Rapid positioning method for non-power frequency current causing voltage distortion of converter bus

Abstract

The invention discloses a rapid positioning method for the non-power frequency current causing voltage distortion of a converter bus. The method mainly comprises steps that (1), the system topology and device parameter information is obtained; (2), a system broadband admittance matrix model is established, and a system broadband impedance matrix model is solved; (3), the frequency scanning methodis utilized to calculate to obtain broadband mutual impedance of a non-power frequency current injection node and a converter station bus node; (4), the broadband mutual impedance information of the non-power frequency current injection node and the converter station bus node is screened and stored; and (5), influence of non-power frequency current injection on the bus voltage of the converter station is evaluated. The method is advantaged in that the method combines advantages of the broadband admittance matrix model and the frequency scanning method, has advantages of clear principle and easy programming, can quickly obtain the non-power frequency current injection position having great influence on the bus voltage of the converter station, and provides reference and guidance for furthersystem simulation and research.

Description

technical field [0001] The invention belongs to the field of power system safety and stability analysis and evaluation, and in particular relates to a method for quickly locating a non-power frequency current injection position that has a great influence on the bus voltage of a converter station. Background technique [0002] In recent years, large-capacity, long-distance EHV / UHV DC transmission has been widely promoted and applied in my country's power grid. The four circuits of UHV DC transmission (Ningdong-Zhejiang, Ximeng-Taizhou, Jinbei-Nanjing, Shanghai Temple-Shandong) in the national air pollution prevention and control action plan "Four Interchanges and Four Directions" projects have been completed and put into operation, and the transmission capacity is even higher. The large ±1100kV Zhundong-Wannan UHV DC transmission project has also started construction. By the end of 2018, the East China Power Grid will have 7 UHV DC drop points and 3 EHV DC drop points, becom...

AI Technical Summary

Problems solved by technology

During the operation of my country's power grid, DC commutation failures or even blockages caused by harmonics also occur from time to time: after the Qinghai-Tibet DC interconnection project was put into operation, the excitation inrush current of the 750kV main transformer in the Northwest Power Grid in 2011 twice caused 100Hz in the Qaidam converter station. Harmonic protection action, resulting in blocking; in 2013, the Liantang UHV main transformer charging excitation inrush current in the East China Power Grid caused continuous commutation failures in the adjacent Fengjing converter station, and eventually caused the DC control and protection system to block the DC

[0004] Large-scale receiving-end power grids such as the East China Power Grid in my country have multiple EHV / UHV DC transmission points, the DC receiving power is large and the electrical distance between each DC point is close, and the injection of non-power frequency harmonic currents such as excitation inrush current in the grid may cause Cause commutation failure in DC transmission, which endangers the safe and stable operation of the large power grid

[0005] Non-power frequency harmonic current injection leads to distortion of AC bus voltage waveform in DC transmission converter station, which is the direct cause of DC commutation failure

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