Siemens 7SC80 Manual page 435

The minimum hysteresis is 0.6 V.
NOTE
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If a setting is selected such that the dropout threshold (= pickup threshold · dropout ratio) results in a
greater value than 120 V/210 V, it will be limited automatically. No error message occurs.
Phase-Specific Pickup Voltages of the Undervoltage Protection 27 of Side 2 Function
The phase-specific pickup voltages of the two undervoltage protection of side 2 elements are set at the
following addresses:
27-1Ph2A Pickup
27-1Ph2B Pickup
27-1Ph2C Pickup
27-2Ph2A Pickup
27-2Ph2B Pickup
27-2Ph2C Pickup
The selectable voltage range depends on the type of connection phase-to-phase voltage or phase-to-ground
voltage (parameter 219).
Phase-Specific Time Delays of the Undervoltage Protection 27 of Side 2
The phase-specific times for tripping delay of the two undervoltage protection of side 2 elements are set at the
following addresses:
27-1 Ph2A Delay
27-1 Ph2B Delay
27-1 Ph2C Delay
27-2 Ph2A Delay
27-2 Ph2B Delay
27-2 Ph2C Delay
Current Criterion for Undervoltage Protection 27 of Side 2
The 27-1 S2 element and the 27-2 S2 element can be supervised by the current flow monitoring setting. If the
CURRENT SUPERV. is switched ON at address 5710 (the factory setting isOFF), the release condition of the
current criterion must be fulfilled in addition to the corresponding undervoltage condition, which means that
a configured minimum current (BkrClosed I MIN, address 212) must be present to make sure that this
protective function can pick up. Thus it can be achieved that pickup of the undervoltage protection drops out
when the line is disconnected from voltage supply. Furthermore, this feature prevents an immediate general
pickup of the device when the device is powered-up without measurement voltage being present.
NOTE
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The Undervoltage protection 27 of side 2 function is activated usually when the recloser is open and no
current flows. In such case, the parameter CURRENT SUPERV. should be set to Disabled.
NOTE
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If parameter CURRENT SUPERV.is set to disabled at address 5710, the device picks up immediately if the
measuring-circuit voltage fails and the undervoltage protection is enabled. Furthermore, configuration can
be performed by pickup of measuring-circuit voltage or blocking of the voltage protection. The latter can be
initiated via device operation in DIGSI and via communication from the control center by means of a
tagging command for blocking the voltage protection. This causes the dropout of the pickup and parame-
terization can be resumed.
SIPROTEC Compact, 7SC80, Manual
E50417-G1140-C486-A8, Edition 07.2017
Address 5712 or 5713
Address 5714 or 5715
Address 5716 or 5717
Address 5718 or 5719
Address 5720 or 5721
Address 5722 or 5723
Address 5724
Address 5725
Address 5726
Address 5727
Address 5728
Adresse 5729
2.30 Additional Applications with 6 Voltage Inputs
Functions
435