Automating relay coordination

The process of setting relays and checking the coordination between primary and backup relays has always been a time consuming process. Automation of various steps of relay setting and checking is easing the tedium of this process for engineers at Consumers Power company. This automation is performed by a series of macros written for use with the Computer-Aided Protection Engineering (CAPE) system, which has been featured in previous issues of IEEE Computer Applications in Power and in other technical papers. This article illustrates how the functions available in the protection system can be linked together through macros that produce graphical and tabular output that demonstrate the state of coordination between primary and backup relays and other protective devices.<>