Arcteq AQ F3 0 Series, Инструкция по эксплуатации

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Instruction manual – AQ F3x0 Feeder protection IED 50 (162
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decision is “Forward” if the voltage and the current is sufficient for directional
decision, and the angle difference between the vectors is inside the set operating
characteristics. If the angle difference between the vectors is outside of the set
characteristics th
e directional decision is “Backward”.
Figure 3-28: Directional decision characteristics.
The voltage must be above 5% of the rated voltage and the current must also be measurable.
If the voltages are below 5% of the rated voltage then the algorithm substitutes the small values
with the voltage values stored in the memory. The input signals are the RMS values of the
fundamental Fourier components of the three-phase currents and three phase voltages and
the three line-to-line voltages.
The internal output status signal for enabling the directional decision is true if both the three-
phase voltages and the three-phase currents are above the setting limits. The RMS voltage
and current values of the fundamental Fourier components of the selected loop are forwarded
to angle calculation for further processing.
If the phase angle between the three-phase voltage and three-phase current is within the set
range (defined by the preset parameter) or non-directional operation is selected by the preset
parameter the function will operate
according to the selected “Forward”, “Backward” or non
directional setting.