A coordination or power flow analysis is the examination of the electrical system and available documentation with the goal of ensuring that overcurrent protection devices are properly designed and coordinated.
Conducting a protective device coordination study can determine if minor revisions in breaker settings or equipment can lead to major reductions of arc flash hazards.
Overcurrent protective devices are rated, selected and adjusted so only the fault current carrying device nearest the fault opens to isolate a faulted circuit from the system. This permits the rest of the system to remain in operation, providing maximum service continuity.
The study consists of time-current coordination curves that illustrate coordination among the devices shown on the one-line diagram. Note that protective devices are set or adjusted so that pickup currents and operating times are short but sufficient to override system transient overloads.