Ice NP900 Series, Инструкция по применению

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Application Guide - NP900 Series 72 (504
)
A996A
value. The setting value is common for all measured phases and single-, dual- or all
phases Im exceed of the Iset value will cause pick-up operation of the function.
The fault has to be in the monitored direction as well to fulfill the terms to trip. Fault
direction can be set to forward or reverse. Tripping area is ±88° (176°) and reference
angle is based on calculated positive sequence voltage U1 angle. In case U1 voltage is
not available and only line to line voltages are measured the angle reference is based on
healthy line to line voltage and during short circuit to impedance calculation. If voltage
drops below 1V secondary the angle memory is used for 0.5 seconds. Angle memory
forces the angle reference to the value that was measured or calculated before the fault.
Angle memory captures the measured voltage angle 100 ms before the fault starts. After
0.5 seconds the angle memory is not used anymore and reference voltage is forced to 0°.
Inbuilt reset ratio for the trip area angle is 2.
Table 3.2.4.3-56 Pick-up characteristics setting
Name Description Range Step Default
Iset Pick-up setting 0.10 … 40.00 x In 0.01 x In 1.20 x In
Center Pick-up center -180.0…180.0° 0.1° 0°
Angle Pick-up area ±1.0…170.0° 0.1° ±88°
The pick-up activation of the function is not directly equal to start-signal generation of the
function. Start signal is allowed if blocking condition is not active.
Figure 3.2.4.3-37 Angle tracking of DOC function (3LN or 3LL+U0 mode).
U1
I1
I1
U1