Tags from CORE1

Easy, Reliable and Cost-Effective Rapid Shutdown Compliance Utilizing the SunSpec Standard

The requirements of 2017 and 2020 National Electric Code (NEC) section 690.12 – entitled Rapid Shutdown of PV Systems on Buildings – currently mean that module-level power electronic (MLPE) devices must be installed with PV systems installed on buildings, even if they are not appropriate for energy optimization reasons.  As microinverters and standard DC optimizers solutions are closed, proprietary solutions, their use locks installers into depending on a single source for equipment and replacements.

As discussed in the first blog post of this series, the SunSpec Alliance has the goal of creating industry-wide standards to resolve issues like compliance with Rapid Shutdown requirements. Their Rapid Shutdown standard allows for multiple vendors to certify equipment to an open, published standard – allowing installers to choose between interoperable devices and avoid being locked into a closed ecosystem to comply with code.

SMA rapid shutdown certified devices.

SMA has been a global leader in PV technology for almost 40 years.  SMA America will celebrate its 20th anniversary in September 2020 and has long been a technology leader: first with UL certified inverter-integrated AFCI as well as the first to achieve UL1741 SA smart inverter certification. SMA’s success is based on ensuring that it delivers safe and reliable equipment that reduces the time installers must spend on a roof installing or servicing PV equipment.  With Rapid Shutdown now requiring module-level power electronics for rooftop PV systems, SMA faced a daunting challenge to provide a fully code-compliant solution that also minimizes reliability impacts, while ensuring optimal energy yields. The SunSpec rapid shutdown standard provided a perfect complement to SMA’s ShadeFix optimized residential and commercial string inverters to achieve this goal.

The functioning of the SunSpec rapid shutdown process is very straightforward.  Two components are required – a transmitter and some number of receivers.  The transmitter is responsible for imparting the SunSpec rapid shutdown power-line signal onto the DC conductors that go between the array and the inverter.  The receivers are responsible for detecting the signal on those conductors.  While the signal is present, the receivers do nothing. When the signal disappears, the receivers are responsible for lowering the array voltage below the code limits within the code specified time after rapid shutdown is “initiated”. They isolate their modules from the string they are part of, without breaking the string, and provide a low, “standby” voltage on their output conductors if the SunSpec signal is absent. This power-line communication signal is a “keep-alive” signal that does not require any additional wired or wireless communications channel between the array and inverter. It is important to highlight that the SunSpec certified receivers do not perform any power conditioning function or transmit information about the array operation, thereby allowing them to be very simple and robust devices.  This is important, as there may be many hundreds of these devices scattered throughout the harshest environmental conditions of a single large commercial rooftop installation. Time spent servicing failed MLPE devices is time not spent installing. rapid-shutdown-cert_vert-color

SMA America has integrated a transmitter certified to the SunSpec rapid shutdown standard into both our residential Sunny Boy US-41 and commercial CORE1 US-41 inverter lines. This transmitter, when enabled during commissioning, begins to impart onto the DC conductors connected to the array the SunSpec rapid shutdown “keep-alive” signal.

SMA’s approved SunSpec certified rapid shutdown receiver can support most residential and commercial module choices, meaning only this part needs to be sourced when using either SMA’s residential or commercial string inverters. This makes stocking and allocating inventory as easy as possible for installers and equipment distributors. Furthermore, SMA’s string inverters do not require the SunSpec shutdown receiver units to function, so if the PV system does not require rapid shutdown (e.g. a ground mount) then the receivers are simply not installed. Commissioning with SunSpec shutdown is fast since there is no detection step required for these MLPE or a layout map creation step for module-level monitoring.

The SMA inverter-integrated SunSpec transmitters are configured to stop broadcasting the “keep-alive” signal whenever the inverter senses a loss of utility voltage and frequency on its AC terminals. A first responder will shut off utility power to a site as an initial step to fight a fire, so this means the rapid shutdown “initiator” – loss of AC power – is something that would be done even if that responder has no formal training on how to recognize and utilize rapid shutdown equipment on a PV system.

Finally, the existence of the SunSpec rapid shutdown open standard means that multiple vendors can provide receiver devices that mirror trends in the PV module market. More devices with a wider range of options and sizes are available to installers than SMA alone could reasonably provide, and module manufacturers can even build the receiver capability within their module’s junction box directly. These devices (and the installer installing them) are not dependent on an SMA inverter to ensure rapid shutdown code compliance, simply another certified transmitter, inverter-integrated or stand-alone.

The existence of the SunSpec rapid shutdown standard has allowed SMA America to improve its ShadeFix optimized string inverters to provide the industry’s fastest-to-install, most reliable and cost-effective solution for any PV system needing to achieve 2017 or 2020 NEC 690.12 compliance.

 

0.00 avg. rating (0% score) - 0 votes

Solar Installation in a Class of Its Own

Carport solar project brings savings to the classroom and the environment.

Students returning to the Smithtown High School West campus this fall will park under a new clean energy solar parking structure. The new solar installation brings the benefits of carports—a cost-effective and innovative way to generate power—to Smithtown, a sprawling eastern New York City suburb on Long Island.

Solar carport with CORE1 inverters

The school district administration understood the carport solar project would significantly reduce the overall electricity bill for the campus. Those savings are now reinvested in educational programs, proving educational solar projects are an investment in the future, in both education and the environment.

By installing solar panels on a parking structure, Smithtown High School West can now leverage this otherwise under-utilized surface to produce clean electricity and actively lower energy costs every day. The system was installed by Sunrise Power Solutions, the leading solar energy partner to the K-12 educational market in the New York area.

“This is a popular option among the K-12 municipal industry as money saved from lower energy bills can be directly reallocated back into education,” said Kristian Ingebrigtsen, chief operations officer at Sunrise Power Solutions.Solar carport

The carport features 5,421 JA Solar panels and 29 SMA SUNNY TRIPOWER CORE1 inverters. The CORE1 products were ultimately selected for this project because of their flexibility,

reliability and competitive cost, which the school district considered as factors that would benefit the community.

“We were proud to work on this project as we know it will benefit the community for years to come,” said Ingebrigtsen .

The project has a total size of 2.06 MW and an estimated annual output of 3.345 KWH. Based on projections, the parking structure will offset 90% of the energy production for the campus, reducing both budget expenses and the amount of carbon in the environment.

SMA Public Relations Contact

5.00 avg. rating (97% score) - 2 votes

Argentinian Company Unearths Clean, Renewable Technology

In Cerro Negro Córdoba, Argentina, sits the Fluorita Cerro Negro hybrid PV-diesel plant. It powers a mining operation that specializes in fluorite extraction and processing, without any grid service to power its operations. Historically, the facility has used diesel generators to keep the power on. This process previously required 42 liters of diesel fuel per hour of operation.

To achieve cost-savings efficiencies and utilize cleaner, renewable technology, the facility has now transitioned to a new PV-diesel hybrid solution. The project features two SMA Sunny Tripower CORE1-50 inverters. In total, the project is estimated to produce more than 150,000 annual kilowatt-hours of energy. The PV system also includes 600 Amerisolar panels on a Magnelis® steel structure and one SMA Hybrid Controller S.

The installation is expected to generate a savings of 45,000 liters (11,800 gallons) of fuel per year, preventing approximately 135 tons of carbon dioxide from entering the atmosphere each year—the equivalent of planting 7,158 trees annually. But the benefits of the installation at the plant extend beyond this environmental benefit.

CORE1 commercial inverter“SMA provides a complete hybrid generation solution with additional features for full integration
between inverters and PPC,” said Juan José Aparicio, system engineer at Ascentio Technologies. “The implemented solution also has a friendly interface that allows remote support, a specialized SCADA solution through Sunny Portal, on-site weather information and performance ratio calculation with real-time trend analysis to simplify activities from O&M.”

When possible, the Hybrid Controller (HyCon) allows PV energy to be used with priority over the energy from the generator. HyCon also protects generators against common problems related to reverse power, the power factor or spinning reserve assurance.

At the facility-level, full integration and digital remote management ultimately made fault detection, isolation and recovery services simple. These benefits are especially valuable in locations, such as Cerro Negro Córdoba, where specialized services are expensive due to distance and difficult access.

The engineering, procurement, construction, and commissioning of the installation at the hybrid PV-diesel plant was completed in 4 months, launching in late 2019.

Visit our picture gallery!

0.00 avg. rating (0% score) - 0 votes

Tech Tip: Installation of the TS4-R-F Line of SMA-Compatible SunSpec Certified Rapid Shutdown Receivers

In our latest Tech Tip video, SMA Solar Academy Senior Technical Trainer Mike Mahon demonstrates how to install the TS4-R-F line of SMA-compatible SunSpec certified rapid shutdown receivers.

These devices, when paired with the SMA US-41 line of Sunny Boy or CORE1 inverters, provide easy-to-install, reliable, module-level shutdown to meet all the 2017 and 2020 NEC requirements.

The Tech Tip video covers the installation of SMA’s TS4-R-F unit—the first SunSpec certified shutdown receiver tested to ensure full compatibility with the Sunny Boy US-41 and CORE1 US-41 lines.

To learn more about all the benefits of the TS4-R-F line, watch this video or visit the webpage.

5.00 avg. rating (96% score) - 1 vote

Paradise Energy Solar Carport Project Revs Up the Savings

When the team at Turn 14 Distribution, a premium vehicle performance warehouse distributor with corporate headquarters in Horsham, Pennsylvania, wanted to install a solar project, it turned to the experts at Paradise Energy. Paradise Energy is a full-service solar installation company that provides turnkey, grid-tied solar installations throughout the mid-Atlantic region for businesses, farmers and homeowners.

Paradise Energy

Continue reading »

5.00 avg. rating (98% score) - 3 votes

SMA Sunny Tripower CORE1 Inverters: Repowering Ready

Part II: Maximize and Protect

In the first installment of this series, we focused on MPP voltage. This post will explain how to maximize the number of strings connected to a string inverter and protect the inverter from damage. The strings are limited by the number of terminals and the maximum short-circuit current of each individual maximum power point tracker (MPPT).

CORE1 multiple strings

There are ultimately two advantages of checking the short-circuit current: to maximize the number of strings per inverter and to prevent inverter damage in the event of a string fault with a high DC current. Compared to 600VDC systems, modern PV systems have longer strings with higher MPP voltage, requiring fewer strings in parallel to reach the same capacity. Contemporary inverters can, as a result, handle a comparatively higher voltage with limited current capacities.

Still, a new inverter placed into an existing system must match the current requirements. There are two numbers to check to ensure that’s the case:

  1. Maximum operating input current
  2. Maximum short-circuit current of the inverter/MPPT

First, system age is an important consideration since older modules may not reach their maximum operating input current, even under the best conditions. In most cases, the DC/AC ratio has more influence on clipping than the maximum operating input current. Customers have, however, in some repowering projects, experienced up to a 20% higher module MPP current than the inverter’s maximum operating input current without a loss in production.

It’s also important to focus on the maximum short-circuit current of each inverter MPPT. As mentioned above, there are two reasons to investigate this value. Let’s dive into the specifics of how and why to ensure you’re ready for repowering.

Ready to Repower?

One reason to repower is to protect the MPPT of the inverter from damaging current. These elements include the maximum short circuit current per MPPT, the safety factor and the short-circuit current of the chosen module of two parallel strings.

Let’s look at an example using the SMA CORE1:

  • Module type: Sunmodule Plus SW290 MONO from SolarWorld
  • Standard safety factor: 1.25
  • Maximum short-circuit current: 9.97A

The maximum short-circuit current of the PV design is then calculated by multiplying the short-circuit current of the module (9.97A) by the number of strings (2) and by the safety factor (1.25). Multiplying these values equals 24.93A. The total must be less than the maximum short-circuit current of one MPPT of the CORE1, which is 30A.

Thus, this design works and matches the inverter limits, allowing connection of two strings directly to one MPPT. Three strings would risk permanent damage to the inverter.

The second reason to check the maximum short-circuit current per MPPT is so you can calculate the maximum number of strings that can be connected to each MPPT. In the aforementioned scenario, two strings are the maximum allowed per MPPT. Some installed modules in older designs, however, have a lower short-circuit current. In such cases, the maximum short-circuit current per MPPT must be divided by the safety factor and by the maximum short-circuit current of the modules installed.

When determining the maximum number of strings to connect to one MPPT in parallel, you can round the results down. Let’s look at an example:

  • Module type: Ultra 175-PC from Shell
  • Maximum short-circuit current: 5.43A

And here’s the math: The maximum short-circuit current of the MPPT (30A) divided by the safety factor (1.25) and by the short-circuit current of the module (5.43) results in 4.42 strings. Once rounded down, it shows that a maximum number of four strings can be connected in parallel to one MPPT.

string inverters formula

Why calculate the maximum number of strings, especially when repowering?

The existing strings are typically very short (about 10 to 14 modules), which results in a low string voltage. Combined with a low current, those strings have a low power output. Using the example above with the Shell modules, a string length of 12 modules with two strings per MPPT puts out 25.2kWp of total power under test conditions. The SMA CORE1, 33-US can handle up to 50.0kWp (DC).

Adding more strings until the chosen DC/AC ratio has been reached makes full use of the inverter capacity—underscoring why this is the second important reason to check on the maximum short-circuit current of the MPPT. Keep in mind, though, when more than two strings operate in parallel, each string requires protection, which is achieved by adding string fuses.

Now that you know how to correctly check both numbers, your repowering is set up for success—ensuring your system will be safe and efficient.

 

 

5.00 avg. rating (98% score) - 4 votes

Central American Clothing Manufacturer Decks Out Its Facilities with Solar Energy

Pinehurst MFG, a distinguished textile manufacturing company, is trusted with clothing production by world-renowned brands such as ADIDAS. The company now powers its operations using a solar system with SMA inverters.

Commercial solar Honduras

Continue reading »

5.00 avg. rating (97% score) - 2 votes

Hilton Hotel Upgrades to Energy Independence

Nestled in the exclusive Villa Fontana area of Managua, Nicaragua, lies the modern DoubleTree by Hilton hotel. Guests have long relaxed in the spacious rooms featuring elegant décor and breathtaking views of Managua Lake. With the new solar installation, guests now also know they are supporting a business that isn’t dependent on fossil fuels.

Solar system Managua

Continue reading »

5.00 avg. rating (97% score) - 2 votes

A Sunny Upgrade for Our Four-Legged Friends

Tucked into the northeast tip of Long Island lies the town of Southold. It’s a picturesque waterfront region with beaches, vineyards and now the first animal shelter in the state to be powered by solar energy.

Solar system drone photo

Continue reading »

5.00 avg. rating (96% score) - 1 vote

SMA Sunny Tripower CORE1 Inverters: Repowering Ready!

Would you like to discover a new level of PV performance? Then this blog post series on SMA Repowering is for you! In this article, our repowering expert Thorsten Hoefer shares insights on which aspects to consider when choosing an inverter for a repowering project and explains which SMA inverters are repowering ready.

Sunny Tripower CORE1 commercial inverter

Continue reading »

5.00 avg. rating (96% score) - 1 vote

Cattle Ranch Beefs Up Savings with Solar Energy

Argentina’s first solar energy plant for self-consumption earns attention!

Sistema solar comercial con SMA

Continue reading »

5.00 avg. rating (98% score) - 4 votes

Solar Spotlight: Naghtaneqed School Graduates to a Cleaner, Quieter Campus

Hakai Energy Solutions Delivers a Solar Hybrid Integration Project for Students in Canada!

solar school projects

The Naghtaneqed Elementary School sits nestled in the expansive Nemaiah Valley, three hours southwest of Williams Lake, British Columbia. In this First Nations reserve and ranching community, the school has—until now—been fully powered by diesel electric gensets for more than 30 years.

High operating costs associated with fuel purchase and ongoing maintenance motivated the district to explore solar power. The reliance on diesel also introduced pollution and noise to the campus. Thanks to clean, renewable energy, those issues are drastically reduced concerns today. The Cariboo-Chilcotin district hired Hakai Energy Solutions to install a solar project expected to save the school $50,000 CAD, roughly $37,000 USD, in annual diesel costs.

In July 2019, the school district invested in a hybrid energy system that integrated solar energy production, advanced energy storage and an expandable inverter platform. Utilizing 140 high-output solar panels, 118 kilowatt-hours of lithium energy storage and SMA inverter technology, this system was designed to offset diesel consumption by reducing generator operation by 6,900 hours each year.

Impressively, Naghtaneqed School is expected to recoup its investment in roughly seven years through reduced fuel consumption of approximately 38,400 L every year, plus generator maintenance and replacement cost avoidance. Not to mention, emissions reductions are also estimated at 2,534,000 kilograms of CO2 over the 25-year lifespan of the system, equivalent to 19,500,000 kilometers driven by a car.

“We’ve used SMA products from day one, and they’re simply unbeatable in terms of reliability, functionality and serviceability,” said Jason Jackson, energy system designer with Hakai Energy Solutions. “Working in remote areas makes product selection vitally important. Over the years, we’ve worked with every major manufacturer of inverters, and these experiences have only reinforced our confidence in SMA products. Every employee in this company—from the installation crews to the finance department—is on the same page. From a team perspective, SMA offers the most dependable and bankable suite of products on the market.”

In November 2019, the solar hybrid integration project was completed at the school. The total size is 57.6-kilowatt PV with 120 kwh lithium (LiFePo)-based energy storage and features 45 and 60 kW gensets. Every year, an estimated 72 megawatt-hours will be generated. What kind of impact does that have on energy consumption? A full 80% of the school’s energy will now come from the sun.

This PV array includes Longi Solar72 cell Mono bi-facial solar panels, six Sunny Islands, 1 SMA multi-cluster box and one 50 kW SMA CORE1. The district received funding for the entire project through the Ministry of Education’s program for carbon neutral funding via a community improvement award from Clean Energy B.C. for the project.

“This project has helped us meet our goal of reducing our environmental impact and improved the quality of experiences students have on our campus,” said Alex Telford, manager of facilities and transportation for the Cariboo-Chilcotin district. “When you factor in the cost savings, it’s a win-win-win!”

Visit our photo gallery to enjoy more pictures of this project!

5.00 avg. rating (97% score) - 2 votes