ABB Relion 670 Series Applications Manual page 109

1MRK 511 407-UUS Rev. J
• If correct fault loop identification is not achieved
• If symmetrical faults are not detected during power swing
• During deadtime of a single pole autoreclosing cycle,
•
•
Instead of the above, a method based on the change of currents (or delta current) supplemented
with the change in ucosφ method is implemented. The phase selection (or correct faulty loop
identification) is accomplished for all types of faults that occur during the power swing even
during the deadtime of a single pole autoreclosing cycle.
It is suggested to perform transient stability studies and hardware-in-loop tests to determine the
placement of power swing unblocking feature in the power network depending upon the power
system operating scenarios.
Blocking all distance protection zones during power swing
This application refers to the blocking of all distance protection zones that may operate for any
power swing and prevent the distance protection zone from issuing a trip signal. Figure
how to configure ZMBURPSB and ZMFPDIS in ACT tool of PCM600 to achieve blocking of all
distance protection zones during power swing.
Based on system studies, one can set the operation of power swing detection to either one-out-
of-three or two-out-of-three phase mode. In this example,
• For one-out-of-three phase mode, REL1PH is set by configuring ON from FXDSIGN function
block
• connect the ZMBURPSB output, PSB_START to input BLKZx (where x = 1,...5, RV and BU) of
ZMFPDIS function block
• adapt PSB and PDIS settings based on the power network and its operating conditions and
set Operation to
• set
is disabled.
Phasor measurement unit RES670
Application manual
this unbalance (caused because of two healthy phases carrying power flow) can inhibit
PSB detection and cause maloperation of distance protection zones during power swing
or
misoperation of distance protection zones because of the blocking of the supervision
elements by taking single pole tripping output. Consequently, system continuity will be
affected during damped power system oscillations (or slow power swings)
It is recommended for a very weak source behind the relay location that power
swing unblocking feature must be disabled (that is,
secure operation. Also, output signal START of ZMBURPSB function must be
connected to BLKZx of ZMFPDIS function to achieve blocking of distance
measuring zone(s) during power swing.
On in both the function blocks
OpModePSU to Off in ZMBURPSB function block, that is, power swing unblocking feature
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Impedance protection
OpModePSU is set to Off ) for
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47
Section 7
depicts
103