New delivery on the radar: Siemens Energy & APS Cholla – Delaney Substation, 500 kV shunt reactors

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Undertaking large transmission projects in the Arizona desert represents one of the greatest technical, logistical, and environmental challenges for energy companies in the United States. It is a strategic region for the expansion of the power system in the western U.S., but one marked by extreme conditions: high temperatures that frequently exceed 45 °C (113 °F), long distances with no supporting infrastructure, arid and rocky terrain, as well as rigorous environmental permitting processes and respect for protected areas and local communities.

Building EHV (extra-high-voltage) substations and 500/525 kV transmission corridors in this setting requires top-tier engineering, equipment designed to operate reliably in harsh environments, and a highly coordinated supply chain. The transport, assembly, and energization of large assets — such as shunt reactors — demand meticulous planning, technical precision, and full integration among designers, manufacturers, and specialized suppliers.

In this context, APS (Arizona Public Service) has been building out strategic substations in western Arizona, such as Delaney Substation, which are essential for long-distance power transfer, the interconnection of new generation projects, and voltage control along extensive transmission corridors that serve load centers in the American West.

It is in this kind of critical project that solid, highly qualified industrial partnerships stand out. Siemens Energy, supplier of the 525 kV shunt reactors, brings cutting-edge technology, operational reliability, and global experience in extra-high-voltage transmission systems.

Complementing this, Alltec Sistemas takes part as the supplier of the reactors’ control, protection, and monitoring cabinets, developed to meet the stringent performance, safety, and availability requirements of EHV substations in extreme environments.

The joint work of specialized companies such as Siemens Energy and Alltec Sistemas enables the implementation of robust, durable solutions, ensuring precise reactive power control, power system stability, and a reliable power supply for the western United States — even in the face of the challenges posed by the Arizona desert.