Photovoltaic surge protection is necessary in both the commercial and residential markets of solar power production. The solar panels that are used in both processes are highly susceptible to damage as a result of both direct and indirect lightning strikes. This is predominantly due to the physical makeup of the panels themselves, as they are flat and large with completely exposed surface areas. In addition to their physical structure, solar panels must be positioned in a way that they are unobstructed so as to collect the largest amount of sunlight that is available. This geographic placement positions them in areas that are both remote and many times the most accessible and available point for lightning to strike in order to make the easiest transfer from the earth. Lightning strikes and surges can couple into power lines running to and from the sites as well, creating double the amount of potential catastrophic failure that can be associated with power surges. The high replacement cost and repair expenditures only add to the losses that are seen when there are significant down times.
The largest cause of failures in PV systems is attributed to the static discharge related to lightning strikes. If the strike happens at the panel it can easily create an extremely large power surge that travels through the system and damages equipment like inverters, electronic controls and string boxes. Even lightning strikes that occur several miles away and may be totally invisible from view within the area of the PV system can produce significant amounts of damage, as voltage surges traveling through the wiring and along the power lines can proceed unimpeded to make contact with sensitive equipment. Without the proper grounding and protection systems built in, massive amounts of damage can occur anywhere between the panel and the equipment utilized in the process.
It is common for residential customers to not provide proper grounding of their systems. Many times a good ground to earth is difficult to achieve, and other times improper grounding is simply a result of poor installation techniques. The most common technique of surge protection is the diversion of lightning strikes to a piece of equipment or area where it can be properly transferred to earth. Without the proper grounding, these types of systems provide little protection. The additional installation of surge protection devices is the most effective method of protecting equipment inside the system, as they are the last line of defense between the sensitive equipment and the incoming power surge. Through the strategic position of these devices at junction boxes and along transfer lines, always installed in a redundant fashion, the brunt of the damage that is caused by lightning strikes can be isolated to the strike point. Through the effective minimization of damage as a result of this common occurrence, solar power production up times can be extended making systems more effective at power production, as well as reducing the operational costs of PV systems in general.