(under subclass 1) Subject matter relating to systems which are responsive to either one or more of the positive, negative or zero sequence components of electricity in a polyphase system.
SEE OR SEARCH THIS CLASS, SUBCLASS:
77, for reverse phase responsive sensing.
85, for quantity comparison to determine a phase fault.
SEE OR SEARCH CLASS
324, Electricity: Measuring and Testing,
107+, for similar subject matter but not protective.
