A Judgment Method for Harmonic Instability of Double-circuit Parallel HVDC Transmission System

A technology of high-voltage direct current transmission and judgment method, applied in the field of electrical information, can solve the problems of harmonic instability, incomplete integration of theoretical support, and low accuracy.

Inactive Publication Date: 2016-01-27
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Harmonic instability is also known as core saturation and harmonic instability. However, the existing method for judging harmonic instability of double-circuit parallel HVDC transmission systems does not include transformer core saturation parameters, which is not fully integrated with theoretical support, and does not consider dual Due to the difference in DC network topology parameters, the judgment method has certain errors, and the accuracy is not very high

Method used

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  • A Judgment Method for Harmonic Instability of Double-circuit Parallel HVDC Transmission System

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Embodiment

[0048] Such as figure 1 As shown, at time t, there is a harmonic component on the DC line 1 side, which is modulated to the AC side by the converter. At time t+Δt, the harmonics are modulated from the AC side to the DC line 1 and DC line 2 sides. The process is A process of harmonic transmission;

[0049] Such as figure 2 As shown, at the time t+2Δt, the harmonics of the DC line 1 side and the DC line 2 side are modulated to the AC side, and the AC side harmonics are the sum of the harmonic modulations of the DC line 1 side and the DC line 2 side to the AC side, at t At +3Δt, the harmonics are transmitted from the AC side to the DC line 1 side and the DC line 2 side, thus serving as the secondary process of harmonic transmission;

[0050] Such as image 3 As shown, the AC side system of the model is connected to the DC system by a converter through a series of filtering devices. The DC system is two parallel DC transmission lines with double circuits, and the two DCs are als...

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Abstract

The invention discloses a method for judging harmonic instability of a double-circuit parallel high-voltage direct-current power transmission system. The method is characterized in that the method is combined with a direct-current bias magnetic effect of a transformer, a direct-current bias magnetic coefficient is introduced to a derivation process, negative sequence impedance parameters of an alternating-current side are omitted, the size and the phase difference of double-circuit direct-current line impedance are considered, whether harmonic instability can happen to the system is judged only through positive sequence secondary impedance of the alternating-current side and fundamental frequency impedance of a direct-current side, and the new method for judging whether harmonic instability can happen to the double-circuit parallel high-voltage direct-current power transmission system is put forward.

Description

technical field [0001] The invention relates to a method for judging harmonic instability of a double-circuit parallel high-voltage direct current transmission system. Specifically, the invention uses the positive-sequence secondary impedance of the AC side and the fundamental frequency impedance of the DC side, and combines switching function theory, harmonic Instability mechanism to determine whether harmonic instability will occur in double-circuit parallel HVDC transmission system belongs to the field of electrical information. Background technique [0002] my country's geographical span is large, the distribution of primary energy is uneven, and energy is mainly concentrated in the western region, while energy consumption is concentrated in the eastern region, so a large-scale power grid is required for power transmission. The transmission distance of traditional AC transmission is difficult to exceed 500-600km, and one of the successful applications of high-voltage dir...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/36G01R31/08
CPCY02E60/60
Inventor 刘天琪丁媛媛李兴源马静陈实王峰李保宏凡航
Owner SICHUAN UNIV
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