Method and system for determining differential DC short-circuit ratio of active device

Abstract

The present invention relates to a method and a system for determining the differential DC short-circuit ratio of an active device, wherein the method comprises: calculating the total three-phase short-circuit current of a DC bus-bar of a generator according to a grid model for calculating the short-circuit current; calculating the short-circuit current provided by a dynamic reactive power active device, wherein the dynamic reactive power source type active device comprises a dynamic reactive power source type active device and a dynamic load type active device; accumulating the influences from the total three-phase short-circuit current of the reactive power source type device on the short-circuit current and the influences eliminating the dynamic reactive power source device from the total three-phase short-circuit current on the short-circuit current; a short circuit of the reactive power source type active device is accumulated from the total three-phase short-circuit current; transversing all DC converter buses and calculating the DC short-circuit ratio indicators. The method and the system of the invention solve the problem that the conventional DC short-circuit ratio fails to evaluate the failure of the AC voltage support capability by taking into account the differences in the dynamic characteristics of the active device, or rather, the difference between the "qualitative" reactive properties and the reactive power "magnitude".

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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