B
L
O
C
K
PD Signal from CB
AND
EXTPDIND
Unsymmetrical
current detection
OR
CLOSECMD
OPENCMD
tTrip+200 ms
AND
OR
AND
T
R
I
P
150 ms
CB oper monitor
ANSI08000014-2-en.vsd
0
0-Trip
ANSI08000014 V2 EN
Figure 129: Simplified block diagram of pole discrepancy function - contact and
current based
The pole discrepancy protection is blocked if the input signal BLOCK is high.
The BLOCK signal is a general purpose blocking signal of the pole discrepancy
protection. It can be connected to a binary input in the IED in order to receive a block
command from external devices or can be software connected to other internal functions
in the IED itself in order to receive a block command from internal functions. Through OR
gate it can be connected to both binary inputs and internal function outputs.
If the pole discrepancy protection is enabled, then two different criteria can generate a trip
signal TRIP:
• Pole discrepancy signaling from the circuit breaker.
• Unsymmetrical current detection.
7.13.7.1 Pole discrepancy signaling from circuit breaker
If one or two poles of the circuit breaker have failed to open or to close (pole discrepancy
status), then the function input EXTPDIND is activated from the pole discrepancy signal
in figure
128. After a settable time tTrip, a 150 ms trip pulse command TRIP is generated
by the pole discrepancy protection.
Section 7 1MRK 506 335-UUS A
Current protection
274
Technical manual
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