There is a clear difference in reliability between complying with a 'selective coordination' requirement and a generic 'coordination' requirement, with the latter being less restrictive.

There is a clear difference in reliability between complying with a 'selective coordination' requirement and a generic 'coordination' requirement, with the latter being less restrictive.

• A. True
• B. False
• C. Not sure
• D. It depends

Answer: (A)

Selective coordination means the protection system is arranged so that, for any fault, only the device closest to the fault operates. This tightens the protection so that a localized problem doesn’t trip upstream equipment, preserving as much of the system as possible and allowing quicker service restoration. Because the criteria are stricter, selective coordination delivers higher reliability by limiting the scope of outages to the smallest possible area. A generic coordination requirement, being looser, may not guarantee that the nearest device trips first. That can lead to upstream devices tripping or multiple devices operating in cascade, resulting in larger outages and more disruption. So there is a clear reliability difference: the more restrictive selective coordination yields better reliability overall. Thus the statement is true.

Selective coordination means the protection system is arranged so that, for any fault, only the device closest to the fault operates. This tightens the protection so that a localized problem doesn’t trip upstream equipment, preserving as much of the system as possible and allowing quicker service restoration. Because the criteria are stricter, selective coordination delivers higher reliability by limiting the scope of outages to the smallest possible area.

A generic coordination requirement, being looser, may not guarantee that the nearest device trips first. That can lead to upstream devices tripping or multiple devices operating in cascade, resulting in larger outages and more disruption. So there is a clear reliability difference: the more restrictive selective coordination yields better reliability overall.

Thus the statement is true.