For US device models (order item 10= C) parameters 205 and 218 are set by default to 5 A..
If address 251 has been set so that ground currents are measured by two inputs (setting options A,G2,C,G;
G->B or A,G2,C,G; G2->B), you have to set the primary rated current of the second ground transformer
connected to Ι
N2
at address 238. secondary ampere rating must conform with the phase current transformer.
To calculated the phase current Ι
B
correctly, the primary rated current of the ground current transformer,
which is used to calculate Ι
B
(address 217 or address 238), must be smaller than the primary rated current of
the phase current transformer (address 204).
Nominal Values of Voltage Transformers (VTs)
At addresses 202 Vnom PRIMARY and 203 Vnom SECONDARY, information is entered regarding the primary
nominal voltage and secondary nominal voltage (phase-to-phase) of the connected voltage transformers.
Transformation Ratio of Voltage Transformers (VTs)
Address 206 Vph / Vdelta informs the device of the adjustment factor between the phase voltage and the
displacement voltage. This information is relevant for the processing of ground faults (in grounded systems
and ungrounded systems), for the operational measured value V
N
and measured-variable monitoring.
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:
[uebersetzung-spannungswandler-020313-kn, 1, en_US]
the factor V
ph
/V
N
(secondary voltage, address 206 Vph / Vdelta) must be set to 3/ √3 = √3 = 1.73 which
must be used if the VN voltage is connected. For other transformation ratios, i.e. the formation of the
displacement voltage via an interconnected transformer set, the factor must be corrected accordingly.
Please take into consideration that also the calculated secondary V
0
-voltage is divided by the value set in
address 206. Thus, even if the V
0
-voltage is not connected, address 206 has an impact on the secondary
operational measured value V
N
.
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 secon-
dary 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.
In address 211 the maximum close command duration TMax CLOSE CMD is set. It applies to the integrated
reclosing function. It must be set long enough to ensure that the circuit breaker has securely closed. An exces-
sive duration causes no problem since the closing command is interrupted in the event another trip is initiated
by a protection function.
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 crite-
rion, overload protection 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 breaker failure protection is set separately (see 2.17.2 Setting Notes).
Functions
2.1 General
42 SIPROTEC 4, 7SJ80, Manual
E50417-G1140-C343-A8, Edition 12.2017
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