2 Functions
174
7ST6 Manual
E50417-G1176-C251-A3
2.18
Protection Function Control
The function logic coordinates the sequence of both the protective and ancillary func-
tions, processes the functional decisions, and data received from the system.
2.18.1 General
The following is included in the function logic:
- Pickup logic
- Tripping logic
- Fault display at the LEDs/LCD
- Switching statistics
2.18.1.1 Line Energization Recognition
During energization of the protected object, several measures may be required or de-
sirable. Following a manual closure onto a short-circuit, immediate trip of the circuit
breaker is usually required. In the distance protection for example, this is implemented
by a special tripping logic for manual reclosure that can be selected with the parameter
SOTF zone
(address
1232
). For example, the zone can be activated for a short
period. In addition at least one stage of each short-circuit protection function can be
selected to trip without time delay following manual closure as described in the corre-
sponding sections. Also see Subsection 2.1.5.1 at margin heading „Circuit Breaker
Status“.
The manual closing command must be indicated to the device via a binary input. In
order to be independent of the duration that the switch is closed, the command is set
to a defined length in the device (adjustable with the address
1150
SI Time
Man.Cl
). Figure 2-53 shows the logic diagram.
Figure 2-53
Logic diagram of the manual closing procedure
If the device has an integrated automatic reclosure, the integrated manual closure
logic of the 7ST6 automatically distinguishes between an external control command
via the binary input and an automatic reclosure by the internal automatic reclosure so
that the binary input
„>Manual Close“
can be connected directly to the control
circuit of the trip coil of the circuit breaker (Figure 2-54). Each reclosure that is not ini-
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