Which statement about the overspeed trip of a steam turbine is true?

The statement that overspeed trip devices are installed on all turbines is correct because overspeed protection is a fundamental safety feature for all types of turbines, including steam, gas, and hydro turbines. An overspeed trip mechanism is crucial for maintaining safe operational limits, as it prevents the turbine from exceeding its design speed, which can lead to catastrophic failure.

When a turbine operates beyond its safe speed, the centrifugal forces acting on the rotating components can become dangerously high, potentially leading to mechanical failure, damage, or even an explosion. Therefore, implementing overspeed trips is a standard safety practice to protect both the equipment and the facility's personnel, regardless of the turbine's size or capacity.

Other options suggest limited application or installation only in specific circumstances, which does not reflect industry standards surrounding turbine safety.