GH- Generator Hydrogen Flashcards
Why was Hydrogen gas chosen as a cooling medium for the Generator?
It has a high thermal conductivity and, because of its small molecular size, provides a low friction environment between the gas and the moving parts of the generator
rotor is cooled by a flow of hydrogen gas between the rotor and stator and
through the ventilation passages in the rotor body and through the stator components
What do we use the Carbon Dioxide for?
Used as an intermediate gas when performing operations involving the initial establishment of a hydrogen atmosphere or the venting off of a hydrogen atmosphere from the generator
How do we determine how much Hydrogen or Carbon Dioxide is in the Generator?
Gas analyzer
determines in percentages the mixtures of the three possible gases in the generator depending on the operation in progress
What is the general flow path of the Hydrogen in the Generator?
Flows between the rotor and stator and through the ventilation passages in the rotor body
Internal components of the main generator excitation system are located in the flow path of the hydrogen and thus are cooled by the hydrogen
Hydrogen is then cooled by a cooler, which the heat sink is TC, and is then circulated through a gas dryer to remove moisture
A portion of the flow also passes through a core monitor and a pyrolysate collector to monitor the generator for over-heating
What are the general steps in establishing a hydrogen atmosphere in the Generator?
Purge air from the Generator using CO2
Purge CO2 from the Generator with hydrogen to achieve a high percentage of hydrogen atmosphere
What are the general steps in establishing an air atmosphere in the Generator?
Purge Hydrogen from the generator using CO2
Purge the CO2 from the generator with air to achieve a safe atmosphere for maintenance activities
Where is the CO2 distribution tube located in the Generator? What other gas uses this same tube?
Bottom of the Generator
service air
Where is the Hydrogen distribution tube located in the Generator? What else can it be used for?
Top of the generator
Can be the exit point for hydrogen, carbon dioxide, or air depending on the purge operation that is in progress at the time
Where are main generator Purge operations controlled from?
Hydrogen Purge Station in the Turbine Building 140’ east end
What system provides the CO2 to the main generator?
Fire protection vaporizer (cardox unit)
What system provides the Hydrogen to the main generator?
Service Gases
What system supplies dry air for purging carbon dioxide from the main generator?
Service Air
In the Generator Hydrogen gas Coolers, what flows through the tubes?
Turbine Cooling Water
flow controlled by a temperature control valve and temp controller
Where are the Generator Hydrogen Coolers located?
In the top of the Generator casing
How do we prevent cross connecting hydrogen and CO2 at the manifold? During normal operations, where is this piece lined up to?
One moveable spool piece that must be installed in either the hydrogen supply piping or the CO2 supply piping to the generator
To supply hydrogen to the generator