Abstract

This study studies the exciting current of transformer affected by DC bias in the Tibet frozen soil structure when the UHVDC system is working in monopole state. Firstly, the model of calculating the ground potential for a typical frozen soil of the Tuotuo River substation was described and then the ground potential around the UHVDC grounding electrode for five-layer soil in summer and winter was calculated. According to the soil parameters, the magnetic bias current of the transformer were calculated. Results indicate that the distance is less than about 4 km and the earth potential is variable in different season. The substation electrode design parameters are complex, so building substation is very inconvenient. And when the distance is adjusted from 4 km to 8km, the earth potential is changed from 400 to 200 V, the exciting current decreased from 45 to 5 mA, the waveform unbalance will also decrease.

Keywords:

Ground electrode, hvdc, soil structure, transformer dc bias,

References

Competing interests

The authors have no competing interests.

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Copyright

The authors have no competing interests.