Geraldo Silveira

With collaboration from Oscar Witzig* Thanks to significant investments in research and technology, the photovoltaic sector has evolved considerably, increasingly bringing more robust products with different electrical characteristics. A great example of this are photovoltaic modules which, in a few years, significantly increased their output power, which consequently changed their main electrical parameters such as current and voltage. Today, it is quite common to come across photovoltaic modules that have a short-circuit current (Isc) with values close to 20 A. This ensures that the entire chain of elements used in direct current circuits has the capability to withstand these current values. This fact becomes more relevant when we consider that these values close to 20 A are in STC (irradiance conditions of 1000 W/m² and temperature of 25 °C) and, in Brazil, we commonly have irradiances significantly higher than 1000 W/m². In IV curve tests in different regions of the country, irradiances above 1.100 W/m² are often recorded, reaching, in some cases, close to or above 1.300 W/m². Since the current produced by the module is proportional to the light that hits the photovoltaic module, that is, it is proportional to the irradiance. This means that if we have 20% more irradiance, this gain will be reflected almost proportionally to the current generated. Thus, photovoltaic modules subjected to irradiances greater than 1.000 W/m² may generate a current higher than that shown in their datasheets, since they are under different conditions than those presented in the equipment's datasheet. An example can be seen in Figure 1, where an irradiance of 1.332 W/m² was measured in commissioning work, performing the IV curve test. Figure 1 - Irradiance and temperature measurement data from a real-world IV curve test. Another aggravating factor is the bifacial gain of the modules. A large number of modules sold in Brazil today are bifacial and these models have the characteristic of having a generation gain from the rear part of the modules, which directly impacts the increase in the output current of these modules. A clear example is the one presented in the datasheet below Figure 2, which presents the electrical data of a photovoltaic module from a large manufacturer on the market. Note that gains of up to 20% are already factored into its datasheet due to the bifacial gain of this module, which significantly alters the current values generated by this equipment. Figure 2 - Datasheet of a photovoltaic module showing the current gains that can be obtained from bifaciality. As connections are extremely important and critical elements to avoid accidents, losses and damage in photovoltaic systems, it is important to have adequate and more robust connectors to withstand the current values of the modules, which have been exceeding their values every year. With this in mind, this article presents the SC-6 connector from Proauto Electric, which, in addition to offering a new and practical way to connect photovoltaic modules, has superior current resistance compared to common connector models on the market. It works with modern photovoltaic module types with higher current capacity such as Trina, Canadian and Jinko. Figure 3 shows an image of the new SC-6 connector. Figure 3 - New SC-6 connector from Proauto Electric The SC-6 connectors were made with people who use solar energy and other renewable energy sources in mind. A major advantage of Proauto Electric's SC-6 connectors is that they have a new male and female fitting, making them safer than older models on the market with lower current ratings. This means it won't come loose easily. So, you can trust it to keep everything working properly and avoid connection problems. This brings more quality and safety, making the photovoltaic system more robust at the most critical points of the installation, which are the connections. Furthermore, Proauto Electric connectors support a much higher volume of power transmission than older models. This is because they have a current withstand of up to 50 A, which is crucial in systems that have increasingly higher currents. Figure 4 shows the electrical characteristics of the Proauto Electric connector when compared to other technologies on the market that also support higher currents. Figure 4 - Comparison with similar connectors on the market Note that the comparisons presented in Figure 4 refer to other connectors with greater current support. When compared to various other types of connectors on the market, the SC-6 connector has much higher tolerance, making it suitable for current modules with higher currents. Figure 5 presents a complete breakdown of the data for Proauto Electric's new SC-6 connector. Figure 5 - Datasheet for the SC-6 connector from Proauto Electric. Having a higher current capacity becomes more important because connectors can be installed in various ways, and installers are often instructed to make several different string connection schemes where paralleling is necessary due to some technical factors. This parallelism, often achieved using the well-known Y connectors, results in a circuit carrying twice the current. Therefore, it is essential to use a connector with a current withstand capability at least twice the value of the worst current that can flow through that string, so the connector must withstand a higher current. Highlighting the use of connectors with greater current flow capacity. Furthermore, the Proauto Electric SC-6 connector is TUV-NORD 62852:2014 certified, complying with international standards and guaranteeing maximum connection quality. And it has an IP-68 degree of protection, resistant to water and dust - and can be used even in the most critical places and with less favorable conditions. In short, Proauto Electric's new connectors are an ideal choice if you need to connect strings of solar power systems in a more robust, reliable and safe way. It is compatible with several different types of connectors and is designed to last a long time. *Oscar Witzig is an electrical engineer specializing in Alternative Energies, graduated from the College of Engineers HSR Hochschule für Technik Rapperswil / Switzerland. Specialist in Protection Systems Against Surges and Atmospheric Discharges. Lectures on Protection Systems at the College of Engineers in Peru and Guatemala, AMERIC Mexico, and the National University of Colombia.