Asco 230 Series - Appendix 3 Power Properties

Appendix 3 Power Properties 27
ASCO Series 230 Automatic Transfer Switch C2000 Intelligent Controller User Manual
Appendix 3 Power Properties
Judgment for power voltage effectiveness
The percentage format of standard voltage is adopted for overvoltage and under-voltage point definitions.
The recovery point can be used to define overvoltage and under-voltage recovery normal control points.
Measurement for power imbalance
Balanced network Unbalanced network
Here is the formula to calculate three-phase imbalance:
ε
L
L
631
631
−+
−−
=
In which,
L =
( )
VVV
VVV
ca
bc
ab
cabcab
222
2
444
++
++
Judgment for power frequency effectiveness
T
%
100
Source available
0.5Hz
0
Over frequency threshold
Over frequency hysteresys
threshold
Under frequency threshold
Under frequency hysteresys
threshold
a
c
b
Uca
Uab Ubc
N
b
a
c
Uca
Uab Ubc
N
a’
b’
c’
N’