A coordination study, sometimes known as protective device coordination analysis, protection study and similar terms, is an “attempt” to select and set devices to minimize the extent of an outage when a fault or overload occurs.  Ideally only the device closest to the fault should operate and clear with the other devices remaining closed.  This minimizes the extent of the outage.

Accomplishing selectivity between devices typically requires that each device further upstream and closer to the source be a bit less sensitive and often have some intentional time delay.  This approach is good for selectivity but what about protection?  Setting devices with more time delay can result in unnecessary damage if the fault is to be cleared by a device that has delay.

Selectivity and protection are two competing objectives.  In this class, Jim Phillips takes you step by step though the coordination study process.  In addition, in this unique class based on his four decades of experience, he shows you how to manually construct the graphs which has become a lost art in the age of “there’s an app for that”

You will see how to make decisions regarding compromises in selectivity that are often necessary to achieve the best overall coordination.  You will also learn about ground fault protection, coordinating current limit fuses, electronic trip circuit breakers, setting protective relays as well as how to protect transformers based on the ANSI C57 thru fault curves.  The final case problem illustrates how to address making compromises when perfect coordination is not attainable.

This class was recorded during the week long “Electrical Power System Engineering Class”