati** not **ly for turbine , but also for boiler and its auxiliaries.
































Items to be c**firmed for Load Rejecti** Test
1-Turbine main valves
2-GV no load valve positi**
3-Lube oil pump auto start test
4-Protective device test
5-Valve transfer from MSV mode to GV mode
6-Overspeed tripping point (111% speed)
7-OPC (Overspeed Protecti** C**troller) functi**
8-Exclusi** of Interlocks (Turbine Trip due to Boiler Trip)


TEST PROCEDURE



*Before Load Rejecti** Test (**e hour)
1-C**firm steady c**diti** of load operati**
2-Perform mechanical Over Speed Oil trip Test
3-Perform Lub. oil pump auto start test
4-change over unit auxiliary bus from unit auxiliary transformer to start up transformer.


*Before Load Rejecti** Test (30 minutes)
1-C**firm that level of( C**denser , De aerator and HP/LP feed water heaters are ****** range
2-c**firm that AVR in automatic mode
3-C**firm that HP and LP Turbine bypass ( valves and Sprays ) are in automatic mode

*Before Load Rejecti** Test (10 minutes)
1-c**firm the appointed time with the load dispatcher
2- Exclude the interlock of (Turbine Trip due to Boiler Trip)

*Before Load Rejecti** Test (0 minute)
1-Open Circuit breaker of the Generator.
2-If the Overspeed trip device doesn't operate c**trary to expectati**s even when the turbine speed exceeds 111% of the rated speed , Trip immediately the turbine.
3-All observers shall read and record "Maximum or Minimum" of the measuring objects during transient c**diti**






After Load Rejecti**
Pay attenti** to the following points and see that there is no distincti** about them.
-Turbine speed
-Rotor Positi** & Vibrati**
-BRG temp. and Vibrati**
-C**denser Vacuum and hotwell level



Stabilizati**
-Stabilizati** will be judged when turbine speed is stabilized approx. 3000 rpm by GV & ICV speed c**trol




Test Acceptance Criteria
If maximum instantaneous speed is restricted below overspeed trip limits (111 %) ,therefore the load rejecti** test is regarded as successful.




C**firmati** items after Stabilizing
-GVs are restored in no load positi**
-turbine speed is c**trolled at near synchr**ous level
-No abnormality is observed at electrical room and local positi**s.




Emergency Case
If boiler trips by boiler protecti** , turbine shall be immediately tripped.


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