ABB REL670 2.2 IEC - Compensated over and Undervoltage Protection COUVGAPC

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 UBase. All outputs are blocked.
tOpLAP: Time delay for trip in case of low active power detection.
OperationLPF: Used to set the low power factor function On or Off.
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.
tOpLPF: Time delay for trip in case of low power factor detection.
16.8.4 Compensated over and undervoltage protection
COUVGAPC
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16.8.4.1 Identification
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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
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Compensated over and undervoltage protection (COUVGAPC) 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).
Long transmission line draws substantial quantity of charging current. If such a line
is open circuited or lightly loaded at the remote end, the voltage at remote end may
exceeds local end voltage. This is known as Ferranti effect and is due to the voltage
drop across the line inductance (due to charging current) being in phase with the
local end voltages. Both capacitance and inductance are responsible for this
phenomenon. The capacitance (and charging current) is negligible in short line but
significant in medium line and appreciable in long line. The percentage voltage rise
due to the Ferranti effect between local end and remote end voltage is proportional
Section 16 1MRK 506 369-UEN B
Scheme communication
730 Line distance protection REL670 2.2 IEC
Application manual