Table of Contents
Advertisement
Functions
2.1 General
Transformation Ratio of Voltage Transformers (VTs)
Address 206 Vph/Vdelta informs the device of the adjustment factor between the phase voltage and the dis-
placement voltage. This information is relevant for the processing of ground faults (in grounded systems and
ungrounded systems), for the operational measured value V
If the voltage transformer set provides open delta windings and if these windings are connected to the device,
this must be specified accordingly in address 213 (see above margin heading "Voltage Connection"). Since the
voltage transformer ratio is normally as follows:
the factor V
/V
ph
N
be used if the V
N
voltage via an interconnected transformer set, the factor must be corrected accordingly.
Please take into consideration that also the calculated secondary V
address 206. Thus, even if the V
erational measured value V
If Vab, Vbc, VGnd is selected as voltage connection type, parameter Vph/Vdelta is used to calculate the
phase-to-ground voltages and is therefore important for the protection function. With voltage connection type
Van, Vbn, Vcn, this parameter is used only to calculate the operational measured value of the „secondary
voltage V
".
N
Trip and Close Command Duration (Breaker)
In address 210 the minimum trip command duration TMin TRIP CMD is set. This setting applies to all protec-
tion functions that can initiate tripping.
Current Flow Monitoring (Breaker)
Address 212 BkrClosed I MIN corresponds to the threshold value of the integrated current flow monitoring
system. This parameter is used by several protection functions (e.g. voltage protection with current criterion).
If the set threshold current 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 breaker failure protection is set separately (see 2.10.2).
Two-phase Time Overcurrent Protection (Protection Operating Quantities)
The two-phase overcurrent protection functionality is used in grounded or compensated systems where inter-
action of three-phase devices with existing two-phase protection equipment is required. Via parameter 250
50/51 2-ph prot the time overcurrent protection can be configured to two or three-phase operation. If the
parameter is set to ON, the value 0 A instead of the measured value for I
comparison so that no pickup is possible in phase B. All other functions, however, operate in three phases.
38
(secondary voltage, address 206 Vph/Vdelta) must be set to 3/ √3 = √3 = 1.73 which must
voltage is connected. For other transformation ratios, i.e. the formation of the displacement
-voltage is not connected, address 206 has an impact on the secondary op-
0
.
N
and measured-variable monitoring.
N
-voltage is divided by the value set in
0
is used permanently for the threshold
B
SIPROTEC, 7SC80, Manual
E50417-G1140-C486-A1, Release date 12.2011
Advertisement
Table of Contents
