Application Guide - NP900 Series
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Figure 3.1.2.1-14 Voltage may be based on line to line voltage or line to neutral voltage.
This selection is completed in “Measured magnitude” –menu under each voltage
protection stage separately. Availability of protection functions depends on IED type.
After the settings are input to the IED scaling factors are also calculated and displayed for
the user. Scaling factor P/S tells the VT primary to secondary ratio. Per unit scaling factors
to primary and secondary values are also shown.
Triggering of voltage protection stage can be based on single, dual or all three fault loops.
Fault loops are either line to line or line to neutral according the “Measured magnitude”
setting.
Figure 3.1.2.1-15 Activation of one fault loop will trip the voltage protection stage as a
default.
There are several different ways to use all four voltage channels. Most common voltage
measurement mode is the three from line to neutral voltages and measured zero
sequence voltage 3LN+U0. For further information see different voltage measurement
mode examples below:
Содержание NP900 Series
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Страница 49: ...Application Guide NP900 Series 49 504 A996A Figure 3 2 1 3 25 Definite time operating characteristics...
Страница 50: ...Application Guide NP900 Series 50 504 A996A Figure 3 2 1 3 26 IEC predefined characteristics NI VI LTI and EI...
Страница 52: ...Application Guide NP900 Series 52 504 A996A Figure 3 2 1 3 28 IEEE predefined characteristics EI MI and VI...
Страница 243: ...Application Guide NP900 Series 243 504 A996A Figure 3 3 2 1 122 NPS biased thermal trip curves with kNPS values 7 and 10...
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