Tripping Logic Of The Entire Device - Siemens siprotec 7SD5 User Manual

2 Functions
Spontaneous Indi- Spontaneous indications are fault indications which appear in the display automatical-
cations ly following a general fault detection or trip command of the device. For the 7SD5,
these indications include:
„Relay PICKUP":
„S/E/F TRIP":
„PU Time":
„TRIP Time":
„dist =":

2.23.1.5 Tripping Logic of the Entire Device

Three-pole Tripping In general, the device trips three-pole in the event of a fault. Depending on the version
ordered (see Section A.1, „Ordering Information"), single-pole tripping is also possible.
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 Single-pole tripping only makes sense on overhead lines, on which automatic reclo-
Tripping sure 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:
• Phase segregated tripping is provided by the device (according to the ordering
• The tripping protection function is suitable for pole-segregated tripping (for exam-
• The binary input „>1p Trip Perm" is configured and activated or the internal au-
In all other cases tripping is always three-pole. The binary input „>1p Trip Perm"
is the logic inversion of a three-pole coupling and is activated by an external auto-re-
closure device as long as this is ready for a single-pole auto-reclosure cycle.
With the 7SD5, 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. This can be
the case, for instance, when two faults at different locations occur simultaneously, but
only one of them is within the range of differential protection or, in the case of distance
protection, within the fast tripping zone (Z1 or Z1B). This is selected with the setting
parameter 3pole coupling (address 1155), 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).
The tripping logic combines the trip signals from all protection functions. The trip com-
mands of those protection functions that allow single-pole tripping are phase segre-
gated. The corresponding messages are named „Relay TRIP L1", „Relay TRIP
L2" and „Relay TRIP L3".
404
code);
ple, not for frequency protection, overvoltage protection or overload protection),
tomatic reclosure function is ready for reclosure after single-pole tripping.
protective function that picked up;
protection function which tripped (only device with
graphic display);
the operating time from the general pickup to the
dropout of the device, the time is given in ms;
the operating time from general pickup to the first trip
command of the device, in ms;
Distance to fault in kilometers or miles derived by the
distance to fault location function (if possible).
7SD5 Manual
C53000-G1176-C169-1