An evaluation method for the dynamic voltage recovery capability of the sending-end AC-DC hybrid system after a fault

Abstract

The invention relates to an assessment method of dynamic voltage recoverability of a sending end alternating-current and direct-current hybrid system after failing. The assessment method includes equating statically a practical system into an equivalent system, solving the dependency of the power angle of a system generator and an output power and the dependency of voltage and power angle, solving an acceleration area and a retardation area, and solving equivalent area stability margin (EASM) index. The higher the EASM index is, the higher the dynamic voltage recoverability of the sending end alternating-current and direct-current hybrid system after failing is. On the premise of not performing a time-domain simulation, the dynamic voltage recoverability of the sending end alternating-current and direct-current hybrid system after failing can be assessed with the assessment method, so that strength of the alternating-current and direct-current hybrid system is reflected. The EASM index can reflect affections of multiple factors on the voltage recoverability; and the multiple factors include generator inertia time constants, system short-circuit ratio, system initial working condition and the like. The problem that simulation precision has to be as precise as a generator inertial time constant in time-domain simulations is avoided.

Description

technical field [0001] The invention relates to an AC / DC hybrid power grid system, in particular to an evaluation method for the dynamic voltage recovery capability after a failure of the AC / DC hybrid system at the sending end. Background technique [0002] With the advancement of my country's western development and power energy strategy, a number of UHV and EHV DC power transmission projects concentrated in the Jinsha River and Yalong River basins in Sichuan have started construction, and the corresponding AC-DC hybrid systems at the sending end of hydropower are also gradually built. However, the completion of the AC / DC hybrid system will cause many problems in the operation of the power grid. [0003] In order to evaluate the interaction between AC and DC systems, it is often necessary to use a variety of indicators to evaluate the strength of the hybrid system. In traditional methods, the short-circuit ratio and the effective inertia time constant are often the two maj...

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Problems solved by technology

[0009] The purpose of the present invention is to provide an evaluation method for the dynamic voltage recovery capability of the sending-end AC / DC hybrid system after a fault, which solves the problem that the existing evaluation method reflects the static performance of the hybrid system and cannot perform the dynamic voltage recovery of the DC sending-end system after a fault. The problem of voltage recovery ability

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