GU Cheng-yu1, SI Wen-rong1, ZHENG Xu1, et al. DC Bias Suppression for Shanghai Region Using Parallel Connection of DC Grounding Electrodes[J]. High voltageapparatus, 2012, 48(4): 65-74.
GU Cheng-yu1, SI Wen-rong1, ZHENG Xu1, et al. DC Bias Suppression for Shanghai Region Using Parallel Connection of DC Grounding Electrodes[J]. High voltageapparatus, 2012, 48(4): 65-74. DOI: 10.13296/j.1001-1609.hva.2012.04.012.
DC Bias Suppression for Shanghai Region Using Parallel Connection of DC Grounding Electrodes
The mechanism of DC bias and the DC bias suppression equipments at transformer neutral point are described.Considering the feature of many DC grounding electrodes in Shanghai region
a method for suppressing DC bias using parallel connection of DC grounding electrodes is proposed.The DC grounding electrodes in Fengxian
Huaxin and Nanqiao 500 kV substations are modeled
and equivalent resistances for each substation are obtained according to the primal construction data.And a four-layer horizontal soil model is established including superficial sedimentary deposit
deep sedimentary deposit
bedrock deposit and earth mantle deposit by considering the geologic frame and the measured resistivity of different soil layer in Shanghai region.The earth potential and DC bias current of transformers in Shanghai region are calculated and analyzed in the cases of independent operation and parallel-connection operation of the DC grounding electrodes with the topological structure of the existing Shanghai power grid.The results show that the earth potential and DC bias current of each 500 kV-level substations can be efficiently suppressed.