Address 8106 Σ I THRESHOLD determines the limit current above which the current sum monitoring is acti-
vated (absolute portion, only relative to Ι
Nom
). The relative portion (relative to the maximum conductor
current) for activating 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 (Ι
N
) of the relay (see Power System Data 1). Furthermore, the fourth current input
(Ι
N
) 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 prop-
erly.
Measured value monitoring can be set to
ON or OFF at address 8101 MEASURE. SUPERV.
Fuse Failure Monitor (FFM)
Via 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 5308. In a
grounded/isolated system, only the parameter 5308 is relevant.
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
N
is higher than the set limit value under address 5302 FUSE FAIL
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-phase 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 three-phase failure is detected. This
threshold value of the current element must be set under address 5308 FFM Idiff (3ph). 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.
NOTE
The setting under address 5310 BLOCK PROT. has no effect on the flexible protection functions. A sepa-
rate blocking can be selected for that purpose.
The function may be disabled in address 5301 FUSE FAIL MON., e.g. when performing asymmetrical tests.
Settings
Addresses which have an appended “A” can only be changed with DIGSI, under “Additional Settings”.
The table indicates region-specific default settings. Column C (configuration) indicates the corresponding
secondary nominal current of the current transformer.
Addr.
Parameter C Setting Options Default Setting Comments
5201 VT BROKEN WIRE ON
OFF
OFF VT broken wire supervision
5202 Σ V> 1.0 .. 100.0 V 8.0 V Threshold voltage sum
5203 Vph-ph max< 1.0 .. 100.0 V 16.0 V Maximum phase to phase
voltage
2.11.1.8
Functions
2.11 Monitoring Functions
164 SIPROTEC 4, 7SJ80, Manual
E50417-G1140-C343-A8, Edition 12.2017
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