TRIP signal if two or more phases have low power. When the remote breaker has opened,
there should theoretically be zero power at the protection measurement point. However,
when fault current is fed to the fault point the power loss in the fault will be detected. For
operation for all unsymmetrical faults 1 out of 3 should be selected.
PU_LAP: Level of low active power detection, given in % of SBase. This parameter
should be set as low as possible to avoid activation during low load conditions at
undisturbed network operation. The measurement is blocked for current levels below 3 %
of IBase and 30% of VBase. All outputs are blocked.
tdelay_LAP: Time delay for trip in case of low active power detection.
OperationLPF: Used to set the low power factor function Enabled or Disabled.
PU_LPF: Level of low power factor detection. The setting should be set lower than the
lowest power factor at undisturbed network operation. A value lower than 0.4 is normally
sufficient.
tdelay_LPD: Time delay for trip in case of low power factor detection.
16.8.4 Compensated over and undervoltage protection COUVGAPC
(59_27)
16.8.4.1 Identification
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Compensated over and undervoltage
protection
COUVGAPC
- 59_27
16.8.4.2 Application
Compensated over and undervoltage protection (COUVGAPC, 59_27) function
calculates the remote end voltage of the transmission line utilizing local measured voltage,
current and with the help of transmission line parameters, that is, line resistance,
reactance, capacitance and local shunt reactor.
For protection of long transmission line for in zone faults this function can be incorporated
with other local criteria checks within direct transfer trip logic to ensure tripping of the line
only under abnormal conditions and to avoid unnecessary tripping during healthy
operation of the line (for example, lightly loaded or unloaded).
Section 16 1MRK 506 369-UUS -
Scheme communication
778 Line distance protection REL670 2.2 ANSI
Application manual
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