2 Functions
398
7SD5 Manual
C53000-G1176-C169-1
If, however, external close commands which should not activate the manual close
function are possible (e.g. external reclosure device), the binary input „>Manual
Close“ must be triggered by a separate contact at the control discrepancy switch
(Figure 2-174).
If in that latter case a manual close command can also be given by means of an inter-
nal control command from the device, such a command must be combined with the
manual CLOSE function via parameter 1152 Man.Clos. Imp. (Figure 2-172).
Figure 2-174 Manual closing with external automatic reclosure device
Besides the manual CLOSE detection, the device records any energization of the line
via the integrated line energization detection. This function processes a change-of-
state of the measured quantities as well as the position of the breaker auxiliary con-
tacts. The current status of the circuit breaker is detected, as described in the following
Section at „Detection of the Circuit Breaker Position“. The criteria for the line energi-
zation detection change according to the local conditions of the measuring points and
the setting of the parameter address 1134 Line Closure (see Section 2.1.4 at
margin heading „Circuit Breaker Status“).
The phase-phase currents and the phase-earth voltages are available as measuring
quantities. A flowing current excludes that the circuit breaker is open (exception: a
fault between current transformer and circuit breaker). If the circuit breaker is closed,
it may, however, still occur that no current is flowing. The voltages can only be used
as a criterion for the de-energized line if the voltage transformers are installed on the
feeder side. Therefore, the device only evaluates those measuring quantities that
provide information on the status of the line according to address 1134.
But a change-of-state, such as a voltage jump from zero to a considerable value (ad-
dress 1131 PoleOpenVoltage) or the occurrence of a considerable current (ad-
dress1130 PoleOpenCurrent) without a line voltage appearing at the same time,
can be a reliable indicator for line energization as such changes can neither occur
during normal operation nor in case of a fault.
The position of the auxiliary contacts of the circuit breakers indicate directly the posi-
tion of the circuit breaker. If the circuit breaker is controlled single-pole, the critierion
for energization is if at least one contact changes from open to closed.
The detected energization is signalled through the message “Line closure” (No.
590). In order to be independent of the duration that the switch is closed, the signal is
set to a defined length in the device (adjustable with the address 1132 SI Time all
Cl.). Figure 2-175 shows the logic diagramm.
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