A method and system for determining DC short-circuit ratio taking into account differences in active equipment

Abstract

The present invention relates to a method and system for determining the DC short-circuit ratio in consideration of differences in active equipment, and calculates the total three-phase short-circuit current of the generator DC commutation bus according to the grid model used for calculating the short-circuit current; calculates the dynamic reactive active equipment The short-circuit current provided, the reactive active equipment includes dynamic reactive power supply active equipment and dynamic reactive load active equipment; and the short-circuit of the reactive power active equipment is accumulated from the total three-phase short circuit current The influence of current, and the influence of short-circuit current of dynamic reactive load active equipment is eliminated from the total three-phase short-circuit current; all DC commutation buses are traversed to calculate the DC short-circuit ratio index. The invention solves the problem of failure of traditional DC short-circuit ratio evaluation of AC power grid voltage support capability by taking into account the difference in dynamic characteristics of active equipment, that is, the difference in "quality" of reactive power attributes and the "quantity" of reactive power.

Description

technical field [0001] The invention relates to the field of power systems, in particular to a method and system for determining DC short-circuit ratios taking into account differences in active equipment. Background technique [0002] The DC short-circuit ratio is a quantitative index defined based on the static electrical parameters of the grid such as the short-circuit current to evaluate the dynamic voltage support capability of the AC grid fed by DC. On this basis, domestic scholars have researched and proposed new improvement indicators that take into account DC external characteristic short-circuit ratio, reactive effective short-circuit ratio and generalized short-circuit ratio. At the beginning of the index definition, except for conventional generators, the short-circuit current provided by other active equipment in the power grid is negligible, so the active equipment has a single type and the same characteristics. The greater the short-circuit current supplied b...

AI Technical Summary

Problems solved by technology

Under the condition of diversified development of active equipment, the difference in dynamic reactive power characteristics of different equipment will significantly affect the effectiveness of short-circuit ratio evaluation of dynamic voltage support capability

[0003] As a result, the traditional short-circuit ratio evaluation failure problem is caused, that is, contrary to the existing evaluation logic, the problem that the larger the short-circuit ratio is, the weaker the voltage support capability is.

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