/PERATING INSTRUCTIONS
3$
6
# ' #
3ETTINGS FOR PILOT WIRE MONITORING
ADDRESS BLOCK
4HE PILOT WIRES BETWEEN THE DIFFERENTIAL RELAYS AT THE
ENDS OF THE PROTECTED LINE FORM AN ESSENTIAL PART OF
THE SCHEME &OR THIS REASON IT IS ALWAYS RECOM
MENDED THAT THE PILOT WIRES BE SUPERVISED BY THE PI
LOT WIRE MONITORING OPTION -ODEL 3$
J
JJJ
J JJ
IS EQUIPPED WITH THIS PILOT WIRE MONITOR !
FURTHER PRECONDITION FOR THIS FUNCTION IS THAT DURING
CONFIGURATION OF THE RELAY ADDRESS 0),/4 -/.
HAS BEEN SET TO
%8)34
REFER TO 3ECTION AND
THAT THE PILOT WIRE MONITOR IS SWITCHED
/.
UNDER AD
DRESS
4HE PILOT WIRE MONITOR OPERATES WITH A PULSED CODE
WHICH IS MODULATED ON A VOICE FREQUENCY SIGNAL OF
(Z 4HE MONITORING CODE IS TRANSMITTED ALTER
NATELY BY ONE RELAY TO THE OTHER AND VICE VERSA )N OR
DER TO ENSURE A DEFINED STARTUP OF THIS HANDSHAKE
OPERATION ONE OF THE RELAYS MUST BE DECLARED AS
MASTER AND THE OTHER AS SLAVE 4HE MAS
TER DEVICE WILL ALWAYS START WITH THE COMMUNICA
TION THE SLAVE DEVICE RESPONDS !DDRESS
DETERMINES WHICH RELAY OPERATES AS MASTER AND
WHICH AS SLAVE
!N INTERRUPTION OR SHORTCIRCUIT ON THE PILOT WIRES MAY
BE ANNUNCIATED ONLY OR ADDITIONALLY THE DIFFERENTIAL
PROTECTION CAN BE BLOCKED ADDRESS 7HEN
THE PILOT WIRES ARE INTERRUPTED THE DIFFERENTIAL PROTEC
TION CANNOT TRIP ANY MORE SINCE NO DIFFERENTIAL CURRENT
CAN BE PRESENT )F THE PILOT WIRES ARE SHORTCIRCUITED
A HIGH THROUGHFAULT CURRENT EXTERNAL FAULT MAY
CAUSE TRIPPING 4HE OVERCURRENT TIME PROTECTION IF IT
IS SET EFFECTIVE WILL CONTINUE ITS OPERATION EVEN DUR
ING PILOT WIRE FAULT !NNUNCIATION OF PILOT WIRE FAILURE
AND BLOCKING ARE DELAYED BY 4 0),/4 ADDRESS
! CERTAIN RECEPTION LEVEL OF THE MONITORING SIGNAL IS
NECESSARY IN ORDER TO ENSURE CORRECT DECODING OF THE
RECEIVED SIGNAL 4HIS LEVEL IS SET UNDER ADDRESS
,%6%, 0- MEANS THAT THE FULL TRANSMITTED
POWER IS AVAILABLE IE NO ATTENUATION ON THE PILOTS
PILOT RESISTANCE EQUALS 4HE RECEPTION LEVEL CAN
BE MEASURED BY THE RELAY ITSELF DURING COMMISSION
ING REFER TO 3ECTION 3ETTING SHOULD BE OF
THE MEASURED RECEPTION LEVEL
4HE PILOT WIRE MONITORING IS NOT OPERATIONAL AS LONG
AS A SYSTEM FAULT IS PRESENT OR AS LONG AS AN INTERTRIP
SIGNAL OR A TRANSFER TRIP SIGNAL IS BEING TRANSMITTED
0 ) , / 4
7 ) 2 %
- / . ) 4 / 2 ) . '
"EGINNING OF BLOCK 0ILOT WIRE MONITORING
0 ) , / 4
- / .
/ & &
/ .
0ILOT WIRE MONITORING
/&&
IS SWITCHED OFF OR
/.
IS SWITCHED ON
3 4 ! 4 ) / .
3 , ! 6 %
- ! 3 4 % 2
3TATION IDENTIFICATION FOR PILOT WIRE COMMUNICATION
3,!6%
DEVICE RESPONDS
-!34%2
DEVICE STARTS COMMUNICATION
$ ) & &
" , / # +
/ .
/ & &
"LOCKING OF THE DIFFERENTIAL PROTECTION DURING PILOT WIRE
FAILURE
/.
IS SWITCHED ON OR
/&&
IS SWITCHED OFF
Summary of Contents for 7SD502
Page 148: ... PPENDIX 3 6 PPENDIX ENERAL DIAGRAMS ONNECTION DIAGRAMS 4ABLES ...
Page 176: ... 3 6 ...