Tips for Replacing PV Modules in Existing Power Stations and Solutions to the Dilemma of Spare Parts (2)

For photovoltaic power plants using centralized inverters, the issues that should also be paid attention to are:

1) In the model of the fuse in the combiner box, the current rating of the fuse should be calculated according to the short-circuit current of the new component, so as to select a more matching fuse.

2) The model of the combiner box circuit breaker. Since the voltage and current of the string will change correspondingly after the component is replaced, it is necessary to judge whether the voltage level and current of the circuit breaker still meet the requirements.

3) Calculate and verify the cross-sectional area of the outgoing cable from the combiner box, and whether the current carrying capacity and the voltage drop of the cable are within the range required by the specification.

4) The optimization problem of the string. Due to cost factors, box transformer capacity limitations, etc., it can only be partially replaced in batches, and the PV strings under the same inverter may have voltage mismatch problems. Therefore, it is also necessary to optimize the voltage of the string through technical means.