PETER W. SAUER (1946-2022)

BY THOMAS OVERBYE AND PHILIP KREIN

PETER WILLIAM SAUER of Urbana, Illinois, passed away peacefully at home on Dec. 27, 2022, at age 76.

Pete was born on Sept. 20, 1946, in Winona, Minnesota, to Alfred von Rohr Sauer and Eleanor Sawyer Sauer, as the fifth of six children. Pete graduated from the University of Missouri at Rolla in 1969 with a degree in electrical engineering. From 1969 to 1973, he was an electrical engineer for the U.S. Air Force. He then obtained his master’s and doctoral degrees in electrical engineering from Purdue University in 1974 and 1977, respectively. After graduation, Pete joined the faculty at the University of Illinois Urbana-Champaign to teach courses and direct research on power systems and electric machines, retiring in January 2020 after more than 40 years of service. He retired as a lieutenant colonel from the Air Force in 1998. At the time of his passing, Pete was the Grainger Chair Emeritus in Electrical Engineering at the University of Illinois and a member of the National Academy of Engineering (NAE).

Professionally, Pete was an individual who made outstanding contributions to the art and science of electrical engineering throughout his 45-plus year career. What is especially unique about Pete is not only that he was a superstar in many aspects of the engineering profession (including research, engineering education, and professional service), but also that he accomplished this with great humility and selfless service to all in our profession, ranging from the most accomplished to undergraduates just beginning their professional journeys.

Almost all of his professional career was spent at the University of Illinois Urbana-Champaign (Illinois) in the Department of Electrical and Computer Engineering as a professor of various ranks. He started in 1977 as an assistant professor, and in 1998 became the prestigious Grainger Chair Professor of Electrical Engineering. Pete retired from Illinois in 2020 but remained active professionally.

During his time at Illinois he excelled in many areas, with his initial accomplishments recognized in 2003 with his election to NAE with the citation: “For technical contributions to the modeling, simulation, and dynamic analysis of power systems and for leadership in power engineering education and research.” Over the years, we have never met anyone as passionately committed to electric power education as Pete. His educational philosophy is perhaps best conveyed in one of his favorite sayings, “Students are candles to be lighted, not bottles to be filled” (adapted from Plutarch). Pete was consistently ranked by Illinois students as one of their top educators, appearing almost every term in the prestigious Illinois list of “Teachers Ranked as Excellent by Their Students,” and not only for small graduate courses but also for large undergraduate courses, in which receiving such a distinction is challenging. Pete’s excellence as an educator and researcher was recognized by the IEEE Power and Energy Society (PES) in 1997 when he received the Outstanding Power Engineering Award, by Illinois in 2015 when he received the Tau Beta Pi Daniel C. Drucker Eminent Faculty Award for dedication to excellence in research and in teaching, in 2020 by the PES when he received its Lifetime Achievement Award, and then in 2022 by IEEE when he received the prestigious Tesla Award for “contributions to dynamic modeling and simulation of synchronous generators and for leadership in power engineering education.” Most recently, Pete is being honored, starting in 2024, as the PES changes the name of its education recognition to the Peter W. Sauer Outstanding Power Engineering Educator Award.

As a key contributor while at Illinois, Pete expanded the research base of its electric power program. During the 1980s and 1990s many universities were closing their power programs, but the Illinois program expanded under Pete’s leadership. Over our combined 50-plus years at Illinois, we witnessed firsthand Pete’s effective leadership and gained greatly from his serving as our faculty mentor. Pete worked effectively with The Grainger Foundation, helping to grow its initial support of the Illinois power program in the early 1980s to gifts that have totaled more than $300 million, resulting in the college being named in 2019 the Illinois Grainger College of Engineering. Much of this successful relationship was due to Pete. He also made the connections that led to The Grainger Foundation Frontiers of Engineering program at the NAE.

In research, he made several key contributions, many of which have been integrated into commercial power system analysis software. One example is the modeling of synchronous machines and large-scale electric grids. This work applied the concept of integral manifolds for systematic reduced-order modeling of electrical machines and power system dynamic models. It introduced the transient algebraic circuit — the basis for systematically including network constraints that arise on slow time scales. At the individual synchronous electric machine level, Pete developed a set of tests for saturation models to ensure their consistency with the premise of conservative coupling fields. The results included a procedure for correcting models that do not satisfy the test, which helps to develop improved saturation models that satisfy conservation of energy in their coupling fields. Another key research contribution related to industry understanding of electric grid stability, Pete identified relationships between steady-state stability and properties of load flow Jacobian matrices, including the development of conditions when a singularity of a load flow Jacobian matrix can indicate actual bifurcation of the dynamic models. This included the consideration of steady-state stability issues in conventional power-voltage curve analysis. Pete’s work with M.A. Pai and their students developed fast methods to enforce transient stability constraints on the calculation of interchange capability. The results provided relationships between steady-state stability and static voltage collapse and improved understanding of fundamental issues involving maximum power transfer and voltage collapse. Pete made broader key conceptual contributions to power system static analysis and visualization. He was a founding researcher in the Illinois Information Trust Institute and initiated a broad range of efforts in cybersecurity for power grids and other public infrastructure.

As an educator, Pete played a key role in the national rejuvenation of university-level electric power programs, many of which diminished or faded away during the 1980s and 1990s. His work at Illinois on curriculum innovation, industry support, and fundamental research became the model for many other universities. He served as a program director at the National Science Foundation, where he worked with the Electric Power Research Institute to create new funding opportunities for the U.S. power engineering academic community. Later, Pete worked with colleagues to create a National Science Foundation center called the Power Systems Engineering Research Center, which continues as a dominant base for academic research nationwide. He served in many leadership roles in the PES, most recently as vice president for education. Pete also served in leadership roles in the NAE, especially in Section 6.

He was an active community member and was treasurer for many years at Trinity Lutheran Church in Urbana. He continued to serve, educate, and conduct research throughout his career. Pete was once asked what he loved about engineering. In response he said, “I love that you get a chance to think big and think small.” The lessons that Pete and his wife Sylvia imparted to their children on a daily basis continue to have tremendous influence. With unending humility, he always attributed his success to Sylvia, his children, and his students. He understood that small thoughtful acts can create a world of impact. He thought big and he thought small. His legacy will continue because he used his gifts to quietly change the lives of countless people, one infamous smile at a time, across the globe.

He is survived by his wife, Sylvia Sauer, and children, Katherine (Chris) McMahon and Daniel (Emily) Sauer. Also surviving are his grandchildren, Evan and Tate Sauer and Julian and Margot McMahon; sisters, Sue (John) Feaster and Rachel (Fred) Hinz; and sisters-in-law, Laura (John) Sauer and Sue (Jim) Sauer.