As solar panels grow in popularity and their voltages rise, there must be built-in functions to extinguish fires caused by arcing faults. These are high-power discharges of electricity that can cause explosions or lightning events due to damaged wires.
Sandia National Laboratories researcher Kenny Armijo has worked with fellow researchers in the labs and the local Guardian Sensors company for 10 years to understand and characterize these dangerous arcing faults. Their work led to the development of in-line electrical connectors that automatically predict and prevent arcing faults in photovoltaics before they can ignite electrical fires.
“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 in-line connector developed by Guardian Sensors – about an inch long and a dime in diameter – contains a metal spring covered with a type of self-extinguishing polymer material that has been developed and tested at Sandia for 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 in this case when high current and voltage flow through damaged connectors, and there is no fully reliable way for the connectors themselves to prevent the hazard. There the new device would fill this gap, said Armijo.
The new in-line connectors are designed to be activated in temperatures above 185 ° F. In this case, the self-extinguishing material melts, fills the crevices or breaks the wires and elongates the spring, increasing the spark gap between the wire conductors so you can no longer produce 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 through 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 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 and the results were successful.
“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. “
Company awarded with prestigious awards
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 human resource development.
“I highly recommend the NMSBA program because with technical assistance we were able to test and validate the circuit breakers,” said Kenny Blemel, program manager, Guardian Sensors. “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. “
In the future, Armijo hopes the research can be extended to other types of power sources and storage devices such as batteries.
“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 something like that to energy storage, like batteries or anything that holds a charge. 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 arcing faults. “
Message from Sandia National Laboratories