4–80
889 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
SYSTEM
CHAPTER 4: SETPOINTS
The phase compensation angle
φ
comp
is the angle by which a winding current is shifted
with reference to the angle of the reference winding, and is calculated by the 889 for each
winding as follows
φ
comp
[w] = |
φ
[w
f
] –
φ
[w] | where Rotation = “ABC”
φ
comp
[w] = |
φ
[w] –
φ
[w
f
] | where Rotation = “ACB”
The following figure: Phase and Zero Sequence Compensation for Typical Values of
φ
comp
,
shows the phase shift compensation equations of transformer winding currents, based on
typical phase compensation angles
φ
comp
, and whether or not the zero sequence current
is removed:
where:
I
A
[w] = uncompensated winding ‘w’ phase A current
I
A
p
[w] = phase and zero sequence compensated winding ‘w’ phase A current
