Siemens 6MD85, Manual

Page: 923 / 1256

[dw_light-and-current, 2, en_US]
Figure 7-200 Layout and Connection of the Optical Point Sensors (Operating Mode = Current and Light)
For this example, the following is assumed:
•
The current-flow criterion offers additional security to prevent unwanted tripping caused by sudden light
influences.
Depending on the arc location in the cable-connection compartment of the feeder, it is not always
possible to measure the current. If an arc is detected in the cable-connection compartment of the feeder,
the current will therefore be evaluated in the infeed.
•
Install the optical point sensors in the busbar compartment, the circuit-breaker compartment, and the
cable-connection compartment of the feeders as well as the busbar compartment of the infeed. Connect
the optical point sensors to the protection device in the infeed.
•
The protection device in the infeed clears all arcs in the busbar compartment, the circuit-breaker
compartment, and the cable-connection compartment of feeder 1 and 2. Furthermore, the protection
device clears arcs in the busbar compartment of the infeed.
•
If the optical point sensors in the busbar compartment, the circuit-breaker compartment, and the cable-
connection compartment of the feeders, or in the busbar compartment of the infeed detect an arc, the
protection device in the infeed evaluates the current as well.
•
If an arc occurs in the circuit-breaker compartment and in the cable-connection compartment of the
infeed, the superordinate protection device must trip.
i
i
NOTE
If the Arc protection function operates with the
Operating mode
=
current and light
, the addi-
tional current-flow criterion prevents unwanted tripping caused by external light influences.
Protection and Automation Functions
7.29 Arc Protection
SIPROTEC 5, High-Voltage Bay Controller, Manual 923
C53000-G5040-C015-9, Edition 11.2017