Zone Selective Interlocking
5.4 SENTRON 3VL
3WL/3VL circuit breakers with communication capability - PROFIBUS
System Manual, 03/2011, A5E01051353-02
121
Note
Cable type recommendation
It is recommended to transfer the ZSI signal via a twisted-pair signal line with a cross-section
of at least 0.75 mm
2
. The maximum length must not exceed 400 m. (Exception: If the higher-
level breaker is equipped with a COM10, the maximum cable length is limited to 20 m).
Recommended cable type: Shielded MSR cable LSYCY (2 x 0.75 mm
2
); made by: Siemens
Communication with LCD trip units that have a "U" as the 9th character in the order number
is only possible with COM2x RELEASE 2 or higher.
5.4.3
Applications
The function of ZSI can be used for the short-circuit between the phases (S), short-circuit to
ground (G), or both simultaneously (S + G).
If a coupling switch is used in a power distribution system, it can be integrated into the ZSI
concept.
5.4.4
Configuration
Data point 421 (Page 275) (Table 8-86) and data set 129 (Page 239) are available for
controlling the ZSI functionality with the help of communication.
You can find more information in the Service & Support Portal
(
Alternatively, with LCD trip units that have a "U" as the 9th character in the order number,
the setting can be made via the menu of the trip unit. At the factory, the ZSI function is
switched off for trip units that can be parameterized using a rotary coding switch, and it is
switched on for trip units that have a menu.
5.4.5
Connection
Up to 20 circuit breakers can be connected in parallel to ZSI IN, and up to 8 circuit breakers
can be connected in parallel to ZSI OUT.
5.4.6
LED
If the ZSI function is activated, the Trip Unit LED on COM2x flashes green.
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