Application Guide - NP900 Series
444 (504
)
A996A
Minimum voltage window size can be calculated as follows:
U >/<
window
= 1.2 × tap step effect
%
This gives 20% more of total band for regulating and with this setting is made sure that the
voltage is inside the voltage window after tap change operation. Regulating sensitivity can
be increased by setting smaller window but it is not advised.
To set the window to the AVR the calculated
U >/<
window
is divided by two and set to the
U> setting (+UTGT) and U< setting (-UTGT) parameters. If both of the window settings
are set equally AVR has same sensitivity for over and undervoltage situations. Voltage
windows as well as all other setting parameters are in relation of the set target voltage
UTGT. If target voltage is changed this given window will follow new target voltage with
same parameters.
Figure 3.6.7.1-210 Set window is too tight in comparison to the tap effect. Voltage
regulator cannot reach the target window and constantly rises and lowers the voltage.
Eventually stabile voltage may be found but next tap change request will cause similar
fluctuation.
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...
Страница 491: ...Application Guide NP900 Series 491 504 A996A 3 7 5 6 SETTING EXAMPLE...
Страница 504: ...Application Guide NP900 Series 504 504 A996A A996A...