A DC system protection method and device based on least squares fitting

A least squares, DC system technology, applied in emergency protection circuit devices, electrical components, etc., can solve problems such as low stability and safety of DC systems

Active Publication Date: 2021-05-18
NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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Problems solved by technology

[0004] In view of the above analysis, the embodiment of the present invention aims to provide a DC system protection method and device based on least squares fitting, to solve the problem that the existing method adopts a fixed delay to restart the DC system, which may cause DC system stability and safety. lower sex problems

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  • A DC system protection method and device based on least squares fitting
  • A DC system protection method and device based on least squares fitting
  • A DC system protection method and device based on least squares fitting

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Embodiment Construction

[0066] Preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the application and together with the embodiments of the present invention are used to explain the principle of the present invention and are not intended to limit the scope of the present invention.

[0067] At present, there are few studies on the identification method of the fault nature of conventional HVDC transmission. The DC fault restart sequence of the DC system mainly uses a fixed delay to restart. After a fault occurs, it may experience multiple restarts, which will cause multiple impacts on the DC and AC systems. Device security poses a threat and affects system stability. For this reason, this application proposes a DC system protection method and device based on least squares fitting. The voltage sampling value is obtained by collecting the voltage on the rectification side of ...

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Abstract

The invention relates to a DC system protection method and device based on least squares fitting, which belongs to the technical field of relay protection, and solves the problem that the existing method uses a fixed delay to restart the DC system, which may cause low stability and safety of the DC system The problem. Including: collecting the voltage on the rectifier side of the faulty DC system to obtain the voltage sampling value; obtaining the voltage fitting value corresponding to the voltage sampling value according to the least square method, and obtaining the voltage fitting error corresponding to the voltage fitting value according to the voltage fitting value; Fitting error and instantaneous / permanent fault criterion to judge the fault type of the DC system; send control signals according to the fault type to control the restart or block of the DC system to realize the protection of the DC system and improve the stability and reliability of the DC system It is conducive to the stable operation of the DC system.

Description

technical field [0001] The invention relates to the technical field of relay protection, in particular to a DC system protection method and device based on least square fitting. Background technique [0002] In the traditional LCC-HVDC (conventional high-voltage direct current transmission, also known as grid-commutated high-voltage direct current transmission) system, the probability of DC line failure is very high, and the direct current system is different from the AC transmission system, and the current does not have a natural zero-crossing point when a fault occurs , the arc at the fault point is difficult to extinguish by itself, so when a fault occurs, the fault current should be cut off first. The fault current of the DC system puts forward high requirements on the breaking capacity of the circuit breaker. However, the large-capacity DC circuit breaker has not been widely used. At present, the LCC-HVDC system mainly adopts changing the trigger angle to make the line ...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/26
CPCH02H7/268
Inventor 马静肖兆杭杨更宇张家铭
Owner NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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