Two drastically different types of differential relays, one with a single set of very high-impedance inputs and another with multiple sets of low-impedance inputs, are available for bus differential protection. This paper discusses for each type of relay the concepts used, the pros and cons, and the importance that current transformer selection plays in applications.

Considerations for Using High-Impedance or Low-Impedance Relays for Bus Differential Protection

This paper describes the replacement of electromechanical relays with microprocessor-based relays at a steel mill. The microprocessor-based relays enable enhanced safety, event analysis, protection, monitoring, and control.

Modernization of Mill Power Systems for Better Control and Visualization

This paper describes a reliable substation protection system that involves busbar protection, station-wide breaker failure protection, and advanced zone selection.

Reliable Busbar and Breaker Failure Protection With Advanced Zone Selection

PROT 405: Industrial Power System Protection

Switchgear Protection

Bus protection products and systems provide complete primary and backup protection for all types of bus and switchgear arrangements. They are suited for use in industrial- and commercial-scale facilities.

Switchgear Protection

Bus Protection Relays

Overcurrent Protection Relays

System Components