Pole Discordance Signaling From Circuit Breaker; Unsymmetrical Current Detection - ABB RET650 Technical Manual

Section 8
Current protection
8.7.7.1
8.7.7.2
188
ContSel
EXTPDIND
CLOSECMD tTrip+200 ms
OR
OPENCMD
CurrSel
Unsymmetrical
current detection
IEC08000014 V2 EN
Figure 85: Simplified block diagram of pole discordance 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 discordance
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 discordance protection is enabled, then two different criteria can generate
a trip signal TRIP:
• Pole discordance signaling from the circuit breaker.
•

Unsymmetrical current detection.

Pole discordance signaling from circuit breaker

If one or two poles of the circuit breaker have failed to open or to close (pole
discordance status), then the function input EXTPDIND is activated from the pole
discordance signal in figure 84. After a settable time tTrip, a 150 ms trip pulse
command TRIP is generated by the pole discordance function.
Unsymmetrical current detection
Unsymmetrical current indicated if:
AND
AND
OR
AND
1MRK 504 135-UEN A
tTrip 150 ms
TRIP
t
IEC08000014-2-en.vsd
Technical manual