ABB Relion 670 Series Applications Manual page 336

Section 15
Control
Transmission protection systems are usually sub-divided and provided with two redundant
protection IEDs. In such systems it is common to provide auto reclosing in only one of the sub-
systems as the requirement is for fault clearance and a failure to reclose because of the auto
recloser being out of service is not considered a major disturbance. If two auto reclosers are
provided on the same breaker, the application must be carefully checked and normally one
must be the master and be connected to inhibit the other auto recloser if it has started. This
inhibit can, for example, be done from an auto recloser for 3-phase operation in progress
signal.
When Single and/or three phase auto reclosing is considered, there are a number of cases
where the tripping shall be three phase anyway. For example:
• Evolving fault where the fault during the dead-time spreads to another phase. The other
two phases must then be tripped and a three phase dead-time and auto reclose initiated
• Permanent fault
• Fault during three-phase dead time
• Auto recloser out of service or circuit breaker not ready for an auto reclosing cycle
"Prepare three-phase tripping" is then used to switch the tripping to three-phase. This signal
is generated by the auto recloser and connected to the trip function block and also connected
outside the IED through IO when a common auto recloser is provided for two sub-systems. An
alternative signal "Prepare 1-phase tripping" is also provided and can be used as an alternative
when the autorecloser is shared with another subsystem. This provides a fail safe connection
so that even a failure in the IED with the auto recloser will mean that the other sub-system will
start a three-phase trip.
A permanent fault will cause the line protection to trip again when it recloses in an attempt to
energize the line.
The auto reclosing function allows a number of parameters to be adjusted.
Examples:
• number of auto reclosing shots
• auto reclosing program
• auto reclosing dead times for each shot
15.2.2.1 Auto reclosing operation Off and On
Operation of the automatic recloser can be set to Off and On by a setting parameter or by
external control. The setting parameter
With the settings
pulses to the inputs On and Off, for example, from a control system or by a control switch.
When the auto recloser is set On, the
operative if other conditions such as circuit breaker is closed and circuit breaker is ready are
also fulfilled, the
start.
15.2.2.2 Start auto reclosing and conditions for start of a reclosing cycle
The usual way to start an auto reclosing cycle, or sequence, is to start it at selective tripping by
line protection by applying a signal to the
trip signals or, only the conditions for differential, distance protection zone 1 and distance
protection aided trip. In some cases also directional earth fault protection aided trip can be
connected to start an auto reclose attempt. If general trip is used to start the auto recloser it
is important to block it from other functions that should not start an auto reclosing sequence.
330
Operation = On and ExternalCtrl = On , the control is made by input signal
SETON output is set, and the auto recloser becomes
READY output is activated (high). Then the auto recloser is ready to accept a
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Operation = Off , or On sets the function to Off or On.
START input. Starting signals can be either, general
1MRK 511 401-UEN Rev. K
M12391-91 v6
M12391-94 v5
Bay control REC670
Application manual