The Founders of Modern Power Systems: Ten Key Pioneers and Additional Candidates

Modern power systems did not emerge suddenly from a single invention, one individual, or one company. From generation, transmission, and distribution to electrical machines, protection, stability, dispatch, optimization, and control, the power grids familiar to us today are the product of more than a century of successive technological advances, their evolution, and their translation into engineering practice. Behind these turning points were technical experts whose work proved decisive.

This article approaches the history of electrical power engineering by selecting the technical pioneers whose contributions have had the most far-reaching influence on the development of modern power systems, along with a number of additional candidates. It discusses 20 individuals in total. Although the ranking has been weighed repeatedly, it inevitably involves subjective judgment; it is neither the only possible ranking nor a universally accepted one.

The starting point is the emergence of modern commercial power systems, with the start of commercial operation at New York’s Pearl Street Station in 1882 serving as a symbolic milestone—144 years ago. Physicists such as Faraday and Maxwell, whose contributions to electromagnetism and electrical technology were even more fundamental and far-reaching, are therefore outside the scope of this comparison.

Modern power systems depend not only on important theories and key inventions but also on technological integration, standardization, engineering organization, and deployment at scale. Accordingly, this article considers both those who originated important theories, methods, equipment, and systematic engineering solutions and those who brought disparate technologies together into complete systems and made large-scale deployment possible.

Influence is assessed along four dimensions: originality—whether the individual introduced an important technology, theory, method, or systematic engineering solution that had not previously existed; foundational importance—how extensively the subsequent power industry built upon the contribution; geographical reach and longevity—whether the results were used over long periods across countries and companies; and overall impact on the power industry and human society.

Just outside the top ten: No. 11 — Hermann W. Dommel: Pioneer of Digital Electromagnetic-Transient Simulation and a Principal Creator of EMTP

The discussion begins at No. 11 and proceeds in reverse order.

Placing Dommel eleventh does not imply a clear gap between him and the top ten. In originality, foundational importance, and lasting influence, he is in fact very close to No. 10, Fred Schweppe. Dommel changed how power engineers analyze and simulate transients in complex networks; Schweppe changed how control centers understand the real-time state of the grid and, beyond that, how they think about electricity’s economic signals. Their respective contributions reach deep into the simulation-and-analysis layer and the real-time operating layer of modern power systems.

Hermann W. Dommel (1933–2025) was born in Ansbach, Germany. A German-born electrical engineer and academic who spent the later part of his career in Canada, he studied electrical engineering at the Technical University of Munich, earning his Diplom-Ingenieur in 1959 and Dr.-Ing. in 1962. From 1959 to 1966, he conducted high-voltage engineering research at Munich. In 1966, he joined the Bonneville Power Administration (BPA) in the United States to develop computer programs for power systems. He joined the University of British Columbia (UBC) in 1973 and later became professor emeritus. Dommel died in 2025 at the age of 91.

During his work in Munich and at BPA, Dommel developed a method for solving power-network electromagnetic transients through nodal analysis, equivalent companion circuits, and trapezoidal integration. After joining BPA in 1966, he developed the software that became known as the Electromagnetic Transients Program (EMTP).

Dommel’s central original contribution was not simply that he “wrote a program.” Rather, he systematically transformed electromagnetic transients—continuous processes described by differential equations—into a network problem that a digital computer could solve step by step. At each time step, dynamic elements such as inductors and capacitors could be represented by companion circuits suitable for nodal equations. A large, complex power network could then be simulated by repeatedly solving algebraic network equations, reproducing switching operations, lightning strikes, faults, overvoltages, and converter processes [1].

In engineering methodology, this established something resembling a new experimental method: many transient phenomena that cannot safely or repeatedly be reproduced on a real power grid can first be studied on a computer. From insulation coordination to high-voltage direct current (HVDC) transmission, flexible AC transmission systems (FACTS), and today’s renewable-energy converters and power-electronics-dominated grids, electromagnetic-transient (EMT) simulation has become an indispensable tool. In this sense, Dommel changed not just a numerical method but the way power engineers conduct experiments.

Dommel’s contributions were not limited to transients. In 1968, he and William F. Tinney published the classic paper “Optimal Power Flow Solutions.” Building on Newton power-flow methods, they used gradient optimization and penalty functions to address control variables and operating constraints, developing a computationally practical method for optimal power flow (OPF) [2]. Jacques Carpentier had already formulated the OPF problem; Dommel and Tinney’s contribution was to turn that optimization concept into numerical algorithms applicable to large real networks. The U.S. National Academy of Engineering subsequently described their paper as one of the clearest and most concise early systematic treatments of OPF. In recognizing Dommel, IEEE likewise highlighted his pioneering contributions to both electromagnetic transients and optimal power flow.

10. Fred C. Schweppe: Principal Founder of Power-System State Estimation and a Pioneer of Spot-Pricing Theory

Fred C. Schweppe (1933–1988) was born in Minneapolis, Minnesota, and grew up in Arizona. An American electrical engineer and MIT professor, he earned his bachelor’s and master’s degrees in electrical engineering at the University of Arizona and his doctorate at the University of Wisconsin in 1959. He joined MIT Lincoln Laboratory after graduation and subsequently moved to MIT’s electrical engineering faculty. In 1967–1968, he also worked at American Electric Power (AEP), gaining practical experience in the planning and operation of large power networks. Schweppe died suddenly of a heart attack in 1988, aged 54.

Around the late 1960s and 1970, Schweppe published his famous series of papers on automated power-system state estimation, establishing the basic framework for modern static state estimation [3]. Later in his career, together with Michael Caramanis, Richard Tabors, Roger Bohn, and others, he developed the theory of real-time and spot electricity pricing, culminating in the 1988 book Spot Pricing of Electricity [4].

Schweppe made foundational contributions to two distinct problems that later became central to modern power systems.

The first was that operators do not actually know the grid’s “true state.” Voltage, current, and power measurements collected by supervisory control and data acquisition (SCADA) systems are noisy or missing and may contain bad data. Schweppe brought statistical estimation theory into power networks, converting redundant and imperfect measurements into the most credible estimates of system-wide bus voltage magnitudes, phase angles, and other states. Without state estimation, much of the security analysis and real-time control performed by a modern energy management system (EMS) would lack a reliable common starting point. MIT’s obituary even noted that network state estimation had become an important component of power-system control centers worldwide.

The second problem connected the physical grid with economic signals. Schweppe and his collaborators treated electricity as a commodity whose value varies by time and location, examining how real-time prices can reflect the costs of generation, transmission, and network constraints. This was not the only theoretical origin of today’s electricity market rules, but it is an important intellectual precursor to real-time pricing, locational marginal pricing, and related modern market mechanisms.

In other words, Schweppe addressed, on the one hand, “What state is the grid actually in right now?” and, on the other, “Given that state, what should electricity be worth?”

9. William Frank Tinney: Founder of Sparse-Matrix Techniques for Large-Scale Power-System Computation

William Frank Tinney (1921–2019) was born in Portland, Oregon. An American electrical engineer, he studied electrical engineering at Oregon State College and served in the U.S. military during World War II, receiving radar training at the Massachusetts Institute of Technology (MIT) and Harvard University. After the war, he earned bachelor’s and master’s degrees at Stanford University. He joined BPA in 1950 and remained there until 1979, subsequently working as a consultant in power-system software and computation. The U.S. National Academy of Engineering identified him as a key founder of modern computer-based power-network solution techniques.

Tinney’s best-known insight was that although a power network’s nodal equations may be enormous, most entries in their matrices are zero. In the 1960s, he systematically applied sparse-matrix storage, elimination ordering, and sparse Gaussian elimination to large power-grid calculations. This work subsequently inspired substantial research in mathematics on more general sparse linear-system solvers [5].

Today, with gigabytes or even terabytes of memory commonplace, it is easy to underestimate what Tinney achieved. In the 1950s and 1960s, treating a network of thousands of buses as a dense-matrix problem caused both computational cost and memory requirements to become prohibitive. Tinney exploited the inherent sparsity of grid topology and recognized that elimination order itself determines how much “fill-in” is generated. This transformed large-network computation from a theoretical algorithm into an engineering technology usable by control centers and planning departments. Subsequent power-flow, short-circuit, state-estimation, transient-stability, and OPF software—as well as much of today’s power-system computing—has inherited this foundation of sparse linear algebra. Tinney’s influence is seldom visible to the general public, but it is embedded deep in almost every major power-system calculation program.

Beyond sparse-matrix techniques themselves, two other advances deserve special mention. The first was his 1967 paper with C. E. Hart on Newton’s method for power-flow computation [6]; Newton-based methods remain fundamental in power-system textbooks. The second was his 1968 OPF paper with Dommel [2].

Tinney’s work also reached far beyond the electric-power industry, profoundly influencing scientific computing. The ordering problem he addressed arises when Gaussian elimination or Cholesky or LU factorization of sparse linear systems generates new nonzero entries in positions that were originally zero—so-called fill-in. Poor ordering can make a matrix rapidly denser, greatly increasing memory requirements and computation. Tinney’s essential approach was to choose a better elimination sequence from the sparse matrix’s graph structure, thereby limiting fill-in. The original paper explicitly stated that the first part of its method was “applicable to any matrix,” while the ordering section concerned sparse matrices with symmetric nonzero patterns. The underlying ideas soon moved beyond power-system applications.

A particularly clear example is finite-element analysis and structural mechanics. In a typical linear-elasticity problem, finite-element discretization produces a large, sparse, usually symmetric stiffness matrix. Its numerical solution resembles that of nodal matrices in power networks. Later finite-element literature explicitly referred to minimum degree as Tinney Scheme 2 and used it to renumber mesh nodes and reduce fill-in during Cholesky factorization. Modern large-scale finite-element programs and sparse direct solvers still use descendants of the minimum-degree family, including approximate minimum degree (AMD).

General-purpose scientific computing subsequently developed a wide range of sparse direct solvers. The AMD and COLAMD algorithms developed by Tim Davis and collaborators have a clear technical lineage connecting them with the minimum-degree ordering of Tinney and Walker; Davis himself has repeatedly cited Tinney’s work. Modern SuiteSparse packages such as CHOLMOD, KLU, and UMFPACK further exemplify the evolution of sparse storage, fill-reducing orderings, and related ideas in general numerical computation. Users of MATLAB, finite-element tools, and other numerical software rarely realize that one important strand of this technical history originated in electrical power engineering.

Another noteworthy indication of this wider influence is that modern research papers on deep-learning hardware, when discussing compressed sparse row (CSR) and compressed sparse column (CSC) storage formats, sometimes trace early descriptions of these formats back to Tinney and Walker’s 1967 work. This does not mean Tinney influenced deep-learning algorithms themselves, but it does show that his work has entered the broader history of numerical computing.

8. Charles Hesterman Merz: Co-Inventor of Differential Protection and a Pioneer of Interconnected Three-Phase AC Grids

Charles Hesterman Merz (1874–1940) was born in Gateshead, northeastern England. A British electrical engineer and power-system pioneer, he entered the Newcastle-area electricity industry as a young man and later partnered with William McLellan to develop the engineering consulting firm Merz & McLellan. In the early twentieth century, Merz systematically addressed large AC supply networks, power-station siting, high-voltage transmission and distribution, and regional interconnection. He became one of the most important figures in early British power-system engineering. The Institution of Engineering and Technology (IET) described him as one of the most distinguished electrical engineers of his generation.

Merz’s foundational role in the history of protective relaying stems from his collaboration with Bernard Price. On February 16, 1904, Merz and Price applied for British Patent No. 3896, proposing a protective method that used pilot wires to compare currents at the two ends of an AC line; they also filed a related application in Germany that year [7]. A history of protection technology published by Germany’s Association for Electrical, Electronic & Information Technologies (VDE) identifies this as the earliest longitudinal current-comparison protection—the principle later known as differential protection.

The idea behind differential protection is remarkably simple and remarkably durable. For a normally operating protection zone, Kirchhoff’s current law requires incoming and outgoing currents to balance ideally. An internal fault disrupts that balance. By comparing currents at the boundary of a protection zone, a relay can therefore determine with high selectivity whether a fault is inside or outside the zone.

From early twentieth-century electromechanical relays through static relays to today’s numerical and digital protection, the basic principle has endured. Modern generator differential protection, transformer differential protection, busbar differential protection, and line current-differential protection all retain the principle established by Merz and Price. Many early electrical technologies have been entirely displaced by new implementations; differential protection is one of the few that still directly underpins the fundamental structure of main protection more than a century later.

Merz’s historical significance, however, extends well beyond protection.

In the early twentieth century, he actively promoted three-phase high-voltage AC supply and regional grid interconnection in northeastern England. The Neptune Bank system in Newcastle, commissioned in 1901, was a landmark in Britain’s early adoption of three-phase supply and regional grid development. Merz advocated three-phase AC and pushed for the standardization of voltage levels and frequency. At a time when British electricity suppliers were highly fragmented and different areas used incompatible technical standards, this was remarkably forward-looking.

Merz went on to promote the interconnection of generating stations and supply areas along England’s northeast coast. He understood that if each city built its own small generating station, reserve capacity would be used inefficiently and generating resources could not be shared across districts. Conversely, connecting larger stations via high-voltage lines would enable load diversity, reserve sharing, and more economical centralized generation. The idea of joining isolated supply systems into a common network captures the basic logic of the large interconnected power systems that followed.

7. Robert H. Park: The Rotating d–q Reference Frame and the Foundations of Electrical-Machine Dynamic Modeling

Robert H. Park (1902–1994) was born in Strasbourg, then part of the German Empire, to American parents, and is generally regarded as an American electrical engineer. He received his bachelor’s degree in electrical engineering from MIT, then studied operational calculus under Professor Henning Pleijel at the Royal Institute of Technology (KTH) in Sweden. He subsequently joined General Electric (GE) and completed GE’s advanced engineering course. It was while researching synchronous machines at GE that Park carried out the work for which he is remembered in electrical engineering history.

In 1929, Park published the first part of his classic paper on the generalized two-reaction theory of synchronous machines. Using the coordinate transformation later named the Park transformation, he transformed three-phase stator variables into a reference frame rotating with the rotor, greatly simplifying synchronous-machine dynamic equations [8].

Park’s significance is that he changed the engineer’s frame of reference for understanding electrical machines. In the stationary ABC three-phase frame, the synchronous-machine rotor keeps rotating, and mutual inductances between stator and rotor vary periodically with time, making the equations complicated. If the observer’s reference frame rotates with the rotor and three-phase quantities are transformed into direct-axis (d), quadrature-axis (q), and zero-sequence components, many inductance coefficients that were periodic functions of rotor position become constant under standard idealized machine assumptions. This greatly simplifies the equations. Importantly, the transformation does not make the d and q axes completely decoupled in every sense: coupling terms such as speed-induced voltages must still be handled in dynamic analysis and controller design.

The Park transformation is therefore much more than a mathematical trick; it became a common technical language connecting electrical machines, power-system dynamics, and control theory.

Today, d–q coordinates appear throughout synchronous-generator transient-stability models, motor control, vector control, and the control of numerous renewable-energy converters. Park could hardly have foreseen the power-electronics-dominated grids of a century later, but the coordinate framework he established has extended from large synchronous generators to modern inverters. Its influence spans synchronous generation, electric drives, and renewable-energy grid integration.

Park was not only the originator of the transformation bearing his name; he was also among the early proponents of the classic equal-area criterion (EAC) in power-system transient-stability analysis. Both lines of work reflect his deep investigation of synchronous-machine dynamics and power-system stability.

6. Charles LeGeyt Fortescue: Symmetrical Components and a Unified Framework for Unbalanced Three-Phase Systems

Charles LeGeyt Fortescue (1876–1936) was born in York Factory, Manitoba, Canada. A Canadian-born electrical engineer, he graduated in electrical engineering from Queen’s University in 1898 and was among its earliest electrical-engineering graduates. He then joined Westinghouse Electric in the United States, spending most of his career there and conducting extensive research on transformers, high-voltage insulation, and transmission and distribution systems.

In June 1918, Fortescue presented to the American Institute of Electrical Engineers (AIEE) his paper “Method of Symmetrical Co-ordinates Applied to the Solution of Polyphase Networks,” setting out symmetrical-component theory systematically. The essential idea is to decompose an arbitrary unbalanced set of polyphase quantities into component sets with precisely defined symmetry. In three-phase systems, this yields the familiar positive-, negative-, and zero-sequence components that every power engineer learns [9].

Before Fortescue, unbalanced three-phase faults involved coupled phase variables and were far harder to analyze than normal balanced operation. His transformation achieved an elegant reformulation of the problem. For linear three-phase networks whose parameters satisfy the relevant symmetry assumptions, a coupled three-phase problem can be converted into the analysis of sequence networks. To this day, symmetrical components remain the basic language for single-line-to-ground, line-to-line, and double-line-to-ground faults, unbalanced loads, and protective-relay settings. The endurance of this method is striking: more than a century later, undergraduate power-system textbooks still teach the conceptual framework developed in 1918.

5. Charles Proteus Steinmetz: Systematizing Complex-Number AC Analysis and Establishing the Law of Hysteresis Loss

Charles Proteus Steinmetz (1865–1923), originally Karl August Steinmetz, was born in Breslau, Prussia (today Wrocław, Poland). Born in Germany, he later emigrated to the United States and became a central figure in American electrical engineering.

After arriving in the United States, Steinmetz entered the electrical-machine manufacturing industry. When his employer became part of General Electric (GE), he emerged as one of GE’s most important technical experts while also teaching electrical engineering at Union College. Around 1892, he published his research on magnetic hysteresis, establishing the well-known Steinmetz relationship for hysteresis loss [10]. At the same time, he greatly developed and promoted symbolic methods of AC-circuit calculation using complex numbers, explaining them systematically in books including Theory and Calculation of Alternating Current Phenomena [11].

AC voltage and current have phase as well as magnitude. If engineers always calculated with time-domain sine functions and differential equations, large AC networks and electrical-machine problems would become extremely cumbersome. Steinmetz systematically brought complex-number operations into engineering AC analysis, representing amplitude and phase together and converting differential relationships into algebraic impedance relationships under sinusoidal steady-state conditions. Historical engineering material from Union College has characterized this as a method that “changed the way engineers calculated AC circuits and machines.” His hysteresis-loss law addressed another immediate industrial problem: before building a motor or transformer, engineers could use an empirical quantitative relationship to estimate magnetic hysteresis losses more systematically, providing an important basis for equipment design.

Steinmetz’s historical role can be summarized as moving alternating current from something engineers could manufacture to something they could calculate, design, and deploy on an industrial scale.

4. George Westinghouse: Bringing AC Power Systems to Large-Scale Commercial and Industrial Use

George Westinghouse (1846–1914) was born in Central Bridge, New York. An American inventor, engineer, and industrialist, he became familiar with mechanical design and manufacturing at an early age through his father’s machine shop. He served in the Union forces during the American Civil War, briefly attended Union College afterward, and then devoted himself to engineering practice. As a young man, he achieved major success with inventions including the railroad air-brake system and built industrial businesses around them. IEEE’s engineering-history material emphasizes that the principles of standardization, system compatibility, and reliability learned from railroad equipment also shaped his later work in electricity.

In the mid-1880s, the electric-power industry was still fiercely divided over direct-current and alternating-current approaches. Around 1885, Westinghouse began importing AC equipment from Europe and organized engineers to improve AC transformers and supply systems. In 1886, engineers at his company, including William Stanley, built an early complete AC distribution system in Great Barrington, Massachusetts. It demonstrated that AC could be stepped up for transmission using transformers and stepped down again near consumers. The Westinghouse Electric & Manufacturing Company was founded the same year. AC was no longer merely an experimental technical proposal: it was becoming a commercial supply system that could be manufactured, installed, and replicated. Westinghouse’s own patents titled “System of Electrical Distribution,” issued in 1886 and 1889, also document his technical design work on AC distribution and system connections [12–13].

In 1888, Westinghouse acquired commercial rights to important Nikola Tesla patents concerning polyphase AC and induction motors. He then organized the company’s engineering teams to address the practical problems of generators, motors, control equipment, and the AC system as a whole. IEEE’s historical accounts emphasize that Tesla’s polyphase patents achieved large-scale commercial success only after further engineering development within the Westinghouse organization. The use of a Westinghouse AC system to power the 1893 World’s Columbian Exposition in Chicago became a highly symbolic demonstration of AC’s scalability. Westinghouse subsequently secured major equipment contracts for the large Niagara Falls hydroelectric project, combining high-capacity AC generation with long-distance transmission in a landmark of centralized AC power-system development.

Westinghouse’s central achievement was not independently inventing AC, the transformer, or the polyphase induction motor. Each technology has its own complex history of invention: Tesla was closely associated with core AC motor patents, while Dolivo-Dobrovolsky and others later advanced the practical three-phase system. What made Westinghouse exceptional was his ability to recognize the connections among technologies and organize transformers, AC generators, polyphase motors, transmission and distribution networks, and large power stations into a complete system capable of industrial production, engineering deployment, and commercial operation.

3. Thomas Alva Edison: Establishing a Landmark Commercial Electric-Power System

Thomas Alva Edison (1847–1931) was born in Milan, Ohio. An American inventor, engineering organizer, and entrepreneur, Edison differed from most figures on this list in having almost no formal university education. He attended school only briefly as a child, was subsequently taught mainly by his mother, and educated himself through extensive reading and experimentation. As a teenager, he worked as a railroad newsboy before learning telegraphy and becoming a professional telegraph operator, which brought him into electrical technology.

In 1876, Edison established his famous Menlo Park Laboratory. Around 1879, he and his team not only improved incandescent lamps but also developed generators, feeders, switches, protective fuses, electricity meters, and an entire range of equipment for supplying electric lighting. On September 4, 1882, New York’s Pearl Street Station began commercial supply. The U.S. National Park Service calls it the first commercial power station in the United States serving incandescent lighting and regards it as a landmark in the beginning of the electrical age.

Edison ranks so highly here not because he “invented the light bulb.” Others had experimented with incandescent lighting before him. His distinctive achievement was what we would now call systems engineering: rather than designing a bulb alone, he addressed the entire chain from generators and distribution networks to end users, built a complete electric-power system, and tackled energy metering and commercial billing. The Pearl Street system brought centralized generation, public distribution, customer metering, and commercial charging together in a systematic way, providing an important early model for the modern electric utility. His patents on electrical distribution systems directly document this system-level engineering approach [14–15].

Edison’s low-voltage DC distribution architecture was later displaced by AC systems. From the standpoint of modern transmission technology, he was therefore not the eventual winner of the “war of currents.” Yet the early outlines of the generating company, utility grid, customer, meter, and electricity bill can all be found in the Pearl Street supply system.

2. Mikhail Osipovich Dolivo-Dobrovolsky: Practical Three-Phase Induction Motors, Three-Limb Transformers, and the Formation of Three-Phase Power Systems

Mikhail Osipovich Dolivo-Dobrovolsky (1862–1919) was born in Gatchina near Saint Petersburg in the Russian Empire, into a noble family of Polish-Russian background. He later acquired Swiss citizenship, while the most significant stage of his career unfolded in Germany. He studied in Riga and, in the 1880s, attended the Technische Hochschule Darmstadt to study electrical engineering under Erasmus Kittler, an important pioneer of electrical-engineering education, serving for a time as his assistant. In 1887, he joined the German Edison company, the predecessor of AEG, and rapidly became a leading electrical engineer.

Inspired by the polyphase AC research of Galileo Ferraris, Nikola Tesla, and others, Dolivo-Dobrovolsky focused on polyphase systems. In 1889, he applied for patents concerning a practical three-phase squirrel-cage induction motor; his U.S. patent “Alternating-Current Motor,” issued in 1890, records an important squirrel-cage rotor design [16]. Around 1890, he developed three-phase transformers and studied star and delta connections and three-phase transmission in depth. In 1891, he collaborated with Charles E. L. Brown, Oskar von Miller, and others on the famous Lauffen–Frankfurt long-distance three-phase transmission demonstration. The project revealed to the European electrical industry the immense technical potential of high-voltage, long-distance three-phase AC transmission.

AC systems already existed, but important questions remained: How many phases should a polyphase system use? And how should motors, transformers, and transmission networks work together as a genuinely industrializable system? After engineering comparisons, Dolivo-Dobrovolsky decisively adopted the three-phase system and developed compatible motors, transformers, and system technologies. Three-phase power offers relatively smooth, efficient transmission with an economical arrangement of conductors. Balanced three-phase currents also produce a rotating magnetic field, providing the basis for high-performance AC machines. The squirrel-cage induction motor, in turn, offered industry a remarkably simple, rugged, low-maintenance machine for mechanical power.

Three-phase AC remains widespread throughout the world, and its basic architecture is highly consistent with the system that emerged at the end of the nineteenth century. Given the immense impact of three-phase AC on the fundamental architecture of modern power systems, Dolivo-Dobrovolsky could reasonably share first place with Tesla.

1. Nikola Tesla: A Principal Founder of Polyphase AC Systems and the Polyphase Induction Motor

Nikola Tesla (1856–1943) was born in Smiljan in the Austrian Empire (now part of Croatia), into an ethnic Serb family, and later emigrated to and became a naturalized citizen of the United States. He attended engineering courses at Graz Polytechnic and later studied and audited classes in Prague, but did not obtain a conventional university degree. He subsequently worked in electrical engineering for the Budapest telephone system and the Continental Edison Company in France. Tesla arrived in the United States in 1884 and worked briefly at Edison Machine Works.

In 1887–1888, Tesla established his own laboratory and developed a series of fundamental patents on polyphase AC, rotating magnetic fields, and induction motors, including the 1888 patents “Electro-Magnetic Motor” and “Electrical Transmission of Power” [17–18]. In 1888, George Westinghouse obtained commercial rights to important patents in this portfolio and integrated Tesla’s technology into the Westinghouse AC system.

Tesla continued exploring high-frequency electricity, wireless communication, and wireless power transmission later in life, but his ultimate technical and commercial ambitions in these areas were not realized. His central place in power-engineering history should therefore rest on his early contributions to polyphase AC, rotating magnetic fields, and induction motors—results validated through sustained engineering practice—not on later notions widely popularized, sometimes mystified, and often unsupported in popular culture.

Tesla did not invent alternating current itself. AC, transformers, and AC generators predated his work; Galileo Ferraris and others also investigated rotating magnetic fields independently. Tesla’s real greatness lay in envisioning a larger system than “AC lighting”: using a rotating magnetic field to build an induction motor. AC was no longer merely a current suited to voltage transformation, long-distance transmission, and lighting; it became part of a general energy system capable of directly producing rotational power for industry. Tesla’s polyphase induction motor used electrical currents themselves to create a rotating magnetic field, allowing the rotor to turn continuously without conventional mechanical commutation. Induction motors subsequently became among the most common machines for mines, pumps, fans, compressors, machine tools, and industrial production lines. Put simply, Tesla made AC not only convenient to transmit but also particularly useful at the point of consumption. Alternating current could provide mechanical power, not just illumination.

Tesla also had a characteristic that most others on this list did not: his work extended to both the grid side and the load side. On the grid side, Westinghouse’s commercialization, Dolivo-Dobrovolsky’s three-phase engineering, and Tesla’s own polyphase AC work together advanced modern AC supply systems.

It would be historically inaccurate to credit Tesla alone with modern AC electrification. Nevertheless, if one must choose a single person who worked directly in power engineering after 1882 and had the greatest combined originality, system-level significance, industrial diffusion, and lasting societal impact, this article places Tesla first in the history of world power systems. His influence on the power industry is immense. In the International System of Units (SI), the tesla is also the unit of magnetic flux density. More than a century later, his name is still widely used for technology products and companies, such as the electric-vehicle brand Tesla and NVIDIA’s former Tesla graphics-processor architecture. His influence did not end within power-engineering history: his name remains present in modern industrial and technological culture, extending his historical reach beyond the usual boundaries of a specialist engineering field.

Additional Candidates Beyond No. 11 (Unranked)

Charles Concordia: A Foundational Figure in Power-System Dynamic Stability Theory

Charles Concordia (1908–2003) was born in Schenectady, New York, and was one of the twentieth century’s most important experts in power-system dynamics. He belonged to an earlier generation of major stability-and-control specialists than Prabha Kundur. Concordia joined General Electric (GE) in 1926, spending much of his career researching synchronous machines, power-system dynamics, automatic control, system protection, and reliability. The U.S. National Academy of Engineering subsequently described him as a world-renowned power-systems engineer and elected him to membership in 1978 for contributions to the analysis of rotating machinery and power-system performance, control, and reliability.

Concordia’s work covered a long period. As early as the 1940s, he investigated the relationship between synchronous-machine excitation and power-system stability and gradually became a leading figure in the study of large interconnected-system dynamics. His 1951 book Synchronous Machines: Theory and Performance systematically examined synchronous-machine theory and performance [19]. Among his most representative contributions to modern power-system stability was the classic 1969 paper with Francisco P. de Mello. It explained why fast, high-gain excitation systems, while improving voltage control and some aspects of stability, can introduce undesirable negative damping under particular operating conditions. The work provided an important theoretical basis for the later analysis and design of power system stabilizers (PSSs) [20].

PSSs remain important control devices for suppressing low-frequency oscillations in large synchronous generators.

August Uno Lamm: Father of Modern HVDC Transmission and Leader of the 1954 Gotland Project

August Uno Lamm (1904–1989) was born in Gothenburg, Sweden. A Swedish electrical engineer and inventor, he grew up in a strongly technical environment: his father, Fredrik Lamm, taught electrical engineering at Chalmers University of Technology. Lamm graduated from the Royal Institute of Technology (KTH) in Stockholm in 1927 and joined the Swedish electrical manufacturer ASEA. In 1929, he was assigned to develop high-voltage, high-power mercury-arc rectifiers. He earned a doctorate in 1943 while continuing his engineering work. Over the following decades, he and his team addressed critical challenges in the insulation, control, arcing behavior, and reliability of high-voltage mercury-arc valves.

In 1954, the HVDC link between the Swedish mainland and the island of Gotland entered commercial operation. Using approximately 100 kV, 20 MW, and 98 km of submarine cable, it became a landmark in modern commercial HVDC transmission. In the 1960s, Lamm also participated in larger projects, including the Pacific DC Intertie in the United States. He is consequently widely called the “father of HVDC transmission.”

Lamm did not invent the idea of DC transmission; the early electric-power industry itself began with DC systems. He solved a different, much harder problem: once AC had become the industry’s mainstream, how could extra-high-voltage DC become a practical, reliable, controllable method of bulk power transmission? The true obstacle was not whether a wire could carry direct current, but how to perform economical and reliable AC/DC conversion at hundreds of kilovolts and high currents at the two ends of a line. Lamm’s team developed mercury-arc valves to an industrially useful level, making the system architecture of AC generation → long-distance DC transmission → receiving-end AC network a reality. His 1964 paper on mercury-arc valves for HVDC transmission illustrates the technical advances accumulated in this critical equipment area [21].

Prabha Shankar Kundur: Synthesizing Modern Power-System Stability and Control and Leading IEEE/CIGRE Stability Classification

Prabha Shankar Kundur (1939–2018) was born in Bengaluru, India, and later spent much of his professional career in Canada. He earned his bachelor’s degree in electrical engineering at Mysore University in 1959 and his master’s degree at the Indian Institute of Science (IISc) in 1961. He then studied at the University of Toronto, receiving an MASc in 1965 and a PhD in 1967. Kundur joined Ontario Hydro in 1969 and spent nearly 25 years analyzing, controlling, and planning the dynamics of large power systems. In the 1990s, he served as president and CEO of Powertech Labs.

In 1994, Kundur published Power System Stability and Control [22], which became one of the most influential standard references on power-system dynamics and stability worldwide. In 2004, the joint IEEE/CIGRE working group he chaired published a paper defining and classifying power-system stability, establishing the now widely used categories of rotor-angle stability, voltage stability, and frequency stability [23].

Unlike Fortescue or Park, Kundur’s greatest historical contribution was not a single mathematical transformation bearing his name. It was the synthesis, practical organization, and standardization of the complex and dispersed body of knowledge on large-network dynamics developed in the second half of the twentieth century, including Concordia’s work. Transient stability, small-signal stability, voltage stability, excitation systems, PSSs, HVDC, and the many elements of control in large interconnected systems form a vast, intersecting knowledge base. Through industrial practice, research, textbooks, and international technical organizations, Kundur helped organize it into a common language shared by generations of engineers.

Arun G. Phadke: A Principal Pioneer of Digital Relaying, Synchrophasors, PMUs, and WAMS

Arun G. Phadke (born 1938) was born in India and later pursued a long career in U.S. power-system research and engineering. He received a bachelor’s degree from Agra University in 1955, graduated from the Indian Institute of Technology Kharagpur (IIT Kharagpur) in 1959, earned a master’s degree in electrical engineering from Illinois Institute of Technology in 1961, and received a PhD from the University of Wisconsin–Madison in 1964. Between 1963 and 1982, he worked extensively in the power industry, including 13 years in the American Electric Power (AEP) organization. He joined Virginia Tech’s faculty in 1982 and later became a distinguished professor and professor emeritus. He was elected to the U.S. National Academy of Engineering in 1993 for contributions to digital control, protection, and monitoring of power systems. He and James S. Thorp jointly received the Franklin Institute’s Benjamin Franklin Medal in Electrical Engineering in 2008, and Phadke received the IEEE Medal in Power Engineering in 2016.

An early major focus of Phadke’s career was moving protective relaying from electromechanical and static-electronic hardware into the era of computers and digital algorithms. Conventional protective devices made judgments about current, voltage, and impedance largely through electromagnetic mechanisms or dedicated analog circuits. Digital protection instead samples voltage and current waveforms, extracts fundamental-frequency phasors, sequence components, impedances, and related information through digital algorithms, and uses software logic to identify faults and issue trip commands. In the 1970s, Phadke researched Fourier algorithms, symmetrical-component distance protection, and computer relaying. His early methods for calculating voltage and current digitally became important foundations of many digital-relay algorithms. He also helped extend computer relaying beyond tripping to fault recording, communications, self-testing, and adaptive settings. His 1988 book with Thorp, Computer Relaying for Power Systems, systematically surveyed the field [25].

While working on digital distance protection, Phadke, Thorp, and colleagues recognized that digital relays were already capable of calculating voltage phasors and their angles in real time. In 1983, Phadke, Thorp, and Adamiak published a paper proposing real-time tracking of voltage phasors, local system frequency, and the rate of change of frequency [24]. This research trajectory subsequently developed into synchrophasor measurement technology.

Conventional SCADA can tell operators about voltage and power at different locations, but without a common time reference for AC phase angles measured at separate substations, precise comparisons across large regions are difficult. Phadke and his collaborators combined accurate common time synchronization with digital phasor calculation, allowing devices hundreds or even thousands of kilometers apart to report voltage and current magnitudes and angles on the same time reference. This enabled synchronized phasors and phasor measurement units (PMUs), from which wide-area measurement systems (WAMS) could be built. Phadke and Thorp’s 2008 book Synchronized Phasor Measurements and Their Applications systematically presented this line of development [26].

Narain G. Hingorani: Introducing FACTS and Bringing High-Power Electronics into AC Transmission Control

Narain G. Hingorani (born 1931) was born in Sindh in British India. His family moved to India after Partition, and he subsequently spent most of his professional career in the United States. He earned a bachelor’s degree in electrical engineering from Baroda University in 1953. After working for the Bombay Electricity Board, he pursued graduate studies in Britain, receiving master’s and doctoral degrees from the University of Manchester Institute of Science and Technology in 1957 and 1961, respectively, and later earning a DSc. He taught at British universities in the 1960s and subsequently joined BPA in the United States. In 1974, he joined the Electric Power Research Institute (EPRI), eventually becoming vice president for Electrical Systems.

An early expert in HVDC, Hingorani participated in projects including the Pacific DC Intertie. In the 1980s, he went further, introducing and promoting the concept of Flexible AC Transmission Systems (FACTS) and subsequently the related idea of Custom Power for distribution systems. His 1993 article “Flexible AC Transmission” was an influential presentation of the FACTS concept [27]. Static var compensators (SVCs), static synchronous compensators (STATCOMs), thyristor-controlled series compensation (TCSC), and unified power flow controllers (UPFCs) gradually formed a comprehensive family of FACTS technologies. His book with Laszlo Gyugyi, Understanding FACTS, provided a systematic account of their principles and techniques [28]. In the renewable-energy era, high-power electronics and their control have been applied increasingly to voltage-source-converter HVDC (VSC-HVDC), energy-storage converters, flexible interconnection, and emerging grid-forming control.

Hingorani did not invent power-electronics technology. His pioneering achievement was elevating high-power electronics into a grid-level means of transmission control and establishing the technology as a systematic concept. This technical direction is becoming increasingly important in the twenty-first century.

Dennis A. Woodford: Originator of EMTDC and an Early Pioneer of Real-Time Digital EMT Simulation

Dennis A. Woodford (born 1945) was born in Melbourne, Australia, and later worked for many years as a power engineer in Canada. He graduated from the University of Melbourne around 1966 and received a master’s degree from the University of Manitoba in 1973. After joining Manitoba Hydro, he participated in studies of 500-kV interconnections and the Nelson River HVDC system. In 1975, to address simulation problems on the Nelson River HVDC system, he began writing the program that evolved into EMTDC. After 1986, he was deeply involved in leading the Manitoba HVDC Research Centre and later founded or led power-system consulting businesses including Electranix.

Woodford wrote the first EMTDC code at Manitoba Hydro in 1975 to provide a sufficiently flexible and powerful tool for analyzing complex HVDC systems. Later, EMTDC was combined with the Power Systems Computer Aided Design (PSCAD) graphical interface to produce the globally used PSCAD/EMTDC simulation platform. His 1983 paper with A. M. Gole and R. W. Menzies, “Digital Simulation of DC Links and AC Machines,” was a representative early publication from this technical trajectory [29].

Woodford’s influence also extended to real-time digital simulation. In 1986, he became executive director of the Manitoba HVDC Research Centre. In 1989, the team produced what RTDS Technologies identifies as the world’s first real-time digital HVDC simulation. Related technology subsequently evolved into the Real Time Digital Simulator (RTDS), commercialized in 1994 by RTDS Technologies, a company founded by members of the research team.

Tomas Enciso Dy-Liacco: Operating States, Security Control, and the Foundations of Modern Energy Control Centers

Tomas Enciso Dy-Liacco (1920–2019) was born in Naga City, Camarines Sur, Philippines. A Filipino-American electrical engineer, he graduated with honors in electrical engineering from the University of the Philippines in 1940 and subsequently studied mechanical engineering. He received a master’s degree in electrical engineering from Illinois Institute of Technology in 1955 and a doctorate in systems engineering from Case Western Reserve University in 1968. He worked for Taiwan Power Company and electricity companies in the Philippines before joining the Cleveland Electric Illuminating Company in 1955, where he studied system planning, protective relaying, and computer control.

In 1967, he published his classic paper “The Adaptive Reliability Control System”, treating power-system control as an integrated combination of automated functions, human decision-making, and information systems, and establishing operating-state concepts such as normal, emergency, and restorative states, together with their associated control principles [30].

Dy-Liacco’s originality did not lie in a single isolated algorithm, but in defining the problem from the perspective of the entire control center and the grid’s progression through operating and recovery conditions. For this reason, he is often regarded as an important pioneer in the theory of modern energy control centers.

Jacques Carpentier: First Formulation of AC Optimal Power Flow

Jacques Carpentier was a French power-system engineer closely associated with Électricité de France (EDF) and a pioneer of power-system computation and optimization in France. In his 1962 work Contribution à l’étude du dispatching économique, he introduced the problem later known as optimal power flow (OPF) [31]. In 1979, he published “Optimal Power Flows,” systematically reviewing the problem’s models, solution methods, and applications to online dispatch [32]. More than half a century later, OPF remains a central mathematical model in electricity markets, dispatch, planning, and numerous renewable-energy optimization problems.

Edmund O. Schweitzer III: Industrializing Digital Protective Relaying at Scale

Edmund O. Schweitzer III is an American electrical engineer, inventor, and entrepreneur, and one of the most important figures in the commercialization of modern digital protective relaying. He received bachelor’s and master’s degrees in electrical engineering from Purdue University in 1968 and 1971 and earned a PhD in electrical engineering from Washington State University (WSU) in 1977. He taught at Ohio University and WSU while continuing his digital-relaying research. In 1982, he founded Schweitzer Engineering Laboratories (SEL) to develop and manufacture digital protection, measurement, monitoring, and control equipment.

Schweitzer’s doctoral research had already examined digital computing for transmission-line protection. It subsequently developed into the SEL-21 digital distance relay. Whereas conventional electromechanical relays chiefly used coils, springs, mechanical contacts, and analog components to implement protection logic directly, the SEL-21 used a microprocessor to compute from sampled currents and voltages and perform fault discrimination through software algorithms. His papers “Filtering for Protective Relays” with Daqing Hou and “Distance Relay Element Design” with Jeff Roberts addressed signal processing and protection-element implementation, respectively, highlighting essential engineering techniques for practical digital protection [33–34].

Schweitzer’s most important historical role was not simply replacing a conventional relay with a microprocessor. What changed was the nature of the protection device itself. Traditional relays were often designed around a single protective principle, and their functions were largely determined by mechanical structures and analog circuits. In the microprocessor era, algorithms and software implement protection logic, so the same hardware platform can perform distance protection, overcurrent protection, fault location, event recording, self-diagnostics, communication, and increasingly measurement and control. Protective relays thus evolved from single-purpose fault-tripping devices into intelligent electronic devices with integrated computation, measurement, recording, communications, and control.

Conclusion: Four Stages in the Development of Power Systems

If the figures are arranged by the dates of their landmark achievements rather than by rank, their contributions cluster into several overlapping historical periods. These periods reflect the different central challenges faced during the development of power systems. First the industry had to answer “How can we build the system?” Then it had to learn “How can we analyze it?” Next came “How can we operate a large system safely and economically?” Today, the challenge increasingly becomes “How can we coordinate diverse devices and multiple participants?”

The stages below are based on technical achievements and their engineering application, not on the individuals’ birth and death dates. They overlap considerably, and a later stage does not replace the foundations of earlier ones. An individual’s work may also span more than one stage.

Stage 1: Physical Formation — From DC Supply to Three-Phase AC and Interconnected Networks

The landmark achievements of this stage were concentrated mainly between the 1880s and the early twentieth century, while coordination of voltage levels and frequency and the development of regional interconnections continued for longer. The central question was how to combine generation, transmission, distribution, and end-use equipment into a complete system that could operate continuously, expand, and sustain a commercial business.

Edison built a commercial DC supply system, exemplified by Pearl Street, encompassing generation, distribution, consumption, metering, and billing. Westinghouse organized engineering development and industrial production of AC equipment, turning AC supply into a replicable, scalable approach. Tesla connected AC supply to induction motors through polyphase currents and rotating magnetic fields. Dolivo-Dobrovolsky’s practical three-phase motors, three-phase transformers, and long-distance transmission demonstrations helped establish the mature three-phase system.

Merz’s work marked a further transition from supply systems to interconnected grids. He promoted high-voltage three-phase supply, regional interconnection, and coordination of voltage and frequency, while jointly developing differential protection with Price so that faults could be cleared selectively. Standardization of voltage levels and frequency did not mean that the entire world ultimately adopted one voltage or one frequency; it meant that equipment and networks could operate compatibly within their respective interconnected systems. This stage established more than a collection of electrical devices: it created the physical structure and basic operating order of modern power systems.

Stage 2: Analytical Foundations — A Common Language for Steady-State, Fault, and Dynamic Analysis

The representative achievements of this stage were concentrated between the 1890s and the 1930s, overlapping with the later part of Stage 1. Before digital computers became widespread, engineers confronting increasingly complex AC systems first needed mathematical transformations that simplified the problem enough for hand calculations, graphical methods, or the computing tools then available.

Steinmetz systematized complex-number notation for AC analysis, enabling the treatment of magnitude, phase, and impedance under sinusoidal steady-state conditions in a unified algebraic language and providing a foundation for steady-state network analysis and equipment design. In 1918, Fortescue introduced symmetrical components, converting unbalanced three-phase problems—under the usual assumptions of symmetrical networks—into combinations of positive-, negative-, and zero-sequence networks. This provided a unified framework for unbalanced operation and short-circuit faults. Park’s classic 1929 work used rotating d–q coordinates to simplify dynamic models of synchronous machines, laying an important foundation for machine dynamics and power-system stability.

In summary, complex phasors, symmetrical components, and d–q coordinates became fundamental languages of steady-state analysis, fault analysis, and dynamic-stability analysis, respectively, although their applications are not strictly confined to those categories. In particular, the d–q transformation mainly removes many coefficients that vary periodically with rotor position; it does not automatically eliminate all inter-axis coupling or replace a complete stability analysis. The lasting achievement of this stage was to move power systems from something engineers could build and operate to something they could model, explain, and design quantitatively.

Stage 3: Making Large Systems Computable and Controllable — Power Electronics, Digital Computing, Dispatch, and Markets

From the middle of the twentieth century, and especially during its second half, two profound changes occurred in parallel: high-voltage, high-power conversion technology became increasingly practical, and digital computers entered planning, simulation, protection, and operational control. These developments reinforced the growth of large interconnected grids and transformed their physical structure, analytical methods, and organization of operations.

In equipment and network architecture, Lamm and his team brought high-voltage mercury-arc valves to engineering maturity, with the 1954 Gotland project marking a major milestone in commercial HVDC. Semiconductor conversion technology developed further, and combined AC/DC networks expanded. Hingorani introduced and promoted FACTS, extending high-power electronics beyond AC/DC conversion into fast control of AC transmission networks. This was not a case of “going around in a circle from DC back to DC.” Rather, it meant using the different strengths of different technologies to build a more flexible grid on the foundation of the already mature three-phase AC system.

Large-scale interconnection also made stability questions more prominent. After faults, the system must not only remain synchronized; it must also manage low-frequency oscillations, relationships between excitation and damping, and various forms of voltage and frequency stability. Concordia and de Mello explained how excitation control affects synchronizing and damping torque, establishing an important theoretical basis for PSS analysis and design. Kundur’s 1994 book and the joint working-group paper published in 2004 further systematized knowledge of large-grid stability and control. Stability problems had existed before this period, but their scale, interconnections, and required control methods developed substantially.

At the same time, growing system size meant that having a model no longer guaranteed that it could be computed. Tinney’s sparse-matrix techniques and Newton power-flow methods made large-network solutions practical under the computing constraints of the day. Dommel transformed electromagnetic transients into network problems solvable by digital computers one time step at a time. Woodford and collaborators advanced EMTDC and related digital-simulation technologies, providing important tools for investigating and validating complex AC/DC systems.

Built on these computational capabilities, Carpentier’s OPF formulation connected economic objectives with network physical constraints, while Dommel and Tinney advanced its practical numerical solution. Dy-Liacco established a security-control framework built around normal, emergency, and restorative operating states. Schweppe’s state estimation allowed control centers to infer credible operating conditions from imperfect measurements, and his spot-pricing research connected network constraints to economic signals. Phadke advanced digital protective relaying and synchronized phasor measurement; Schweitzer promoted large-scale engineering deployment of digital relays, further integrating measurement, protection, recording, and communication.

Together, these advances supported computer-based dispatch automation and EMS platforms, and provided essential models, algorithms, and information-processing capabilities for spot electricity trading. Electricity markets were not simply “invented” by one individual or paper: market development also requires rules, metering, communications, and institutions. Nevertheless, security assessment, optimal dispatch, and market clearing in a modern large power system cannot function without practical computing systems. The grid had become more than a physical network for transporting energy; it had become a complex engineered system that could be continuously monitored, analyzed, protected, optimized, and controlled—and could support electricity trading.

Stage 4: The Present and Future — Renewable Energy, Distributed Resources, and Multi-Actor Coordination

In the twenty-first century, and especially with the expansion of renewable energy and distributed resources, power systems are undergoing another structural transformation. The traditional dominant pattern of centralized generation, hierarchical transmission and distribution, and end consumption now coexists with distributed generation, storage, and flexible loads. Some customers not only consume electricity but can also generate it, store it, or provide flexibility, while power flows in distribution networks may reverse direction. Here, the transition “from one-way to two-way” refers chiefly to traditional producer–consumer roles and distribution-system hierarchies; it does not imply that meshed transmission systems in the past lacked bidirectional power flows.

The central change is not merely the source of generation. The dynamic characteristics of connected equipment, control approaches, and participating actors are all becoming more diverse. A large share of sources now connect through power converters, requiring traditional synchronous-machine-dominated stability analysis to expand. Participation by distributed generators, storage, flexible loads, and their aggregators introduces more temporal and spatial scales and more information constraints into forecasting, dispatch, protection, and market coordination. Systems must address physical security, operational economics, stakeholder interests, and uncertainty together, rather than rely solely on a simple organizational model of “generation follows load.”

Artificial intelligence and related methods will play roles in forecasting, state awareness, assisted analysis, and operational decision-making. Their engineering use, however, must be integrated with power-system physics, security constraints, reliability requirements, and verifiable control mechanisms. The central challenge of this stage can be stated as follows: under high renewable penetration, greater power-electronics penetration, and participation by multiple actors, how can we achieve coordination that is safe, economical, flexible, and sustainable?

This article treats Stage 4 as an outlook and does not add to or revise the historical ranking on that basis. This does not mean that the stage lacks major achievements or outstanding experts. Rather, the selection criteria emphasize historical influence demonstrated through long-term engineering use of original contributions. Contemporary technical directions and their effects are still evolving and need longer observation. The principal basis for selecting the figures in this article therefore comes from the first three stages.

Viewed through these four stages, the central trajectory of modern power systems is the formation of their physical structure, the establishment of analytical languages, the development of large-system computation and control, and their continuing evolution toward renewable-energy integration and coordination among multiple actors. The ranking itself is not the most important point. What matters is recognizing that these experts’ contributions are not isolated: together, they constitute the technical foundations of modern power systems and provide the starting point for their next stage of development.

References

[1] DOMMEL H W. Digital computer solution of electromagnetic transients in single- and multiphase networks[J]. IEEE Transactions on Power Apparatus and Systems, 1969, PAS-88(4): 388–399. DOI: 10.1109/TPAS.1969.292459.

[2] DOMMEL H W, TINNEY W F. Optimal power flow solutions[J]. IEEE Transactions on Power Apparatus and Systems, 1968, PAS-87(10): 1866–1876. DOI: 10.1109/TPAS.1968.292150.

[3] SCHWEPPE F C, WILDES J. Power system static-state estimation, Part I: Exact model[J]. IEEE Transactions on Power Apparatus and Systems, 1970, PAS-89(1): 120–125. DOI: 10.1109/TPAS.1970.292678.

[4] SCHWEPPE F C, CARAMANIS M C, TABORS R D, BOHN R E. Spot pricing of electricity[M]. Boston: Kluwer Academic Publishers, 1988. DOI: 10.1007/978-1-4613-1683-1.

[5] TINNEY W F, WALKER J W. Direct solutions of sparse network equations by optimally ordered triangular factorization[J]. Proceedings of the IEEE, 1967, 55(11): 1801–1809. DOI: 10.1109/PROC.1967.6011.

[6] TINNEY W F, HART C E. Power flow solution by Newton’s method[J]. IEEE Transactions on Power Apparatus and Systems, 1967, PAS-86(11): 1449–1460. DOI: 10.1109/TPAS.1967.291823.

[7] MERZ C H, PRICE B. Improvements in the method of and means for protecting apparatus on alternating current systems: British patent No. 3896/1904[P]. Filed: 1904-02-16.

[8] PARK R H. Two-reaction theory of synchronous machines—Generalized method of analysis—Part I[J]. Transactions of the American Institute of Electrical Engineers, 1929, 48(3): 716–727. DOI: 10.1109/T-AIEE.1929.5055275.

[9] FORTESCUE C L. Method of symmetrical co-ordinates applied to the solution of polyphase networks[J]. Transactions of the American Institute of Electrical Engineers, 1918, 37(2): 1027–1140. DOI: 10.1109/T-AIEE.1918.4765570.

[10] STEINMETZ C P. On the law of hysteresis[J]. Transactions of the American Institute of Electrical Engineers, 1892, 9(1): 1–64. DOI: 10.1109/T-AIEE.1892.5570437.

[11] STEINMETZ C P. Theory and calculation of alternating current phenomena[M]. New York: The W. J. Johnston Company, 1897.

[12] WESTINGHOUSE G Jr. System of electrical distribution: US342552A[P]. 1886-05-25.

[13] WESTINGHOUSE G Jr. System of electrical distribution: US399639A[P]. 1889-03-12.

[14] EDISON T A. Electric distribution and translation system: US264642A[P]. 1882-09-19.

[15] EDISON T A. System of electrical distribution: US274290A[P]. 1883-03-20.

[16] DOLIVO-DOBROWOLSKY M von. Alternating-current motor: US427978A[P]. 1890-05-13.

[17] TESLA N. Electro-magnetic motor: US381968A[P]. 1888-05-01.

[18] TESLA N. Electrical transmission of power: US382280A[P]. 1888-05-01.

[19] CONCORDIA C. Synchronous machines: Theory and performance[M]. New York: John Wiley & Sons, 1951.

[20] DE MELLO F P, CONCORDIA C. Concepts of synchronous machine stability as affected by excitation control[J]. IEEE Transactions on Power Apparatus and Systems, 1969, PAS-88(4): 316–329. DOI: 10.1109/TPAS.1969.292452.

[21] LAMM U. Mercury-arc valves for high-voltage D.C. transmission[J]. Proceedings of the Institution of Electrical Engineers, 1964, 111(10): 1747–1753. DOI: 10.1049/piee.1964.0286.

[22] KUNDUR P. Power system stability and control[M]. New York: McGraw-Hill, 1994. ISBN: 9780070359581.

[23] KUNDUR P, PASERBA J, AJJARAPU V, et al. Definition and classification of power system stability[J]. IEEE Transactions on Power Systems, 2004, 19(3): 1387–1401. DOI: 10.1109/TPWRS.2004.825981.

[24] PHADKE A G, THORP J S, ADAMIAK M G. A new measurement technique for tracking voltage phasors, local system frequency, and rate of change of frequency[J]. IEEE Transactions on Power Apparatus and Systems, 1983, PAS-102(5): 1025–1038. DOI: 10.1109/TPAS.1983.318043.

[25] PHADKE A G, THORP J S. Computer relaying for power systems[M]. Taunton: Research Studies Press; New York: John Wiley & Sons, 1988.

[26] PHADKE A G, THORP J S. Synchronized phasor measurements and their applications[M]. New York: Springer, 2008. DOI: 10.1007/978-0-387-76537-2.

[27] HINGORANI N G. Flexible AC transmission[J]. IEEE Spectrum, 1993, 30(4): 40–45. DOI: 10.1109/6.206621.

[28] HINGORANI N G, GYUGYI L. Understanding FACTS: Concepts and technology of flexible AC transmission systems[M]. New York: IEEE Press, 2000. DOI: 10.1002/9780470546802.

[29] WOODFORD D A, GOLE A M, MENZIES R W. Digital simulation of DC links and AC machines[J]. IEEE Transactions on Power Apparatus and Systems, 1983, PAS-102(6): 1616–1623.

[30] DY LIACCO T E. The adaptive reliability control system[J]. IEEE Transactions on Power Apparatus and Systems, 1967, PAS-86(5): 517–531. DOI: 10.1109/TPAS.1967.291728.

[31] CARPENTIER J. Contribution à l’étude du dispatching économique[J]. Bulletin de la Société Française des Électriciens, 1962, série 8, vol. 3: 431–447.

[32] CARPENTIER J. Optimal power flows[J]. International Journal of Electrical Power & Energy Systems, 1979, 1(1): 3–15. DOI: 10.1016/0142-0615(79)90026-7.

[33] SCHWEITZER E O III, HOU D. Filtering for protective relays[C]//19th Annual Western Protective Relay Conference. Spokane, WA, 1992.

[34] SCHWEITZER E O III, ROBERTS J. Distance relay element design[C]//19th Annual Western Protective Relay Conference. Spokane, WA, 1992.