NOVELTY - The plant (32) has photovoltaic devices (27) e.g. thin-film photovoltaic cells, including positive/negative input terminals (30, 31) connected to an electronic switch (12) e.g. multiple-pole single-throw switch, which is in turn connected to a point (10) held at a voltage relative to ground (11). The switch is controlled in response to parameters. A power converter is connected to the terminals. The switch is integrated into the converter. Photovoltaic modules (26) are fed into an inverter e.g. transformerless type inverter, which is in turn connected to alternating current (AC) output (29).    USE - Photovoltaic solar power plant for capturing energy light from sun.    ADVANTAGE - The plant is designed such that fixation of the terminals at defined voltages with respect to ground is made via a switchable connection, so that the configuration of the plant can be changed simply by changing switch settings, thus achieving simple and flexible operation of the plant. The plant is designed such that switch setting is performed in an automated way at regular intervals and adaption of the switch settings, voltage level and the monitoring of the parameters can be limited to times when the photovoltaic power plant generates electric power. The plant can be switched off to save energy at night. The plant is designed such that voltages to ground appearing at the negative terminal of the photovoltaic devices are measured and the terminals with negative voltage are connected to the point held at the voltage relative to ground by closing the relevant switch, so that parts of the thin-film photovoltaic devices can be kept at a positive potential relative to ground potential.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for controlling a photovoltaic power plant.    DESCRIPTION OF DRAWING(S) - The drawing shows a circuit diagram of a photovoltaic power plant.    Point (10)    Ground (11)    Electronic switches (12, 13)    Photovoltaic modules (26)    Photovoltaic devices (27)    AC output (29)    Positive/negative input terminals (30, 31)    Photovoltaic power plant (32)