Inverters for solar installations offer greater flexibility and are capable of adjusting to the changing levels of solar radiation. These inverters come with displays to monitor current and power, and have robust designs in keeping with the functions they perform
By Shweta Sengar
Thursday, December 18, 2014: The inverters for solar installations are commonly known as ‘power centres’. They form the most significant part of the solar power system. A power centre is basically a combination of inverters, charge controllers and safety components. Together these are responsible for running the solar power system. These inverters come in the form of grid-tied or on-grid inverters and off-grid inverters. Inverters for solar installations convert solar power/DC electricity into utility grade electricity/AC electricity that is fed directly into homes and commercial buildings. Through the displays on the inverters one can also find out how much energy or power the system is producing and how much is being used. Inverters for solar installations are available for various applications ranging from small solar energy systems to MW plants. These inverters are highly efficient. Also, there are inverters available in the market that are very useful for sites that receive low levels of solar radiation.
The latest in the market
With time and with technology upgradation, inverters for solar installations have become more advanced and smarter. There are many players manufacturing these inverters. Currently, they offer numerous features which have made them more efficient. The latest inverters are capable of rapidly adjusting to ever changing solar radiation levels, come with displays to monitor current and power, and have a robust design in keeping with the functions they perform.
User friendly: Conergy recently launched its IPG T series of inverters for solar installations. These are three phase string inverters for grid-connected medium sized photovoltaic (PV) systems. The Conergy IPG T series is available in performance categories of 8, 11 and 15kW. Extraordinary peak efficiency factors and high quality make these inverters an apt choice for high system yields. The inverters are simple to operate and this makes them more user friendly. They are easy to install and maintain, and come with external and internal mounting options. The three phase design of the inverter rules out any possibility of imbalanced grid loads. Also, the Conergy IPG T inverters are flexible and run with almost all system configurations and module types.
Connectivity and controls: Su-Kam has launched a series of inverters for solar installations, branded the Solar PCU series in the following configurations: 100VA/24V, 500VA/24V, 600VA/24V and 1000VA/24V. The inverters offer higher efficiency in charging as well as discharging with galvanic isolation in low DC bus system. Additionally, the inverters are also equipped with an improved power factor in grid charging, on-board data logging with RTC, a high end processor to control system functions and input/output energy measurement. The inverters have a MPPT based solar charge controller with a peak efficiency of 96 per cent in low DC bus system.
Interesting additions to these products are a remote connectivity and monitoring facility, and a smart control scheme to give preference to solar power utilisation. They have an output energy meter that displays the following parameters—inverter output AC V, I, VA and kWh. The charging and discharging current, along with the graphical indication of battery status, is displayed on the panel. The inverters utilise solar power as a primary source of energy. Also, the inverter has an integrated MPPT based solar charge controller that uses a microcontroller for accurate tracking of the maximum power point of the PV module, with efficiency. Apart from this, the inverters from Su-Kam give a true sine wave output to increase load life and have in-built protection against overload and short circuits.
Sturdy designs: Eaton’s Power Xpert 1500/1670kW solar inverters are specifically designed to bring down the cost of electricity. The inverters lower the installation and upfront costs, thereby boosting a plant’s dependability and minimising maintenance expenses. The sturdy and feature laden inverters have a fault tolerant and segmented design consisting of 3 x 500kW (550kW) stacks. The compact design boosts the efficiency and life of the inverters. Eaton’s inverters are designed keeping in mind the harsh weather conditions and working environments in India. Additionally, the MW block design of the inverter cuts installation costs by decreasing equipment count, field wiring essentials as well as transportation and handling expenditure. Its liquid cooled design enables critical equipment to be encapsulated in a dust- and water-free environment.
Maximum output at minimum costs: SMA Solar India’s Sunny Central 900CP XT is a powerful inverter for solar installations available at fairly affordable prices. The inverter can achieve maximum yields at minimum system costs. The Sunny Central CP XT is also perfect for cold temperatures, as low as -40°C and with full nominal power for round the clock operation at up to 50°C. The inverter encompasses all grid management utilities. The customised computer platform allows for optimal monitoring and control. The inverter yields a peak output of up to 1MW. It also has an intelligent power management system and a wide DC input voltage ambit for versatile use in diverse power configurations. The inverter is equipped with advanced technology. It is powered with all grid management functions and includes pure reactive power operation.
How to choose the right product
There are lots of choices when it comes to zeroing in on an inverter for solar installations. There are many big companies manufacturing inverters for solar installations—companies like Su-Kam, Nordic, Conergy and Eaton, to name a few. Here are a few factors that users should keep in mind before purchasing an inverter for solar power systems.
Efficiency: Efficiency is the most important factor that must be borne in mind. A buyer must note how efficient any inverter is. This can be ascertained by enquiring about the input/output ratio, usage and solar power utilisation. Apart from this, an inverter should also offer protection from short circuits and overload.
Design and durability: Design is an important factor that a potential buyer must consider. It is of utmost importance that the strength of the inverter is studied. One should make a note of the raw material used in the production of inverters for solar installations. The body of the inverter should be well built so that it lasts long. These days, inverters for solar installations can also be mounted on a wall, which frees up valuable floor space.
Features: The latest inverters for solar installations come loaded with features. With the advances in technology, these inverters are equipped with numerous features.
IEC certifications: Experts suggest that a buyer should always invest in inverters that comply with all the energy standards. A buyer must check that the inverter being purchased has IEC certifications for efficiency, climatic conditions and safety.
Maintenance, warranty and service support: Maintenance of these inverters is another big factor that should be kept in mind when making a purchase decision. The maintenance cost of the inverter should not be high. Besides this, users should always opt for products that offer a good warranty and after sales services.
Conergy IPG T inverters
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Split second variable tracking for variable light conditions
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Peak efficiency factor of
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98 per cent
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Optimum energy yield even in low light
Su-Kam inverters
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Peak inverter efficiency of 89 per cent
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RS-232 port for monitoring and data logging/retrieval
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IEC test reports as per MNRE guidelines
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Input power factor of grid battery charger with >85 per cent efficiency
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Solar charge controller with peak efficiency of 96 per cent
Eaton’s Power Xpert 1500/1670kW solar inverters
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True reactive power (VAR) support
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No power de-rating up to a ± 0.91 power factor range
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Liquid cooled design
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3 x 500kW (550kW) stacks
SMA Solar India’s Sunny Central 900CP XT
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Maximum input voltage of 1000V
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Maximum DC power of 1010kW
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MPP voltage range—722V – 850V/656V – 850V
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Rated input voltage – 620V
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Maximum input current – 1400A
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HMI touchscree
