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Resistor healthy
state
se�ng
Switch on
delay 1
Time on 1
Switch on
delay 2
Time on 2
Switch
off
delay 1
Time
off
1
Switch
off
delay 2
Time
”Off”
EARTH_FAULT
Resistor
control
sequence
during
earth-
fault
Repeat part
Repeat part
”On”
Figure 928: Resistor control sequence
When the earth-fault indication becomes inactive, any active single sequence or
repeat sequence is cancelled, and the resistor is switched back to its initial state.
The resistor control sequence contains a repeat part which can be repeated after
the whole sequence is executed once. The number of repetitions can be selected
with
Resistor repeats setting. Additionally, the pause between the consecutive
repeats can be selected with
Resistor pause setting. If the resistor status is the
opposite to the
Resistor healthy state when the earth-fault recovers, the resistor is
restored to healthy state at latest after one second from the last resistor change. If
the resistor already is in its healthy state when the earth-fault recovers, the status
remains.
It is also possible to manually trigger the resistor control sequence with
ST_RESIS_SEQ
binary input.
9.11.6.7
Blocking
The
BLK_AUTO
input blocks the automatic operation of the function. PASANCR's
automatic operation is blocked internally if the ASC is disconnected at the
substation, that is,
COIL_STS
signal is low. The
BLK_MANUAL
input blocks the
manual control of the coil. The
BLK_RESISTOR
input disconnects the parallel
resistor and blocks its switching on, for example, due to resistor overheating.
9.11.7
Application
PASANCR is a numerical automatic controller for arc suppression coil (Petersen
coil) and the parallel resistor. It can be applied to compensated networks
where a switched parallel resistor is optionally connected in parallel with the arc-
Control functions
1MRS759142 F
1744
REX640
Technical Manual