Functions
2.11 Automatic Reclosure Function 79 (Optional)
SIPROTEC, 7SD80, Manual
E50417-G1140-C474-A1, Release date 09.2011
145
Handling of Evolving Faults
If reclose cycles are executed in the power system, particular attention must be paid to evolving faults.
Sequential faults are faults which occur during the dead time after clearance of the first fault.
To detect an evolving fault, you can select either the trip command of a protection function during the dead
time or every further pickup as the criterion for an evolving fault.
It is possible to select the desired response of the internal automatic recloser following the detection of a se-
quential fault.
• EV. FLT. MODE Stops 79:
The reclosure is blocked as soon as an evolving fault is detected. There are no further reclosure attempts;
the automatic reclosure is blocked dynamically (see also margin heading „Blocking reclosure“, above).
• EV. FLT. MODE starts 3p AR:
The separately settable dead time for sequential faults starts with the clearance of the sequential fault; after
the dead time the circuit breaker receives a close command.
If reclosing is blocked due to an evolving fault without the protection device issuing a trip command (e.g. in the
case of evolving fault detection with pickup), the device can send a trip command (intertrip).
Intertrip
The intertrip of the device acts immediately once the circuit-breaker auxiliary contacts signal an implausible
circuit-breaker position.
The device trips via its tripping logic (Section 2.16). Trip commands from external devices (Section 2.10 or the
reception of a remote trip (Section 2.13) act immediately on the tripping logic of the device.
Connecting an External Automatic Recloser
The interaction of the device with an external automatic recloser can be controlled via binary outputs:
501 „Relay PICKUP“ Start of protection device, general (if required by external recloser device.
511 „Relay TRIP“ Protection device trip.
Figure 2-55 Connection example with external reclosure device for 3-pole AR
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