CHAPTER 5: SETTINGS GROUPED ELEMENTS
B90 LOW IMPEDANCE BUS DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL 5-167
5
DIRECT INPUT 5 DEVICE: "2" (message received from IED 2)
DIRECT INPUT 5 BIT NUMBER: "14" (this is BKRSUPV 3 HISET OP for Phase B)
DIRECT INPUT 6 DEVICE: "2" (message received from IED 2)
DIRECT INPUT 6 BIT NUMBER: "15" (this is BKRSUPV 3 LOSET OP for Phase B)
DIRECT INPUT 7 DEVICE: "3" (message received from IED 3)
DIRECT INPUT 7 BIT NUMBER: "13" (this is BKRSUPV 3 SUPV OP for Phase C)
DIRECT INPUT 8 DEVICE: "3" (message received from IED 3)
DIRECT INPUT 8 BIT NUMBER: "14" (this is BKRSUPV 3 HISET OP for Phase C)
DIRECT INPUT 9 DEVICE: "3" (message received from IED 3)
DIRECT INPUT 9 BIT NUMBER: "15" (this is BKRSUPV 3 LOSET OP for Phase C)
The received flags are now to be configured for in the Breaker Failure 3 logic as follows:
BF 3 AMP SUPV OP A: "Direct Input 1 On"
BF 3 AMP HISET OP A: "Direct Input 2 On"
BF 3 AMP LOSET OP A: "Direct Input 3 On"
BF 3 AMP SUPV OP B: "Direct Input 4 On"
BF 3 AMP HISET OP B: "Direct Input 5 On"
BF 3 AMP LOSET OP B: "Direct Input 6 On"
BF 3 AMP SUPV OP C: "Direct Input 7 On"
BF 3 AMP HISET OP C: "Direct Input 8 On"
BF 3 AMP LOSET OP C: "Direct Input 9 On"
The B90 current supervision elements reset in less than 0.7 of a power cycle up to the multiple of pickup of 100 (threshold
set at 0.01 of the actual fault current) as in the following figure.
Figure 5-89: Breaker failure overcurrent supervision reset time
As the overcurrent supervising flags must be sent via Direct I/Os to the B90 IEDs that perform the BF functionality, an extra
delay is introduced. Consequently, the following is recommended for coordinating the BF time:
Total BF Reset Time = 0.7 of a power cycle + 0.2 of a power cycle x Direct I/O bridge count Eq. 5-3
where
0.7 of a power cycle = the reset of the BF overcurrent elements
Direct I/O bridge count = the number of "bridges" between the source and destination of the Direct I/O messages
(Direct I/O delay)
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