Overvoltage Protection 59 - Siemens SIPROTEC 4 Manual

Connection, threephase
(parameter213)
Vab, Vbc, VGnd
Vab, Vbc
Vab, Vbc, VSyn
Vab, Vbc, Vx
Vph-g, VSyn
The positive and negative sequence voltages stated in the table are calculated from the phase-to-ground
voltages.
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.

Overvoltage Protection 59

2.6.2
Function
The overvoltage protection has two 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 59 element picks up and trips after an adjust-
able time delay has elapsed. The time delay is not dependent on the magnitude of the overvoltage.
The dropout ratio for the two overvoltage elements (= V
The following figure shows the logic diagram of the overvoltage protection function.
SIPROTEC 4, 7SJ80, Manual
E50417-G1140-C343-A8, Edition 12.2017
Selectable voltage
parameter 614/ 615
Vphph (smallest phase-to-phase voltage)
V1 ((positive sequence voltage)
None (direct evaluation of the voltage connected to
voltage input 1)
Threshold to be set as
Phase-to-phase voltage
Positive sequence voltage· √3
Direct voltage value
/V ) can be set.
dropout value pickup value
Functions
2.6 Voltage Protection 27, 59
123