Functions
2.1 General
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A4, Release date 08.2010
44
Trip and close command duration (Breaker)
In address 210 the minimum trip command duration TMin TRIP CMD can be set. This setting applies to all
protection functions that can initiate tripping.
Current Flow Monitoring (Breaker)
In address 212 BkrClosed I MIN the pickup threshold of the integrated current flow monitoring function can
be set. This parameter is used by several protection functions (e.g. voltage protection with current criterion,
overload protection, load jam protection, restart inhibit for motors and circuit breaker maintenance). If the set
current value is exceeded, the circuit breaker is considered closed.
The threshold value setting applies to all three phases, and must take into consideration all used protection
functions.
The pickup threshold for the circuit-breaker failure protection is set separately (see 2.12.2).
When using the device as motor protection and using the overload protection, load jam protection and restart
inhibit, the protective relay can distinguish between a running motor and a stopped motor, as well as take into
account the different motor cooldown behavior. For this application, the set value must be lower than the
minimum no-load current of the motor.
Circuit-breaker Maintenance (Breaker)
Parameters 260 to 267 are assigned to CB maintenance. The parameters and the different procedures are
explained in the setting notes of this function (see Section 2.18.2).
Pickup Thresholds of the Binary Inputs (Thresholds BI)
At address 220 Threshold BI 1 to 226 Threshold BI 7 you can set the pickup thresholds of the binary
inputs of the device. The settings Thresh. BI 176V, Thresh. BI 88V or Thresh. BI 19V are possible.
Two-phase Time Overcurrent Protection (Protection Operating Quantities)
The two-phase time overcurrent protection functionality is used in isolated or resonant-grounded systems
where interaction of three-phase devices with existing two-phase protection equipment is required. Via param-
eter 250 50/51 2-ph prot the time overcurrent protection can be configured to two or three-phase opera-
tion. If the parameter is set to ON, the value 0 A instead of the measured value for I
B
is used permanently for
the threshold comparison so that no pickup is possible in phase B. All other functions, however, operate in
three-phase mode.
Ground Fault (Protection Operating Quantities)
Parameter 613 Gnd O/Cprot. w. lets you specify whether the directional and the non-directional ground
fault protection, the breaker failure protection or the fuse failure monitor will use the measured values Ignd
(measured) or the values 3I0 (calcul.) calculated from the three phase currents. In the first case, the
measured quantity at the fourth current input is evaluated. In the latter case, the summation current is calculat-
ed from the three phase current inputs. If the device features a sensitive ground current input (measuring range
starts at 1 mA), the ground fault protection always uses the calculated variable 3I0. In this case, parameter 613
Gnd O/Cprot. w. is not available.
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