/PERATING INSTRUCTIONS
3$
6
# ' #
-EASUREMENT IS FINISHED AFTER THE CAPACITANCE IS DIS
PLAYED
4HE PILOT WIRE CAPACITANCE IS THEN SET UNDER ADDRESS
#X 4HE CAPACITANCE OF THE PILOT WIRE MONITOR IF
APPLICABLE IS AUTOMATICALLY INCLUDED IN THE DIS
PLAYED VALUE IT NEED NOT BE CONSIDERED WHILE SETTING
#X 3ETTING IS EQUAL AT BOTH LINE ENDS )T IS SUFFICIENT TO
PERFORM THIS MEASUREMENT ONLY FROM ONE LINE END
4HE REMAINING OF THIS SUBSECTION IS RELEVANT ONLY FOR
THREETERMINAL LINES TEED LINES )N THIS CASE THE PILOT
WIRE CAPACITANCES MUST BE MEASURED FOR BOTH PILOT
WIRE PAIRS WHICH ARE CONNECTED AT A CERTAIN STATION
#X ADDRESS IS ALWAYS THE CAPACITANCE OF THE
PILOT WIRE PAIR WHICH IS CONNECTED IMMEDIATELY TO THE
RELAY UNDER CONSIDERATION IE WITH WHICH THE CAPACI
TANCE HAS BEEN MEASURED #Y ADDRESS IS THE
CAPACITANCE OF THE PILOT WIRE PAIR WHICH IS CONNECTED
TO THE ADJACENT RELAY IN THE SAME STATION 4HUS FOR
THE ADJACENT RELAY #X AND #Y ARE INTERCHANGED 4HE
TWO OPPOSITE RELAYS WHICH ARE CONNECTED WITH THE
SAME PILOT WIRE PAIR ALWAYS GET THE SAME SETTING FOR
#X &IGURE ILLUSTRATES THIS RELATION 4HE FIRST CAPI
TAL LETTER OF EACH RELAY IN THE FIGURE INDICATES THE STA
TION WHERE THE RELAY IS BUILT IN THE SECOND SMALL LET
TER INDICATES THE OPPOSITE END STATION WHERE THE
RELAY IS CONNECTED
-EASURING AND SETTING OF THE PI
LOT WIRE RESISTANCE
4HE OPERATION PRINCIPLE OF THE TWOPILOTWIRE DIFFEREN
TIAL PROTECTION REQUIRES THE ADJUSTMENT OF THE RATIO
BETWEEN THE EXTERNAL PILOT WIRE RESISTANCE 2
X
AND THE
INTERNAL SHUNT RESISTANCE 2
B
3$ CARRIES OUT THE
ADJUSTMENT BY INTERNAL CALCULATION THUS ADDITIONAL
RESISTORS ARE NOT NECESSARY &OR THIS THE PROTECTION
MUST BE INFORMED ABOUT THE PILOT WIRE LOOP RESIS
TANCE ADDRESS 2X
4HE LOOP RESISTANCE OF THE PILOT WIRES CAN BE CALCU
LATED FROM THE CABLE CHARACTERISTICS OR EVEN BE MEA
SURED BY THE RELAY ITSELF
4HE PILOT WIRE PAIR MUST BE CONNECTED TO THE RELAYS AT
BOTH LINE ENDS #OMPENSATION OF THE PILOT WIRE CA
PACITANCE IF NECESSARY MUST HAVE BEEN SET CORRECT
LY BEFOREHAND REFER TO 3ECTION
-EASUREMENT REQUIRES A CURRENT OF AT LEAST TIMES
THE RATED RELAY CURRENT )T CAN BE INJECTED AS A SEC
ONDARY CURRENT INTO THE SUMMATION TRANSFORMER
7HEN ASSESSING THE CURRENT MAGNITUDE IT MUST BE
CONSIDERED THAT THE CURRENT WHICH IS EVALUATED BY
THE RELAY DEPENDS ON THE CONNECTION MODE OF THE IN
PUT WINDINGS OF THE SUMMATION TRANSFORMER 4HE CUR
RENT MUST BE KEPT CONSTANT DURING MEASUREMENT
2ESISTANCE MEASUREMENT CAN BE CALLED UP IN AD
DRESS
- % ! 3
2 X
4 % 3 4
!FTER CONFIRMATION WITH THE 9ES KEY
*9
THE RESISTANCE
WILL BE MEASURED
#ONFIRM WITH THE 9ES KEY
*9
4HE RELAY CALCULATES
THE RESISTANCE USING THE VOLTAGE DROP ACROSS THE
SHUNT RESISTER 2
B
AND THE PILOT CURRENT 4HE RESULT IS
DISPLAYED IMMEDIATELY "UT IF A SYSTEM FAULT IS DE
TECTED NO MEASUREMENT CAN TAKE PLACE ! CORRE
SPONDING MESSAGE IS DISPLAYED
Summary of Contents for 7SD502
Page 148: ... PPENDIX 3 6 PPENDIX ENERAL DIAGRAMS ONNECTION DIAGRAMS 4ABLES ...
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