Setting Notes - Siemens SIPROTEC 7SJ62 Manual

2.11.1.8 Setting Notes

Measured Value Monitoring
The sensitivity of measured value monitor can be modified. Default values which are sufficient in most cases
are preset. If especially high operating asymmetries in the currents and/or voltages are to be expected during
operation, or if it becomes apparent during operation that certain monitoring functions activate sporadically,
then the setting should be less sensitive.
Address 8102 BALANCE V-LIMIT determines the limit voltage (phase-to-phase), above which the voltage
symmetry monitor is effective. Address 8103 BAL. FACTOR V is the associated symmetry factor; that is, the
slope of the symmetry characteristic curve.
Address 8104 BALANCE I LIMIT determines the limit current, above which the current symmetry monitor is
effective. Address 8105 BAL. FACTOR I is the associated symmetry factor; that is, the slope of the symmetry
characteristic curve.
Address 8106 Σ I THRESHOLD determines the limit current above which the current sum monitor is activated
(absolute portion, only relative to I
tivating the current sum monitor is set at address 8107 Σ I FACTOR.
Note
Current sum monitoring can operate properly only when the residual current of the protected line is fed to the
fourth current input (I
may not be sensitive.
Note
The connections of the ground paths and their adaption factors were set when configuring the general Power
System Data. These settings must be correct for the measured values monitoring to function properly.
Measured value monitoring can be set to ON or OFF at address 8101 MEASURE. SUPERV.
Fuse Failure Monitor (FFM)
Via the address 5301 FUSE FAIL MON. you select under which system conditions the FFM works. Depending
on that, make the required settings in the grounded system via the parameters 5302, 5303 and 5307. In a
grounded/isolated system, the parameter 5307 is important.
The settings for the fuse failure monitor must be selected in such manner that reliable activation occurs if a
phase voltage fails, but that false activation does not occur during ground faults in a grounded network. Address
5303 FUSE FAIL RESID must be set as sensitive as required (with ground faults, below the smallest fault
current).
The FFM picks up if the ground voltage V
3Vo and if the ground current IN lies below the set limit value under address 5303 FUSE FAIL RESID.
In order to detect a three-pole failure, the progress in time of current and voltage is monitored. If the voltage
sinks below the threshold value without a change in the current value, a 3-pole failure is detected. This thresh-
old value of the current element must be set under address 5307 I> BLOCK. The threshold value should be
identical with the definite time overcurrent protection.
Under address 5310 BLOCK PROT. it can be determined whether the protection functions should be blocked
upon pickup by the FFM.
SIPROTEC, 7SJ62/64, Manual
C53000-G1140-C207-2, Release date 01.2008
). The relative portion (relative to the maximum conductor current) for ac-
Nom
) of the relay (see Power System Data 1). Furthermore, the fourth current input (I
N
is higher than the set limit value under address 5302 FUSE FAIL
N
Functions
2.11 Monitoring Functions
)
N
209