A method, system and device for suppressing flexible DC high-frequency resonance

A flexible DC and high-frequency resonance technology, applied to AC networks to reduce harmonics/ripples, harmonic reduction devices, AC network circuits, etc., can solve problems such as deteriorating the dynamic characteristics of power systems, and reduce the risk of resonance. Effects of improving safety and suppressing harmonics

Active Publication Date: 2022-04-29
ELECTRIC POWER RESEARCH INSTITUTE, CHINA SOUTHERN POWER GRID CO LTD +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] The present invention provides a flexible DC high-frequency resonance suppression method, system and equipment, which are used to solve the problem of deteriorating the dynamic characteristics of the power system when filters are used to suppress the high-frequency resonance of flexible DC transmission lines in the prior art technical problem

Method used

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  • A method, system and device for suppressing flexible DC high-frequency resonance
  • A method, system and device for suppressing flexible DC high-frequency resonance
  • A method, system and device for suppressing flexible DC high-frequency resonance

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Embodiment 1

[0056] like figure 1 As shown, this embodiment provides a flexible DC high-frequency resonance suppression method, which is suitable for pre-installing a virtual grid adaptive filter in the feedforward link of the flexible DC current inner loop controller. The method includes the following steps:

[0057] S1: Real-time detection of the dq-axis components of the actual AC voltage of the flexible direct current transmission line through the sensor, and calculation of the effective value of the actual AC voltage according to the dq-axis components of the actual AC voltage, where the calculation formula for the effective value of the actual AC voltage is:

[0058]

[0059] Among them, V sd , V sq are the voltage of the d-axis component and the voltage of the q-axis component in the dq-axis components, respectively.

[0060] S2: Compare the effective value of the actual AC voltage with the preset voltage threshold, the voltage threshold ranges from 0.7pu to 0.9pu; if the effec...

Embodiment 2

[0064] like figure 1 As shown, a flexible DC high-frequency resonance suppression method provided in this embodiment is suitable for pre-installing a virtual grid adaptive filter in the feedforward link of a flexible DC transmission line. The method includes the following steps:

[0065] S1: Real-time collection of the actual AC voltage of the flexible DC transmission line,

[0066] Transform the actual AC voltage in the dq coordinate system to obtain the positive-sequence dq-axis component and the negative-sequence dq-axis component of the actual AC voltage, where the dq-axis component includes the d-axis component and the q-axis component, according to the actual AC voltage positive sequence dq The axis component and the negative sequence dq axis component calculate the effective value of the actual AC voltage. The formula for calculating the effective value of the actual AC voltage is:

[0067]

[0068] Among them, V sd , V sq are the voltage of the d-axis component a...

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Abstract

The invention discloses a flexible DC high-frequency resonance suppression method, system and equipment, including: under normal working conditions, the input volume and output volume of the adaptive filter of the virtual power grid are completely isolated physically, and the harmonics of the actual electrical volume will not Reflected on the virtual electrical quantity, it has the effect of suppressing harmonics. When the effective value of the actual AC voltage input is reduced from the normal value to meet the preset conditions, the virtual electrical quantity is completely equal to the actual electrical quantity, realizing complete real-time tracking of the actual electrical quantity, and improving the dynamic characteristics of the power system at the moment of failure; After a period of full tracking, if the effective value of the actual AC voltage is less than the preset threshold, it will enter adaptive tracking until the actual electrical quantity returns to a stable value. The invention can reduce the risk of high-frequency resonance of the flexible DC, avoid deterioration of the dynamic characteristics of the flexible DC under fault conditions, avoid damage to devices or equipment caused by overstress, and improve the safety of the flexible DC fault ride-through.

Description

technical field [0001] The invention relates to the field of electric power, in particular to a method, system and equipment for suppressing flexible DC high-frequency resonance. Background technique [0002] Flexible DC transmission is the trend of future power system development. There are several key technical problems that need to be solved in the application of flexible DC transmission, one of which is to suppress the high-frequency resonance between the flexible DC and AC systems. The resonance caused by the negative impedance of the flexible DC converter amplifying the system harmonics is mainly caused by the impedance mismatch between the flexible DC converter and the AC system. This resonance is mainly related to control link delay and feedforward strategy. For this resonance, the main solution in the current flexible DC project is to reasonably configure the filter strategy in the feedforward link of the inner loop controller of the flexible DC station. Studies ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/36H02J3/01
CPCH02J3/36H02J3/01H02J2003/365Y02E40/40Y02E60/60H02J3/00125H02J3/24H02J3/241H02J3/06
Inventor 饶宏李桂源黄伟煌李岩许树楷
Owner ELECTRIC POWER RESEARCH INSTITUTE, CHINA SOUTHERN POWER GRID CO LTD
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