Sel 751A - Power and Power Factor Measuring Accuracy; Figure 10.4 Wye Voltage Source Connections; Table 10.4 Power Quantity Accuracy-Wye Voltages

10.7
Date Code 20100129 Instruction Manual SEL-751A Relay
Testing and Troubleshooting
Commissioning Tests
Power and Power Factor Measuring Accuracy
Wye-Connected Voltages
Perform the following steps to test wye-connected voltages:
Step 1. Connect the current source to the relay, as shown in
Figure 10.3.
Step 2. Connect the voltage source to the relay, as shown in
Figure 10.4. Make sure that DELTA_Y := WYE.
Figure 10.4 Wye 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
Table 10.4.
Values are given for PHROT := ABC and PHROT := ACB.
Step 5. Use the front-panel
METER function or the serial port MET
command to verify the results.
|IA| = 0.9 • I
NOM
13%
|IB| = 1.1 •
I
NOM
|IC| = 1.1 • I
NOM
Table 10.3 Current Unbalance Measuring Accuracy (Sheet 2 of 2)
|I| Applied (A secondary) Expected Reading (%) Actual Reading (%)
SEL-751A
E01
E02
E03
E04
Voltage
Test
Source
VA
VB
VC
VN
Table 10.4 Power Quantity Accuracy—Wye 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 = 0.4523 • CTR • PTR
Expected:
Q = 0.2211 • CTR • PTR
Expected:
pf = 0.90 lag
Va = 6 7 ∠0
Vb = 67 ∠−120
Vc = 67 ∠+120
Measured: Measured: Measured: