/PERATING INSTRUCTIONS
3*
6
# ' #
$IRECTION CHECK WITH LOAD CURRENT
#ORRECT CONNECTIONS OF CURRENT AND VOLTAGE TRANS
FORMERS ARE CHECKED USING LOAD CURRENT OVER THE PRO
TECTED LINE 4HE LINE MUST BE ENERGIZED AND MUST
CARRY A LOAD CURRENT OF AT LEAST OF THE RATED CUR
RENT THIS SHALL BE OHMIC OR OHMIC INDUCTIVE 4HE DI
RECTION OF THE LOAD CURRENT MUST BE KNOWN )N CASES
OF DOUBT INTERCONNECTED OR RING NETWORKS MUST BE
ISOLATED
$IRECTION ANNUNCIATIONS SHOULD BE GENERATED BY THE
DIRECTIONAL OVERCURRENT TIME PROTECTION 4O ACHIEVE
THIS THE PICK UP VALUES OF THE DIRECTIONAL OVERCUR
RENT TIME PROTECTION EG ADDRESSES AND
MUST BE REDUCED SO THAT THIS PROTECTION CAN PICK UP
ON LOAD CURRENT AND DETERMINE THE DIRECTION 4HE DI
RECTION
IS
OUTPUT
BY
THE
ANNUNCIATIONS
<))P,
FW
FOR FORWARD LOAD OR
<))P, RW
FOR REVERSE LOAD
REPRESENTS
ANY CONCERNED PHASE .OTE THAT THE FORWARD DIREC
TION IS DEFINED AS THE DIRECTION TO THE PROTECTED OB
JECT WHICH MUST NOT NECESSARILY BE EQUAL TO THE LOAD
DIRECTION DURING NORMAL OPERATION
4HE CORRECT DIRECTION ANNUNCIATIONS CORRESPONDING
TO THE LOAD FLOW MUST APPEAR FOR ALL THREE PHASES )F ALL
DIRECTIONS ARE WRONG THE POLARITY OF THE MEASURING
TRANSFORMERS AND THE PROGRAMMED POLARITY ADDRESS
3ECTION DO NOT AGREE WITH EACH OTHER
#HECK THE POLARITY AND PROGRAM CORRECTLY )F THE DI
RECTIONS GIVEN IN THE DISPLAY DIFFER FROM EACH OTHER
THE INDIVIDUAL PHASES IN THE CURRENT OR VOLTAGE TRANS
FORMER CONNECTIONS ARE INTERCHANGED OR THE PHASE
RELATIONSHIP IS NOT CORRECT #HECK THE CONNECTIONS
)F THE LOAD IS CAPACITIVE CAUSED FOR EXAMPLE BY UN
DEREXCITED GENERATORS OR CHARGING CURRENTS BORDER
LINE CASES CAN OCCUR WITH RESPECT TO THE DIRECTIONAL
CHARACTERISTICS WHICH WILL LEAD TO UNDEFINED OR INCON
SISTENT DIRECTIONAL INFORMATION "Y MEANS OF THE LOAD
POWER DISPLAY IN ADDRESS BLOCK THE POSITION OF THE
LOAD POWER VECTOR CAN BE DETERMINED SEE &IGURE
!TTENTION
)F SETTING VALUES HAVE BEEN CHANGED FOR
THESE TESTS MAKE SURE THAT THE ORIGINAL SETTINGS ARE
RESTORED
!CTIVE POWER IN
LINE DIRECTION
0OSITIVE REACTIVE POWER
$IRECTION
3
,OAD
.EGATIVE REACTIVE POWER
0 POSITIVE
CHARACTERISTIC
1
0
REVERSE DIRECTION
FORWARD DIRECTION
0 NEGATIVE
&IGURE ,OAD POWER VECTOR
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