In-line connector developed at Sandia can forestall solar panel fires earlier than they ignite


Sandia National Laboratories has developed an in-line connector that can automatically predict and prevent arcing faults in solar modules before they start electrical fires. Sandia researcher Kenny Armijo has worked with fellow researchers in the labs and local Guardian Sensors Inc. for 10 years to understand and characterize these dangerous arcing faults.

Sandia National Laboratories researcher Kenny Sandijo uses an arc fault generator that was developed by researchers to help determine how dangerous an arc fault is. (Photo by Bret Latter)

“When solar panels become more efficient, they can produce more electricity,” said Armijo. “More power means that they will have higher currents and higher voltage levels. As you increase the current and voltage levels in next generation solar panels, it becomes a little more dangerous because the higher the voltage, you get a higher propensity for arc faults. This new self-erasing mechanism could solve this problem. “

The inline connector developed by Guardian Sensors – approx. 1 inch. long and the diameter of a dime – contains a metal spring covered with a special self-extinguishing polymer material developed and tested at Sandia over the past five years. Like current connectors, the self-extinguishing mechanisms would link a series of solar panels like a series of Christmas lights that could work together on a field or on a roof.

All connectors are susceptible to corrosion, damage, or improper installation, which can create reliability issues, especially if the crevices have tiny cracks or breaks. Currently, sparks and devastating fires can occur when high currents and voltages flow through damaged connectors. Unfortunately, there is no absolutely reliable way of preventing the hazard for the connectors themselves. The new device would fill this gap there, said Armijo.

If there were a spark, a special polymer developed by Sandia National Laboratories would melt inside the in-line connectors and a spring would extend inside the connector to allow for a greater spark gap and stop the flames, like on this one Photo shown. (Courtesy photo by Kenny Armijo)

The new inline connectors are designed to be activated at temperatures above 185 ° F. When this happens, the special self-extinguishing material melts, fills the crevices or breaks the wires and elongates the spring, increasing the spark gap between the wire conductors so that they can no longer generate energy that leads to heat and fires. A combination of the material’s reaction speed and refractory properties will stop a fire before it starts – in less than 2 seconds – said Armijo.

The self-extinguishing materials used in the connectors were developed from Sandia-based research that emerged from the laboratory-driven research and development program. Current work with Guardian Sensors is funded by the New Mexico Small Business Assistance Program, which provides technical assistance from the Sandia and Los Alamos national laboratories to companies seeking scientific problem solving.

Through the NMSBA program, Sandia Guardian Sensors was able to provide access to a patented, specialty arc fault generator located in the laboratories. It was developed by researchers to help determine how dangerous arcing faults are and it can test various materials for reliability in high voltage connectors and electrical wiring. For this project Armijo was able to test a prototype of the connector for Guardian Sensors with the arc fault generator. The results were successful.

This picture shows an example of an in-line connector test performed at Sandia National Laboratories at the time of an arc fault and sudden self-extinguishing. The graphic shows a sudden voltage drop that occurred in less than a second as the inline connector put out a spark. (Courtesy photo by Kenny Armijo)

Armijo has several photos, videos and data from several tests. A key example is a graphical representation of lines that increase with voltage peaks. “Then bam – the self-extinguishing mechanism works,” he said, pointing to where all the lines in the graph suddenly drop vertically to zero.

“You see this quick shutdown and it does it by itself,” said Armijo. “For me this is indicative because it is actually a set-it-and-forget-it system. I think that’s what makes this whole system really useful and powerful. “

Because of its tech support and success, Guardian Sensors received $ 225,000 and US Department of Energy’s Solar Prize vouchers and offered research opportunities to three New Mexico universities. The company was also able to hire a new engineer and expand.

The company also received the Ben Lujan Award for Small Business Excellence, presented to an NMSBA contestant who demonstrates the most significant business growth for improving New Mexico’s economy through sustainability and people development.

“I highly recommend the NMSBA program because with technical assistance we were able to test and validate the breaker switches,” said Guardian Sensors program manager Kenny Blemel. “Without the help of Sandia researchers and special equipment, we could not have achieved this. We look forward to bringing this to market for the benefit of alternative energy companies and the safety of the public. “

Armijo hopes that the research can be extended to other types of power sources and storage devices such as batteries in the future.

“We want to extend this research to more than just connectors,” said Armijo. “I think the next step is to see if we can extend this to energy storage, e. B. Batteries or anything that is charged. Ultimately, the opportunity to make renewable energies work and be better used is to have storage. Guardian Sensors and I develop ideas and research into advanced energy storage technologies that can reduce arc faults. “

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