-ETHOD OF OPERATION
6%
6
# ' #
UNIT !PART FROM THE GALVANIC AND LOW CAPACITIVE
ISOLATION PROVIDED BY THE INPUT TRANSFORMERS FILTERS
ARE PROVIDED FOR THE SUPPRESSION OF INTERFERENCE 4HE
FILTERS HAVE BEEN OPTIMIZED WITH REGARD TO BANDWIDTH
AND PROCESSING SPEED TO SUIT THE MEASURED VALUE
PROCESSING 4HE MATCHED ANALOG VALUES ARE THEN
PASSED TO THE ANALOG INPUT ON THE PROCESSOR PCB
4HE ANALOG INPUT SECTION CONTAINS INPUT AMPLIFIERS
SAMPLE AND HOLD ELEMENTS FOR EACH INPUT ANALOG
TO DIGITAL CONVERTERS AND MEMORY CIRCUITS FOR THE
DATA TRANSFER TO THE MICROPROCESSOR
&OR EACH MEASURED VOLTAGE OF THE TWO SOURCES DE
FINED AS 5 AND 5 THREE MEASURED VALUE INPUTS
ARE AVAILABLE 4WO MEASURED VALUE INPUTS OF EACH SET
WILL BE CONNECTED TO THE PHASE TO PHASE VOLT
AGES WHICH ARE TO BE PARALLELED WITH RESPECTIVELY RE
VERSED POLARITY )N CONJUNCTION WITH THE THE TWO DIFFER
ENT AND LOGICALLY INDEPENDENT MEASURING METHODS
AND THE TWO INDEPENDENTLY CONTROLLED CLOSING RELAYS
DUAL CHANNEL PROCESSING IS ACHIEVED 4HE RESPEC
TIVE THIRD MEASURED VALUE INPUT CAN BE USED TO CON
NECT ANOTHER PHASE TO PHASE VOLTAGE SO THAT THE
UNIT IS EVEN ABLE TO CHECK THE PHASE SEQUENCE
!PART FROM CONTROL AND SUPERVISION OF THE MEASURED
VALUES THE MICROPROCESSOR PROCESSES THE ACTUAL
PARALLELING FUNCTIONS 4HESE INCLUDE IN PARTICULAR
FILTERING AND FORMATION OF THE MEASURED QUANTITIES
CALCULATION OF THE VOLTAGES AND THE VOLTAGE MAGNI
TUDE DIFFERENCE
CALCULATION OF THE FREQUENCIES AND THE FREQUENCY
DIFFERENCE
CALCULATION OF THE PHASE ANGLE DIFFERENCE
SCANNING OF LIMIT VALUES AND TIME SEQUENCES FOR
SYNCHRONOUS SWITCHING
PREDETERMINATION OF THE IDEAL CLOSING INSTANT FOR
ASYNCHRONOUS SWITCHING
OUTPUT OF CONTROL COMMANDS TO THE VOLTAGE AND
SPEED REGULATOR FOR AUTOMATIC SYNCHRONIZATION IN
6%
OUTPUT OF THE CLOSING COMMAND TAKING INTO AC
COUNT THE BREAKER OPERATING TIME
STORAGE AND ISSUE OF MESSAGES
"INARY INPUTS AND OUTPUTS TO AND FROM THE PROCESSOR
ARE CHANNELLED VIA THE INPUTOUTPUT ELEMENTS &ROM
THESE THE PROCESSOR RECEIVES INFORMATION FROM THE
SWITCHGEAR EG START TO SYNCHRONIZE OR FROM OTH
ER EQUIPMENT /UTPUTS INCLUDE IN PARTICULAR THE
COMMAND TO THE CIRCUIT BREAKER THE CONTROL COM
MANDS FOR VOLTAGE AND SPEED WITH 6% AND SIG
NALS FOR REMOTE SIGNALLING OF IMPORTANT EVENTS AND
CONDITIONS AS WELL AS VISUAL INDICATORS ,%$S AND AN
ALPHANUMERICAL DISPLAY ON THE FRONT PLATE
4WO COMMAND RELAYS ARE PROVIDED FOR THE CLOSING
COMMAND 4HESE ARE DUAL CHANNEL CONTROLLED BY
EACH OF THE RESULTS OF THE TWO MEASUREMENT METH
ODS 4HE CONTACTS ARE CONNECTED IN SERIES SO THAT A
CLOSING COMMAND CAN ONLY BE GIVEN WHEN BOTH RE
LAYS HAVE PICKED UP
!N INTEGRATED MEMBRANE KEYBOARD IN CONNECTION
WITH THE BUILT IN ALPHANUMERICAL ,#$ DISPLAY EN
ABLES COMMUNICATION WITH THE UNIT !LL OPERATIONAL
DATA SUCH AS SETTING VALUES PLANT DATA ETC ARE EN
TERED INTO THE DEVICE FROM THIS PANEL REFER TO 3ECTION
5SING THIS PANEL THE PARAMETERS CAN BE RE
CALLED AND THE RELEVANT ANNUNCIATIONS AND MES
SAGES CAN BE READ OUT REFER TO 3ECTION 4HE DIA
LOG WITH THE RELAY CAN BE CARRIED OUT ALTERNATIVELY VIA
THE SERIAL INTERFACE IN THE FRONT PLATE BY MEANS OF A
PERSONAL COMPUTER
! POWER SUPPLY UNIT PROVIDES THE AUXILIARY SUPPLY ON
THE VARIOUS VOLTAGE LEVELS TO THE DESCRIBED FUNCTIONAL
UNITS 6 IS USED FOR THE RELAY OUTPUTS 4HE ANALOG
INPUT REQUIRES q 6 WHEREAS THE PROCESSOR AND ITS
IMMEDIATE PERIPHERALS ARE SUPPLIED WITH 6 4RAN
SIENT FAILURES IN THE SUPPLY VOLTAGE UP TO MS
WHICH MAY OCCUR DURING SHORT CIRCUITS IN THE DC
SUPPLY SYSTEM OF THE PLANT ARE BRIDGED BY A DC VOLT
AGE STORAGE ELEMENT RATED AUXILIARY VOLTAGE
6DC
