Hi Anand,
In functional side of a power plant the area where equipment installed plays a major role.
Persons in Operation & Maintenance used to refer or locate a technical object with reference to the area it locates.
Example:
Turbine area,
Oil tank area,
Hot well area, etc,.
So mapping the equipment based on this will be helpful for users too.
Turbine area consists of Turbine (Main equip), Gear box(Sub equipment), Generator, Filters (Sub equipment), even we can map instrumentation equipment based this.
Boiler area consists of Boiler as main, boiler drum, feeders, etc., are sub equipment.
Regards
Varun