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

A power transmission system, high-voltage direct current technology, applied in the field of electrical information, can solve problems such as harmonic instability, low accuracy, and judgment method errors

Inactive Publication Date: 2016-04-27
SICHUAN UNIV
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  • 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 methods for judging harmonic instability of single-circuit HVDC transmission systems based on switching function modulation do not include transformer core saturation parameters, which are somewhat different from theoretical support. The criterion is mainly based on the positive sequence and negative sequence impedance of the AC side and the impedance of the DC side to judge whether the system will have harmonic instability. 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 Single-circuit HVDC Transmission System

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Embodiment

[0041] Such as figure 1 As shown, at time t, there are harmonic components on the DC side, which are modulated to the AC side by the converter; figure 2 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 left side of the converter is the AC side, and the right side is the DC side. The DC side is also equipped with a series of filtering devices.

[0042] Such as figure 2 As shown, the model parameters are shown in Table 1, and the transformer parameters are shown in Table 2. The disturbance is set as a three-phase short circuit at the AC busbar, which lasts for 0.1s. The AC-DC system model with only rectifiers is selected as a power system simulation example, and simulated in the software PSCAD. The AC side voltage is set to 100kV, and the DC side voltage is set to 100kV, the converter is controlled by CIGRE constant current.

[0043] Table 1 Calculation parameter setting

[0044]

[0045] T...

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Abstract

The invention discloses a method for determining harmonic instability of a single-circuit high-voltage direct-current power transmission system. The method is characterized in that the direct-current magnetic bias effect of transformers is taken into account, a direct-current magnetic bias coefficient is introduced to the process of derivation, a negative sequence impedance parameter of the alternating-current side is omitted, and only positive sequence secondary impedance of the alternating-current side and fundamental frequency impedance of the direct-current side are adopted to determine whether the system suffers from harmonic instability. A novel method for determining whether a single-circuit high-voltage direct-current system suffers from harmonic instability is put forward.

Description

technical field [0001] The invention relates to a method for judging harmonic instability of a single-circuit 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 the switching function theory, harmonic instability The stability mechanism is used to determine whether harmonic instability occurs in a single-circuit DC line system, which 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 ...

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晏小彬张英敏付伟穆子龙王峰
Owner SICHUAN UNIV
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