49results about How to "Avoid loss of life and property" patented technology

The invention discloses a photovoltaic system fault arc detection method of mixing quadratic form time frequency distribution characteristics and self-adapting product function analysis. A local mean is used to decompose and analyze a current signal, and a first-order product function is selected to be used as a characteristic value. Quadratic form time frequency distribution is used to analyze the current signal, and a plurality of frequency components in a frequency range used for indicating generating of a fault arc effectively are selected to be used as another group of characteristic values. A real-time range method is used to process a plurality of groups of characteristic values to acquire a real-time range value, which is input in an extreme learning machine, and whether the fault arc exists is determined by the output value of the extreme learning machine, and finally, a cut-off signal is transmitted according to a set trigger standard. The selected characteristic values are used to discover the fault arc accurately, and essential differences before and after the occurrence of the fault arc are distinctly distinguished, and the extreme learning machine is used to determine the fault arc in various load working conditions quickly and accurately, and a fault arc branch is cut off. Compared with a conventional direct current fault arc detection technology, the photovoltaic system fault arc detection method has advantages of wide application range and strong expandability.

Disclosed are an alarm message sending method, a base station, and a storage medium. The method comprises: a base station issuing, after receiving an alarm message issued by a core network, the alarm message to a terminal; and in a message sending window where the alarm message is located, repeatedly sending the alarm message, wherein a time interval of the repeated sending is greater than a measurement time of a terminal measurement process.

The invention discloses an arc detection method for the fault of a photovoltaic system under an abnormal light condition. When an MPPT algorithm dynamic regulating system operating point is not caused by a fault arc accident, by allowing the fault arc characteristic quantity threshold value to tightly track the system operation point variation curve regulated by the MPPT algorithm, the circumstances that the fault arc detection electric quantity varies dynamically or lowers continuously caused by light change can be dealt, and the detection device can effectively detect fault arc in the photovoltaic system at any time can be ensured. According to the detection method, the fault arc detection precaution capacity of the photovoltaic system under abnormal light condition caused by changes of weather and environment is greatly improved, the misoperation problem caused by that the original set threshold value of the photovoltaic fault arc protection device is invalid is effectively solved, and the loophole that the traditional detection device is difficult to detect potential arc threats under the special situations is filled.