A protection method for multi-terminal flexible UHV DC transmission system

An ultra-high voltage DC and power transmission system technology, applied in emergency protection circuit devices, electrical components, power transmission AC networks, etc., can solve the problem of not being able to put into backup protection, etc., and achieve the effect of reducing the peak value of fault current and the level of voltage reduction

Active Publication Date: 2021-06-08
CHONGQING UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method cannot quickly switch to backup protection when the primary protection action fails, so this paper proposes a strategy to quickly identify faults in the primary protection zone and trigger appropriate DC circuit breakers

Method used

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  • A protection method for multi-terminal flexible UHV DC transmission system
  • A protection method for multi-terminal flexible UHV DC transmission system
  • A protection method for multi-terminal flexible UHV DC transmission system

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Embodiment Construction

[0025] The technical solutions in the embodiments of the present invention will be described clearly and in detail below with reference to the drawings in the embodiments of the present invention. The described embodiments are only some of the embodiments of the invention.

[0026] The technical scheme that the present invention solves the problems of the technologies described above is:

[0027] The present invention provides a machine learning-based k-means classifier to determine the threshold range and action time framework of primary protection and backup protection, and determine and classify fault types by measuring local voltage and current, thereby realizing fast backup protection action. Compared with the existing protection, the protection method realizes faster protection action and avoids the generation of large fault current. When the primary protection fails, the backup protection will act after accelerating to 0.2ms. At the same time, the relay protection sys...

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Abstract

The present invention claims a protection method for a multi-terminal flexible DC transmission system, which includes a fast primary protection strategy and a backup protection strategy when the primary fails. This strategy is a non-unit protection strategy based on voltage and current. By sampling local location voltage and current signals, combined with the change rate of fault current over time and k-means in machine learning, the short-circuit area is determined, and then the judgment is made. The threshold level and action time of forward fault and backward fault action can be determined to quickly identify, select and trigger the appropriate DC circuit breaker when the primary protection of the multi-terminal flexible DC transmission system fails, thereby clearing the short-circuit fault in a shorter time. Reduce the peak value of short-circuit current to achieve the purpose of improving the safety and stability of the power grid system.

Description

Technical field [0001] The invention belongs to the field of power system protection, and in particular relates to a protection method for a multi-terminal flexible DC transmission system. Background technique [0002] With the development of DC transmission technology and the widespread application of UHV AC and DC technology, my country has now formed a large-scale multi-infeed DC transmission system and receiving end system. Multi-terminal DC systems have higher compatibility, stability, reliability and security. However, an AC failure in the receiving end system may cause the collapse of the entire system, resulting in the interruption of DC transmission power, ultimately threatening the safe and stable operation of the entire AC and DC system. DC fault protection of multi-terminal flexible DC systems is one of the key technologies for the development of DC systems. The main technical difficulties include reliable identification and rapid isolation of DC faults. When a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/26H02J3/36
CPCH02H7/262H02J3/36Y02E60/60
Inventor 杨帆贺婷婷高兵王金浩郑惠萍刘新元薄利明郝鑫杰程雪婷郝捷张颖
Owner CHONGQING UNIV
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