电力系统英文翻译.doc

Electric Power System and Power System Automatic Electirc Prower Systems,components that transform other types of energy into electrical energy and transmit this energy to a consumer. The production and transmission of electricity relavtively efficient and inexpensive,although unlike other forms of energy,electricity is not easily stored-up and thus must generally be used as it is being produced. Components of an Electric Power System A modern electric power system consists of six main components:(1)the power station, (2)a set of transformers to raise the generated power to the high voltages used on the transmission lines,(3)the transmission lines,(4) the substations at which the power is stepped down to the voltage on the distribution lines,(5)the distribution lines,and(6)the transformers that lower the distribution voltage to the level used by the consumers equipment. Power Station The power station of a power system consist of a prime mover, such as a turbine driven by water,steam,or combustion gases that operate a system of electric motors and generators.Most of the worlds electric power is generated in steam plants driven by coal,oil,nuclear energy,or gas.A smaller percentage of the worlds electric power is generated by hydroelectric(waterpower ),diesel,and internal-combustion plants. Transformers Modern electric power system use transformer to convert electricity into different voltage.With transformers,each stage of the system can be operated at an appropriate voltage.In a typical system, the generators at the power station deliver a voltage of from 1,000 to 26,000 volts(V ).Transformers step this voltage up to values ranging form 138,000to 765,000 V for the long-distance primary transmission line because higher voltage can be transmitted more efficiently over long distances.At the substation the voltage may be transformed down to levels of 69,000 to 138,000 V for further transfer on the distribution system. Another set of transformers step the voltage do