Siemens 7SJ85 - Structure of the Function

The following protection functions are automatically blocked in the case of a measuring-voltage failure:
•
Distance protection
•
Directional negative-sequence protection
•
Ground-fault protection for high-resistance faults in grounded-neutral systems
Structure of the Function
The function is part of protection function groups which are connected with a 3-phase voltage and current
measurement point.
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Figure 9-4 Structure/Embedding of the Function
The function is broken down into 3 subfunctions (see Figure 9-5):
•
Supervision for unbalanced measuring-voltage failure
•
Supervision for 3-phase measuring-voltage failure
•
Supervision for switching onto a 3-phase measuring-voltage failure
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Figure 9-5
Breakdown of the Measuring-Voltage Failure Detection Function
Each subfunction creates its own monitoring indication. The function summarizes these indications via the
group indication Alarm.
The response to the detection of a measuring-voltage failure is explained in the specific protection-function
descriptions.
9.3.2.2
Supervision Functions
9.3 Supervision of the Secondary System
SIPROTEC 5, Overcurrent Protection, Manual 1245
C53000-G5040-C017-8, Edition 07.2017