What is Permissives, Protections and Interlocks?


#1

These terms are commonly used while doing maintenance of power plants.Read the following to know about these.

Permissives:

Permissives are set of conditions required to be satisfied before start of an activity to safeguard the system/equipment/process.

Thus, permissives are implemented in series.

Protections:

Once an activity starts based on system parameters, protections are set of conditions that initiate the closure/stoppage of that activity to safeguard the system/equipment/process.

As any condition in the set should stop the activity, they are implemented in parallel.

Interlocks:

Interlocks, as the name itself suggests, are the set of conditions for an activity, where one activity initiates another activity to safeguard the system/equipment/process.