Functions
6-2977SA6 Manual
C53000-G1176-C156-2
• “dist =”: the distance to fault in kilometres or miles derived by the
distance to fault location function.
6.22.4 Overall Tripping Logic of the Device
Three-Pole
Tripping
In general, the device trips three-pole in the event of a fault. Depending on the version
ordered, (13th position of the ordering code = “4” to “7”) single-pole tripping is also
possible (see below). If, in general, single-pole tripping is not possible or desired, the
output function “
Relay TRIP 3ph.” is used for the trip command output to the circuit
breaker. In these cases the following sections regarding single-pole tripping are not of
interest.
Single-Pole
Tripping
Single-pole tripping only makes sense on overhead lines, on which automatic
reclosure shall be carried out and where the circuit breakers at both ends of the line
are capable of single-pole tripping. In such cases, the faulted phase may be tripped
single-pole and subsequently reclosed; in the case of two-phase and three-phase
faults with or without earth, three-pole tripping is usually carried out.
Device prerequisites for phase segregated tripping are:
• that phase segregated tripping is provided by the device (according to the ordering
code);
• that phase segregated tripping is provided by the protection function which trips (ac-
cordingly not e.g. earth fault protection, high-current switch-on-to-fault protection,
overvoltage protection, overload protection);
• that the binary input “>1p Trip Perm” is configured and activated or the internal
automatic reclosure function is ready for reclosure after single-pole tripping.
In all other cases tripping is always three-pole. The binary input “
>1p Trip Perm”is
derived from an external automatic reclose device and is equivalent to the logic inver-
sion of a three-pole coupling signal. This signal is present as long as the external
reclosure is ready for single-pole automatic reclosure.
With the 7SA6, it is also possible to trip three-pole when only one phase is subjected
to the trip conditions, but more than one phase indicates a fault detection. With dis-
tance protection this is the case when two faults at different locations occur simulta-
neously but only one of them is within the range of the fast tripping zone (Z1 or Z1B).
This is selected with the setting parameter
3pole coupling, which is set to with
Pickup
(every multiple-phase fault detection causes three-pole trip) or with Trip
(in the event of multiple-phase trip commands the tripping is three-pole).
Thetrippinglogiccombinesthetripsignalsfromallprotectionfunctions.Thetripcom-
mands of those protection functions that allow single-pole tripping are phase segre-
gated. The corresponding alarms are “
Relay TRIP L1”, “Relay TRIP L2”and
“
Relay TRIP L3”.
These alarms can be allocated to LEDs or output relays. In the event of three-pole trip-
ping all three alarms pick up.
For the local display of fault event messages and for the transmission of event mes-
sages to a personal computer or a centralized control system, the device also provides
asummarizedimageofthetripsignals,e.g.“
Dis.Trip 1pL1”, “Dis.Trip 1pL2”,
“
Dis.Trip 1pL3” for single-pole tripping as well as “Dis.Trip 3p” for three-pole
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