ABB RELION 670 SERIES Applications Manual page 786

Section 16
Scheme communication
780
The trip signal issued by compensated over and under voltage function should be
accompanied by a transfer trip signal received from the remote end. The trip signal should
be used as a release signal which can permit a remote transfer trip to be used to trip the
local circuit breaker.
Setting of over voltage and under voltage levels for compensated voltage should be same
as the remote end over and under voltage levels. This will ensure proper operation of
voltage protection of the transmission line.
The definite delay time for compensated over and under voltage can be shorter than that
at remote end, but not too short. A short delay time would result in frequent operation of
compensated over and under voltage function without corresponding transfer trip
received from remote end.
Switchable shunt reactors located on both line terminals and substation bus-bars are
commonly used on long radial EHV transmission networks for the purpose of voltage
control during daily/seasonal load variations.
The function can internally correct for the current through the local shunt reactor. The
setting EnShuntReactor should be Enabled if there is a shunt reactor on the line. Change
in this setting will be effected only when IED is restarted. Hence this setting should be
configured during installing and then connection and disconnection of shunt reactor
breaker should be handled by the input SWIPOS. In figure 383, if the measured current I
is configured in the IED, then internal shunt reactor correction should be used (The setting
EnShuntReactor should be Enabled if there is a shunt reactor on the line. Change in this
setting will reboot the IED to take effect of X
during installing and then connection and disconnection of shunt reactor breaker should
be handled by the input SWIPOS). Also, for shunt reactor connected through the breaker
or disconnector, status of the same must be configured in the IED as shown in figure 383.
Frequently, the input current to the line protection IED is already corrected for the current
through the local shunt reactor. In figure
IED then even if local shunt reactor is present its correction should not be done inside the
function, otherwise this will result into incorrect calculation for compensated voltage.
. Hence this setting should be configured
SR
383 if the measured current I
Line distance protection REL670 2.2 ANSI
1MRK 506 369-UUS -
S
is connected to the
L
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