Additional damping inner loop control method for multi-terminal flexible direct current system and additional damping controller

An additional damping, DC system technology, applied in the direction of reducing/preventing power oscillations, can solve problems such as not being able to meet the requirements of suppressing SSO, and achieve the effect of subsynchronous oscillation

Pending Publication Date: 2020-06-09
ELECTRIC POWER SCI & RES INST OF STATE GRID TIANJIN ELECTRIC POWER CO +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The above two methods applied to the additional damping controller in the voltage source converter can be effectively applied to the two-terminal AC-DC hybrid system, but they cannot meet the requirements of suppressing SSO when the operation mode of the multi-terminal system is switched.

Method used

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  • Additional damping inner loop control method for multi-terminal flexible direct current system and additional damping controller
  • Additional damping inner loop control method for multi-terminal flexible direct current system and additional damping controller
  • Additional damping inner loop control method for multi-terminal flexible direct current system and additional damping controller

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Effect test

Embodiment 1

[0064] An additional damping inner loop control method for multi-terminal flexible DC systems, as shown in Figure 1 to image 3 shown, including the following steps:

[0065] Step 1. Obtain the modal deviation signal in the system from the AC bus voltage of the converter station through a phase-locked link;

[0066] When a fault or abnormal operation occurs in the AC-DC system, the oscillation or fluctuation of the sub-synchronous frequency will be excited in the AC system, and the fluctuation is reflected on the AC bus connected to the converter station as the AC component containing the sub-synchronous frequency in the AC voltage . As shown in Figure 1(a) and Figure 1(b), the signal of the sub-synchronous frequency component in the AC bus voltage is filtered out first through the deviation signal extraction link.

[0067] The concrete steps of described step 1 include:

[0068] (1) First, phase-lock the AC voltage signal to extract the phase deviation caused by system osc...

Embodiment 2

[0110] The present invention designs additional damping controller based on the same inventive concept, as Figure 4 As shown, it includes: a modal deviation signal extraction device, a filtering device, a phase compensation device and an additional signal superposition device;

[0111] The modal deviation signal extraction device is used to obtain the frequency deviation signal in the system through the phase-locked link from the AC bus voltage of the converter station (the signal contains various frequency information and phase information at the same time);

[0112] The filtering device is used to extract sub-synchronous frequency signals from each frequency signal;

[0113] The phase compensation device is used to perform phase compensation on a signal of a specific frequency through multiple lead-lag links, and has achieved the best sub-synchronization suppression effect;

[0114] The additional signal superposition device is used to superimpose the signal after the phas...

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Abstract

The invention relates to an additional damping inner loop control method for a multi-terminal flexible direct current system and an additional damping controller. The method comprises the steps of 1,obtaining modal deviation signals in the system from an alternating current bus voltage of a converter station through a phase locking link; 2, filtering the modal deviation signals which are extracted in the step 1 and contain frequency information and phase information at the same time, and extracting sub-synchronous frequency signals from the frequency signals; 3, based on the sub-synchronous frequency signals in the frequency signals extracted in the step 2, carrying out phase compensation on the magnitude of phase change generated when each sub-synchronous modal component passes through the alternating current and direct current system; and 4, superposing the signals after the phase compensation link in the step 3 to a control system of the converter. The method can be applied to themulti-terminal flexible direct current system and a traditional double-terminal flexible direct current system at the same time.

Description

technical field [0001] The invention belongs to the technical field of power system stability control, and relates to an additional damping inner loop control method and a controller for a flexible DC system, in particular to an additional damping inner loop control method and a controller for a multi-terminal flexible DC system. Background technique [0002] At present, sub-synchronous oscillation (SSO) of power system is a very serious grid stability problem, which may cause damage to the main shaft of the generator. In recent years, with the rapid development of flexible DC transmission and distribution technology, the grid environment has become increasingly complex, and the risk of SSO in the system has increased. [0003] After searching, the following two documents were found: [0004] The document "VSC_HVDC Multi-channel Additional Damping Controller Suppresses Subsynchronous Oscillation (Power Automation Equipment, Volume 31, Issue 9, 2011)" discloses a design idea...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/24
CPCH02J3/24
Inventor 李树鹏刘云刘亚丽霍现旭李国栋胡晓辉吕金炳于光耀王峥陈培育
Owner ELECTRIC POWER SCI & RES INST OF STATE GRID TIANJIN ELECTRIC POWER CO
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