Calculation method of short-circuit current and voltage considering the interaction of different ports in DC system

摘要

The characteristics of the pole-to-pole fault in the tree-structured DC system are complicated, and the transient analytic expressions of high-order current and voltage can make the calculation difficulty increase significantly. In response to this phenomenon, on the one hand, when the parameters are the same, the impact of the changes of the number about the terminals on the waveform is considered. On the other hand, when the number of terminals is fixed, the influence of the change of the parameter on the waveform is studied. Taking the interaction between different ports into account, correct the short-circuit current and voltage expression of single-ended DC system and the calculation method of short-circuit current and voltage expression for multi-ended DC system is proposed. This method can reduce the computational complexity of transient expression for multi-ended DC system. The calculation results are verified by MATLAB/Simulink simulation tool. The calculated transient expressions of voltage and current are in good agreement with the results of simulation, which provide the theoretical basis for the fault location and calculation of setting value.