DC circuit fault isolation and reclosing strategy taking DC circuit breaker as main

A technology of DC line faults and DC circuit breakers, which is applied in the direction of automatic disconnection emergency protection devices, circuit devices, emergency protection circuit devices, etc. AC system impact and other issues

Active Publication Date: 2017-07-07
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This will impact the AC system at the sending end, and the connected converter stations may be blocked one after another. It may also cause a large load adjustment of the AC system at the receiving end, which will increase the impact range of the DC line fault and bring great impact to system safety. risk, the recovery time of the DC system becomes longer, and the reliability of power transmission of the system decreases
And in fact, more than 90% of the instantaneous faults of the DC line can resume normal operation through the reclosing and restarting process similar to the AC system after the fault, and there is no need to continuously block the DC system

Method used

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  • DC circuit fault isolation and reclosing strategy taking DC circuit breaker as main
  • DC circuit fault isolation and reclosing strategy taking DC circuit breaker as main
  • DC circuit fault isolation and reclosing strategy taking DC circuit breaker as main

Examples

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Embodiment Construction

[0052] The following examples are used to describe the present invention in detail. It is necessary to point out that this example is only used to further illustrate the present invention and cannot be understood as a limitation of the scope of protection of the present invention. Those skilled in the art can follow the above-mentioned invention. Some non-essential improvements and adjustments have been made to the content.

[0053] 1. Choose fault detection method F. In order to avoid the secondary overcurrent caused by the rapid discharge of the DC capacitor after the reclosing permanent fault, this method should determine whether the fault still exists after the reclosing as soon as possible.

[0054] In this embodiment, a PSCAD / EMTDC two-end flexible DC transmission project model based on a three-phase two-level converter is taken as an example. The project has a DC transmission capacity of 1000MW, a DC voltage of ±320kV, and a DC current of 1600A. DC circuit breakers are arra...

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Abstract

The invention discloses a DC circuit fault isolation and reclosing strategy taking a DC circuit breaker as main and a converter as auxiliary in a flexible DC power transmission system. The DC circuit fault isolation and reclosing strategy is characterized in that after a DC circuit fault, a shunting signal of the converter is isolated, the fault is disconnected by tripping of the DC circuit breaker, and the DC circuit breaker is reclosed to recovery a DC system after a preset delay, and the converter is locked again if the DC circuit breaker is not successfully reclosed. The strategy has the advantages that a fault current is rapidly cut off by the DC circuit after the fault, and the converter is not immediately locked and is locked after a permanent fault is judged when the DC circuit breaker is not successfully reclosed; and since many DC overhead circuit faults are transient faults, the DC system can be rapidly recovered after the fault, the power transmission loss is reduced, the probably that the converter is successively locked due to impact of converter locking on an AC system is also greatly reduced, and the stability of the AC / DC system is improved.

Description

Technical field [0001] The invention relates to a strategy for a DC line fault isolation and reclosing recovery system with a DC circuit breaker as the mainstay and a converter as the auxiliary in a flexible DC transmission system, which belongs to the field of flexible DC transmission. Background technique [0002] The flexible DC transmission technology based on voltage source converters is currently the main direction of HVDC development because of its unique advantages in solving the problems of grid connection and consumption of new energy. However, the related technologies of flexible HVDC transmission are still relatively weak, one of which is the rapid clearing of DC line faults. Due to the rapid development of DC system faults and the DC current has no zero-crossing point, the arc duration of the DC fault point is longer than the AC arc time of the same initial amplitude; and the anti-parallel diode in the voltage source converter is blocked after the converter is blocke...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/26H02H3/06
CPCH02H3/066H02H7/262H02H7/268
Inventor 王渝红王媛龚鸿刘程卓邹朋阳莉汶刘永强
Owner SICHUAN UNIV
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