Can an eighty year old standard still be relevant? This one (IEEE C37.2) clearly is

The predecessor to ANSI IEEE C37.2 "standard electrical power system device function numbers and contact designations" was first published as AIEE No. 26 in 1928. Since then, it has been revised eight times, but in each case retained the original concept of device numbers 1 through 99 for substation control and protection devices. Those numbers have become the shorthand (or second language) of control and protection engineers. The 2007 revision broke from that pattern by adding thirteen acronyms (not numbers) for new functions not previously covered by IEEE C37.2. This revision also includes a method of describing the intra-substation communication systems now in common usage.