5. Protections
5.1 Protections
5.1.1 General
The protections are all of the definite time type, that is a set point and time is selected.
If, for example, the function is over-voltage, the timer will be activated if the set point is exceeded. If the volt-
age value falls below the set point value before the timer runs out, the timer will be stopped and reset.
When the timer runs out, the output is activated. The total delay will be the delay setting + the reaction time.
When parameterising the DEIF controller, the measuring class of the controller and an ade-
quate "safety" margin must be taken into consideration.
An example:
A power generation system must not reconnect to a network when the voltage is 85 % of Un
+/-0 % <U <110 % +/-0 %. In order to ensure reconnection within this interval, a control unit’s
tolerance/accuracy (Class 1 of the measuring range) has to be taken into consideration. It is
recommended to set a control unit’s setting range 1 to 2 % higher/lower than the actual set
point, if the tolerance of the interval is +/-0 %, to ensure that the power system does not re-
connect outside the interval.
Phase-neutral voltage trip
If the voltage alarms are to work based on phase-neutral measurements, you must adjust menus 1200 and
1340 accordingly. Depending on the selections, either phase-phase voltages or phase-neutral voltages will be
used for the alarm monitoring.
GPC-3 DRH 4189340587 UK Protections
DEIF A/S Page 94 of 122
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