Quantitative evaluation indices of DC pole-to-pole short-circuit current in MMC-HVDC power grid
With the expansion of the scale of the modular multilevel converter(MMC)based high voltage DC pow-er grid,the short-circuit current presents the characteristics of fast rising rate and large peak value at the initial stage of the DC short-circuit fault.These new features severely limit the development of HVDC power grid.In order to quantitatively evaluate the short-circuit current at the DC side of MMC-HVDC power grid,a quantitative evalua-tion index of short-circuit current at the initial fault stage of MMC-HVDC power grid is established from the perspec-tive of the inherent characteristics of the system to guide the planning and operation of DC power grid.Firstly,a short-circuit current calculation method based on MMCs'input-output characteristics is proposed.This provides theoretical support for the quantitative assessment of short-circuit current.Secondly,the pole-to-pole short-circuit current of DC power grid is decoupled,and the quantitative evaluation indices of the initial stage short-circuit cur-rent are established from the perspective of system inherent characteristics.Finally,the proposed decoupling short-circuit current calculation method and quantitative indices are verified in DC power grid with different parameters and structures.The verification results show that the proposed index can effectively evaluate the short-circuit cur-rent of MMC-HVDC power grid without calculating the short-circuit current,and can guide the planning of DC pow-er grid,the formulation of operation mode and the selection of system parameters.
VSC-HVDC power gridmodular multilevel converterDC short-circuit currentquantitative indices
NETL
NSTL
万方数据
维普
