Working with EPCs — End-to-End Renewable Energy Engineering Learn More
Blymyer senior engineer speaks on arc flash hazards at IEEE meeting
Members of the Oakland East Bay IEEE Industry Application Society (IAS) came together this November 21, 2024, to hear Blymyer Senior Electrical Engineer Benjamin Liu give a presentation on Arc Flash Hazards in Utility-Scale PV and BESS Systems. Liu has extensive experience addressing these hazards, having designed and engineered many utility-scale photovoltaic systems and BESS (battery energy storage systems).
Current calculation methods overestimate PV system DC arc flash hazard
NFPA 70E and IEEE 1584 describe calculation methods for alternating current (AC) arc flash incident energy, but contain little guidance for arc flash calculations with direct current (DC) sources. Industry-standard software often uses correlation equations derived from arc flash testing of battery and DC power supplies. But recent EPRI testing of a large scale PV array proves that PV DC arc flash is less hazardous than current methods predict.
UL 9540 requires BESS manufacturers to calculate DC arc flash hazard
- UL 9540 requires BESS manufacturers to prepare a DC arc flash risk assessment and arc flash labels. The BESS system engineer of record must closely review the manufacturer’s DC arc flash study to verify it applies to the actual project configuration, and also to verify no hazard locations have been omitted from study.
- BESS DC arc flash hazard is relatively low, despite the high arcing current of large Li-ion batteries. This is due to implementation of ultra-fast semiconductor fuses.
- AC output BESS projects can have very high AC arc flash incident energy. The engineer of record must prepare a site-specific AC arc flash study and labels for these projects. A custom-engineered protective relaying system is likely required to reduce incident energy.
- BESS enclosures have both DC and AC arc flash hazards. Even if a UL 9540 DC arc flash study is available, the auxiliary power terminals of the enclosure require a site-specific AC arc flash study.
Best practices for utility-scale PV and BESS arc flash calculations
“Protecting life safety is an engineer’s most important task,” remarked Liu. “Our goal is to provide arc flash warning labels which comply with standards while reflecting engineering best practices and the latest product level knowledge.”
“The arc flash presentation was enthusiastically received,” said Mikaela Lenci, Blymyer Executive Business Administrator, who was also in attendance. “The audience was engaged throughout, and asked thoughtful and probing questions.”
About the IEEE IAS
The Institute of Electrical and Electronics Engineers Industry Application Society (IEEE IAS) is a volunteer organization for engineering professionals looking to advance the theory and practice of electrical and electronic systems. One of the largest special interest societies within the IEEE, the IAS focuses specifically on the unique needs of industry and commerce and has an 11,000+ membership worldwide. Through a network of over 370 chapters globally (including the Oakland East Bay chapter that Liu addressed), regional events, and national and international conferences, the society keeps members abreast of current developments in the area of technology in electricity and electronics. Alexey Kondrashov, Blymyer’s Director of High Voltage Projects, is also a member of the Oakland East Bay IEEE chapter.