Siemens 7SC80 Manual page 188

Functions
2.6 Voltage Protection 27, 59
Function Three-phase connec-
(Parameter 213
Undervoltage
Van, Vbn, Vcn
Vab, Vbc, VGnd
Vab, Vbc
The positive-sequence voltage in the table is calculated from the phase-to-ground voltage.
Measured Values Displacement Voltage Protection
Depending on the voltage connection type entered at address 213 VT Connect. 3ph, you can use meas-
ured or calculated quantities for the displacement voltage protection.
•
With the setting Van, Vbn, Vcn, you can use the calculated voltage 3V0 or the measured voltage Vx.
•
With the setting Vab, Vbc, VGnd, you can use the measured voltage VN or Vx.
•
With the setting Vab, Vbc, Vx.
Which quantity is used is set in the parameters of the displacement voltage protection (see Section
2.6.5 Setting Notes).
Current Criterion
Depending on the system, the primary voltage transformers are arranged either on the supply side or the load
side of the associated circuit breaker. These different arrangements lead to different behaviour of the voltage
protection function when a fault occurs. When a tripping command is issued and a circuit breaker is opened,
full voltage remains on the supply side while the load side voltage becomes zero. When voltage supply is
suppressed, undervoltage protection, for instance, will remain picked up. If pickup is to drop out, the current
can be used as an additional criterion for pickup of undervoltage protection (current supervision CS). Under-
voltage pickup can only be maintained when the undervoltage criterion satisfied and a settable minimum
current level (BkrClosed I MIN) are exceeded. Here, the largest of the three phase currents is used. When
the current decreases below the minimum current setting after the circuit breaker has opened, undervoltage
protection drops out.
NOTE
i
i
If parameter CURRENT SUPERV. is set to disabled in address 5120, the device picks up immediately
without measurement voltage and the undervoltage protection function in pickup. Apply measuring
voltage or block the voltage protection to continue with configuration. Moreover you have the option of
setting a flag via device operation for blocking the voltage protection. This initiates the reset of the pickup
and device configuration can be resumed.
188
tion
(Parameter 613/614
Vphph (smallest phase-to-phase voltage) Phase-to-phase voltage
Vph-n (smallest phase-to-ground
voltage)
V1 (positive sequence voltage)
Vphph selective (phase-specific
phase-tophase voltage)
Vph-n selective (phase-specific
phase-to-ground voltage)
Vphph (smallest phase-to-phase voltage) Phase-to-phase voltage
V1 (positive sequence voltage)
Vphph selective (phase-specific
phase-tophase voltage)
Selectable voltage
E50417-G1140-C486-A8, Edition 07.2017
Threshold to be set as
Phase-to-ground voltage
Positive sequence voltage ·
√3
Phase-specific phase-to-
phase pickup voltage
Phase-specific phase-to-
ground pickup voltage
Positive sequence voltage ·
√3
Phase-specific phase-to-
phase pickup voltage
SIPROTEC Compact, 7SC80, Manual