Pole Discordance Signaling From Circuit Breaker; Unsymmetrical Current Detection - ABB RED650 Technical Manual

Section 8
Current protection
8.7.7.1
8.7.7.2
224
is connected to a signalization "1phase autoreclosing in progress" from the external
autoreclosing device.
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 the pole
discordance status, then the function input EXTPDIND is activated from the pole
discordance signal derived from the circuit breaker auxiliary contacts (one NO
contact for each phase connected in parallel, and in series with one NC contact for
each phase connected in parallel) and, after a settable time interval tTrip (0-60 s), a
150 ms trip pulse command TRIP is generated by the Polediscordance function.
Unsymmetrical current detection
Unsymmetrical current indicated if:
• any phase current is lower than CurrUnsymLevel of the highest current in the
three phases.
• the highest phase current is greater than CurrRelLevel of IBase.
If these conditions are true, an unsymmetrical condition is detected and the internal
signal INPS is turned high. This detection is enabled to generate a trip after a set
time delay tTrip if the detection occurs in the next 200 ms after the circuit breaker
has received a command to open trip or close and if the unbalance persists. The 200
ms limitation is for avoiding unwanted operation during unsymmetrical load
conditions.
The pole discordance protection is informed that a trip or close command has been
given to the circuit breaker through the inputs CLOSECMD (for closing command
information) and OPENCMD (for opening command information). These inputs
can be connected to terminal binary inputs if the information are generated from
the field (that is from auxiliary contacts of the close and open push buttons) or may
be software connected to the outputs of other integrated functions (that is close
command from a control function or a general trip from integrated protections).
1MRK 505 394-UEN A
Line differential protection RED650 2.2 IEC
Technical manual
M13946-18 v4
M13946-21 v4