5.9
Date Code 20081022
Instruction Manual
SEL-787 Relay
Metering and Monitoring
Metering
Analog Input
Metering
The SEL-787 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. These values
can then be used for monitoring automation and control applications.
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
for an explanation of how to set up analog inputs for reading
transducers.
shows an example of analog input metering.
=>
MET AI <Enter>
SEL-787 Date: 01/23/2008 Time: 13:44:44
TRNSFRMR RELAY Time Source: Internal
Input Card 3
AI301 (mA) -0.008
AI302 (mA) -0.007
AI303 (mA) -0.001
AI304 (mA) -0.006
=>
Figure 5.11
METER AI Command Report
Demand Metering
The SEL-787 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)
The relay provides demand (
METER DE
command) and peak demand
(
METER PE
command) metering for the winding selected (Winding 1 or
Winding 2).
shows the values reported.
provides an
example of the
METER DE
(Demand) command report and
provides an example of the
METER PE
(Peak Demand) command report.
Refer to
for detailed descriptions and settings
selection.
Table 5.7
Demand Values
Relay Option
Demand/Peak Demand Values
All
Demand/Peak Demand values of line currents IAW
n
, IBW
n
, and
ICW
n
magnitudes (A primary)
Demand/Peak Demand Value of IGWn (residual ground fault
current) magnitude (A primary)
Demand/peak demand value of negative-sequence current
(3I2W
n
) magnitude (A primary), where
n
= 1 or 2 depending on
the winding selected.
Summary of Contents for SEL-787
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