NOVELTY - The system (1) has an active maintaining element (20) i.e. tensioning cable, formed of a part to be connected to a parallelepiped photovoltaic panel and a frame (3) and another part to be mechanically tensioned for contributing maintaining of the photovoltaic panel on the frame. The maintaining element is elongated and extended between two ends (20A, 20B), and an adjustment unit (21) adjusts mechanical tension applied to the maintaining element. The maintaining element is inserted into a support element (4) i.e. tube, to which the photovoltaic panel is attached.    USE - System for supporting a parallelepiped photovoltaic panel that converts solar energy into electrical energy, on a frame during construction of a building such as house or a simple concrete slab.    ADVANTAGE - The active maintaining element is formed of the part to be connected to the photovoltaic panel and the frame and another part to be mechanically tensioned for contributing maintaining of the photovoltaic panel on the frame, thus assuring stable, safe and solid maintenance of the photovoltaic panels on the frame. The maintenance of the system is adaptable and adjustable to all type of frames. The system is simple to implement, easy to assemble and inexpensive. The configuration of the system allows reinforced maintaining of the photovoltaic panel in a simple and easy manner, limits the risk of overheating of the solar panel and optimizes available space on the frame. The system ensures optimum adjustment and ease of positioning the photovoltaic panels, limits the risk of electrocution and allows an optimized transfer of the produced direct current. The maintaining element is rigid and inflexible under the mechanical tension forces, thus increasing mechanical resistance of the system.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) a method for installing a photovoltaic panel supporting system    (2) a medium comprising a computer program with a set of instructions for implementing a method for installing a photovoltaic panel supporting system.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic front view of a parallelepiped photovoltaic panel supporting system in which a maintaining element is attached to a frame.    Photovoltaic panel supporting system (1)    Frame (3)    Support element (4)    Active maintaining element (20)    Ends (20A, 20B)    Adjustment unit (21)