doble M4110 - Calculating Leakage Reactance Results

M4110 Leakage Reactance Interface User Guide
72A-2243-01 Rev. B 9/04 2-5
September 17, 2004
How Results are Calculated
Three-phase Equivalent Test
The resulting leakage reactance in % is calculated as follows:
%X = [(1/60)ΣΧ
M
][S
3ϕ
(in kVA)/V
2
L-L
(in kV)]
where
ΣΧ
M
– sum of the individual reactances of each phase, measured in
ohms
S
3ϕ
base three-phase power of the winding where the measurements
are performed, obtained from the transformer nameplate
V
2
L-L
– base line-to-line voltage of the winding where the
measurements are performed, obtained from the nameplate
Per-phase Test
The resulting leakage reactance in % is calculated as follows:
• For test performed from a delta-connected winding
%X = [(1/30)][S
3ϕ
(in kVA)/ V
2
L-L
(in kV)]
• For test performed from a wye-connected winding
%X = [(1/10) Χ
M
][S
3ϕ
(in kVA)/ V
2
L-L
(in kV)]
where:
Χ
M
– measured reactance in ohms
S
3ϕ
– base three-phase power of the winding where the measurements
are performed, obtained from the transformer nameplate
V
L-L
– base line-to-line voltage of the winding where the
measurements are performed, obtained from the transformer
nameplate.
• For the test performed from the zig/zag-connected winding, the results
are analyzed in ohms without conversion into %
Single-phase Two-winding Test
The resulting leakage reactance in % is calculated as follows:
%X = [(1/10) Χ
M
][S(in kVA)/V
2
(in kV)]
where Χ
M
is the measured reactance ohms, and S and V are the base
power and voltage of the winding where the measurements are performed,
obtained from the transformer nameplate.