Research On Calculation Method Of DC Bias Current Based On GIC Standard

With the increase of DC transmission project,and supply capacity,the increase of the operating current,DC transmission grounding effect on AC power grid becomes more and more large;at the same time,the DC bias control and demand management device maintenance,we need to calculate the grid bias current.However,due to the complex structure of the power grid,many factors,the earth conductivity is difficult to calculate,and the accuracy of the DC bias current calculation is not high.According to the geomagnetic induced current calculation of power unit of American Electric Power Research Institute(GIC)and the 2012 launch of the GIC-Benchmark standard,this paper presents a method of calculating the DC grounding grid causes transformer DC bias current based on GIC-Benchmark.The calculation method for the construction of DC grounding electrode of DC magnetic bias control theory.Firstly,for the GIC and the bias current HVDC compared,to illustrate the feasibility GIC-Benchmark model applied DC bias calculation.Secondly,based on the GIC standard,a model of grounded magnetic bias current was established.Considering the influence of transformer type,wiring,and high resistance,a grid DC bias current model influenced by the grounding poles of components was established.Then calculation method is studied DC bias current grid model on the basis of the proposed method of calculating the full node voltage DC bias current grid.Finally,the flow path of the grid and the direct current voltage of the grid account for the interaction of different direct current levels to Zha Lute-Qingzhou±800kV HVDC project end grid by calculating the bias current value caused by the DC transmission as an example.The results are compared with measured data show that,near the grounding grid model based on the establishment of the standard GIC could accurately calculate the DC voltage level of a large multi-grid bias current.This paper establishes a GIC-Benchmark-based ±800kV UHVDC transmission grounding DC bias magnetic network model,which solves the problem of inaccurate calculation of the bias current of the AC power grid caused by the grounding pole of the HVDC transmission,and gives the basic of the power grid.The component model and analysis of all possible influencing factors in the bias current..