"Theory is when you know all and nothing works. Practice is when all works and nobody knows why. In this case we have put together theory and practice: nothing works... and nobody knows why! (Albert Einstein)
From IEEE C37.2
"(60) voltage or current balance relay
A device that operates on a given difference in voltage, or current input or output, of two circuits."
A comprehensive list that is updated frequently is
IEEE C37.2 (recently revised in 2008)
IEEE Standard for Electrical Power
System Device Function Numbers,
Acronyms, and Contact
Designations
few note worthy changes are
The use of (16) for communication devices and symbol for (11) - multifunction device. They also added a cross reference of device designations b/w IEEE and IEC (Annex D)
• AFD – arc flash detector
• CLK – clock or timing source
• DDR – dynamic disturbance recorder
• DFR – digital fault recorder
• ENV – environmental data
• HIZ – high impedance fault detector
• HMI –human machine interface
• HST – historian
• LGC – scheme logic (the function, as in a RAS– not a device like a PLC)
• MET – substation metering
• PDC – phasor data concentrator
• PMU – phasor measurement unit
• PQM – power quality monitor
• RIO - remote input/output device
• RTU – remote terminal unit / data concentrator
• SER – sequence of events recorder
• TCM — trip circuit monitor
