LCC-HVDC commutation failure immunity evaluation method and system in consideration of transmission power limit

Abstract

The invention discloses an LCC-HVDC commutation failure immunity evaluation method in consideration of a transmission power limit, and belongs to the technical field of line commutated converter HVDCtransmission. The method comprises the steps of: firstly establishing a power-voltage correlation equation at a conversion busbar based on a single feed-in LCC-HVDC quasi-steady state model; transforming the correlation equation to obtain the reactive power disturbance at the conversion busbar, namely a busbar voltage change rate; then obtaining the voltage sensitivity factor of the conversion busbar; further analyzing the power transmission limit of the DC transmission system by using the maximum transmittable power condition of the DC system to obtain a power limit short-circuit ratio (PLSCR); and introducing the PLSCR into the expression of a commutation failure immune index, and providing a rapid evaluation method of an inverter station commutation failure immunity based on a correction result. The present invention also provides an LCC-HVDC commutation failure immunity evaluation system in consideration of the transmission power limit. The method achieves accurate evaluation results and high calculation efficiency.

Description

technical field [0001] The invention belongs to the technical field of high-voltage direct current transmission of grid commutation converters, and more specifically relates to a method and system for evaluating immunity to commutation failure of LCC-HVDC considering transmission power limit. Background technique [0002] In my country, the distribution of various energy resources and the distribution of main electricity loads present a serious asymmetry. High Voltage Direct Current (HVDC) technology has the advantages of low cost of long-distance transmission, large capacity, and strong controllability, so it has become an effective means to solve the problem of large-scale long-distance power transmission in my country. West-to-East Power Transmission" and "North-to-South Power Transmission" projects have been widely used and developed rapidly, and have become important technical means to promote the development of my country's energy strategy. However, since the tradition...

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Problems solved by technology

Although such indicators can qualitatively reflect the strength of the AC system to a certain extent, they often lack rigorous and detailed theoretical derivation. The selection of critical values ​​is often based on simulation results, and cannot be reflected in the different operations of rectifier stations and inverter stations in the DC system. In the working mode, the influence of AC and DC system interaction on the strength of AC system

Furthermore, after obtaining the evaluation index of AC system strength, some studies did not further analyze the impact of this index on the immunity of DC system commutation failure

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