Siemens SIPROTEC 7SJ531, Инструкция по эксплуатации

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/PERATING INSTRUCTIONS 3*
6
# ' #
3ETTINGS FOR UNBALANCED LOAD PROTECTION ADDRESS BLOCK
-ODEL 3* J JJJJ JJJJ PROVIDES AN UNBAL
ANCED LOAD PROTECTION SEE 3ECTION 4HIS FUNC
TION CAN OPERATE WHEN IT HAS BEEN CONFIGURED AS %8
)34 IN ADDRESS 3ECTION
.%'!4)6%
3%15%.#% 02/4
"EGINNING OF THE BLOCK .EGATIVE SEQUENCE PROTECTION
2
.%' 3%1
/&&
/.
.
n
3WITCHING /&& OF THE NEGATIVE SEQUENCE PROTEC
TION
3WITCHING /. OF THE NEGATIVE SEQUENCE PROTECTION
4HE UNBALANCED LOAD PROTECTION MEASURES THE NEG
ATIVE SEQUENCE CURRENT AND IS OF DUAL STAGE DESIGN
4HE HIGH NEGATIVE SEQUENCE CURRENT STAGE ) IS
SHORTLY DELAYED AND THE STAGE ) IS NORMALLY AS
SIGNED WITH A LONGER DELAY TIME 4HESE STAGES CAN
BE MATCHED TO THE CAPABILITY OF UNBALANCED LOAD OF
THE PROTECTED OBJECT EG A MOTOR 4HE PRESET VALUES
ARE ADEQUATE IN MOST CASES )F VALUES ABOUT THE PER
MISSIBLE NEGATIVE SEQUENCE CURRENT ARE AVAILABLE
AS STATED BY THE MOTOR MANUFACTURER THESE SHOULD
BE CONSIDERED .OTE THAT THE STATED VALUES ARE RE
FERRED TO THE MOTOR S RATED CURRENT )F FOR EXAMPLE
THE MAXIMUM CONTINUOUSLY PERMISSIBLE NEGATIVE SE
QUENCE CURRENT OF THE MOTOR IS KNOWN IT IS CONVERTED
TO THE SETTING VALUE ) AS FOLLOWS
3ETTING VALUE )
)
MAX C
)
. MOTOR
)
. MOTOR
)
. PRIM
WITH )
MAX C
MAX CONTINUOUS NEGATIVE SE
QUENCE CURRENT OF THE MOTOR
)
. MOTOR
RATED CURRENT OF THE MOTOR
)
. PRIM
PRIMARY RATED CURRENT OF THE CURRENT
TRANSFORMERS
4HE ) STAGE CAN BE SET TO TRIP IN SHORT TIME AFTER A
TOTAL PHASE FAILURE 7HEN RUNNING ON TWO PHASES THE
MOTOR S NEGATIVE SEQUENCE CURRENT AMOUNTS TO
)
)
.
)
)
.
))
.
%XAMPLE
-OTOR )
.
!
)
MAX C
)
MAX
FOR 4
MAX
S
#URRENT TRANSFORMER ! !
3ETTING VALUE )
!
!
3ETTING VALUE )
!
!
4HE NEGATIVE SEQUENCE PROTECTION DETECTS ADDI
TIONALLY INTERRUPTIONS SHORT CIRCUITS AND SWOPPED
PHASE CONNECTIONS OF THE CURRENT TRANSFORMER CIR
CUITS 3INGLE PHASE AND TWO PHASE SHORT CIR
CUITS CAN BE DETECTED EVEN WHEN THE FAULT CURRENT IS
TOO SMALL TO BE DETECTED BY THE OVERCURRENT TIME PRO
TECTION 4HE FOLLOWING CONSIDERATIONS ARE VALID
A TWO PHASE FAULT WITH FAULT CURRENT ) PRODUCES A
NEGATIVE SEQUENCE CURRENT OF
)
)
.
)
.
))
.
A SINGLE PHASE FAULT WITH FAULT CURRENT ) PRODUCES
A NEGATIVE SEQUENCE CURRENT OF
)
)
.
)
.
))
.
ONLY FOR MODEL 3* J JJJJ JJJJ
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