Method for judging direct current arc fault based on real-time measured multi-band frequency component rate

Abstract

The invention relates to a method for judging a direct current arc fault based on a real-time measured multi-band frequency component rate. Along with the large-scale application of photovoltaic generation, and particularly the wide application of a photovoltaic solar panel to the roof and the external wall of a building, fires caused by a photovoltaic generation system happen in many places. Through analysis, people find that the fires are basically caused by the direct current arc fault of the photovoltaic generation system, and therefore, detecting and isolating the direct current arc fault for causing equipment damage and fire hidden danger become problems needed to be solved, however, due to the specificity of the direct current arc fault of the photovoltaic generation system, the conventional fault waveform based arc fault detection principle is not suitable for the direct current arc fault of the photovoltaic generation system. The method has the core thought that the overlarge energy is contained in the arc to cause the fire damage caused on the basis of the fault arc, and by using a method for detecting the energy source ratio of the frequency spectrum component energy of multiple bands in a voltage and current waveform to the total spectrum, the direct current arc faults possibly causing fires can be rapidly and reliably detected without being affected by other noises in the system, and the safety of the photovoltaic generation system is ensured.

Description

technical field [0001] The invention belongs to the technical field of photovoltaic electrical fault detection. More precisely, the invention relates to a method for judging whether a DC arc fault occurs in a photovoltaic system based on real-time measurement of frequency component proportions of multiple frequency bands in voltage and current. Background technique [0002] Arc fault protection is not a new thing. Studies have found that the fault arc caused by a small current has enough energy to trigger ignition and cause a fire when no overcurrent occurs. Since the 1990s, in North America, Equipping arc fault protectors in AC systems has become a mandatory standard for safety. With the large-scale application of photovoltaic power generation, especially the widespread application of photovoltaic panels on building roofs and exterior walls, fires caused by photovoltaic power generation systems have occurred in many places. Through analysis, it is found that this type of f...

AI Technical Summary

Problems solved by technology

This method is still feasible in the AC low-voltage system, but in the photovoltaic DC system, because the characteristics of photovoltaic power generation are unpredictable with time and the environment; the interference waveforms of various inverters are also different and vary with the load; There are varying numbers of intervals between the place where the arc fault occurs and the detection point, which causes the distortion of the fault arc waveform to be unpredictable. Therefore, the aforementioned two modes of comparison with known fault characteristics and self-learning are not applicable. DC Arc Fault Detection in Photovoltaic Power Generation Systems

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