Calculation of ground potential and magnetic bias current of power grid near the grounding electrode of Chen’an Village

Abstract

In view of the high operating current of ±800 kV UHVDC， the influence of earth current at the grounding electrode on the magnetic bias of transformers and the treatment has become a research topic. Given the construction of the ±800kV Baihetan-Zhebei DC transmission project， historical magnetotelluric detection data was used to establish a three-dimensional grounding resistivity model near the grounding electrode of Chen’an Village in northern Zhejiang province. The calculation of station ground potential of power grid near the grounding electrode was completed according to the working condition of 5， 000 A grounding current， and the ground potential calculation results of 124 power plants and substations in the north Zhejiang power grid were obtained. Moreover， a power grid bias current model was established， the bias current was calculated， and a bias treatment plan was proposed. The research results show that compared with the influence of the Jinsi earth pole of the ±800 kV Xiluodu-West Zhejiang DC project， the influence of the current of the grounding electrode in Chen’an Village is less because the transmission lines of North Zhejiang power grid are relatively denser and the lines are short.

Keywords

• uhvdc
• grounding electrode
• transformer magnetic bias
• magnetic bias treatment