-AINTENANCE AND FAULT TRACING
3*
6
# ' #
-AINTENANCE AND FAULT TRACING
3IEMENS DIGITAL PROTECTION RELAYS ARE DESIGNED TO RE
QUIRE NO SPECIAL MAINTENANCE !LL MEASUREMENT AND
SIGNAL PROCESSING CIRCUITS ARE FULLY SOLID STATE AND
THEREFORE COMPLETELY MAINTENANCE FREE )NPUT MOD
ULES ARE EVEN STATIC RELAYS ARE HERMETICALLY SEALED OR
PROVIDED WITH PROTECTIVE COVERS
4HE DISPLAY MUST NOT BE TOUCHED NOR TREATED WITH
SHARP ARTICLES )T MUST NOT BE CLEANED WITH AGGRES
SIVE DETERGENTS NOR WITH ALCOHOL
)F THE DEVICE IS EQUIPPED WITH A BACK UP BATTERY FOR
SAVING OF STORED ANNUNCIATIONS AND THE INTERNAL TIME
CLOCK THE BATTERY SHOULD BE REPLACED AFTER YEARS
OF OPERATION AT THE LATEST WHEN THE OPERATIONAL AN
NUNCIATION
&AIL"ATTERY
HAS APPEARED REFER TO
3ECTION 4HIS RECOMMENDATION IS VALID INDEPEN
DENT ON WHETHER THE BATTERY HAS BEEN DISCHARGED BY
OCCASIONAL SUPPLY VOLTAGE FAILURES OR NOT
!S THE PROTECTION IS ALMOST COMPLETELY SELF MONI
TORED FROM THE MEASURING INPUTS TO THE COMMAND
OUTPUT RELAYS HARDWARE AND SOFTWARE FAULTS ARE AU
TOMATICALLY ANNUNCIATED 4HIS ENSURES THE HIGH AVAIL
ABILITY OF THE RELAY AND ALLOWS A MORE CORRECTIVE RATH
ER THAN PREVENTIVE MAINTENANCE STRATEGY 4ESTS AT
SHORT INTERVALS BECOME THEREFORE SUPERFLUOUS
7ITH DETECTED HARDWARE FAULTS THE RELAY BLOCKS ITSELF
DROP OFF OF THE AVAILABILITY RELAY SIGNALS EQUIPMENT
FAULT )F THERE IS A FAULT DETECTED IN THE EXTERNAL MEA
SURING CIRCUITS GENERALLY AN ALARM IS GIVEN ONLY
2ECOGNIZED SOFTWARE FAULTS CAUSE THE PROCESSOR TO
RESET AND RESTART )F SUCH A FAULT IS NOT ELIMINATED BY
RESTARTING FURTHER RESTARTS ARE INITIATED )F THE FAULT IS
STILL PRESENT AFTER THREE RESTART ATTEMPTS THE PROTEC
TIVE SYSTEM WILL SWITCH ITSELF OUT OF SERVICE AND INDI
CATE THIS CONDITION BY THE RED ,%$ "LOCKED ON THE
FRONT PLATE $ROP OFF OF THE AVAILABILITY RELAY SIGNALS
EQUIPMENT FAULT
4HE REACTION TO DEFECTS AND INDICATIONS GIVEN BY THE
RELAY CAN BE INDIVIDUALLY AND IN CHRONOLOGICAL SE
QUENCE READ OFF AS OPERATIONAL ANNUNCIATIONS UNDER
THE ADDRESS FOR DEFECT DIAGNOSIS REFER TO 3EC
TION
)F THE RELAY IS CONNECTED TO A LOCAL SUBSTATION AUTO
MATION SYSTEM ,3! DEFECT INDICATIONS WILL ALSO BE
TRANSFERRED VIA THE SERIAL INTERFACE TO THE CENTRAL CON
TROL SYSTEM
%NSURE THAT THE CONNECTION MODULES ARE NOT
DAMAGED WHEN REMOVING OR INSERTING THE
DEVICE MODULES (AZARDOUS VOLTAGES MAY
OCCUR WHEN THE HEAVY CURRENT PLUGS ARE
DAMAGED
7ARNING
2OUTINE CHECKS
2OUTINE CHECKS OF CHARACTERISTICS OR PICK UP VALUES
ARE NOT NECESSARY AS THEY FORM PART OF THE CONTINU
OUSLY SUPERVISED FIRMWARE PROGRAMS 4HE PLANNED
MAINTENANCE INTERVALS FOR CHECKING AND MAINTE
NANCE OF THE PLANT CAN BE USED TO PERFORM OPERATION
AL TESTING OF THE PROTECTION EQUIPMENT 4HIS MAINTE
NANCE SERVES MAINLY FOR CHECKING THE INTERFACES OF
THE UNIT IE THE COUPLING WITH THE PLANT 4HE FOLLOW
ING PROCEDURE IS RECOMMENDED
2EAD OUT OF OPERATIONAL VALUES
-%.5
/0
%2!4)/. -%.5
OPTION /0%2!4)/.!,
-%!352%$ 6!,5%3 AND COMPARISON WITH THE
ACTUAL VALUES FOR CHECKING THE ANALOG INTERFACES
3IMULATION OF AN INTERNAL SHORT CIRCUIT WITH X )
.
FOR CHECKING THE ANALOG INPUT AT HIGH CURRENTS
(AZARDOUS VOLTAGES MAY BE PRESENT ON
ALL CIRCUITS AND COMPONENTS CONNECTED
WITH THE SUPPLY VOLTAGE OR WITH THE MEAS
URING AND TEST QUANTITIES
7ARNING
4EST CURRENTS LARGER THAN TIMES )
.
MAY
OVERLOAD AND DAMAGE THE RELAY IF APPLIED
CONTINUOUSLY REFER TO 3ECTION FOR
OVERLOAD CAPABILITY /BSERVE A COOLING
DOWN PERIOD
#AUTION
#IRCUIT BREAKER TRIP CIRCUITS ARE TESTED BY ACTUAL
LIVE TRIPPING 2ESPECTIVE NOTES ARE GIVEN IN 3EC
TION
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