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Scientists in the United Arab Emirates have developed a novel lightning rod mast design that reportedly eliminates the shading effect on photovoltaic panels. The proposed approach also addresses ground grid requirements under varying humidity conditions.
A team of scientists from the University of Wollongong in Dubai has proposed a new approach to deploying direct lightning protection technology at sites hosting east-west oriented photovoltaic systems with limited separation between panels.
They explained that the integration of direct lightning protection in this type of solar arrays is difficult in terms of compliance with the requirements of the Terrestrial Terminal System (ETS) and direct lightning protection, especially in rooftop installations.
“The proposed method introduces equations to support the innovative approach for horizontal lightning masts and addresses ground grid requirements under varying humidity conditions,” the group said. “The equations provided by the paper allow engineers to configure the panel layout for both east and west orientations using only three sets of data while ensuring compliance with direct lightning strike protections.”
In the article “ A novel lightning mast layout to Eliminate Shading Effect on PV panels ” published in Electric Power Systems Research , the research group explained that conventional lightning protection solutions such as high mast installations can result in considerable shading on panels, and stated that the proposed approach enables appropriate steel arrangement of panels to meet lightning protection standards without any shading.
“In a scenario where solar panels are installed back to back, with one side facing east and the other west, traditional installation of lighting masts is not feasible without causing shading of the panels,” the academics stated, noting that shading can lead to hot spots and decreased panel efficiency. “The innovative approach is to install horizontal lightning rods along the length of the panel instead of vertical ones.”
The proposed system also uses horizontal rods made of copper strips fixed to the steel support structure of the panels. “This configuration ensures that the length of the horizontal copper rod is kept short and varies depending on the length of the panel,” the academics stress. “These lengths are based on panels of up to 600 W on the market today.”
They also cautioned that the selected copper shielding strap, rod or cable should not sag under its own weight or in high wind conditions and said project developers could also consider using copper-clad steel rods that meet the required current-carrying capacity and are resistant to damage from lightning strike energy. “Such rods or straps offer high tensile strength,” they said. “The distance between the down conductors should comply with relevant standards and policies as outlined in the reference.”
According to the research group, the proposed guidelines can provide adequate protection against the risk of lightning damage in storm conditions and also contribute to reducing grounding network costs. |
