Siemens SIPROTEC 7SD610 Manual page 225

The phase currents and the phase-to-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-energised line if the voltage transformers are installed on the feeder side. There-
fore, the device only evaluates those measuring quantities that provide information on the status of the line ac-
cording to address 1134.
But a change-of-state, such as a voltage jump from zero to a considerable value (address 1131
PoleOpenVoltage) or the occurrence of a considerable current (address 1130 PoleOpenCurrent), can be
a reliable indicator for line energization as such changes can neither occur during normal operation nor in case
of a fault. These settings can only be changed via DIGSI at Display Additional Settings.
The position of the auxiliary contacts of the circuit breakers directly indicate the position of the circuit breaker.
If the circuit breaker is controlled single-pole, energization takes place if at least one contact changes from open
to closed.
The detected energization is signalled through the message „Line closure" (No. 590). The parameter
1132 SI Time all Cl. is used to set the signal to a defined length. These settings can only be changed
via DIGSI at Display Additional Settings. Figure shows the logic diagram.
In order to avoid that an energization is detected mistakenly, the state „line open", which precedes any energi-
zation, must apply for a minimum time (settable with the address 1133 T DELAY. SOTF). The default setting
for this enable delay is 250 ms. This setting can only be changed using DIGSI at Additional Settings.
Figure 2-102 Generation of the energization signal
The line energization detection enables the time-overcurrent protection and high-current switch onto fault pro-
tection to trip without delay after energization of their line was detected.
SIPROTEC, 7SD610, Manual
C53000-G1176-C145-6, Release date 02.2011
2.16 Function Control and Circuit Breaker Test
Functions
225