If you are a solar investor, a system designer or a solar architect, the question of choosing the right inverter for your solar installation must have crossed your mind several times. As it is one of the integral decisions of your investment.
If an array of solar panels is the body of a solar system then the inverter is its brain. Apart from its core function i.e. converting the direct current into an appliance/grid-friendly current, these inverters also function as a modest computing device and perform voltage tracking, grid communication and emergency shutoff.
In addition to that, they deliver analytical information to aid in regulating operations for maintenance to fix the potential issues in the solar installation.
With years of perpetual advancement in technology and innovation in design, solar inverters have now become smarter and play an essential role in the success of the solar power generation cycle.
Solar inverters can be classified into three parts;
- Central inverter
- String inverter
These are high-capacity inverters, majorly used in utility-scale and commercial solar farm projects, they centralize the power output in one place for the conversion of electricity from DC to AC.
For instance, let’s assume a central inverter topology where a PV array has three strings, each string consists of three panels connected in a series configuration. Before the connection of these strings to the utility grid, there is a necessity of a power conditioning unit to interface between them. Solar installers can employ a central inverter as shown in the picture, where all these strings are connected to the DC side of the inverter and only one AC output is connected to the grid.
It is one of the most conventional topologies, with a low cost per watt. Because of the simple system design, maintenance and troubleshooting, central inverters are convenient and handier in a big solar power plant.
This inverter has been prevailing in the solar industry for many decades. It is the most credible, tried-and-tested and cost-efficient inverter available in the market. It only optimizes the power output at a string level, not individual panel level.
It is best suited for installation with southern exposure without shade and the spaces which do not face multiple directions such as M-shaped roof or gabled roof. However, after considerable innovations and updates in the past few years, they are now suitable for a wider range of applications.
Typically, the power rating of string inverters ranges from a few 100 watts to 10 KW. As the name suggests, each PV array has an individual string inverter at the DC side and all the AC side is connected to the utility grid.
String inverters are extensively popular because they are smaller in size compared to the central ones and guarantee better MPPT capability. They have shorter DC wires and they monitor the solar installation at a string level. Further, they also offer scalability for future expansion. They are 1/4th the size of central inverters and can handle numerous sets of strings, depending on the size of the installation.
Micro inverters provide the most progressive technology with its plug-and-play feature. Rather than a string of panels, it is sized to suit the needs of an individual panel. Since it works independently, it offers superior production meaning one shaded or dirty panel will not affect its performance. It is inherently a reliable and safer option as there is no single point of failure.
These inverters mandate less maintenance as one impaired panel does not harm the harvest of other panels. They are effortlessly expandable and need less wiring. Nevertheless, they come with a higher initial cost and cannot be of any use in big solar plants, they can be used only on residential properties.
Why string inverters are better for utility-scale solar plants
With the continual evolution of technology and the immense adoption of solar worldwide, the demand for voltage and higher power ratings is also expanding. Solar investors, system designers and solar architects are constantly on the lookout for new ways to optimize the power conversion to make the solar system more cost-effective.
Nothing impacts the cost and performance of installation more than the decision of choosing the promising inverters for the solar plants. Earlier, utility-scale solar arrays were supported by central inverters for more efficient DC to AC conversion with better economies until high-power string inverters came into the picture.
Here are some reasons which make string inverters a well-suited option for commercial building and utility-scale solar plants;
Reap more yield with fewer inverters
String inverters allow optimization of high-voltage capacity through combiner-free design and with a limited number of PV clusters. By doing that, it curtails the Levelized cost of electricity (LCOE). The system will need 35-65% fewer number of inverters to deliver the same AC capacity which saves a lot of installation time, material, labour and expertise.
Due to accessibility, better redundancy, removal of DC cabling losses and high reliability, string inverters have a proven trajectory in the solar industry.
Serviceability – Operation and maintenance
These inverters are not as big as central inverters, should there be any failure, they can be easily replaced with the new one without the requirement of heavy machinery and expert crew. String inverters offer a high level of redundancy and plant availability.
For instance, if a solar plant has 100 string inverters and 2 of them breaks down, the energy yield of the 98 inverters will remain unchanged, providing 98% of system availability. Similarly, if the same happens in the central inverter, the production output will be severely hampered.
This way, string inverters ensure better performance, modularity and harvest efficiency. Meaning if some portion of the solar plant is under a shade or dust and the rest of them are in the sun/clean, the harvest will remain unharmed.
The weather-proof and fuse-free design with MPP tracker and wide DC input voltage range balance the cost of the overall system over the array’s lifetime.
Improved CapEx and OpEx
To make the most of the reduced operational and capital expenditure against the total system cost, the utility market is now driven to build the plant with higher voltage and power capacity. With MPPT efficiency greater than 99.9%, string inverters improve the LCOE of the plant by minimizing environmental impact and by enhancing trustworthiness. It has now become one of the preferred choices of solar architects and system designers as it drops the OpEx between 30-40%.
The key differentiator for future solar plants will be exceptional efficiency, durability, stability and its compatibility with the grid and within the architecture of the cluster. Owing to its smart communication, intelligent remote monitoring and control features, many solar utility farms are switching to string inverters.
It ensures maximum uptime and strengthens the productivity levels while streamlining the commissioning and installation processes.
Way forward with Novergy
We are a one-stop-shop for commercial, industrial and utility-scale solar installations. Novergy is a renowned EPC player with 13+ years of experience in the industry. It combines an expansive range of products with technical support and project management expertise under its umbrella.
Novergy solar inverters are available in a broad range of models and power ratings to meet the specific needs of a solar project. Novergy inverters have gone under a robust manufacturing process to meet IEC and MNRE standards.
The IGPB series which has power rating from 6kw to 67kw and the IGPB high power series which has power rating from 100kw to 250kw. They all come with a 5-year warranty and a 25-year design life. These inverters incorporate the best features such as very low DC-AC conversion losses, LCD, MPPT technology and pure sine wave output.
To explore our selection of inverters, visit novergysolar.com now!