Sel 751A - Appendix K Analog Quantities

Date Code 20100129 Instruction Manual SEL-751A Relay
Appendix K
Analog Quantities
The SEL-751A Feeder Protection Relay contains several analog quantities
that can be used for more than one function. The actual analog quantities
available depend on the part number of the relay used. Analog quantities are
typically generated and used by a primary function, such as, metering and
selected quantities are made available for one or more supplemental functions,
for example, the load profile.
Note that all analog quantities available for use in SEL
OGIC are processed
every 100 ms and may not be suitable for fast-response control and protection
applications.
Table K.1 lists analog quantities that can be used in the following specific
functions:
➤ SELOGIC control equations (see Section 4: Protection and
Logic Functions.)
➤ Display points (see Section 8: Front-Panel Operations.)
➤ Load profile recorder (see Section 5: Metering and
Monitoring.)
➤ DNP (see Appendix D: DNP3 Communications.)
➤ Fast Meter (see Appendix C: SEL Communications
Processors.)
For a list of analog quantities available for Modbus communications, see
Appendix E: Modbus RTU Communications.
Table K.1 Analog Quantities (Sheet 1 of 6)
Label Description Units
Display Points SELOGIC Load Profile DNP Fast Meter
Fundamental Instantaneous Metering
IA_MAG A-phase line current A primary xxxxx
IA_ANG Angle of the A-phase line current degrees xxxx
IB_MAG B-phase line current A primary xxxxx
IB_ANG Angle of the B-phase line current degrees xxxx
IC_MAG C-phase line current A primary xxxxx
IC_ANG Angle of the C-phase line current degrees xxxx
IN_MAG Neutral current A primary xxxxx
IN_ANG Angle of the neutral current degrees xxxx
IG_MAG Calculated-residual current A primary xxxxx
IG_ANG Angle of the calculated-residual current degrees xxxx
IAV Average line current A primary xxxx
3I2 Negative-sequence current A primary xxxx