Time
The fault
occurs
Protection
operate time
Trip and Start
CCRBRF
Normal t
cbopen
Margin
Retrip delay t1 t
cbopen
after re-trip
t
BFPreset
Minimum back-up trip delay t2
Critical fault clearance time for stability
IEC05000479_2_en.vsd
IEC05000479 V2 EN
Figure 21: Time sequences for breaker failure protection setting
7. Set t2 to 0.17 s
3.1.9 Calculating settings for pole discordance protection
CCRPLD
Pole discordance protection (CCRPLD) detects situations where the bus coupler
breaker has different switching states in the phases (one open and two closed or two
open and one closed). Pole discordance can be detected either from auxiliary breaker
contact status or by current measurement.
1. Set GlobalBaseSel to 1
The settings are made in primary values. The values of the base primary
quantities are set in Global base 1.
2. Set Operation to On
3. Set tTrip to 3 s.
When asymmetry is detected, a trip signal is activated. The delay must be so long
that asymmetrical faults will not cause an unwanted trip.
4. Set ContSel to On if the primary auxiliary contact circuits are connected.
5. Set CurrSel to Continuous monitor.
The detection by means of current measurement can be constantly activated
(Continuous monitor) or activated in connection of breaker actions only (CB
oper monitor).
6. Set CurrRelLevel to 10 % of IBase .
1MRK 505 291-UEN A Section 3
REQ650 setting examples
59
Application manual
To Next Page
Loading...
