Two examples of photovoltaic generators on a high-voltage overhead line

Low-power electrical supply requirements appear throughout an electrical energy transmission network (e.g., for tower lighting and for reamplification of data transmitted along the line via appropriate media coaxial cable or optical fibers incorporated in the earth wire). It is pointed out that solar energy is an advantageous way to meet these requirements, but the insertion of a photovoltaic generator in a tower poses a certain number of specific problems, in terms of mechanics, electricity, and access. These problems have been studied through two experimental photovoltaic generator installations, paying particular attention to the function of the regulator. Based on the data acquired, the following recommendations are made for the next generation of installations. The installation should be equipped with a charge/voltage regulator, and, as soon as the battery voltage reaches a threshold level equal to 120% of its nominal value, the regulator should totally stop the charging process until the next sunrise. When these rules have been applied, it is expected that the battery will have a longer life and will operate without maintenance during its entire lifetime