10.8
SEL-751A Relay
Instruction Manual
Date Code 20100129
Testing and Troubleshooting
Commissioning Tests
Delta-Connected Voltages
Perform the following steps to test delta-connected voltages:
Step 1. Connect the current source to the relay, as shown in
Step 2. Connect the voltage source to the relay, as shown in
. Make sure that DELTA_Y := DELTA.
Figure 10.5
Delta Voltage Source Connections
Step 3. Using the front-panel
SET/SHOW
or the serial port
SHOW
command, record the CTR, PTR, and PHROT setting values.
Step 4. Apply the current and voltage quantities shown in Column 1 of
.
Values are given for PHROT := ABC and PHROT := ACB.
Step 5. Use the front-panel
METER
or the serial port
MET
command to
verify the results.
PHROT := ACB
Ia = 2.5
∠−
26
Ib = 2.5
∠
+94
Ic = 2.5
∠−
146
Expected:
P = 0.4523 • CTR • PTR
Expected:
Q = 0.2211 • CTR • PTR
Expected:
pf = 0.90 lag
Va = 67
∠
0
Vb = 67
∠+
120
Vc = 67
∠−
120
Measured:
Measured:
Measured:
Table 10.4
Power Quantity Accuracy—Wye Voltages
(Sheet 2 of 2)
Applied Currents and Voltages
Real Power
(kW)
Reactive Power (kVAR)
Power Factor
(pf)
SEL-751A
E01
E02
E03
E04
Voltage
Test
Source
VA
VB
VC
VN
Table 10.5
Power Quantity Accuracy—Delta Voltages
(Sheet 1 of 2)
Applied Currents and Voltages
Real Power
(kW)
Reactive Power
(kVAR)
Power Factor
(pf)
PHROT := ABC
Ia = 2.5
∠
–26
Ib = 2.5
∠
–146
Ic = 2.5
∠
+94
Expected:
P = 0.4677 • CTR • PTR
Expected:
Q = 0.2286 • CTR • PTR
Expected
pf = 0.90 lag
Vab = 120
∠
+30
Vbc = 120
∠
–90
Measured:
Measured:
Measured:
Summary of Contents for 751A
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