Siemens Automatic Transfer Switch (ATS) Panel

The Siemens Automatic Transfer Switch (ATS) Panel integrates Siemens low-voltage switchgear and control products into IEC 61439-compliant ATS assemblies for automatic changeover between mains, generator sets and UPS sources. Typical implementations use the SIVACON S8 type-tested switchboard as the mechanical and busbar backbone (SIVACON supports main bus ratings up to 7400 A), with Siemens 3VA/3WA power circuit breakers or air circuit breakers for source isolation and fault interruption. SIRIUS contactors and SIPROTEC or dedicated transfer relays provide motorized/static transfer operations, and SENTRON/SIPROTEC metering devices and protection relays supply voltage, frequency and phase-sequence monitoring plus event logging. For generator paralleling and synchronizing, SIPROTEC synchro-check and synchronising modules are available. Design verification and routine tests follow IEC 61439-1 (general requirements) and IEC 61439-2 (power switchgear assemblies), while transfer-switch specific performance references include IEC 60947-6-1 (transfer switching equipment) and, for hazardous locations, IEC 60079 series guidance. ATS panels can be built for rated currents up to 4 000 A (panel spec) and, if using SIVACON bus configurations, up to 7 400 A for site-specific engineered assemblies. Short-circuit withstand is engineered per IEC 61439 short-circuit verification; typical factory designs are validated for prospective fault currents from 25 kA up to 100 kA Icw depending on breaker choice (3VA/3WA selection), busbar bracing and bolted connection ratings. Forms of separation (Form 1, Form 2, Form 3b, Form 4b) are selectable during design — ATS applications commonly use Form 2 or Form 3b to segregate incoming sources, the transfer mechanism, and the outgoing functional unit to simplify maintenance and reduce risk during source transfer. Transfer mechanics support break-before-make (to avoid paralleling sources) or make-before-break for specialized paralleling systems when synchronized operation is permitted and governed by SIPROTEC or equivalent protection. Communication and SCADA integration are implemented via Profinet/Profibus, Modbus TCP, IEC 61850 gateway options and the Siemens SENTRON PAC family for submetering and power quality. Typical features include adjustable transfer and retransfer delays (0.1–10 s range), source monitoring (undervoltage/overvoltage, frequency thresholds, phase rotation), load prioritization and shedding, mechanical interlocks, earthing switch options, and auxiliary supply design per IEC 61439 Annexes. When comparing vendor ecosystems, Siemens SIVACON-based ATS assemblies deliver tight integration with SIPROTEC protection and SENTRON metering; alternative type-tested systems on the market include ABB MNS and Schneider Electric Prisma Set, but all must be verified to IEC 61439-1/2 and transfer-specific IEC 60947-6-1 criteria for safe, reliable automatic transfer performance.