Method for checking a separation point of a photovoltaic inverter, and photovoltaic inverter

A method for checking a photovoltaic inverter separator (14) between the photovoltaic inverter (1) and a power supply network (7), comprising multiple phases (L1, L2, L3) and a neutral conductor (N), wherein multiple switching contacts of multiple relays (18-21) of the separator (14) are controlled by the photovoltaic inverter (1), and each voltage (30, 31, 32 and 33, 34, 35) at each phase (L1, L2, L3) is measured upstream and downstream of the separator (14) in relation to the neutral conductor (N), wherein in the separator (14) at least one phase (L2, L3) upstream of the separator (14) and at least one phase (L2, L3) downstream of the separator (14) is cross-bonded, and wherein the switching contacts of the separator (14) are connected and checked in steps according to a switching pattern, wherein the switching pattern is implemented by a stepwise change of the switching contacts of the separator (14) from one switching state to another switching state, and wherein each switching state is assigned a measurement result in accordance with an evaluation table, and the functionality of the switching contacts of the separator (14) is derived in each switching state of the switching pattern in that, in each switching state, each voltage (30, 31, 32 and 33, 34, 35) is measured at at least one phase (L1, L2, L3) upstream and downstream of the separator (14) in relation to the neutral conductor (N), and the voltages are compared to the measurement results of the evaluation table.

A photovoltaic inverter (1) for converting a direct voltage to an alternating voltage with multiple phases (L1, L2, L3) and a neutral conductor (N), and for feeding the alternating voltage to a power supply network (7) with multiple phases (L1, L2, L3) and a neutral conductor (N), with a separator (14) of multiple relays (18-21) with multiple switching contacts for galvanic separation to the phases (L1, L2, L3) and the neutral conductor (N) of the power supply network (7), wherein means are provided for measuring the voltages (30, 31, 32 and 33, 34, 35) of the phases (L1, L2, L3) in relation to the neutral conductor (N) upstream and downstream of the separator (14), wherein the separator (14) comprises four relays (18-21) with at least one switching contact each, wherein every two switching contacts of two relays (18-21) that are switchable independently of each other are connected in series for each connection of the phases (L1, L2, L3) and of the neutral conductor (N), and wherein in the separator (14) at least one phase (L2, L3) upstream of the separator (14) and at least one phase (L2, L3) downstream of the separator (14) is cross-bonded, and wherein two independent controllers (15, 16) are provided for processing the voltages (30, 31, 32 and 33, 34, 35) of the phases (L1, L2, L3) measured upstream and downstream of the separator (14) in relation to the neutral conductor (N), said controllers being connected with each other via a data bus (17), and wherein the controllers (15, 16) are designed for deriving the functionality of the switching contacts in each switching state by comparing the measured voltages (30, 31, 32 and 33, 34, 35) with measurement values assigned in an evaluation table.