Fig 1.
The framework to study the effect of the shield on the surge voltage distribution.
Fig 2.
(A) Standard switching impulse generator circuit; (B) standard switching impulse voltage waveform (250/2500 μs).
Table 1.
Impulse generator circuit specification for standard switching impulse.
Fig 3.
(A) Oscillating switching impulse generator circuit; (B) oscillating switching impulse waveform (50/1000 μs).
Table 2.
Impulse generator circuit specification for oscillating switching impulse.
Fig 4.
Front cross-sectional view of the winding for a single phase of the 33/11 kV transformer.
Table 3.
HV winding geometry specification of the 33/11 kV transformer.
Table 4.
LV winding geometry specification of the 33/11 kV transformer.
Fig 5.
(A) Transformer equivalent circuit with 96 discs of HV layers in the winding and 25 layers of LV winding; (B) schematic diagram of 96 discs of the HV winding in the subsystem; (C) schematic diagram from layer 1 to layer 25 of LV winding in the subsystem for the 33/11 kV transformer.
Table 5.
RLC parameters of the HV winding for the 33/11 kV transformer.
Fig 6.
Transformer winding model with different cases of shield placement.
Table 6.
Existing and updated RLC parameters of HV winding with shield placement for the 33/11 kV transformer.
Fig 7.
Transient voltage for unshielded winding under SSI.
Fig 8.
Transient voltage for shield placement as conductor 7 in HV winding under SSI.
Fig 9.
Transient voltage for shield placement between conductor 1 and 2 of HV winding under SSI.
Fig 10.
Transient voltage for shield placement between HV and LV windings under SSI.
Fig 11.
Transient voltage for unshielded winding under OSI.
Fig 12.
Transient voltage for shield placement as conductor 7 under OSI.
Fig 13.
Transient voltage for shield placement between conductor 1 and 2 under OSI.
Fig 14.
Transient voltage for shield placement between HV and LV windings under OSI.
Fig 15.
The effect of shield on initial voltage distribution under SSI.
Fig 16.
The effect of shield on initial voltage distribution under OSI.
Table 7.
SEb under SSI.