GE MiCOM P747 Agile Technical Manual page 438

Appendix A - Symbols and Glossary
Symbol
Resistance
R
A distance zone resistive reach setting: Used for ground (earth) faults.
R Gnd.
R Ph A distance zone resistive reach setting used for Phase-Phase faults.
Rct Secondary winding resistance
Rl Resistance of single lead from relay to current transformer
Rr Resistance of any other protective relays sharing the current transformer
Resistance of relay neutral current input
Rrn
Rrp Resistance of relay phase current input
Rs Value of stabilizing resistor
Rx Receive: typically used to indicate a communication receive line/pin.
S1 Used in IEC terminology to identify the secondary CT terminal polarity: Replace by a dot when using ANSI standards.
S2 Used in IEC terminology to identify the secondary CT terminal polarity: The non-dot terminal.
A time delay.
t
t' Duration of first current flow during auto-reclose cycle
T1 Primary system time constant
tfr Auto-reclose dead time
tIdiff Current differential operating time
Ts Secondary system time constant
Transmit: typically used to indicate a communication transmit line/pin.
Tx
V Voltage.
V< An undervoltage element.
V<1 First stage of undervoltage protection: Could be labeled 27-1 in ANSI terminology.
V<2 Second stage of undervoltage protection: Could be labeled 27-2 in ANSI terminology.
V> An overvoltage element.
First stage of overvoltage protection: Could be labeled 59-1 in ANSI terminology.
V>1
V>2 Second stage of overvoltage protection: Could be labeled 59-2 in ANSI terminology.
V0 Zero sequence voltage: Equals one third of the measured neutral/residual voltage.
V1 Positive sequence voltage.
V2 Negative sequence voltage.
Negative sequence polarizing voltage.
V2pol
Phase A voltage: Might be phase L1, red phase.. or other, in customer terminology.
VA
VB Phase B voltage: Might be phase L2, yellow phase.. or other, in customer terminology.
VC Phase C voltage: Might be phase L3, blue phase.. or other, in customer terminology.
Vf Theoretical maximum voltage produced if CT saturation did not occur
Vin Input voltage e.g. to an opto-input
Required CT knee-point voltage.
Vk
IEC knee point voltage of a current transformer.
Neutral voltage displacement, or residual voltage.
VN
Nominal voltage
Vn
Vn The rated nominal voltage of the relay: To match the line VT input.
VN>1 First stage of residual (neutral) overvoltage protection.
VN>2 Second stage of residual (neutral) overvoltage protection.
Vres. Neutral voltage displacement, or residual voltage.
Value of stabilizing voltage
Vs
418
Description
MiCOM P747
Units
W
W
W
W
W
W
W
s
s
s
s
s
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
P747-TM-EN-1
P747-TM-EN-1.1