A current-limiting type fast reclosing DC circuit breaker topology structure and control method

A DC circuit breaker and topological structure technology, applied in the direction of emergency protection circuit devices, electrical components, etc., can solve the problems of accelerating the discharge speed of inductance energy on the fault side, high cost, etc., to reduce the peak value, slow down the rising speed, and reduce the withstand current The effect of pressure

Inactive Publication Date: 2019-01-11
SHANDONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] In order to solve the above problems, the present invention proposes a current-limiting fast reclosing DC circuit breaker topology and control method, which can effectively solve the high cost problem caused by two sets of current branches, limit the fault current rising rate and peak value, And greatly accelerate the energy discharge speed of the fault side inductance, which is conducive to fast reclosing

Method used

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  • A current-limiting type fast reclosing DC circuit breaker topology structure and control method
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  • A current-limiting type fast reclosing DC circuit breaker topology structure and control method

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Experimental program
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Effect test

Embodiment 1

[0051] figure 1 It is a topological structure diagram of the current-limiting fast reclosing DC circuit breaker proposed by the present invention, including: including the following five parts:

[0052] ①Current-carrying circuit; composed of fast mechanical switch and auxiliary commutation switch;

[0053] ②Current limiting circuit: including two inductances of equal size, which are connected in series on both sides of the current-carrying circuit;

[0054] ③ commutation circuit; also known as diode bridge commutation circuit, which is connected in parallel with the current-carrying circuit, including four diode bridge arms and two damping resistors;

[0055] ④ Cut-off circuit; connected in series between the upper and lower bridge arms of the commutation circuit, including power electronics branch and lightning arrester branch;

[0056] ⑤ Freewheeling circuit; connected in series between the lower bridge arm of the commutation branch and the ground, also known as the freewh...

Embodiment 2

[0059] The DC circuit breaker disclosed in Embodiment 1 is placed in a single-ended DC transmission line for research, assuming that a ground fault occurs on the right side of the DC circuit breaker, then L 1 is the non-fault side inductance, L 2 is the fault side inductance. figure 2 is the specific timing diagram of the circuit breaker action, combined with figure 2 , and describe the specific action sequence of fault breaking as follows:

[0060] t=t 0 , a ground fault occurs in the circuit on the right side of the DC circuit breaker;

[0061] t=t 1 When the protection device detects that a fault occurs, the circuit breaker receives the action signal; the DC circuit breaker breaks the auxiliary commutation switch of the current-carrying circuit and closes the power electronic branch of the current-breaking branch at the same time. 1 , turn on the IGBTs in all SMs; the current is gradually commutated from the current-carrying circuit to the commutation circuit and the...

Embodiment 3

[0073] Embodiment Three: Reclosing

[0074] combine figure 2 Tell about the operation sequence of the circuit breaker proposed by the present invention when reclosing:

[0075] Suppose the fault occurs at t = t 5 When it is successfully cut off, after a short delay, it starts to reclose;

[0076] t=t 6 When , the power electronic branch is closed, that is, the IGBTs in all SMs are turned on; the current will rise again

[0077] t=t 7 , detect the electrical quantity of the fault circuit to determine whether the fault still exists; for example, detect the current rise rate di / dt, if it exceeds the preset threshold, indicating that the fault still exists, then block all IGBTs in the SM, and reclose the failure; If it is lower than the preset threshold, it means that the fault is removed, and then a conduction signal is sent to the fast mechanical switch to proceed to the next step;

[0078] t=t 8 When , the fast mechanical switch is closed, then the auxiliary commutation...

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Abstract

The invention discloses a current-limiting type fast reclosing DC circuit breaker topology structure and control method. The structure comprises a current carrying circuit, a current limiting circuit,a current converting circuit, a current cutting circuit and a freewheeling circuit. The current-carrying circuit comprises a mechanical switch and an auxiliary current-converting switch which are connected in series in turn. The current limiting circuit is serially connected with both sides of the current carrying circuit, and the current converting circuit is connected with the current carryingcircuit in parallel. The current converting circuit comprises an upper bridge arm and a lower bridge arm composed of two diodes. The current cutting circuit is serially connected between the upper bridge arm and the lower bridge arm, and the current freewheeling circuit is serially connected between the lower bridge arm of the current converting circuit and the earth. The cut-off circuit comprisesa power electronic branch and a lightning arrester branch which are connected in series by a plurality of sub-modules. The lightning arrester branch is connected in parallel with the power electronicbranch. The invention has the beneficial effects of effectively solving the problem of high cost caused by two sets of through current branches, limiting the rise rate and peak value of the fault current, greatly accelerating the energy release speed of the fault-side inductor, and facilitating rapid reclosing.

Description

technical field [0001] The invention relates to the field of flexible direct current transmission of electric power systems, in particular to a topology structure and control method of a current-limiting fast reclosing direct current circuit breaker. Background technique [0002] In recent years, with the rapid development of flexible DC transmission technology, the DC circuit breaker to ensure its safe and stable operation has become a research hotspot. Compared with the conventional AC grid, the flexible DC grid lacks a natural zero-crossing point, the grid damping is low, the fault current rises faster, and the smoothing reactor is larger, and the energy to be discharged is higher. Reliable cut-off, fast action, effective energy discharge and other three requirements. [0003] Current DC circuit breakers are often divided into three types of solutions based on technical principles: mechanical, solid-state and hybrid DC circuit breakers. Among them, the hybrid DC circuit...

Claims

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Application Information

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IPC IPC(8): H02H7/26
CPCH02H7/268
Inventor 郝全睿李博伟王淑颖
Owner SHANDONG UNIV
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