NOVELTY - Retaining system (1) for installing a photovoltaic module (6) on a substrate (8) using base support (2), comprises a supporting head, a base support body (22) and a base-side substrate surface, which counteracts a penetration of the base supports into the substrate, where the base supports on the head side include a supporting plate obliquely positioned at an inclination angle against the substrate. The base supports are provided and arranged, such that the supporting plates of a pair of base supports are vertically spaced from one another with respect to the substrate.    USE - The retaining system is useful for installing a photovoltaic module on a substrate using base supports.    ADVANTAGE - The system produces a structurally simple and cost-effective supporting structure for installing a ground-mounted photovoltaic system with improved flexibility, avoids the necessity of drilling the roof panel, and thus it avoids leakage, and absorbs higher load.    DETAILED DESCRIPTION - Retaining system (1) for installing a photovoltaic module (6) on a substrate (8) using base support (2), comprises a supporting head, a base support body (22) and a base-side substrate surface, which counteracts a penetration of the base supports into the substrate, where the base supports on the head side include a supporting plate obliquely positioned at an inclination angle against the substrate. The base supports are provided and arranged, such that in the mounted state the supporting plates of a pair of base supports are vertically spaced from one another with respect to the substrate and are horizontally spaced from one another in adaptation to the photovoltaic module and are aligned with one another. An INDEPENDENT CLAIM is also included for a photovoltaic system comprising the above mentioned retaining system and a multiple of photovoltaic modules, where the first base supports and the second base supports, respectively form a multiple of mutually parallel extending rows, and the number of second base supports are arranged between the two rows of the first base supports.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of a first arrangement of the photovoltaic modules arranged on multiple pairs of the base supports.    Retaining system (1)    Base support (2)    Photovoltaic module (6)    Substrate (8)    Base support body (22)