Pickup Logic Of The Entire Device - Siemens Siprotec 7VK61 Manual

Functions
2.8 Function Control
1-pole dead time
During a 1-pole dead time, the load current flowing in the two healthy phases forces a current flow via earth
which may cause undesired pickup. The developing zero sequence voltage may also prompt undesired re-
sponses of the protective functions.
The indications „1pole open L1" (No. 591), „1pole open L2" (No. 592) and „1pole open L3" (No.
593) are additionally generated if the „Open Pole Detector" detects that current and voltage are absent in one
phase – however, it also detects that no current is flowing in the other phases. In this case, one of the indica-
tions will only be maintained while the condition is met. This enables a single-pole automatic reclosure to be
detected on an unloaded line.
Specially for applications with busbar side voltage transformers the indication „1pole open Lx" is addition-
ally transmitted if the phase-selective CB auxiliary contacts clearly show a single-pole open circuit breaker, and
the current of the affected phase falls below the parameter 1130 PoleOpenCurrent.
Depending on the setting of parameter 1136 OpenPoleDetect., the Open Pole Detector evaluates all avail-
able measured values including the auxiliary contacts (default setting w/ measurement) or it processes only
the information from the auxiliary contacts including the phase current values (setting Current AND CB). To
disable the Open Pole Detector, set parameter 1136 to OFF.

2.8.1.4 Pickup Logic of the Entire Device

Phase Segregated Fault Detection
The fault detection logic combines the fault detection (pickup) signals of all protection functions. In the case of
those protection functions that allow for phase segregated pick-up, the pick-up is output in a phase segregated
manner. If a protection function detects an earth fault, this is also output as a common device alarm. Thus the
alarms „Relay PICKUP L1", „Relay PICKUP L2", „Relay PICKUP L3" and „Relay PICKUP E" are
available.
The above alarms can be allocated to LEDs or to output relays.
General Pickup
The pickup signals are combined with OR and lead to a general pickup of the device. It is signalled with „Relay
PICKUP". If no protective function of the device has picked up any longer, „Relay PICKUP" disappears (in-
dication „OFF").
General device pickup is a precondition for a series of internal and external functions that occur subsequently.
The following are among the internal functions controlled by general device pickup:
• Opening of fault case: from general device pickup to general device dropout, all fault indications are entered
in the trip log.
• Initialization of fault storage: the storage and maintenance of fault values can also be made dependent on
the occurrence of a trip command.
• Generation of spontaneous indications: Certain fault indications can be displayed as spontaneous indica-
tions (see margin heading „Spontaneous Indications"). In addition, this indication can be made dependent
on the general device trip.
• Start action time of automatic reclosure (if available and used).
External functions may be controlled by this indication via an output contact. Examples are:
• Channel boost in conjunction with signal transmission by PLC.
• Further additional devices or similar.
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SIPROTEC, 7VK61, Manual
C53000-G1176-C159-3, Release date 05.2009