Siemens 7SJ82 - Application and Setting Notes

Logic
[locbsymm-100611-01.tif, 2, en_US]
Figure 9-26
Logic Diagram of the Current-Balance Supervision
The Threshold min/max parameter is the criterion by which unbalance in the phase currents is measured.
The device calculates the ratio between the minimum (I
min
) and the maximum (I
max
) phase current.
Enter the lower limit of the maximum phase current (I
max
) with the parameter Release threshold. This
specifies the lower limit of the operating range of this function.
Operate delay
If it falls below the balance factor Threshold min/max and at the same time the maximum phase current
exceeds the Release threshold, the tripping delay begins. If both conditions persist during this time, the
indication Failure is generated.
Blocking the Function
The following blockings reset the picked up function completely:
•
Externally or internally via the binary input signal >Block function
•
A protection pickup
The pickup signal of a protection function blocks the indication Failure .
Application and Setting Notes
Parameter: Threshold min/max
•
Recommended setting value (_:102) Threshold min/max = 0.5
The Threshold min/max parameter is used to set the ratio between the minimum (I
min
) and the maximum
(I
max
) phase current.
9.3.10.4
Supervision Functions
9.3 Supervision of the Secondary System
1274 SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017