RFL Electronics RFL 9300 - Figure 2-3. Logic Diagram, Strong-Feed Trips (for 2- and 3- Terminal Systems)

a. Logic diagram, strong-feed trip for two terminal systems
b. Logic diagram, strong-feed trip for three terminal systems
CCD, OR WCM
FROM REMOTE
TERMINAL
AND
LOCAL
CCD
WORD
A/D CONVERSION
AND CALCULATION OF 1/2
CYCLE CHARGE
(CURRENT > 0.5A,
PULSE WIDTH > 6 ms)
NEST
?
CALCULATE SCALAR
SUM, ARITHMETIC SUM
& % DIFFERENTIAL
BIAS LEVEL
(SEE FIG. 2-4a)
ARITHMETIC
SUM>BIAS
LEVEL
?
AND
COMPOSITE
FAULT DETECTOR
(See Figure 2-2)
TRIP
ENABLED
?
YES
NO
NO
YES
NO
YES
NO
YES
TRIP
AND SEND
CCT-U TO
REMOTE
TERMINAL
VALIDATED CCD
OR WCM FROM
REMOTE TERMINAL #1
AND
LOCAL CCD
WORD STORED
IN CHARGE
COMPARISON
BUFFER
A/D CONVERSION
AND CALCULATION OF
CONTROL CT
CURRENT TRANSIENT
1/2 CYCLE CHARGE
BOTH
REMOTE
VALUES
NEST
?
CALCULATE SCALAR
SUM, ARITHMETIC SUM
& % DIFFERENTIAL
BIAS LEVEL
(SEE FIG. 2-4b)
ARITHMETIC
SUM>BIAS
LEVEL
?
AND
COMPOSITE
FAULT DETECTOR
(See Figure 2-2)
TRIP
ENABLED
?
YES
NO
NO
YES
NO
YES
NO
YES
TRIP
AND SEND
CCT-U TO
REMOTE
TERMINAL
VALIDATED CCD
OR WCM FROM
REMOTE TERMINAL #2
Figure 2-3. Logic diagram, strong-feed trips (for 2- and 3- terminal systems)
RFL 9300 RFL Electronics Inc.
October 29, 2001 2 - 15 (973) 334-3100