Generator Hydrogen(GH) Flashcards
(46 cards)
What’re the Hydrogen Coolers used for ?
Removes heat from hydrogen after the hydrogen removes heat from rotor
What cooling water is used for hydrogen coolers ? How is cooling water regulated ?
-Cooled by turbine cooling water
-TC auto regulated by Generator Hydrogen Temperature
Why can hydrogen leak into the TC system ?
Generator Hydrogen is at a Higher pressure than TC, to prevent TC water from leaking into generator
How do we remove hydrogen that’s leaked into the TC system?
-Vents at the TC outlet of hydrogen coolers
-8 vents directed to a drainbox maintained at 2-5 drops per minute, allows hydrogen to vent off from TC
What does the Hydrogen Dryer/ Moisture Remover used for ??
Removes moisture from hydrogen, that prevents oxidation & corrosion inside generator
What is the driving motive force that pushes hydrogen through Dryer Moisture Remover? What is used to absorb moisture inside of it ?
-Driving force is DP developed by shaft mounted fans in generator
-Has activated alumni drying agent that removes moisture
What color does the Dryer Moisture Remover alumina change when it absorbs moisture ?
It’s turns from Blue color to a Pink color
How does the reactivation process of the Dryer Moisture Remover work ?
-Isolate from Generator
-Align to suction of seal oil system
-Align instrument air
-Energize heaters
-Reactivation is complete once alumina turns back to Blue color
During reactivation of Dry Moisture Remover what must you establish first before turning heaters on ?
Must establish instrument air flow, or else you could damage crystals from heater
What is the Generator Hydrogen Mass Flow Meter used for ?
-Provides continuous monitoring on hydrogen leakage
-Eliminates need to perform monthly hydrogen pressure drop test
What does the flow meter do to monitor hydrogen leakage ? What alarms will flow meter alarm ?
-It measure hydrogen makeup to the generator casing
-If more than normal makeup means there may be a hydrogen leak
-Hydrogen supply from Hydrogen Storage Tank to Generator is high will cause alarm
What parameters do the Hydrogen Control Cabinet provide?
-Generator Gas(casing) Pressure
-Generator Gas Analyzer
-Generator Fan DP(could be used to determine Hydrogen Purity)
-Generator Gas Temperature
What alarms does the Hydrogen Control Cabinet have ?
-Machine Gas Pressure High-Low
-Machine Gas Purity Low
-Machine Gas Temperature High
-Generator Casing Liquid Detector Full
What does the Generator Gas Analyzer do ?
-Monitor & provide real time indications of Hydrogen Purity
-Have to have high Hydrogen Purity to have high effective cooling & efficient operation of generator
What’re the 4 modes for the Generator Gas Analyzer ?
-Normal Mode H2 in air
-H2 in CO2 (purging H2 with CO2)
-Air in CO2(Purging CO2 with Air)
-H2 in CO2(Purging CO2 with H2)
What is driving force for flow through the Generator Gas Analyzers ?
Accomplished by DP across analyzers
What drives flow though the Generator Gas Analyzers when the generator fans aren’t available?
-Generator shutdown flow is accomplished by vent path to atmosphere via 3-way valve
What’re the Analyzer Inlet& outlet Filter/Dryers used for ?
Absorbs moisture & will turn pink
What are the Generator Gas Monitoring used for ?
Core monitor detected byproducts of overheating in generator known as pyrolysate
How does the core monitor work ?
-Ionizes gas by alpha radiation in ion chamber, which creates small current
-Current is amplified & displayed on front of core monitor
What is the amplified signal adjusted to during normal operation ?
Produces 90%reading on core monitor during normal operation
What does it mean when ion chamber signal decreases from 90% full ?
Signal Rate decreases dependent on extent of overheating within generator
What does the GGMS controller do for the core monitor ?
Signal digitally sent GGMS Controller which monitors,displays, & stores ion chamber signal of core monitor
What is the driving force for the flow unit the core monitor ?
The Generator Fan DP will drive the flow
