Application Guide - NP900 Series
324 (504
)
A996A
Figure 1.1.1.5-156 Natural differential current sources.
Differential current sources in normal operation:
-
Primary side CT measurement accuracy (CTE pri)
-
Secondary side CT measurement accuracy (CTE sec)
-
Relay measurement accuracy (primary and secondary) (REm)
-
Tap changer on load side (TCE)
-
Possible auxiliary transformer or auxiliary winding, which currents are not measured
separately (AUTE)
-
Transformer core magnetizing current (TME)
-
Safety margin (SME)
Now how to get the base sensitivity setting limit
I
d>Pick
-
up
, errors have to be calculated
part by part.
CTEpri: In this example case primary side CT:s are class 10P which means 10% of
measurement error.
CTEsec: In this example case secondary side CT:s are class 5P which means 5% of
measurement error.
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...