Method for determining stability of small interference of direct-current power grid

A technology of DC power grid and determination method, applied in AC network circuits, power transmission AC networks, circuit devices, etc., can solve the problems of unclear interaction mechanism and lack of basic theory.

Active Publication Date: 2017-05-24
GLOBAL ENERGY INTERCONNECTION RES INST CO LTD +2
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AI Technical Summary

Problems solved by technology

But so far, the basic theory related to the DC grid is lacking, the interaction mechanism between the AC grid and the DC grid is not clear, and the voltage variation law inside the DC grid and the coupling e

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  • Method for determining stability of small interference of direct-current power grid
  • Method for determining stability of small interference of direct-current power grid
  • Method for determining stability of small interference of direct-current power grid

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Embodiment Construction

[0131] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

[0132] Such as figure 1 As shown, the present invention provides a method for judging the stability of small disturbances in DC power grids. The DC power grid is provided with a flexible DC converter station; the flexible DC converter station is provided with modular multilevel converters; Voltage or current signals within ±10% of the voltage or current value;

[0133] The method includes the following steps:

[0134] Step 1. The main circuit of the modula...

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Abstract

The invention provides a method for determining stability of small interference of a direct-current power grid. A main circuit of a modular multi-level converter is equivalent to a simplified equivalent model; a converter electromagnetic transient model and a converter controller system are established and then are processed by linearization to obtain an active power small interference basic mathematical model; a small interference linearization Thevenin equivalent model of a converter and a small interference linearization generalized mathematical model of a direct-current power grid are established; and a small interference stability determination basis of the direct-current power grid is obtained. According to the determination method, the architecture is clear and simple; the method is easy to understand; the internal commutation process of the converter is simplified; a mathematic model can be established and analyzed conveniently. A small interference linearization model of a converter can be popularized and restriction of the original equivalent model is broken through, so that the method is suitable for all work conditions; and the direct current oscillation can be suppressed and a stability analysis can be realized conveniently. And a reliable and accurate basis for studying the mutual influence of alternating-current and direct-current power grids is provided, so that the operation reliability of the alternating-current and direct-current power grids can be improved.

Description

technical field [0001] The invention relates to the technical field of flexible direct current transmission, in particular to a method for judging the small disturbance stability of a direct current power grid. Background technique [0002] Flexible DC transmission technology is a new type of power transmission technology after AC transmission and conventional DC transmission technology. Its emergence has brought power transmission technology to a new level. Since active power and reactive power can be independently controlled and power flow reversal is easy to achieve, it has major technical advantages in new energy generation grid connection and consumption, transnational power trading, asynchronous grid interconnection, and offshore island power supply. [0003] The AC grid has voltage, frequency, and power angle stability problems, but the DC grid does not have the problem of power angle stability and frequency stability compared with the AC grid. The stability of the DC...

Claims

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Application Information

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IPC IPC(8): H02J3/36
CPCH02J3/36H02J2203/20Y02E60/60
Inventor 安婷贺之渊庞辉李云丰孔明韩丛达
Owner GLOBAL ENERGY INTERCONNECTION RES INST CO LTD
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