Method of repowering a photovoltaic plant

A repowering kit for repowering a photovoltaic power plant from a first configuration, the first configuration comprising a pair of combiners connected in series between two homeruns via a PV tie device, wherein the combiners are configured to combine DC power produced by solar generators respectively connected thereto and provide the combined DC power at outputs thereof, wherein the PV tie device is configured to couple a midpoint potential of the series connected combiners to ground during operation of the power plant, and wherein the homeruns transmit the combined DC power to an old inverter for conversion into AC power for feeding into an AC grid connected to the old inverter, the repowering kit comprising:

• at least one galvanically isolating DC/DC-converter for each combiner of the pair of combiners configured to galvanically isolate the homeruns from the solar generators;
• a new inverter configured to vary a potential on the homeruns relative to ground during operation of the power plant;
• and
• an interconnection structure for interconnecting the combiner outputs between the homeruns,
• wherein:
• a number of galvanically isolating DC/DC converters equals the number of combiners,
• the solar generators each comprise a number of strings, and the number of galvanically isolating DC/DC converters equals the number of strings, or
• the solar generators each comprise a number of strings, and the number of galvanically isolating DC/DC converters equals half, one third or one fourth of the number of strings.

A method of repowering a photovoltaic power plant from a first configuration, wherein in the first configuration, a pair of combiners is connected in series between two homeruns via a PV tie device, wherein the combiners are configured to combine DC power produced by solar generators respectively connected thereto and provide the combined DC power at outputs thereof, wherein the PV tie device is configured to couple a midpoint potential of the series connected combiners to ground during operation of the power plant, and wherein the homeruns transmit the combined DC power to an old inverter for conversion into AC power for feeding into an AC grid connected to the old inverter, the method comprising:

• removing the PV tie device and interconnecting the combiner outputs by an interconnection structure with no coupling to ground;
• introducing at least one galvanically isolating DC/DC-converter at a combiner output for each combiner of the pair of combiners such that the homeruns at outputs of the respective galvanically isolating DC/DC-converters are galvanically isolated from any of the solar generators;
• coupling one terminal of each of the respective solar generators to ground;
• and
• replacing the old inverter with a new inverter, wherein the new inverter is configured to vary the potential on the homeruns relative to ground during operation of the power plant.