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Functions
2.6 Flexible Protection Functions
in the according parameters. The associated parameter BLK.by Vol.Loss is only available if the character-
istic is based on a voltage measurement.
When using the flexible function for power protection or power monitoring, it will be blocked if currents fall
below 0.03 · Ι
Nom
Operating Mode, Measured Quantity, Measurement Method
The flexible function can be tailored to assume a specific protective function for a concrete application in
parameters OPERRAT. MODE, MEAS. QUANTITY, MEAS. METHOD and PICKUP WITH. Parameter
OPERRAT. MODE can be set to specify whether the function works 3-phase, 1-phase oder no refer-
ence, i.e. without a fixed phase reference. The three-phase method evaluates all three phases in parallel. This
implies that threshold evaluation, pickup indications and trip time delay are accomplished selectively for each
phase and parallel to each other.
When operating single-phase, the function employs a phase's measured quantity, which must be stated explic-
itly.
If the characteristic relates to the frequency or if external trip commands are used, the operating principle is
without (fixed) phase reference. Additional parameters can be set to specify the used MEAS. QUANTITY and
the MEAS. METHOD. The MEAS. METHOD determines for voltage measured values whether the function uses
the RMS value of the fundamental component or the normal RMS value (true RMS) that evaluates also
harmonics. All other characteristics use always the rms value of the fundamental component. Parameter
PICKUP WITH moreover specifies whether the function picks up on exceeding the threshold (>-element) or
on falling below the threshold (<-element).
Characteristic Curve
The function's characteristic curve is always "definite time"; this means that the time delay is not affected by
the measured quantity.
Function Logic
The following figure shows the logic diagram of a three-phase function. If the function operates on one phase
or without phase reference, phase selectivity and phase-specific indications are not relevant.
72
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SIPROTEC 4, 7RW80, Manual
C53000-G1140-C233-4, Edition 07.2018
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