ABB REG650 Technical Manual page 91

1MRK 502 043-UUS B
Technical Manual
I_A_W1 is the fundamental frequency phase current in phaseA on W1 side
I_B_W1 is the fundamental frequency phase current in phaseB on W1 side
I_C_W1 is the fundamental frequency phase current in phaseC on W1 side
I_A_W2 is the fundamental frequency phase current in phaseA on W2 side
I_B_W2 is the fundamental frequency phase current in phase B on W2 side
I_C_W2 is the fundamental frequency phase current in phase C on W2 side
I_A_W3 is the fundamental frequency phase current in phase A on W3 side
I_B_W3 is the fundamental frequency phase current in phaseB on W3 side
I_C_W3 is the fundamental frequency phase current in phaseC on W3 side
Vn_W1 is transformer rated phase-to-phase voltage on W1 side (setting parameter)
Vn_W2 is transformer rated phase-to-phase voltage on W2 side (setting parameter)
Vn_W3 is transformer rated phase-to-phase voltage on W3 side (setting parameter)
A, B and C are three by three matrices with numerical coefficients
Values of the matrix A, B and C coefficients depend on:
1. Power transformer winding connection type, such as wye (Y/y) or delta (D/d)
• Note! The capitalized letter Y or D is used to represent the high voltage
(HV) side of the transformer and the smaller letter y or d to represent lower
voltage(LV) level. When neutral bushing of a wye winding is brought out,
the same may be represented as YN or yn depending on whether the winding
is HV or LV.
2. Transformer phase shift such as Yd1, Dy11, YNautod5, Yy0d5 and so on, which
introduce phase displacement between individual windings currents in multiples of
30°. Since the HV and LV winding voltages are in phase for wye/wye or Delta/
Delta transformers, the same is represented in IEC as represented as Dd0, Yy0.
Polarity reversal in one of the windings would give 180 degree phase displacement
which can be represented by clock position 6. Such transformers can thus be
represented as Dd6, Yy6. It is also possible to rename the phases ABC to CAB or
BCA, giving 120 or 240 degree displacements, represented by clock positions 4 &
8 . Polarity reversals in one of the windings would provide clock positions 10 & 2.
These can all be represented for example: Yy0, Yy2, Yy4, Dd0, Dd6. ANSI wye/
Delta or Delta/wye transformers have the HV winding leading the LV winding by
30degrees. This can be represented by Yd1 or Dy1. Again considering polarity
reversals and renaming of phases gives rise to other clock positions 4,7,5,11
3. Settings for elimination of zero sequence currents for individual windings.
When the end user enters all these parameters, transformer differential function
automatically determines the matrix coefficients based on the following rules:
Section 6
Differential protection
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