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Commutation failure prediction method based on direct current finite time domain prediction

A technology of direct current and commutation failure, applied in the direction of power transmission AC network, etc., can solve the problems of large difference in arc extinguishing angle and poor predictive control effect, and achieve the effect of high prediction accuracy, good prediction effect and easy realization

Active Publication Date: 2019-11-08
STATE GRID XINJIANG ELECTRIC POWER CO ECONOMIC TECH RES INST +1
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Problems solved by technology

Many studies have pointed out that the calculated arc extinguishing angle and the actual arc extinguishing angle during the fault transient state are quite different, resulting in poor predictive control effect

Method used

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  • Commutation failure prediction method based on direct current finite time domain prediction
  • Commutation failure prediction method based on direct current finite time domain prediction
  • Commutation failure prediction method based on direct current finite time domain prediction

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Embodiment 1

[0031] A commutation failure prediction method based on DC current finite time domain prediction, comprising the following steps:

[0032] Step 1: Detection of voltage difference: After the system runs stably, detect the DC voltage difference ΔU and its derivative dΔU / dt on both sides of the DC line rectification and inverter in real time, and turn to step 2 when the change is greater than the preset threshold, otherwise turn to step 1;

[0033] Step 2: Calculate the critical value of DC current variation:

[0034]

[0035] In the formula: N is the number of 6-pulse converters in the actual project; k is the conversion ratio of the converter transformer; γ min Take 7.2° for the limit turn-off angle; X c is the commutation reactance of the inverter, α is the firing angle of the inverter; I d (α) is the instantaneous value of the DC current, ΔU is the rectification of the DC line and the voltage difference on both sides of the inverter, and E is the effective value of the A...

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Abstract

The invention discloses a commutation failure prediction method based on direct current finite time domain prediction. According to the method, after a system operates stably, a direct-current voltagedifference [delta] U and a derivative d [delta] U / dt thereof on two sides of rectification and inversion of a direct-current line are detected in real time; when the change is larger than a preset threshold value, a direct-current variable quantity critical value is calculated, and meanwhile, an iterative function is constructed to calculate a direct-current prediction value xk through a Steffensen iterative algorithm. And when the direct current prediction value xk is greater than the critical direct current variation quantity [delta] Id *, a commutation failure prediction signal is sent out. The prediction method can achieve the successful prediction of the first commutation failure, does not need to additionally increase equipment or change a topological structure of a converter, and is easier to achieve.

Description

technical field [0001] The invention relates to a method for predicting commutation failure of a high-voltage direct current transmission system, in particular to a method for predicting commutation failure based on direct current finite time-domain prediction, and belongs to the technical field of power system operation and control. Background technique [0002] Due to its advantages of long distance, large capacity, low loss, quick and flexible power regulation, etc., HVDC transmission is widely used in AC asynchronous networking and long-distance large-capacity power transmission all over the world. my country's energy and load centers present a reverse distribution trend, so HVDC transmission has an extremely broad application background in my country. [0003] Commutation failure is one of the most common faults in HVDC transmission systems, which will cause instantaneous interruption of system transmission power. At the same time, if it is not properly controlled, it w...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/36
CPCH02J3/36Y02E60/60
Inventor 赵志强李凤婷宋新甫张增强尹纯亚李海峰张高航余中平关洪浩陈伟伟边家瑜任娟
Owner STATE GRID XINJIANG ELECTRIC POWER CO ECONOMIC TECH RES INST
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