Fronius launches inverter with integrated SunSpec rapid shutdown transmitter

Fronius rapid shutdown inverter

String inverter manufacturer Fronius launches the new Fronius Symo Advanced, a three-phase string inverter with an integrated Power Line Communication (PLC) transmitter based on the SunSpec Rapid Shutdown communication standard. In conjunction with the Tigo TS4-F cover, solar installers get a simple and cost-effective solution for Module Level Shutdown.

Jurisdictions with National Electrical Code (NEC) 2017 adoption require module level shutdown functionality in new solar systems starting January 1st of 2019. This requires all conductors within 1 foot of an array to be de-energized to 80V or less within 30 seconds of rapid shutdown initiation. This new requirement can potentially cause challenges and additional cost for solar installers, if the industry does not innovate.

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To provide solar installers with cost-effective, simple and innovative solutions, multiple members of the SunSpec Alliance defined an open industry standard for communication between modules, inverters and string combiners to support module level rapid shutdown requirements. This multi-vendor industry standard was published in September of 2017.

Fronius has been a driving force in developing this industry standard and was among the first ones to announce a product based on the standard. “We not only believe that industry standards have economic advantages for distributors and installers, but that they also ensure better safety. Since solutions based on a standard are known throughout the entire supply chain, we can achieve more safety and reliability. This is beneficial for the entire industry”, says Adrian Noronho, CEO of Fronius USA. “Furthermore, open standards give customers more choice”.

The new Fronius Symo Advanced three-phase inverter has an integrated Power Line Communication (PLC) transmitter based on the SunSpec Rapid Shutdown communication standard. This allows for plug & play connection with SunSpec based module electronics directly via the DC wires. In a first step the Tigo TS4-F cover is available. The solution eliminates the need for any additional communication hardware and provides the most cost-effective option for code compliance today.

This new inverter combines the benefits of the Fronius Symo with the convenience of an open industry standard. Featuring ten models ranging from 10 kW to 24 kW, the Fronius Symo Advanced is the ideal compact three-phase inverter for commercial applications. The light weight design, the SnapINverter mounting system and true field-serviceability allow for easy installation and highest reliability over the lifetime of a system.

In states with NEC 2014 requirements, the Symo Advanced can be mounted next to the array, eliminating the need for rapid shutdown boxes, since the inverter itself acts as rapid shutdown device. Thus, the Fronius Symo Advanced inverter provides a solution that adapts easily to the different requirements in different states – all with the same stock keeping unit (SKU).

Fronius starts shipping the Fronius Symo Advanced in January 2019.

— Solar Builder magazine

Rapid Shutdown and Beyond: Inside NEC 2017 and the effort to streamline PV design

collaboration illustration

New codes and regulations are notorious for raising prices and halting innovation in industries, but the new rapid shutdown requirements facing the solar industry are having the opposite effect. Thanks to a coalition of manufacturers and interested parties across solar, the solutions being developed to meet NEC 2017 Module Level Rapid Shutdown requirements will achieve something solar technology has long needed: common language.

“The intent is to create an open protocol for any manufacturer to apply,” says Michael Mendik, head of solution management, Solar Energy Division at Fronius USA. He has been an active member of the SunSpec Alliance, the group that has developed these standards. “Inverter manufacturers can build and design their own transmitters and then the rapid shutdown boxes will also be tuned to that language and can receive the signal. There is no proprietary stuff.”

“The current systems were designed to meet the previous rapid shutdown requirements using mostly proprietary communication systems,” says Mario Thomas, product manager at ABB. “Future system design will be vendor independent, allowing a better choice for the customer and the installer.”

“The solar industry is experiencing significant growth with new requirements, so we welcome the vendor coordination efforts and the wide adoption by many vendors working to improve the safety of clean energy production,” says Danny Eizips, VP of engineering at Tigo. “This is a great opportunity for multivendor support.”

This standard protocol has ramifications beyond the context of rapid shutdown, but let’s start there.

NEC 2017 changes

The 2017 edition of the National Electrical Code (NEC 2017) includes an update to section 690.12 Rapid Shutdown of PV Systems on Buildings. The update pushes the requirement to “module-level” rapid shutdown instead of the “array level” that was listed in NEC 2014. Effective Jan. 1, 2019, this requires conductors inside the array boundary to be discharged to 80 volts or less within 30 seconds of initiating a rapid shutdown event. This requirement comes in addition to the outside the array boundary voltage being limited to 30 volts or less.

At first glance, the changes didn’t require such a collaborative effort. Module-level electronics could have done the trick and piecemeal proprietary products and one-off collaborations from various manufacturers could have continued as usual. Luckily, that wasn’t the case.

The SunSpec solution

Formed in 2009, the SunSpec Alliance is a trade alliance of more than 100 solar and storage distributed energy industry participants, together pursuing information standards to enable plug-and-play system interoperability.

After nearly two years of intense technical collaboration, the Communication Signal for Rapid Shutdown Interoperability Specification was published in September 2017 as a method to comply with NEC 2017. This spec defines a communication protocol that uses the cabling of the solar array to transmit messages over the DC power lines between the PV modules and a master control device located near the inverter.

In addition, PV module manufacturers can implement the protocol on intelligent devices embedded in the junction box of each PV module. A master control device associated with the inverter communicates with the PV modules. Altogether, the specification enables plug-and-play interoperability and any-to-any rapid shutdown solutions.

“This open standard delivers multiple benefits to the distributed energy industry, most notably lower integration costs and the freedom to choose from an array of interoperable products,” saysTom Tansy, chairman of the SunSpec Alliance.

What’s this mean for me right now?

  1. If you are a big fan of installing microinverters, you’re already meeting these rapid shutdown requirements.
  2. As mentioned earlier, the implementation date for NEC 2017 is Jan. 1, 2019. Depending on the Authority Having Jurisdiction where you do business, you may not even be held to the NEC 2014 requirement right now, let alone NEC 2017 when it arrives. The Northeast portion of the country will be the earliest adopters, followed by California.
  3. If you are going to be held to NEC 2017 — or just generally would like to comply on your own — sit back and wait for these SunSpec-certified products to hit the market and design systems the way you always have.

“The complexity here is not on the installer end,” Mendik says. Manufacturers had to develop a transmitter that’s hooked to the DC line and puts in the signal.

Some of these solutions are already available, like the Fronius Symo. Other companies announcing immediate plans to incorporate the technology into their product lines include ABB, Maxim Integrated, Omron, Outback, SMA and Tigo. You can expect to see most of these around Q2 this year. There is no UL testing protocol yet to certify these products, but UL is part of the SunSpec Alliance, and you can expect this to happen soon.

Why else is this a big deal?

Not to be flippant about the importance of safety, but this protocol opens the door for way more impactful product developments. There’s an opportunity here to make your life even easier and bring the costs of a system down even more.

1. Proprietary boundaries will come down.

For starters, the array-to-rapid-shutdown-box-to-inverter architecture is more flexible. Prior to any updates, you had to procure the rapid shutdown box and the inverter from the same manufacturer. No more.

“The installer can install the systems as before and doesn’t have to worry about matching inverters of rapid shutdown boxes,” Mendik says.
So, that’s cool, but that flexibility goes way beyond the rapid shutdown, inverter pairing. “There’s no specific [module-level electronics] on the roof,” Mendik continues. “If there are different panels, they will be working with different rapid shutdown boxes. If one type of inverter in a system breaks, it can be replaced with another, and it will still work. A distributor can have different inverter types in stock for replacement, and everything will still be in line with the protocol.”

2. System designs will be streamlined.

Today, that rapid shutdown box is just an added expense, even now, after the protocol. This is why many installers prefer module-level electronics like microinverters, which meet rapid shutdown module-level requirements while also adding optimization, monitoring and design flexibility.

In the not-too-distant future though, this rapid shutdown box will be gone completely, even in a string inverter design. Soon, using this common language, module manufacturers will be including supped up junction boxes or chips from a company like Maxim instead of diodes. These will meet NEC 2017 and provide MLE performance with a string inverter design. This will keep costs and industry part counts down.

“An integrated module in the future, where the installer doesn’t have to buy and wire a specific rapid shutdown box … it’ll be like going back in time to when he didn’t have to worry about that,” Mendik says. “This also means you won’t have complex electronics on the roof. The standard forces you into more complexity for rapid shutdown, but the solution we’re looking at is simple electronics, not power electronics and doesn’t convert power from DC to AC.”

Thomas sums it up: “The customer in the end has a choice. I think that’s a big benefit. Customers don’t want to get stuck with one vendor and want the right to choose between different manufacturers. Having this choice and competition will reduce costs in the end.”

— Solar Builder magazine

SMA, Tigo offer new unit just for module-level rapid-shutdown

Tigo rapid shutdown SMA

SMA and Tigo have announced support of a new SunSpec compatible module-level rapid shutdown unit, the TS4-F (Fire Safety). The solution joins the current TS4 platform with a focus on emergency responder safety. It uses proven MLPE technology from SMA and Tigo to provide a rapid shutdown compliant platform, strictly focused on NEC compliance.

Two options

Tigo and SMA are offering two options for installation: The TS4-F is integrated into a smart module. The TS4-R-F retrofits a regular standard module with a module-level rapid shutdown device and is available through SMA.

“We have learned that commercial installers often need rapid shutdown capability but may see less need for optimization or module-level monitoring. Thus, they are looking for a cost-effective solution to provide the necessary safety functions,” said Nick Morbach, executive vice president of SMA’s Residential and Commercial Business Unit. “The new TS4-F and TS4-R-F units in combination with our SunSpec compatible string inverters will meet their needs, offering a high-quality option to comply with the NEC 2017 rapid shutdown requirements.”

The new rapid shutdown solution is a cost-effective way to fulfill UL 1741, NEC 2014, and NEC 2017 requirements – especially the stricter requirements for inside the array boundary that will be effective in January 2019. It will be compatible with the power line-based SunSpec Communication Signal for Rapid Shutdown, making it simple and robust. Using the existing DC wires between the inverter and module-level electronics as a communication channel will significantly reduce installation time.

The full system safety is enhanced by the integration with SMA’s arc fault detection (AFCI). They join SMA’s portfolio of products that comply with rapid shutdown requirements, including the Power+ Solution and the Rapid Shutdown System.

“We value SMA’s collaboration to offer this solution for residential and commercial installers,” said Zvi Alon, CEO of Tigo Energy. “We are confident that the safety features and cost-effectiveness of the TS4 platform will meet the needs of many customers.”

SMA is planning for its U.S. string inverter portfolio to be fully SunSpec Rapid Shutdown compliant in time for customers to meet the module-level rapid shutdown requirements of NEC 2017, which will become mandatory in most states by January 1, 2019.

— Solar Builder magazine

Tigo debuts its most cost-effective rapid shutdown solution yet

Tigo TS4 rapidshut down

Tigo released its new TS4-F (Fire Safety) to join the current TS4 Platform of integrated and retrofit/add-on junction box covers. As the most cost-effective rapid shutdown solution in the TS4 Platform, the TS4-F will accompany the family of products in the form of integrated PV modules by manufacturers worldwide. Consult your preferred PV module supplier or visit Tigo’s website for the new “integrated TS4-F” or “retrofit/add-on TS4-R-F,” available in Q1 2018.

As part of the TS4 Platform, the TS4-F utilizes the Ultra-High Definition Core (UHD-Core) and supports any PV module up to 475W with voltage up to 90V and current up to 12A. Furthermore, TS4-F uniquely supports the SunSpec Alliance signaling specification with powerline communication (PLC) and will work with any SunSpec-compliant rapid shutdown initiator. Tigo tested compatibility with multiple inverter suppliers – including SMA – and will continue to expand its compliant inverter portfolio .

The highlights of TS4-F include:

• NEC 690.12 2017 Rapid Shutdown solution
• Compatible with all modules up to 475W
• Supports SunSpec Alliance rapid shutdown specifications
• Compatible with all SunSpec initiators
• Module-level deactivation
• Automatic or manual shutdown
• Over-temperature and over-voltage protection
• Patent protected
• Easy installation
• Ultra-High Definition Core (UHD-Core) technology for superior performance
• UL-certified pending
• Available as a PV module integrated and retrofit/add-solution

“TS4-F was developed to offer our customers the first patent-protected MLPE in the market that supports SunSpec Alliance signaling specifications,” says Zvi Alon, CEO at Tigo. “For PV system owners who wish to address only the mandatory shutdown needs and do not require optimization or monitoring, the TS4-F provides a certified, cost-effective rapid shutdown solution with all the safety features of the TS4 Platform.”

What’s the difference between TS4-F and TS4-S?

Tigo’s TS4-F and TS4-S are both rapid shutdown devices, however TS4-F is a PLC SunSpec-compliant signaling while TS4-S uses wireless signaling. TS4-F requires an initiator to comply with the rapid shutdown requirements while TS4-S uses Tigo’s CCA and Gateway to transmit a rapid shutdown signal. TS4-F cost-effectively targets rapid shutdown while TS4-S includes module-level monitoring with rapid shutdown. Both TS4-F and TS4-S are patent-protected.

Tigo’s TS4-F is ready to ship as an integrated solution with module manufacturers worldwide. For price and delivery call +1.408.402.0802 ext. 1, email sales@tigoenergy.com, or visit www.tigoenergy.com.

— Solar Builder magazine

Details on new commercial rapid shutdown solution coming from SMA, Tigo

SMA tigo

SMA and Tigo have announced a new rapid shutdown solution for the commercial market, which will be available in the second half of 2018.

“Since we introduced the Power+ Solution, we have received feedback from installers who are looking for a more cost-optimized way to achieve rapid shutdown in commercial installations,” said Nick Morbach, executive vice president of SMA’s Residential and Commercial Business Unit. “This new offering gives our commercial customers an SMA branded option to comply with the NEC 2017 rapid shutdown requirement, and gives them the specific functionality they need.”

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The new rapid shutdown solution will fulfill UL 1741, NEC 2014 and NEC 2017 requirements – particularly the stricter module-level shutdown requirements that will be effective in January 2019. It will be compatible with the power line-based SunSpec Communication Signal for Rapid Shutdown, making it simple and robust. Using the existing DC wires between the inverter and module-level electronics as a communication channel will drastically reduce installation time. Mechanically, it will be compatible with Tigo’s existing TS4 platform.

The product will offer outstanding system safety thanks to full integration with SMA’s world-leading AFCI function. It joins SMA’s portfolio of products that comply with rapid shutdown requirements, including the Power+ Solution and the Rapid Shutdown System.

“We are pleased to work with SMA to develop an option that meets the needs of commercial installers,” said Zvi Alon, CEO of Tigo Energy. “The rapid shutdown solution will be compatible with a variety of modules, and we anticipate that commercial integrators will widely adopt the module-integrated platform.”

— Solar Builder magazine