6.17.1 Check before generator gas replacement and notices for replacement
6.17.1.1 Sealing oil system runs reliably and oil-hydrogen differential pressure maintains within
about 0.084MPa.
6.17.1.2 Gas displacement should be operated when generator is stop, and turning gear speed
is lower than 1000r/min.
6.17.1.3 Relevant meters and alarming devices are tested and calibrated to be qualified. 6.17.1.4 All fire works in turbine hall are completed.
6.17.1.5 There is a certain pressure inside generator.
6.17.1.6 Confirm that sealing oil differential pressure regulation valve characteristic test is
qualified. Pressure inside generator during gas replacement keeps at about 50KPa.
6.17.1.7 Inform hydrogen generator station to prepare sufficient hydrogen before charging
hydrogen; make sure that hydrogen supplying stops before discharging hydrogen. There is sufficient CO2 at site for gas replacement and its purity is qualified.
6.17.1.8 Generator gas tightness test is qualified.
6.17.1.9 Valves in hydrogen system should be opened or closed slowly, operate it manually if it
is possible, and copper spanner can be used under special conditions. During
operation, hydrogen should be prevented from sudden washing which may cause fire.
6.17.1.10 Check the switches status in system according to H2 system valve check card
（before replacing CO2 by air）.
6.17.2 Replacing air inside generator with CO2
6.17.2.1 Close isolation valve to generator compressed air.
6.17.2.2 Close general valve from hydrogen generating station to hydrogen head pipe. 6.17.2.3 Close hydrogen cylinder supplying general valve.
6.17.2.4 Close check valve before hydrogen pressure regulation valve, check valve after
hydrogen pressure regulation valve and bypass valve of hydrogen pressure regulation valve.
6.17.2.5 Close hydrogen supplying pipe general valve. 6.17.2.6 Open hydrogen replacement valve.
6.17.2.7 Close CO2 replacement valve.
6.17.2.8 Open CO2 supplying general valve.
6.17.2.9 Open general valve of CO2 supplying pipe of CO2 cylinder.
6.17.2.10 Open and regulate gas replacement general air discharging valve and keep
6.17.2.11 When purity inside generator is higher than 90％, clean generator and discharge
with CO2 totally, open liquid leakage detector discharging valve of stator air-side &
supervision cabinet inlet discharging valve of generator working condition & supervision cabinet outlet discharging valve of generator working condition & star-point liquid leakage detector discharging valve & outlet box liquid leakage detector discharging valve & hydrogen dryer inlet discharging valve & hydrogen dryer outlet discharging valve in sequence once time for about 2 minutes.
6.17.2.12 Open valve from hydrogen to hydrogen purity analysis meter. Close it after CO2
purity is qualified.
6.17.2.13 Open valve from hydrogen to hydrogen purity analysis meter. Open hydrogen
humidity meter air inlet manual valve and hydrogen humidity meter discharging air manual valve.
6.17.2.14 Open hydrogen discharging valve. Close hydrogen humidity meter air inlet manual
valve and hydrogen humidity meter discharging air manual valve after CO2 purity is
qualified.
6.17.2.15 Open valve from hydrogen to hydrogen dryer. Close hydrogen valves and hydrogen
discharging valve.
6.17.2.16 Close valve from hydrogen to hydrogen humidity meter.
6.17.2.17 When CO2 purity inside generator is higher than 95%, close general valve of CO2
supplying pipe of CO2 cylinder, CO2 supplying general valve, H2 replacement valve
and replacement general discharging valve.
6.17.3 CO2 replacement inside generator by H2
6.17.3.1 Check and make sure that hydrogen purity analysis meter inlet valve and returning
valve are closed.
6.17.3.2 Cut off power of H2 purity analysis meter and send power when H2 purity inside
generator reaches to be higher than 90％.
6.17.3.3 Make sure that manual valve from unit compressed air to hydrogen pipe is strictly
closed.
6.17.3.4 Make sure that CO2 inside generator is higher than 95% and pressure inside
generator is about 40 KPa.
6.17.3.5 Contact with hydrogen generating station to supply hydrogen.
6.17.3.6 Open general valve from hydrogen generating station to hydrogen head pipe. 6.17.3.7 Open check valve before hydrogen pressure regulation valve and check valve after
hydrogen pressure regulation valve.
6.17.3.8 Open general valve of hydrogen supplying valve.
6.17.3.9 Check and make sure that hydrogen replacement valve is strictly closed.
6.17.3.10 Regulate hydrogen pressure regulation valve to make hydrogen supplying head pipe
pressure be higher than 50KPa.
6.17.3.11 Open CO2 replacement valve.
6.17.3.12 Open and regulate gas replacement general discharging valve and keep pressure at
50KPa inside generator. Make sure that sealing oil differential pressure regulation valve actuates normally to ensure sealing oil pressure is 84KPa higher than pressure inside generator.
6.17.3.13 When H2 purity inside generator is higher than 90％, clean generator and discharge
with CO2 totally, open liquid leakage detector discharging valve of stator air-side &
6.17.3.14 Open generator discharge valve, close generator discharging valve after H2 purity is
qualified.
6.17.3.15 Open valve from hydrogen to hydrogen purity analysis meter after H2 purity is qualified.
6.17.3.16 Open valve from hydrogen to hydrogen purity analysis meter. Open hydrogen
humidity meter air inlet manual valve and hydrogen humidity meter discharging air manual valve.
6.17.3.17 Open hydrogen discharging valve. Close discharge valve after H2 purity is qualified. 6.17.3.18 Open valve from hydrogen to hydrogen dryer. Open hydrogen discharge valve.
Close hydrogen discharge valve after H2 purity is qualified.
6.17.3.19 When H2 purity inside generator is higher than 98%, close CO2 replacement valve
and gas replacement general discharging valve. Replacement is completed.
6.17.4 Hydrogen cooler start
6.17.4.1 Close discharge valve of inlet & outlet pipes of cooler.
6.17.4.2 Open hydrogen cooler water inlet valve slowly, close air discharging valve when cooler
air discharging pipe sees water.
6.17.4.3 Open outlet water valve of hydrogen cooler.
6.17.4.4 Open isolation valves before and after hydrogen temperature regulation valve, close
bypass valve and put hydrogen cooler temperature regulation valve into ‘Automation’.
6.17.5 Hydrogen cooling system supervision during generator operation
6.17.5.1 When generator is running normally, hydrogen pressure inside generator should keep within 0.38～0.42MPa, it alarms when the pressure is higher 0.43MPa than or lower than 0.385MPa. When hydrogen pressure is too high, air discharging valve can be opened to discharge part hydrogen and decrease pressure to normal value. When hydrogen pressure lower than 0.38MPa, contact chemical operator to supply hydrogen with 0.40MPa.
6.17.5.2 During unit operation, H2 purity inside generator is higher than 96％, O2 purity inside
generator is lower than 1％, H2 humidity inside generator is lower than 29/M3 . if purity or temperature is unqualified, blow down should be done and hydrogen should be supplemented to generator to improve purity and decrease humidity.
6.17.5.3 During generator normal operation, H2 moisture removal device should be put into
operation.
6.17.5.4 During generator normal operation, hydrogen cooling system should work normally
and sealing oil system must work normally.
6.17.5.5 During generator normal operation, hydrogen coolers should be working. If one of the
hydrogen coolers exits, generator load limit is 80% of rated load.
6.17.5.6 During normal operation, it must be ensured that generator inlet hydrogen temperature
is lower than generator stator cooling water inlet temperature. It should be kept that all the temperatures of four temperature detection points at outlet of hydrogen cooler are lower than generator stator cooling water inlet temperature.
6.17.5.7 When any detection point temperature at hydrogen outlet is higher than the average
value of the other three detection points, maintenance person should be contacted for treatment.
6.17.5.8 When temperature of any detection point at generator hydrogen cooler outlet is higher
than generator stator cooling water inlet temperature, hydrogen temperature or stator cooling water temperature should be checked and regulated to be normal. If it is due to wrong detection point indication, maintenance person should be contacted for
treatment.
6.17.6 H2 replacement inside generator by CO2
6.17.6.1 Close isolation valve to generator compressed air.
6.17.6.2 Close general valve from hydrogen generating station to hydrogen head pipe. 6.17.6.3 Close hydrogen cylinder general supplying valve.
6.17.6.4 Close check valve before hydrogen pressure regulation valve, check valve after
hydrogen pressure regulation valve and bypass valve of hydrogen pressure regulation valve.
6.17.6.5 Close hydrogen supplying pipe general valve. 6.17.6.6 Open hydrogen replacement valve.
6.17.6.7 Close CO2 replacement valve.
6.17.6.8 Open CO2 supplying general valve.
6.17.6.9 Open general valve of CO2 supplying pipe of CO2 cylinder.
6.17.6.10 Open and regulate gas replacement general air discharging valve and keep
pressure inside generator be within 40～50KPa. Make sure sealing oil pressure is 84KPa higher than pressure inside generator.
6.17.6.11 When CO2 purity inside generator is higher than 90％, clean generator and
discharge with CO2totally, open liquid leakage detector discharging valve of stator
air-side & supervision cabinet inlet discharging valve of generator working condition & supervision cabinet outlet discharging valve of generator working condition & star-point liquid leakage detector discharging valve & outlet box liquid leakage detector discharging valve & hydrogen dryer inlet discharging valve & hydrogen dryer outlet discharging valve in sequence once time for about 2 minutes.
6.17.6.12 Open valve from hydrogen to hydrogen purity analysis meter. Close it after CO2
purity is qualified.
6.17.6.13 Open valve from hydrogen to hydrogen purity analysis meter. Open hydrogen
humidity meter air inlet manual valve and hydrogen humidity meter discharging air manual valve.
6.17.6.14 Open hydrogen discharging valve. Close hydrogen humidity meter air inlet manual
valve and hydrogen humidity meter discharging air manual valve after CO2 purity is
qualified.
6.17.6.15 Open valve from hydrogen to hydrogen dryer. Close hydrogen valves and hydrogen
discharging valve.
6.17.6.16 Close valve from hydrogen to hydrogen humidity meter.
6.17.6.17 When CO2 purity inside generator is higher than 95%, close general valve 122 of
CO2 supplying pipe of CO2 cylinder, CO2 supplying general valve, H2 replacement
valve and replacement general discharging valve.
6.17.7 CO2 replacement inside generator by compressed air
6.17.7.1 Close general valve from hydrogen generating station to hydrogen head pipe,
hydrogen cylinder supplying general valve, check valve before hydrogen pressure regulation valve, check valve after hydrogen pressure regulation valve and bypass valve of hydrogen pressure regulation valve.
6.17.7.3 Close hydrogen replacement valve, CO2 supplying general valve and general valve
of CO2 supplying pipe of CO2 cylinder.
6.17.7.4 Open CO2 replacement valve.
6.17.7.5 Open hydrogen supplying pipe general valve.
6.17.7.6 Open and regulate gas replacement general air discharging valve and keep pressure
inside generator be within 40～50KPa.
6.17.7.7 Open isolation valve to generator compressed air, keep pressure in generator about
0.04MPa. when air purity inside generator is higher than 90％, clean generator and discharge with CO2 totally, open liquid leakage detector discharging valve of stator
air-side & supervision cabinet inlet discharging valve of generator working condition & supervision cabinet outlet discharging valve of generator working condition & star-point liquid leakage detector discharging valve & outlet box liquid leakage detector discharging valve & hydrogen dryer inlet discharging valve & hydrogen dryer outlet discharging valve in sequence once time for about 2 minutes.
6.17.7.8 When CO2 purity inside generator is lower than 5％, close hydrogen supplying pipe
general valve, CO2 replacement valve and air isolation valve to generator
compressed air.
6.17.7.9 Close gas replacement general air discharging valve.