Function Three-phase connec-
tione Side 2 (Param-
eter 219)
Selectable Voltage (Param-
eter 616/617)
Threshold to be set as
Undervoltage protec-
tion 27 of side 2
V2an,V2bn,V2cn
Vphph (smallest phase-to-
phase voltage)
Phase-to-phase voltage
Vph-n (smallest phase-to-
ground voltage)
Phase-to-ground voltage
V1 (positive sequence
voltage)
Positive sequence voltage · √3
Vphph selective (phase-
specific phase-to-phase
voltage)
Phase-specific phase-to-phase pickup
voltage
Vph-n selective (phase-
specific phase-to-ground
voltage)
Phase-specific phase-to-ground pickup
voltage
V2a2b,V2b2c,VGn
V2a2b, V2b2c
Vphph (smallest phase-to-
phase voltage)
Phase-to-phase voltage
V1 (positive sequence
voltage)
Positive sequence voltage · √3
Vphph selective (phase-
specific phase-to-phase
voltage)
Phase-specific phase-to-phase pickup
voltage
The positive-sequence voltage in the table is calculated from the phase-to-ground voltage.
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
If parameter CURRENT SUPERV. is set to disabled in address 5710, 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.
Overvoltage Protection 59 of Side 2
Function
The Overvoltage protection 59 of side 2 function has 2 elements. In case of a high overvoltage, tripping
switch off is performed with a short-time delay, whereas in case of less severe overvoltages, the tripping is
performed with a longer time delay. When one of the adjustable settings is exceeded, the Overvoltage
protection 59 of side 2 function element picks up and trips after an adjustable time delay has elapsed. The
time delay is not dependent on the magnitude of the overvoltage.
The dropout ratio for the two overvoltage of side 2 elements (= V
dropout value
/V
pickup value
) can be set.
2.30.2.3
Functions
2.30 Additional Applications with 6 Voltage Inputs
428 SIPROTEC Compact, 7SC80, Manual
E50417-G1140-C486-A8, Edition 07.2017
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