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A Circuit for Reducing Commutation Failure of Converter Valve

A commutation failure and commutation valve technology is applied in the direction of converting AC power input to DC power output, electrical components, output power conversion devices, etc. , increase the reactive power consumption of the system, etc., to achieve the effect of small transformation cost, simple design, and reducing the occurrence of commutation failure

Active Publication Date: 2015-10-28
STATE GRID CORP OF CHINA +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] 2. Use a larger smoothing reactor to limit the rise of transient DC current
The two trigger pulse control methods have their own advantages and disadvantages, but they still cannot prevent the occurrence of commutation failures
Increasing the leading firing angle β will sacrifice the transmission power, increase the reactive power consumption of the system, and reduce the economy of the HVDC transmission system

Method used

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  • A Circuit for Reducing Commutation Failure of Converter Valve
  • A Circuit for Reducing Commutation Failure of Converter Valve
  • A Circuit for Reducing Commutation Failure of Converter Valve

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Embodiment Construction

[0026] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0027] The main principles are as follows:

[0028] Firstly, the mechanism of commutation failure is introduced, such as figure 1 Shown is the wiring diagram of the six-pulse converter valve on the inverter side, I d is the direct current, L d It is a smoothing reactor, take V6 and V5 conduction, and commutate from V5 to V1 as an example, explain the mechanism of commutation failure, the schematic diagram is as follows figure 2 As shown, where μ is the commutation overlap angle, β is the leading firing angle, and γ is the arc extinguishing angle.

[0029] In the process of commutating from V5 to V1, the two ends of V1 are e a with e c , withstand positive pressure e ac . To achieve commutation from V5 to V1, e must be satisfied c a , so the commutation must be at the natural commutation point c 0 completed before. Since V5 needs a carrier rec...

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Abstract

The invention discloses a circuit capable of reducing current conversion valve commutation failure. Diodes are connected in parallel reversely at the positions of bridge arm thyristors of a current conversion valve, and the diodes are reversely connected in parallel between the thyristors which are connected in series. According to the circuit, the diodes are connected in parallel reversely at the positions of the bridge arm thyristors, and parts of the thyristors are quick thyristors, and reverse voltages borne by a bridge arm and needing to be shut off are concentrated to parts of the thyristors (preferably the quick thyristors) in the commutation process. Firstly, parts of the thyristors are shut off, so that the whole bridge arm is shut off. After the bridge arm is shut off, the rest of the thyristors has enough shut off time and can be shut off smoothly. Therefore, quick shut-off of the bridge arm is realized, the total voltages, time and area needed by bridge arm shut-off are reduced, quick commutation of the current conversion valve is realized, and commutation failure is reduced. Current conversion valve commutation failure is one of the most common types of failure in high-voltage direct current transmission, and the fact that commutation failure is effectively reduced has important significance to stable and normal operation of a power system.

Description

technical field [0001] The invention relates to a circuit for reducing phase commutation failure of a converter valve. Background technique [0002] At present, based on the national power industry development strategy of "power transmission from west to east, north-south mutual supply, and national networking" and the national medium- and long-term scientific and technological development plan, high-voltage direct current transmission (HVDC) has become an important direction for the future development of the power industry. With its significant advantages in long-distance large-capacity transmission, cable transmission and AC grid interconnection, HVDC transmission has achieved considerable development and progress in the past ten years, and China has become the largest country in DC transmission. [0003] HVDC transmission plays an irreplaceable role in long-distance large-capacity transmission and AC power grid interconnection, and its stable operation has important pract...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M7/515H02M1/06
Inventor 刘民云玉新姚金霞
Owner STATE GRID CORP OF CHINA
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