Direct current system protection method and device based on least square fitting

A least squares method and DC system technology, applied in emergency protection circuit devices, electrical components, etc., can solve the problems of low stability and safety of DC systems, achieve improved stability and safety, less complexity, and simple calculations Effect

Active Publication Date: 2020-11-03
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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  • Direct current system protection method and device based on least square fitting
  • Direct current system protection method and device based on least square fitting
  • Direct current system protection method and device based on least square 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 direct-current system protection method and device based on least square fitting, belongs to the technical field of relay protection, and solves the problems of low stability and safety of a direct-current system possibly caused by adopting a fixed delay to restart the direct-current system in methods in the prior art. The method comprises the steps of: collecting voltage of a fault direct-current system rectification side to obtain a voltage sampling value; acquiring a voltage fitting value corresponding to the voltage sampling value according to a least square method, and acquiring a voltage fitting error corresponding to the voltage fitting value according to the voltage fitting value; determining the fault type of the direct current system based on the voltage fitting error and the instantaneous / permanent fault criterion; sending a control signal according to the fault type to control the restart or locking of the direct current system, so that the directcurrent system is protected. By means of the method and device, the stability and reliability of the direct current system are improved, and the stable operation of the direct current system is facilitated.

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 Applications(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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