Function Control; Detection Of Line Energization - Siemens siprotec 7SA6 User Manual

Functions
6.20

Function Control

6.20.1 Detection of Line Energization

6-268
The function control is the control centre of the device. It coordinates the execution of
the protection and supplementary functions, processes their decisions and the
information that emanates from the plant. In particular the following
• switch-in recognition,
• processing of the circuit breaker position,
• fault detection logic,
• tripping logic.
During energization of the protected object, several measures may be required or
desirable. Following a manual close onto a short-circuit, immediate trip of the circuit
breaker is usually required. In the distance protection for example, this is implemented
by activation of the overreaching zone Z1B for a short period following manual closure.
The high-current switch-on-to-fault protection in particular is intended to trip
immediately following energization of a feeder on to a fault (refer to Sub-section
6.10.1). 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
corresponding sections. In this regard refer also to Sub-section 6.1.3 under the margin
heading "Circuit Breaker Status".
The manual close command must be routed 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  6, 7LPH 0DQ&O).
Fig. 6-138 shows the logic diagram.
FNo 356
>Manual Close
FNo 2851
AR CLOSE Cmd.
Figure 6-138 Logic diagram of the manual closure handling
If the device has an integrated automatic reclosure, the integrated manual closure
logic of the 7SA6 automatically distinguishes between an external control command
via the binary input and an automatic reclosure by the internal auto-reclosure function
so that the binary input "!0DQXDO &ORVH" can be connected directly to the control
circuit of the close coil of the circuit breaker.
If, however, external close commands which should not activate the manual close
function are possible (e.g. external reclosure device), the binary input "!0DQXDO
&ORVH" must be triggered by a separate contact of the control switch (Figure 6-140).
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FNo 561
> Manual Close
7SA6 Manual
C53000-G1176-C133-1