Transformers are one of the fundamental building blocks of the electric grid; essentially all electric energy delivered flows through at least one. Through electromagnetic coupling, these components change the voltage of electric power, increasing it to transmit electricity more efficiently over long distances and decreasing it to a safe level for final delivery to end users. Power transformers are optimized for high efficiencies and are typically located at generator plants and within substations, making them critical infrastructure assets from a resiliency standpoint. Distribution transformers are designed to accommodate a wide range of loading conditions and are typically located on poles and in enclosures within industrial, residential, and commercial areas, directly supplying power to the end user at low or medium voltages.

In addition to conventional transformers, solid state transformers (SSTs) and hybrid transformers can also be important components of the grid modernization process due to their advanced functionalities. Traditionally, an SST is composed of front-end and back-end power electronic converters, coupled through an isolation transformer that can connect two different AC voltages. The primary benefit of this design, compared to a conventional line frequency (e.g., 60 Hz) transformer, is the ability to use a high frequency (HF) link that enables significant size and weight reductions at the same power rating. In addition to the increased power density, these power electronic systems can provide a range of capabilities depending on their design and configuration.

Hybrid transformers, on the other hand, involve the integration of conventional line frequency transformers with power electronic converters to achieve advanced functionalities. While similar in principle to SSTs, the key difference is that hybrid transformers do not require converters to be rated at the full power of the system or the voltage levels they are connecting. Utilizing fractionally rated converters or converters only on the low voltage end of the system enables mature power electronic technologies to be combined with legacy component designs. This simplifies the system and helps address concerns of the high costs and typically lower reliability of traditional SSTs.

The objective of this funding opportunity announcement (FOA) is to stimulate innovative designs, prototypes, and field demonstration exercises for advanced distribution and/or power transformers (e.g., flexible, modular, scalable, hybrid, and solid-state transformers) that can be readily utilized across a range of distribution to transmission scale applications. Proposals must be able to demonstrate a process for evaluating the performance and extrapolating results to the targeted power and voltage ratings of the final design demonstrating high efficiency, variable/controllable impedance, and the ability to accommodate a range of high-side and low-side voltages. Therefore, this FOA is divided into two Area of Interests: (1) RD&D for Distribution Transformers, and (2) RD&D for Power Transformers.

Area of Interest 1 – RD&D for Distribution Transformers:

This Area of Interest seeks applications to carry out RD&D activities related to advanced distribution transformers to support the following FOA objectives:

• Flexible and adaptable designs that promote interchangeability and greater standardization
• High-efficiency, long-lifetime, and modular prototypes that can facilitate replacement
• More efficient designs that incorporate additional functionalities, sensing, and communications, including the use of power electronics
• Novel converter topologies with efficient thermal management to expand Solid State Transformer (SST) functionalities
• Techno-economic analyses to determine value propositions
• Opportunities that can leverage the next-generation materials, innovations in components and support systems (e.g., bushings, cooling systems), and advanced monitoring and control technologies (e.g., sensors, communications, data analytics)
• Desired technical specifications are competitive with those seen in conventional distribution transformers
• Demonstrate how advanced distribution transformers at scale perform, and its benefits in a real-world environment providing a solution to an problem.

Area of Interest 2 – RD&D for Power Transformers:

This Area of Interest seeks applications to carry out RD&D activities related to advanced power transformer designs to promote flexibility and greater standardization while maintaining high efficiencies and long-life operations. Technical criteria for the proposed advanced power transformer designs support the following FOA objectives:

• Flexible and adaptable designs that promote interchangeability and greater standardization
• High-efficiency, long-lifetime, and modular prototypes that facilitate replacement and reduce transportation costs, transportation duration, and installation times. Applications should address how these new designs and features will facilitate installation, commissioning, and integration into existing substations as well as opportunities to increase cyber-physical security (e.g., maintaining safe operations when relays have been compromised)
• Techno-economic analyses of systems to determine value propositions
• Opportunities that can leverage the next-generation materials, innovations in components and support systems (e.g., bushings, cooling systems), and advanced monitoring and control technologies (e.g., sensors, communications, data analytics)
• Demonstrate how advanced power transformers at scale perform, and their benefits in a real-world environment providing a solution to a problem.
• Desired technical specifications and overall cost are competitive with those seen in conventional power transformers