DC fault electric arc detection method and system

Abstract

The invention relates to a DC fault arc detection method and system The DC fault arc detection method comprises steps of performing collection on DC voltage outputted by a photovoltaic battery according to set sampling frequency to obtain output voltage data, performing time domain processing on output voltage data, obtaining a voltage average value Uavg, a voltage variance sigma and a maximum peak value difference Um in each detection cycle, comparing with a last detection cycle, when a difference value delta Uavg of a voltage average value is greater than a first threshold value, if the difference value delta sigma of the voltage variance is greater than a second threshold value or a biggest peak value difference value delta Um is greater than a third threshold value, performing time domain processing on output voltage data, calculating a harmonic wave energy sum of each frequency band, constructing a characteristic vector space of the harmonic wave energy sum, and using a pre-trained BP nerve network and the characteristic vector space to determine whether an electric arc is generated. The DC fault arc detection method and system solve problems that the current fault arc detection is not accurate and high in misjudgment, and can improve safety of a photovoltaic power generation system.

Description

technical field [0001] The invention relates to the technical field of arc detection, in particular to a DC fault arc detection method and system. Background technique [0002] Arc is a gas discharge phenomenon. Electric hot plugging and contact switch on and off may generate arcs, but such arcs generally do not cause electrical faults. Arcs are divided into DC arcs and AC arcs according to current. Arc discharge phenomenon It often contains huge energy, which poses a threat to the safety of surrounding equipment and staff. [0003] In recent years, with the widespread application of photovoltaic power generation systems, especially the large-scale application of photovoltaic panels on building roofs and exterior walls, and the installation of most photovoltaic arrays, they use long strings of high-voltage DC power sources. Added safety concerns related to arcing. Since fault arcs have little influence on the output characteristics of photovoltaic cells, traditional overvo...

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Problems solved by technology

[0005] The invention provides a DC fault arc detection method and system, which solves the problems of inaccurate DC fault arc detection, susceptibility to interference, and high misjudgment rate in the existing photovoltaic power generation system, and improves the safety of the photovoltaic power generation system

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