String Inverter

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String Inverter

A solar inverter is one of the instruments that is used to convert energy produced by solar panels into a current that is usable for a household. Solar Inverters are a key piece of equipment in the electrical energy generation process. They are used to convert direct current (DC) energy into alternating current (AC) energy. This is important because household appliances are not compatible with DC energy and cannot use it directly because of its high voltage. An inverter is needed to convert the energy to AC energy, which is the form of electricity used by virtually all household appliances and electronics.

How String Inverter Work

String inverters are one of the main options when it comes to converting the energy collected by solar panels into a more manageable form that is suitable for home use. The energy gathered by solar panels cannot be directly used in most applications because it is produced in the form of direct current energy. This current contains high voltage that is too high to be safely used by common appliances. Since direct current is incompatible with most electronic devices, solar panels need inverter systems that can convert their generated energy into a usable form. An inverter works by converting generated DC energy into AC energy that can supply the electricity needs of the home.

String inverters have been around for quite some time and they are older than other types of inverters, such as micro inverters and power optimizers. Because of this, the string inverter is already a tried and tested design for solar panel systems. String inverters are designed to work in a sequence. Imagine Christmas lights where the lights are connected by a wire and the string is controlled by one plug. Solar panel systems with string inverters are set up similarly. A wire runs from panel to panel and connects them in a particular sequence. The energy collected from each of these panels is sent to a central inverter where the DC energy is converted to AC energy. In this setup, there is only one central inverter that processes the energy generated by the entire system. The string inverter definition is essentially any system by which a series of solar panels are connected by wires to create a solar string that sends the energy to a central inverter for conversion to usable AC power. The solar string is a cost-effective option to set up a system since the design relies on only a single inverter to perform all the energy conversion for an entire string panel sequence.

The Pros and Cons of an Inverter String System

An inverter string comes with several advantages and disadvantages. As the method that has been used for the longest time, it has already been extensively developed to iron out past issues. It is cost-effective compared to other inverter technologies since it does not require multiple pieces of equipment to set up. Having a limited number of hardware pieces in the system ensures simplified maintenance and upkeep since there are fewer components that can malfunction.

The central inverter may also be placed in an easily accessible location, such as on a wall or in a sheltered area. This prevents the inverter from getting exposed directly to sunlight and other harsh weather conditions, which is an issue with micro inverters wherein the inverter is set up near the solar panels. Having the essential equipment placed in an accessible location also makes it easier to maintain as well as more convenient to repair.

On the downside, a string inverter system needs a constant supply of sunlight. This technology is not recommended if the string panel system has an uneven supply of sunlight across the generation area. A solar string is only as good as the weakest panel. For example, if one panel is shaded or malfunctioning and is underperforming, its performance would affect the output of the whole system. The performance of each panel is dependent on the others in the series. If one panel is not working, it creates a limitation that hampers or even shuts down the entire series. The solar panel system can be rendered useless until repair when a part of the system is damaged.

For this reason, a solar string inverter is not recommended for areas where the sunlight on the surface area is not dependable. This includes uneven roofs as well as areas at risk of shade from trees and nearby tall structures. Once a panel is shaded, it will affect the sequence of the inverter string, affecting the energy output of the system as a whole.

Considering Multi String Inverters

In cases of a larger setup with multiple solar panels, a multi string inverter setup may be needed. For example, consider a system that requires 30 solar panels. It would be hard to set up a single string to form a line of 30 panels. The panels may be laid into six rows with five panels. In this case, a multi string inverter setup would run individual strings for the six rows and connect them with a single string inverter.

How 3 Phase String Inverter Work

One of the innovations of string inverters is the 3 phase string inverter. The 3 phase string inverter was once limited to the small- and medium-scale commercial market but is now available for residential applications as well. It is designed for applications in which a higher conversion capacity is needed.

A single central inverter can only handle so much energy, which limits the number of solar panels that it will support. This issue can be addressed by micro inverters, which installs an independent inverter for every solar panel, but this setup can be costly.

A 3 phase string inverter is a viable option to save on cost, especially if the size of the project is too large for a system to provide a separate micro inverter for every solar panel. In addition to a larger capacity, three-phase string inverters also allow more flexibility in managing environmental factors. This inverter can accommodate variable string lengths to allow for more flexibility in the setup.

Although not as efficient as micro inverters, the cost difference is something to consider when factoring in which would be more viable in a given situation.

SMA string inverter is one of the leading providers of string inverters. They provide different inverter options depending on the needs of the user. The products that they provide feature innovations aimed at addressing the issues arising in a solar panel system. Sunny Boy string inverter is one such product. It features easy plug-and-play installation and installs automatic updates to its software via ethernet and WLAN. While a string panel requires a single inverter for the system, SMA can minimize downtime by providing a replacement within one to three days if the inverter is faulty. They also provide compensation if a replacement cannot be provided within three days.

Inverters have a maximum capacity that dictates how many solar panels they can accommodate. In order to calculate the maximum voltage that an inverter is capable of handling, you’ll need a solar panel string calculator.

SMA provides a free calculator to help their customer compute their needs and match it with the proper inverter system. The SMA string calculator can be used to determine both the number of strings and the number of modules per string for a solar panel system setup.

The SMA string calculator can also compute the ideal load for each inverter and match those numbers with the product best suited to handle your needs.

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