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Harmonic resolution method of alternating-current/direct-current interconnection system

An interconnected system, AC and DC technology, applied in the field of power systems, can solve the problems of not considering the harmonic interaction of the AC and DC system, and the asymmetric working state of the converter without considering the asymmetric fault.

Inactive Publication Date: 2010-03-17
SOUTH CHINA UNIV OF TECH
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  • Abstract
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  • Claims
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AI Technical Summary

Problems solved by technology

Existing harmonic analysis methods based on switching functions do not consider the harmonic interaction of the AC-DC system, nor the asymmetric working state of the converter under the asymmetric fault of the AC system

Method used

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  • Harmonic resolution method of alternating-current/direct-current interconnection system
  • Harmonic resolution method of alternating-current/direct-current interconnection system
  • Harmonic resolution method of alternating-current/direct-current interconnection system

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Embodiment Construction

[0089] The present invention will be described in further detail below in conjunction with the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0090] 1. The structure of the converter in the HVDC transmission system of the present invention is as follows figure 1As shown, using the known fundamental frequency component of the three-phase commutation bus voltage (converted to the valve side) U a(1) , U b(1) and U c(1) ,Such as:

[0091]

[0092]

[0093]

[0094] Calculate the corresponding fundamental frequency component of the line voltage:

[0095]

[0096]

[0097]

[0098] 2. Put U ab(1) , U bc(1) and U ca(1) Convert to alpha component and beta components

[0099]

[0100] = 2 3 1 - 1 / 2 ...

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Abstract

The invention discloses a harmonic resolution method of an alternating-current / direct-current interconnection system. The method comprises the following steps: calculating the actual triggering angle,the phase transformation angle and the delay conduction angle of each current transformation valve in a current transformer according to the interphase fundamental-frequency voltage of current transformation buses and the direct-current component of direct current and the triggering angle command of a direct-current control system; calculating a three-phase voltage switching function and a three-phase current switching function and transforming the three-phase voltage switching function switching function and the three-phase current switching function into positive-sequence and negative-sequence components; establishing a sequence component model of the current transformer by the positive-sequence and negative-sequence current switching function and the positive-sequence and negative-sequence voltage switching function; and combining the model and an equivalent harmonic network of the alternating-current / direct-current system and carrying out simultaneous resolution on the total system, thereby calculating each subharmonic voltage and current of both sides of alternating current and direct current of the current transformer. The method realizes the harmonic resolution of the alternating-current / direct-current system under a condition that an asymmetric fault occurs in an alternating-current system, lowers the calculation quantity, has higher calculation accuracy and can be applied to the harmonic analysis of the alternating-current / direct-current interconnection system under various normal operation working conditions and faults.

Description

technical field [0001] The invention relates to a method for solving harmonics in the field of power systems, in particular to a method for solving harmonics of an AC / DC interconnection system applicable to various operating conditions and failures. Background technique [0002] In order to meet the continuously growing power demand in the future and realize the optimal allocation of resources in a wider range, high-voltage direct current (HVDC) transmission systems are increasingly widely used. By the end of 2007, 4 high-power DC transmission systems had been fed into the Guangdong area, with a total of 10,800MW of DC power delivered. The Guangdong region has become the largest multi-infeed AC-DC hybrid system in the world. When an asymmetrical fault occurs in the AC system, the various characteristic and non-characteristic harmonics generated by the AC and DC system may affect the safe and stable operation of the system. Therefore, it is necessary to establish a harmonic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/04
Inventor 王钢李志铿李海锋王智东
Owner SOUTH CHINA UNIV OF TECH
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