Protection design

Protection design is a three stage procedure: first we need to provide immediate aid to enable continuous operation, then we need to fix or replace the spoiled component, and finally we need to reconstruct normal operation.

First aid

First aid is required to enable continuous operation, with minimal damage to the system performance or reliability. Forms of first aid include:

Structural, typically by redundancy. For example, two parts may be joined using two screws. Additional screws may be added to ensure that the parts are joined even after a first screw has been torn out.
Dynamic protection, by activating special procedures.

Dynamic protection

Dynamic protection is required when redundancy is not possible or not practical. Dynamic protection is a two stage procedure: first the fault should be identified, then the system should respond, to mitigate its risks.

Fault identification

Faults may be identified either automatically, or manually, through alarming and a troubleshooting procedure.

The speed and reliability of the troubleshooting is sometimes critical to successful protection. Troubleshooting failure is a common obstacle to recovery.

It is a primary design goal that troubleshooting will be fast and reliable.

Types

Hardware faults may be classified as either persistent or temporary.

First aid response to a fault

Form of effective responding include:

Automation, such as by activating a backup system. For example, backup pipes may be used when a primary pump system stops operating.
Manual, by the operators. For example, operators can disable a mal-functioning unit, or shut down the whole operation.

Reconstruction

Reconstruction is a two stage procedure: first, the system should notify the operators about the need fix or replace the unit. Then, assuming the the operators noticed the notification and perceive the situation correctly, the operators are expected to fix the faulty unit. Following fixing the unit or replacing it, the operators are expected to resume normal operation.