<P> The AC power systems was developed and adopted rapidly after 1886 due to its ability to distribute electricity efficiently over long distances, overcoming the limitations of the direct current system . In 1886, the ZBD engineers designed the world's first power station that used AC generators to power a parallel - connected common electrical network, the steam - powered Rome - Cerchi power plant . The reliability of the AC technology received impetus after the Ganz Works electrified a large European metropolis: Rome in 1886 . </P> <P> In the UK, Sebastian de Ferranti, who had been developing AC generators and transformers in London since 1882, redesigned the AC system at the Grosvenor Gallery power station in 1886 for the London Electric Supply Corporation (LESCo) including alternators of his own design and transformer designs similar to Gaulard and Gibbs . In 1890 he designed their power station at Deptford and converted the Grosvenor Gallery station across the Thames into an electrical substation, showing the way to integrate older plants into a universal AC supply system . </P> <P> In the US William Stanley, Jr. designed one of the first practical devices to transfer AC power efficiently between isolated circuits . Using pairs of coils wound on a common iron core, his design, called an induction coil, was an early (1885) transformer . Stanley also worked on engineering and adapting European designs such as the Gaulard and Gibbs transformer for US entrepreneur George Westinghouse who started building AC systems in 1886 . The spread of Westinghouse and other AC systems triggered a push back in late 1887 by Edison (a proponent of direct current) who attempted to discredit alternating current as too dangerous in a public campaign called the "War of Currents". In 1888 alternating current systems gained further viability with introduction of a functional AC motor, something these systems had lacked up till then . The design, an induction motor, was independently invented by Galileo Ferraris and Nikola Tesla (with Tesla's design being licensed by Westinghouse in the US). This design was further developed into the modern practical three - phase form by Mikhail Dolivo - Dobrovolsky and Charles Eugene Lancelot Brown . </P> <P> The Ames Hydroelectric Generating Plant (spring of 1891) and the original Niagara Falls Adams Power Plant (August 25, 1895) were among the first hydroelectric alternating current power plants . The first long distance transmission of single - phase electricity was from a hydroelectric generating plant in Oregon at Willamette Falls which in 1890 sent power fourteen miles downriver to downtown Portland for street lighting . In 1891, a second transmission system was installed in Telluride Colorado . The San Antonio Canyon Generator was the third commercial single - phase hydroelectric AC power plant in the United States to provide long - distance electricity . It was completed on December 31, 1892 by Almarian William Decker to provide power to the city of Pomona, California which was 14 miles away . In 1893 he next designed the first commercial three - phase power plant in the United States using alternating current was the hydroelectric Mill Creek No. 1 Hydroelectric Plant near Redlands, California . Decker's design incorporated 10 kV three - phase transmission and established the standards for the complete system of generation, transmission and motors used today . The Jaruga Hydroelectric Power Plant in Croatia was set in operation on 28 August 1895 . The two generators (42 Hz, 550 kW each) and the transformers were produced and installed by the Hungarian company Ganz . The transmission line from the power plant to the City of Šibenik was 11.5 kilometers (7.1 mi) long on wooden towers, and the municipal distribution grid 3000 V / 110 V included six transforming stations . Alternating current circuit theory developed rapidly in the latter part of the 19th and early 20th century . Notable contributors to the theoretical basis of alternating current calculations include Charles Steinmetz, Oliver Heaviside, and many others . Calculations in unbalanced three - phase systems were simplified by the symmetrical components methods discussed by Charles Legeyt Fortescue in 1918 . </P>

Who developed the first alternating current electric system