Analysis and Design of Electrical Power Systems

6Three‐Phase Alternating Current

6.1 Generation of Three‐Phase Current

Three‐phase current is generated almost exclusively with three‐phase generators that are operated in the regenerative operating range. Synchronous generators are rotating energy converters (electrical machines) that convert mechanical energy into electrical energy. For example, energy is generated in power plants by using huge synchronous generators (with, in some cases, over one thousand megawatt output) mechanically driven by a turbine driven by water vapor; the mechanical drive energy is finally dissipated by the generator at high speed and efficiency into electrical energy. Figure 6.1 shows the basic structure of three‐phase synchronous machines. The machine consists ...