UL 1741 SB Certification Evidence Package Guide (PDF)

UL 1741 SB represents a critical evolution in DER interconnection standards, mandating dynamic, grid-responsive behaviors beyond basic safety and isolation requirements. The Evidence Package Guide provides manufacturers with prescriptive instructions on how to compile and present technical evidence—including test plans, lab reports, firmware versioning records, functional block diagrams, and verification matrices—to substantiate conformance to each SB requirement. It emphasizes traceability: every functional capability (e.g., 'LVRT at 0.5 pu for 2 seconds') must be mapped to specific test cases, configuration settings, and validation data. The guide also addresses cybersecurity considerations introduced in SB (e.g., secure firmware update mechanisms), software lifecycle documentation, and the role of third-party validation. Crucially, it supports microgrid protection coordination by ensuring inverters respond predictably under fault conditions and during islanded/grid-connected transitions—enabling selective coordination with upstream breakers, relays, and microgrid controllers without unintended tripping or instability.