A Brief History of Electrical Power Systems

Electric power has a great influence on industry and contributes to the welfare, progress, and technological advances of humanity. The growth of the world's electric energy consumption truly remarkable. In the U.S. alone, the sales of electric energy have grown to well over 400 times in the period between the turn of the century and the early 70s. This growth rate is 50 times the growth rate in all other energy forms used during the same period. The installed kW capacity per capita in the U.S. is estimated to be close to 3kW.

Edison Electric Illuminating Company inaugurated the Pearl Street Station in 1881. The station had a capacity of four 250hp boilers supplying steam to six engine-dynamo sets. Edison's system was a 110Vdc underground distribution network with copper conductors with jute insulation. The first water wheel-driven generator was installed in 1882 at Appleton, Wisconsin. The low voltage of the circuits has limited the service area of a central station, and consequently, many central stations has been constructed throughout metropolitan areas.

Ottó Bláthy, Miksa Déri, Károly Zipernowsky of the Austro-Hungarian Empire First designed and used the transformer in both experimental, and commercial systems. Later on Lucien Gaulard, Sebstian Ferranti, and William Stanley perfected the design.

The property of induction was discovered in the 1830's but it wasn't until 1886 that William Stanley, working for Westinghouse built the first reliable commercial transformer. His work was built upon some rudimentary designs by the Ganz Company in Hungary (ZBD Transformer 1878), and Lucien Gaulard and John Dixon Gibbs in England. Nikola Tesla did not invent the transformer as some dubious sources have claimed. The Europeans mentioned above did the first work in the field. George Westinghouse, Albert Schmid, Oliver Shallenberger and Stanley made the transformer cheap to produce, and easy to adjust for final use.

The invention of the transformer, then known as the "inductorium", made ac systems possible. Early AC distribution utilized 1000-V overhead lines. Nikola Tesla invented the induction motor in 1888 helped replace dc motors and hastened the advance in use of AC systems.

The first American single-phase ac system was installed in Oregon in 1889. Southern California Edison Company established the first three phase 2.3 kV system in 1893.

The subsequent consolidation of electric companies enables the realization of economies of scale in generating facilities, the introduction of equipment standardization, and the utilization of the load diversity between areas. Generating unit sizes of up to 1300 MW are in service, an era that was started by the 1973 Cumberland Station of the Tennessee Valley Authority.

Underground distribution at voltages up to 5kV was made possible by the development of rubber-base insulated cables and paper-insulated, lead- covered cables in the early 1900s. Since then, higher distribution voltages have been necessitated by load growth that would otherwise overload low-voltage circuits and by the requirement to transmit large blocks of power over greater distances.

The growth in size of power plants and in the higher voltage equipment necessitated the interconnections of the generating facilities. These interconnections reduced the probability of power service interruptions, made the utilization of the most economical units possible, and decreased the total reserve capacity required to meet equipment-forced outages.

The use of sophisticated analysis tools such as the network analyzer is then a necessary tool. Central control of the interconnected systems was introduced for reasons of economy and safety. The advent of the load dispatcher heralded the dawn of power systems engineering, an exciting area that strives to provide the best system to meet the load requirements reliably, safely, and economically, utilizing state-of-the-art computer facilities.

In 1954, the Swedish State Power Board energized the 60-mile, 100-kV dc submarine cable utilizing U. Lamm's Mercury Arc valves at the sending and receiving ends of the world's first high-voltage direct current (HVDC) link connecting the Baltic Island of Gotland and the Swedish mainland. Currently, numerous installations with voltages up to 800-kV dc are in operation around the world.

The electric power industry has undergone fundamental changes since the deregulation of the telecommunication, gas, and other industries. The generation business rapidly become market driven. The advent of open transmission access has resulted in wholesale and retail markets. Utilities may be divided into power generation, transmission, and retail segments. Generating companies sell directly to an independent system operator which is responsible for the operation of the grid and matching demand and generation dealing with transmission companies as well. The power industry continues to evolve to create a more competitive environment for electricity markets to promote greater efficiency. The industry always faces new challenges and problems associated with the interactivity of power system entities in their efforts to make crucial technical decisions while striving to achieve the highest level of human welfare.

Introduction to Electrical Power Systems, 2008
Mohamed E. El-Hawary
IEEE Press Series on Power Engineering