A Damping Control Method for Improving the Stability of DC Ports in Flexible DC Power Grids

A damping control and stability technology, applied in the direction of power transmission AC network, circuit devices, electrical components, etc., to ensure safe and stable operation, good damping effect, and improve the effect of frequency impedance characteristics

Active Publication Date: 2020-09-29
STATE GRID ECONOMIC TECH RES INST CO +2
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

With this change, the traditional virtual damping control strategy will have certain limitations

Method used

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  • A Damping Control Method for Improving the Stability of DC Ports in Flexible DC Power Grids
  • A Damping Control Method for Improving the Stability of DC Ports in Flexible DC Power Grids
  • A Damping Control Method for Improving the Stability of DC Ports in Flexible DC Power Grids

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Embodiment Construction

[0034] The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

[0035] A damping control method for improving the stability of a DC port of a flexible DC power grid provided by the present invention includes the following steps:

[0036] Step 1: Collect the actual value v of the three-phase AC voltage at the grid-connected point of the fixed power station in the flexible DC grid abc , The actual value of the three-phase AC current i abc and the actual value of the DC side voltage u dc , and carry out per unitization;

[0037] figure 1 The structure diagram of a typical four-terminal ring flexible DC grid system is shown; the system includes four MMC converter stations, and the DC side is connected into a ring network structure. ...

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Abstract

The invention discloses a damping control method for improving the stability of a direct-current port of a flexible direct-current power grid. The control method only needs to add direct-current voltage based pre-stage control to current control of a constant-power station of the flexible direct-current power grid, and only needs a damping coefficient link and a band-pass filtering link; and the damping link is equivalent to the process of connecting a virtual resistor to the direct-current side of the constant-power station in parallel, and has the effect of improving the frequency impedancecharacteristic. When the direct-current port in the flexible direct-current power grid is disturbed to generate low-frequency oscillation, the control method transmits the change of a direct-current voltage to the control of an alternating current, and the alternating current can correspondingly cause the active power change when being changed to damp the low-frequency oscillation of the direct-current port, so that stable operation of the converter station can be kept, a relatively good damping effect is provided for the low-frequency oscillation of the direct-current port, and safe and stable operation of the flexible direct-current power grid is guaranteed.

Description

technical field [0001] The invention belongs to the field of safe operation of flexible DC transmission, and in particular relates to a damping control method for improving the stability of a DC port of a flexible DC power grid, which is used to improve the static stability of the flexible DC power grid and avoid current oscillations at the DC port of the flexible DC power grid. Background technique [0002] In recent years, with the gradual establishment of large-capacity flexible DC power grid projects, its potential stability problems have become increasingly prominent. The flexible DC power grid is a complex system coupled with multiple controllers, and there are many DC ports. Any unstable DC port may cause instability or even collapse of the entire system. Among them, the DC side impedance of the constant power station presents a negative impedance characteristic in the low frequency band, which may easily cause low frequency oscillations at the DC port. Excessive res...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/36H02J3/24H02J3/38
CPCH02J3/24H02J3/36H02J3/382H02J2003/365Y02E60/60
Inventor 梅念乐波王跃王璋尹太元徐鹏帆
Owner STATE GRID ECONOMIC TECH RES INST CO
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