Schweitzer Engineering Laboratories SEL-321 - Out-Of-Step Blocking Logic; Phase Distance Element Test Using Three Voltage Sources and One Current Source

Date Code 20011026 Maintenance and Testing 7-33
SEL-321/321-1 Instruction Manual
elements are blocked from operating. This may result in a phase distance element characteristic
that appears to have a bow-tie shaped section missing near the area of the resistive axis. Double-
check the relay Load-Encroachment logic settings if your test results appear incorrect near the
resistive axis.
Out-of-Step Blocking Logic
The relay includes Out-of-Step Tripping and Blocking logic that operates based on the Zone 5
and Zone 6 positive-sequence impedance zones and several timers. If you suspect that the Out-
of-Step logic is blocking operation of a phase distance element under test, check the relay
settings associated with the Out-of-Step function and review the relay event report.
Phase Distance Element Test Using Three Voltage Sources and One Current Source
Note: This test refers directly to the Zone 2 phase distance element, but may be applied to
any other forward-reaching phase-to-phase distance element zone. To test reverse-
reaching zones, simply add 180° to the calculated test current phase angle. Verify
correct operation of the 32QR element for the test voltage and current signals using
Equation 7.2 in the Negative-Sequence Directional Element Test Procedure.
Step 1. Execute the SHOWSET command and verify the following relay settings: Z1MAG,
Z1ANG, PMHOZ, DIR2, Z2P, 50PP2, Z2F, and 50QF. The example relay settings
use the following settings: Z1MAG = 7.8; Z1ANG = 83.97°; PMHOZ = 3; DIR2 =
F; Z2P = 9.36 Ω; 50PP2 = 2.22; Z2F = 0.77 Ω; 50QF = 0.5 amps secondary.
Execute the SET command and change the example ELOP setting from Y to N. This
prevents the relay Loss-of-Potential logic from blocking operation of the relay
distance elements.
Step 2. Select an output contact to indicate operation of the M2P element. In this example
we use the OUT7 output.
From Access Level 2, execute the SET L n command to configure Output 7 to close
for assertion of the M2P element.
=>>SET L 1 OUT7 <ENTER>
SET L 1 OUT7 <ENTER>SET L 1 OUT7 <ENTER>
SET L 1 OUT7 <ENTER>
SELogic group 1
OUT7 =NA
? M2P
M2PM2P
M2P <ENTER>
<ENTER><ENTER>
<ENTER>
OUT8 =32QR
? END <ENTER>
END <ENTER>END <ENTER>
END <ENTER>
After you type END <ENTER> to end the set procedure, the relay displays the
current logic settings. Type Y <ENTER> to accept those settings.
Connect output OUT7 to the sense input of your test set, an ohmmeter, or some other
contact sensing device.