The solar power panel, which is an electric power generator that uses the photovoltaic effect to convert solar energy directly into electric power, has attracted attention as an electric power source using renewable energy to generate power steadily from natural energy and has been adopted in a broad range of industrial sectors. Conversion efficiency improvements and production cost reductions have led to wide utilization, that now extends even to ordinary homes, while a concomitant rise in maintenance requirements has led to the development of various detection systems going beyond visual inspection that include, inter alia, ones employing stationary equipment-based methods, as well as ones that detect failure sites using aerial photography.
The solar power panel is an assembly of multiple modules and/or cells, namely, of multiple electrically interconnected modules and/or cells. As a solar power panel exhibits a phenomenon of conversion efficiency decline in proportion as temperature of the modules and/or cells increases, a problem of conversion efficiency degradation arises even when no failure of the power generation or power storage has occurred. In light of this, malfunction detection systems and the like have been developed for performing repair that use thermographic cameras to detect not only heating owing to module and/or cell failure or similar but also module and/or cell temperature increase owing to, for instance, heating caused by aging degradation or the like.
Conventional failure site detection methods use detectors installed array-by-array of series-connected module strings or parallel-connected strings to perform malfunction detection by monitoring power generation condition, but they need considerable labor and time to detect which cell of which module failed. A variety of systems have therefore been developed including, inter alia, ones that involve an inspector carrying a thermographic camera or other measuring instrument to the installation and directly photographing the solar power panel, ones that periodically detect surface temperature anomalies with a thermographic camera or the like installed at a fixed observation point, and attachment type ones that detect malfunction at a fixed angle by utilizing mechanical control to slide a thermographic camera or other mechanically controlled detector at fixed intervals defined on a surface.
Solar panels of industrially applicable scale need to be of at least a certain size, and since use of sunlight is necessary, the prevailing situation is that installation sites are generally expansive and located in places where inspection is difficult. With the aforesaid conventional search/detect systems using a manual or fixed thermographic camera or the like, problems are encountered during search and detection of it being impossible to maintain the thermographic camera or other detection instrument at an optimum angle and fixed distance with respect to the solar panel. On the other hand, in the attachment type system, although a fixed angle and distance can be maintained against the solar power panel, inconveniences arise in that detection instruments must be installed prior to search/detect and that equipment installation is costly and time consuming when the solar power panel is large scale.
Further, solar power panels are constituted of multiple identically shaped modules (or cells) electrically and continuously interconnected, so that when a malfunction is discovered from detection data from a large-scale solar power panel, a problem arises of much time being required to precisely pinpoint the location of the failed module (or cell) during later part replacement work carried out on an individual module (or cell) basis.
Development has therefore been desired of a search system for detecting solar power panel failure that does not require deployment of many workers or provision of a search unit on the solar power panel at the installation site, that can constantly maintain a fixed distance between a search unit and the solar panel, that can continuously maintain an optimum fixed angle between an ultrasonic or laser beam emitted by the search unit and the solar panel, and that enables accurate and suitable pinpointing of a detected malfunction or failure site instantaneously during replacement work.
Patent document 1: JP2012-205061A