VAMP 259 - Abbreviations and Symbols

Technical description
10 Abbreviations and symbols
294
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VM259.EN007
10. Abbreviations and symbols
ANSI
American National Standards Institute. A standardization
organisation.
CB
Circuit breaker
CBFP
Circuit breaker failure protection
cos
Active power divided by apparent power = P/S. (See power
factor PF). Negative sign indicates reverse power.
CT
Current transformer
CT
pri
Nominal primary value of current transformer
CT
sec
Nominal secondary value of current transformer
Dead band
See hysteresis.
DI
Digital input
DO
Digital output, output relay
DSR
Data set ready. An RS232 signal. Input in front panel port of
VAMP devices to disable rear panel local port.
DST
Daylight saving time. Adjusting the official local time
forward by one hour for summer time.
DTR
Data terminal ready. An RS232 signal. Output and always
true (+8 Vdc) in front panel port of VAMP devices.
FFT
Fast Fourier transform. Algorithm to convert time domain
signals to frequency domain or to phasors.
Hysteresis
I.e. dead band. Used to avoid oscillation when comparing two
near by values.
I
set
Another name for pick up setting value I>
I
0set
Another name for pick up setting value I
0
>
I
01n
Nominal current of the I
01
input of the device
I
0n
Nominal current of I
0
input in general
In
Nominal current. Rating of CT primary or secondary.
IEC
International Electrotechnical Commission. An international
standardization organisation.
IEEE
Institute of Electrical and Electronics Engineers
IEC-101
Abbreviation for communication protocol defined in standard
IEC 60870-5-101
IEC-103
Abbreviation for communication protocol defined in standard
IEC 60870-5-103
LAN
Local area network. Ethernet based network for computers
and devices.
Latching
Output relays and indication LEDs can be latched, which
means that they are not released when the control signal is
releasing. Releasing of lathed devices is done with a separate
action.
NTP
Network time protocol for LAN and WWW
P
Active power. Unit = [W]