Protection and Control Device Numbers and Functions - IEC 60617
IEC 60617 Standard Series Symbols and Designations
Symbol | Description | Symbol | Description |
I | Current | Z | Impedance |
I | Reverse current | f | Frequency |
Id | Differential current | n | Rotational speed |
Id/I | Percentage differential current (current restraint) | F | Magnetic flux |
Inf | Current of nth harmonic | j | Phase angle |
I1, (Ip) | Positive sequence current component | SYNC | Synchronizing (check) |
I2, (In) | Negative sequence current component | BLOCK | Element is blocked from operating |
Io, (Ih) | Zero sequence current component | LO | Lock-out |
Irsd | Residual current | TCS | Trip circuit supervision |
I | Earth fault current | START | Protection element is engaging (Same as ALARM in ANSI) |
I | Current to frame | TRIP | Protection element settings have been met |
IN | Current in the neutral conductor | X/Y | Translation of signal |
IN-N | Current between neutrals of two | A/D or /# | Analog to digital conversion |
Iub | Polyphase systems | > | Operation above a set value e.g. overcurrent |
U | Current unbalance | < | Operation below a set value e.g. undervoltage |
dP/dt | Voltage | >> | Operation well above a high set stage |
Q | Reactive power | << | Operation well below a low set stage |
R | Resistance | >>> | Operation above a very high set stage |
X | Reactance | <<< | Operation very below a low set stage |