ABB Relion 670 Series Applications Manual page 191

1MRK 505 370-UUS Rev. K
If TRBU has been given and CBCLDLx still has value one in the CB Pos mode or if the CB position part
of the Current or CB Pos mode is active, TRBU and TRRET will internally be reset intentionally after
approximately 10 seconds.
This reset is deliberately done in order to make easier power system restoration after operation of the
breaker failure protection. Another way of resetting TRBU and TRRET, when the CB position criterion is
used, is either to shortly activate BLOCK input or setting CCRBRF to blocked when the IED is in test
mode.
StartMode: By this setting it is possible to select how t1 and t2 timers are run and consequently how
output commands are given from the function:
• Option 1 - LatchedStart: "By external start signals which is internally latched".
When function is once started by external START signal, the timers t1 and t2 will always elapse and
then measurement criterion defined by parameter FunctionMode will be always checked in order to
verify if the appropriate command shall be given out from the function. Timers cannot be stopped by
removing the external START signal. Function can be started again only when all of the following
three timers t1, t2 and fixed timer of 150ms in function internal design has expired and the
measurement criterion defined by parameter FunctionMode has deactivated, see
that this option corresponds to the function behavior in previous versions of the 670 Series from
version 1.0 up to and including version 2.1.
• Option 2 - FollowStart: "Follow the external start signal only".
The timers t1 and t2 will run while external START signal is present. If they elapse then
measurement criterion defined by parameter FunctionMode will be checked in order to verify if the
appropriate command shall be given out from the function. Timers can be always stopped by
resetting the external START signal, see
• Option 3- FollowStart&Mode: "Follow external start signal and selected FunctionMode" .
The timers t1 and t2 will run while external START signal is present and in the same time the
measurement criterion defined by parameter FunctionMode is active. If they elapse then the
appropriate command will be given out from the function. Timers can be stopped by resetting the
external START signal or if the measurement criterion de-activates, see
When one of the two "follow modes" is used, there is a settable timer tStartTimeout which will block the
external START input signal when it times-out. This will automatically also reset the t1 and t2 timers and
consequently prevent any backup trip command. At the same time the STALARM output from the
function will have logical value one. To reset this signal external START signal shall be removed. This is
done in order to prevent unwanted operation of the breaker failure function for cases where a permanent
START signal is given by mistake (e.g. due to a fault in the station battery system). Note that any backup
trip command will inhibit running of tStartTimeout timer.
Busbar protection REB670
Application manual
Figure
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102.
Figure
Section 7
Current protection
Figure 101. Note
103.
185