The second part of the PV system consists of protective and control devices. These include overcurrent protection devices (circuit breakers, fuses), disconnect switches, and surge protectors. In large PV applications, a monitoring or measurement system may also be used. The configuration of these devices depends on the system size, the number of strings, their connection, and other requirements. These devices are typically installed in special enclosures, known as ‘photovoltaic installation enclosures’ (string box, combiner box, array box, junction box). It should be noted that in large systems, these devices may be part of the main inverter. DC distribution boards for photovoltaics are an integral part of every residential solar power system. The market offers a wide range of options, and the key to choosing the right DC box is to match it to the safety requirements of the photovoltaic installation.
The final segment of the DC part of the system is the inverter. It converts direct current (DC) into alternating current (AC). Inverters can be divided based on the input and output power, the number of phases on the output side, the type of system used – grounded or ungrounded, grid-connected or standalone.
