Siemens 6MD85, Manual

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Parameter Value Description
2 channel
2-channel start is used if there is a risk that the circuit-breaker failure protec-
tion causes a tripping due to a faulty activation of the start binary input.
This is the case in the following situations:
a) The CBFP pickup value (threshold value) is set to less than the load
current.
b) There can be operating conditions under which the current flow is higher
than the pickup value.
To avoid a possible overfunction, Siemens recommends using the 2-channel
start.
1 channel
The 1-channel start must be used where only one control circuit is available
for starting the CBFP.
Input Signals: >Start, >Release
The start and release input signals have a filtering time of
10 ms
as default setting. If a transient control signal
to the binary inputs is to be expected due to the design of the external binary-input control circuits and due to
environmental conditions, the filtering time can be extended. This delays the start of the CBFP function.
Input Signals (3-Pole Circuit
Breaker) Description
>Start
The start input signal is linked with the tripping of the external protection
device (see
Figure 7-17 ).
>Release
The release input signal is normally linked with the pickup of the external
protection device (see
Figure 7-17 ). Another common configuration is the
parallel wiring of the external trip initiation to both binary inputs (start and
release).
Input Signals (1/3-Pole Circuit
Breaker) Description
>Start pole A
>Start pole B
>Start pole C
>Start 3-pole
The start input signal is linked with the tripping of the external protection
device. If the external protection trips phase-selectively, the CBFP can be
started phase-selectively via the input signals
>Start phsx
(see
Figure 7-18 ).
>Release 1-pole
>Release 3-pole
The release input signal is normally linked with the pickup of the external
protection device (see
Figure 7-18 ). Another common configuration is the
parallel wiring of the external trip initiation to both binary inputs (start and
release).
Parameter: Supervision time for release signal
•
Default setting (3-pole circuit breaker)
(_:111) Sup.time for release signl
=
0.06 s
•
Default setting (1/3-pole circuit breaker)
(_:108) Sup.time for release signl
=
0.06 s
The setting depends on the external function which generates the release signal. If the pickup or tripping of
the external protection is used as release signal, the default setting can be kept. If it is ensured that the release
signal is always present before the starting signal, the time can be set to 0.
Parameter: Holding internal signal
•
Recommended setting value
(_:105) Holding int. start signal
=
yes
Protection and Automation Functions
7.1 Circuit-Breaker Failure Protection
SIPROTEC 5, High-Voltage Bay Controller, Manual 531
C53000-G5040-C015-9, Edition 11.2017