Device and method for supporting detection of direct-current arc fault of photovoltaic system

Abstract

The invention relates to a device and a method for supporting detection of a direct-current arc fault of a photovoltaic system. A data acquisition module is used for collecting the cascade current andcascade voltage provided by each string, and a current detection module is used for detecting first and second types of arc characteristics of the total current obtained after the cascade currents ofall the strings are summarized. When the total current conforms to one or more first arc characteristics and one or more second arc characteristics, the cascade current and the cascade voltage of allthe parallel strings are analyzed, and when there are multiple strings with reduced cascade voltages and increased cascade currents, the rest strings with reduced cascade voltages and reverse cascadecurrents are regarded as strings with direct-current arc faults.

Description

technical field [0001] The present invention mainly relates to the field of photovoltaic energy, more precisely, relates to an arc detection device and an arc detection method for detecting DC arc phenomena applied to a photovoltaic power generation system. Background technique [0002] With the shortage of chemical energy and the development of electric power technology, photovoltaic energy has received more and more attention. The use of photovoltaic energy in electric power must meet safety regulations. Arc is a gas discharge phenomenon, and the spark generated by the current flowing through an insulating medium such as air is the manifestation of gas discharge. Detecting arcs and taking proactive countermeasures are key elements in keeping photovoltaic energy systems within safety regulations. Although the industry is trying its best to find the rules and commonality of the arc phenomenon in order to find the accurate detection method of the arc, the unavoidable fact is...

AI Technical Summary

Problems solved by technology

The application of the well-known alternating current is earlier and there are relatively mature detection methods and commercial products for AC fault arcs. However, the photovoltaic system started relatively late and the essential characteristics of direct current arcs are quite different from those of alternating current. Typical examples include direct current and There is no zero-crossing characteristic like alternating current, so the detection method of alternating current arc cannot be applied in photovoltaic applications

The variables that affect the electrical properties of the DC arc are already numerous and diverse, and the arc is complicated by the different environments in which photovoltaics are used.

It is generally recognized in the industry that it is difficult to establish a mathematical model of a DC arc. Although some arc models have been mentioned, these simplified models are usually based on some single characteristics or several very limited characteristics of the arc. In fact, the photovoltaic environment Inevitably existing noise and sporadic interference of the power system can easily mislead arc detection, resulting in wrong detection results, dynamically changing light intensity and ambient temperature, and a large number of switching noises are the sources of misjudgment and missed judgment.

Images