Is using the string box really necessary?

The application of the string box, although it is gaining more and more prevalence in the photovoltaic energy market, is still poorly understood.

Therefore, there are still those who opt for manufacturers that offer inverters with protection devices – such as DPS (Surge Protection Devices) – already integrated.

The objective of this article is to explain to you why the string box is a much better option for your production, both in a practical and profitable sense.

String box protection is greater

A DPS coupled to the inverter provides the system with much less protection. Therefore, a higher intensity surge puts the inverter at risk of suffering a series of internal damages due to the abrupt increase in temperature.

If the inverter does not stop functioning at the first intense overvoltage it detects, the wide range of damage received can reduce the DPS's protection capacity and shorten its useful life.

On the other hand, the DPS systems present in string boxes have a greater protection capacity, absorbing overvoltage energy in a much less damaging way to the system. Furthermore, the DPS will be isolated from the rest of the system, not causing damage to the inverter in the event of a maintenance problem.

String box inspection and maintenance are much more practical

Firstly, the ABNT NBR 5410 standard does not allow components linked to a specific supply to share distribution boards and lines with elements from another supply.

When protection is integrated into the inverter, it does not allow visualization and inspection to be carried out in a practical way, making maintenance difficult.

In this case, it is essential that the protection device is visible and separated from the power supply board, so that it is accessible for inspections. The string box meets the demands of the standard, allowing access to the protection system in a practical and visually easy way.

Replacing parts in the string box is much faster

Replacement parts are, without a doubt, the string box’s greatest asset. Once the DPS reaches the end of its useful life, replacing components is simple, quick and safe, as replacement parts are available for purchase in easily accessible places, such as in specialized stores or from the manufacturer.

In the case of the integrated inverter, the process is a little more complicated. Changing parts in the attached DPS is much more expensive — because it is fixed to the board, there needs to be a removal process. Then, the parts to be replaced are much more difficult to find and, in many cases, the device will have to be returned to the manufacturer for maintenance.

The complete process can take months. These are months when production will be on stand-by, damaging earnings.

Is the string box really necessary?

The conclusion to be drawn from this text is that, yes, the string box is the recommended option for protecting photovoltaic systems. The use of inverters with integrated DPS is proven to be less effective and potentially harmful to long-term production, as their durability and useful life are much shorter.

Therefore, in the planning stage, it is necessary that all parties involved have the vision that the string best meets regulatory demands and guarantees greater quality and safety for a long-lasting and lasting system.

The opinions and information expressed are the sole responsibility of the author and do not necessarily represent the official position of the author. Canal Solar.