5.10
SEL-751 Relay Instruction Manual Date Code 20170927
Metering and Monitoring
Metering
Analog Input
Metering
The SEL-751 can monitor analog (transducer) quantities that it is measuring if
equipped with optional analog inputs. Analog input metering shows
transducer values from standard voltage and current transducers. You can then
use these values for automation and control applications within an industrial
plant or application.
Through the global settings, you can set each type of analog input to the type
of transducer that drives that analog input. You also set the range of the
transducer output. Analog inputs can accept both current and voltage
transducer outputs. Ranges for the current transducers are ±20 mA and ranges
for the voltage transducers are ±10 V. You also set the corresponding output of
the analog inputs in engineering units. See Section 4: Protection and Logic
Functions for an explanation of how to set up analog inputs for reading
transducers. Figure 5.10 shows an example of analog input metering
.
Arc-Flash Light
Intensity Metering
When the SEL-751 is ordered with the arc-flash detection (AFD) option
(order the 2 AVI /4 AFDI card or 8 AFDI card for slot E), the relay provides
light metering data with the METER LIGHT (METER L command) report.
The light inputs LS1–LS4 for 2AVI/ 4AFDI card or LS1-LS8 for 8AFDI card
are given in percent of full scale.
Figure 5.11 provides an example of the METER L (Light) command report
for a 2 AVI/ 4 AFDI card.
Demand Metering
The SEL-751 offers the choice between two types of demand metering,
settable with the enable setting:
EDEM = THM (Thermal Demand Metering)
or
EDEM = ROL (Rolling Demand Metering)
=>MET AI <Enter>
SEL-751 Date: 11/28/2010 Time: 16:22:22
FEEDER RELAY Time Source: Internal
Input Card 4
AI401 (psi) 99.97
AI402 (mA) 2.013
AI403 (Volts) -0.0027
AI404 (ft-lbs) 993
AI405 (HP) 1423
AI406 (mA) 9.013
AI407 (mA) -3.014
AI408 (mA) -0.013
=>
Figure 5.10 METER AI Command Response
=>>MET L <Enter>
SEL-751 Date: 12/01/2010 Time: 15:45:14
FEEDER RELAY Time Source: External
Light Intensity
LS1 (%) 2.4
LS2 (%) 1.9
LS3 (%) 0.7
LS4 (%) 2.3
=>>
Figure 5.11 METER L (Light) Command Response
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