Island effect detecting method of grid-connected photovoltaic power system

A grid-connected power generation and island effect technology, applied in the direction of electrical digital data processing, special data processing applications, instruments, etc., to achieve accurate detection and eliminate potential safety hazards

Inactive Publication Date: 2015-06-24
嘉兴金尚节能科技有限公司
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  • Island effect detecting method of grid-connected photovoltaic power system
  • Island effect detecting method of grid-connected photovoltaic power system
  • Island effect detecting method of grid-connected photovoltaic power system

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[0035] The specific implementation manner of the present invention will be introduced below, and in conjunction with Attached picture To aid in understanding:

[0036] The invention applies the combination of fuzzy neural network and wavelet transform to the specific problem of island detection. At first some principles of the present invention are disclosed:

[0037] Wavelet transform is the most effective method for analyzing non-stationary signals or signals with singularity, and it is suitable for island detection, which produces transient abrupt signals. Therefore, this paper uses the Mallat algorithm commonly used in discrete wavelet transform to realize wavelet decomposition, and its mathematical expression c j + 1 = Hc j ...

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Abstract

The invention relates to the field of power system and signal transmission and discloses an island effect detecting method of a grid-connected photovoltaic power system. Data of an inverter system and a public coupling point are used, and detecting is carried out based on a fuzzy neural network and wavelet transformation. The method comprises the steps that output current signals of the inverter system and voltage signals of the public coupling point are collected; the current signals and the voltage signals are subjected to wavelet transformation, and wavelet components in various dimensions are obtained; the wavelet components are subjected to mathematical treatment; and signals obtained after treating are used as a feature vector space to be provided for an input layer of the fuzzy neural network, and the fuzzy neural network judges whether an island happens according to input feature vectors. According to the technical scheme, detecting and early warning can be carried out on the island effect accurately, during stable operation, grid-connected current is not affected obviously, and the requirements of the NB/T32004-2013 standard are met.

Description

technical field [0001] The invention relates to the field of electric power system and signal transmission, in particular to an islanding effect detection method of a photovoltaic grid-connected power generation system based on fuzzy neural network and wavelet transform. Background technique [0002] Under normal conditions, photovoltaic systems are connected to the grid and deliver electrical energy to it. When the power grid is interrupted due to electrical failure or other reasons, the system may still supply power to local loads, thus forming a self-sufficient power supply island that the power company cannot control. This phenomenon is called the islanding effect. The danger lies in: because the inverter system works in the current control mode, the voltage and frequency in the island cannot be controlled without the support of the large power grid, which will bring safety hazards to the normal operation of the user's equipment; and the island operation will keep the li...

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Application Information

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IPC IPC(8): G01R31/08G06F19/00
Inventor 周皓陈小忠
Owner 嘉兴金尚节能科技有限公司
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