Three-phase unbalance detection method based on improved S transform

A detection method and technology of balance degree, applied in the field of power quality problem detection, can solve problems such as poor anti-harmonic ability and slow detection speed, so as to solve the problem of poor anti-harmonic ability, solve slow detection speed, improve calculation speed and accuracy degree of effect

Inactive Publication Date: 2018-03-02
西安翌飞核能装备股份有限公司
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Problems solved by technology

[0004] Aiming at the problems of slow detection speed and poor anti-harmonic ability of existing detection methods, this invention proposes a three-phase unbalance detection method based on improved S-transform, which is applied to three-phase

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  • Three-phase unbalance detection method based on improved S transform
  • Three-phase unbalance detection method based on improved S transform
  • Three-phase unbalance detection method based on improved S transform

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Embodiment Construction

[0026] The invention uses S transformation to detect the fundamental wave component in the three-phase voltage, and obtains its amplitude and phase information. By introducing two adjustment factors, the detection speed can be guaranteed while ensuring the detection accuracy. Then use the obtained voltage amplitude and phase information to calculate the three-phase unbalance degree of the power grid.

[0027] like figure 1 As shown, first sample the real-time signal of the three-phase voltage of the power grid, then use the improved S transformation method of the present invention to extract the fundamental wave component in the voltage signal, and obtain the vector of the three-phase fundamental wave voltage (U a , U b , U c ), and then use the symmetrical component method to calculate the positive sequence, negative sequence and zero sequence components of the three-phase fundamental voltage (U p , U n , U 0 ). Finally, the unbalance degree of the system is calculated...

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Abstract

The invention presents a three-phase unbalance detection method based on improved S transform, which can improve the detection speed and accuracy of fundamental wave amplitude and phase information and enhance the detection effect of three-phase unbalance of the system. The detection method includes the following steps: sampling real-time signals of the three phases of voltage of a power grid; extracting the fundamental components in the voltage signals through improved S transform to get the vectors (Ua, Ub, Uc) of the three phases of fundamental voltage, wherein the improved S transform refers to that two regulation factors are introduced to the Gaussian window expression of the traditional S transform to form two degrees of freedom so the time-frequency resolution can be flexibly regulated; calculating the positive-sequence, negative-sequence and zero-sequence components (Up, Un, U0) of three phases of fundamental voltage through a symmetrical component method according to the vectors (Ua, Ub, Uc) of the three phases of fundamental voltage; and calculating the system unbalance according to the positive-sequence, negative-sequence and zero-sequence components (Up, Un, U0) of three phases of fundamental voltage.

Description

technical field [0001] The invention belongs to the detection technology of power quality problems, and in particular relates to a detection method of three-phase unbalance degree in a power system. Background technique [0002] With the development of the power system, the types of loads in the distribution network are becoming increasingly complex, and the mixed use of single-phase and three-phase loads makes the problem of voltage imbalance in the distribution network increasingly serious. The three-phase unbalance of the system will lead to the increase of loss, voltage over-limit operation and other problems. Serious three-phase unbalance even endangers the safety of the system. Therefore, it is very important to detect the unbalance degree of distribution network accurately and quickly. [0003] At present, the national standard has relevant regulations on the calculation method of the unbalance degree of the three-phase voltage of the system. Existing detection met...

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Application Information

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IPC IPC(8): G01R29/16
CPCG01R29/16
Inventor 阚忠杰
Owner 西安翌飞核能装备股份有限公司
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