Sel SEL-787 - Figure 10.4 CTR1 Current Source Connections; Table 10.3 CTR1 Phase Current Measuring Accuracy

10.7
Date Code 20150130 Instruction Manual SEL-787 Relay
Testing and Troubleshooting
Commissioning Tests
Step 25. If your relay is equipped with voltage inputs, check the
following:
➢ Phase voltage magnitudes should be nearly equal.
➢ Phase voltage phase angles should be balanced and
have proper phase rotation.
The SEL-787 is now ready for continuous service.
Functional Tests
Phase Current Measuring Accuracy
Step 1. Connect the current source to the relay, as shown in
Figure 10.4.
Figure 10.4 CTR1 Current Source Connections
Step 2. Using the front-panel SET/SHOW or the serial port SHO
command, record the CTR1 and PHROT setting values.
Step 3. Set the phase current angles to apply balanced three-phase
currents in accordance with the PHROT setting. Refer to
Figure 10.2.
Step 4. Set each phase current magnitude equal to the values listed in
Column 1 of Table 10.3. Use the front-panel to view the phase
current values. The relay should display the applied current
magnitude times the CTR1 setting.
Step 5. Repeat Step 1 through Step 4 using Figure 10.5 and Table 10.4.
Table 10.3 CTR1 Phase Current Measuring Accuracy
|I| Applied
(A secondary)
a
a
I
NOM
= rated secondary amps (1 or 5).
Expected
Reading
CTR1 x |I|
A–Phase
Reading
(A primary)
B–Phase
Reading
(A primary)
C–Phase
Reading
(A primary)
0.2 x I
NOM
0.9 x I
NOM
1.6 x I
NOM
SEL-787
Current
Test
Source
IA
IB
IC
IC
IB
IA
IN
Z01
Z02
Z03
Z04
Z05
Z06