Corrente reversa no sistema fotovoltaico - O que é e como evitar

Gain access to all the spreadsheets from this channel, plus a complete solar energy course at the link below: https://hotm.art/pxYmAX Recommended books for photovoltaic energy professionals in my Amazon bookstore: https://amzn.to/3JBJItz Learn how to create automated spreadsheets like mine: https://go.hotmart.com/F92694337C?ap=... Are you a beginner in the solar energy market? Check out our e-book: https://www.hotmart.com/product/traba... Follow us on social media: Instagram: @eng.marcelbetoni Facebook: MCEletricaOficial Solar energy PAYBACK:    • Como calcular o PAYBACK da Energia Solar   The photovoltaic system is very safe, but if the installer doesn't know what they're doing, accidents like this can occur. This is the effect of reverse current in the strings. If you don't want this to happen with your projects and installations, watch this video until the end. Let's talk about solar energy? I invite you to join our FOTOTIPS community and receive first-hand the videos published on this channel, the content of our blog, and even exclusive weekly content. It's free, just click the link in the description. You've heard me say this a few times here on the channel, one of them was in this video, about some limitations of using string inverters, which are: 1- Do not place modules with different characteristics in the same string; 2- Do not place strings with different physical arrangements in the same MPPT; 3- Do not place strings with different numbers of modules in the same MPPT; 4- Adding a fourth item: Carefully evaluate shading; Ultimately, what all these rules mean is: DO NOT CONNECT STRINGS WITH DIFFERENT VOLTAGE LEVELS IN PARALLEL. Or as NBR 16690 states: "Photovoltaic series connected in parallel must have similar open-circuit voltages within a 5% margin." And why is that? When we connect strings in parallel with the same voltage level, the strings add their currents and power the MPPT of the photovoltaic inverter. When we connect strings in parallel with different voltage levels, the string with the lowest voltage will behave as a load in relation to the others. So, instead of adding the currents and powering the inverter, one (or more) strings will start powering another string as if it were a load. We know that if we only have two strings in parallel, the current level will be "low," or at least low enough for the photovoltaic modules. However, if we have three strings in parallel and two of them join to power the third as a load, the current can reach twice the short-circuit current, and can damage the modules in that string, even causing a fire. Reverse current usually occurs when the voltage difference between the strings approaches 10%. How to avoid it? The only way to avoid this effect is by using blocking diodes or overload fuses. Remember that overload fuses are provided for in NBR 16690 for arrangements with 3 or more strings. So, if your string diodes are burning out from time to time, know that the culprit is reverse current. Therefore, check if: Any area affected by shading is unbalancing the voltage level between the strings; All strings have the same number of modules; All modules used are of the same model, or very similar within a 5% tolerance of voltage level variation; Modules positioned differently from the others are causing voltage level imbalance in the strings. Once you identify the problem, just fix it. So? Did you already know everything about reverse current? Have you ever experienced a problem like this? Leave a comment below, and also share your suggestions for future videos. Thank you very much for watching this far, and until next time!