Regenerative fuel cell system and method of operating the same

A regenerative fuel cell system comprising:

• a water electrolysis device configured to generate hydrogen gas and pressurized oxygen gas from water that is supplied, and cause the pressurized oxygen gas to be stored in an oxygen tank through an oxygen supply path;
• a hydrogen compression device configured to generate pressurized hydrogen gas from the hydrogen gas supplied from the water electrolysis device through a first hydrogen supply path and cause the pressurized hydrogen gas to be stored in a hydrogen tank through a second hydrogen supply path, and further configured to return hydrogen gas that has not been pressurized, to the first hydrogen supply path through a hydrogen discharge path;
• a fuel cell configured to perform power generation by an electrochemical reaction by the oxygen gas stored in the oxygen tank and the hydrogen gas stored in the hydrogen tank being supplied and to generate the water;
• and
• external relief valves, wherein the external relief valves include:
• a first external relief valve provided between the oxygen supply path communicating with the water electrolysis device and a vacuum space;
• a second external relief valve provided between the second hydrogen supply path communicating with the hydrogen compression device and the vacuum space;
• a third external relief valve provided between the hydrogen discharge path communicating with the hydrogen compression device and the vacuum space;
• and
• a fourth external relief valve provided between the first hydrogen supply path communicating with the hydrogen compression device and the vacuum space.