外文翻译---变电站基本设备的技术状态和架空线以及提高可靠性的措施.docx

英文文献ENERGY SYSTEMS AND ELECTRICAL NETWORKSTECHNICAL STATE OF BASIC EQUIPMENTOF SUBSTATIONS AND OVERHEAD TRANSMISSION LINESAND MEASURES FOR RAISING THEIR RELIABILITYAbstractA brief description of the state of basic equipment employed in 110 – 750-kV power networks is presented. Problems arising in operation of this equipment are outlined and recommendations on improving its reliability are made. Transformer equipment, high-voltage circuit breakers, disconnectors, measuring transformers, nonlinear overvoltage suppressors, and transmission lines are considered.Keywords: transformer equipment; high-voltage circuit breakers; disconnectors,;measuring transformers; overvoltage suppressors; transmission lines; service life.The existing 110 – 750-kV power networks have been created in the Soviet Union and are now experiencing the following problems:— a large volume of time-worn electric equipment at substations;— poor controllability of the network and inadequate volume of devices for voltage control;— low design reliability of the active transmission lines;— outdated design of overhead lines;— use of some outdated technologies and kinds of network equipment and control systems;— low level of automation of network objects and absence of fully automated substations;— inadequate performance specification and maintenance of network facilities;— high operating costs.A great part of the installed equipment has exhausted standardized minimum service life. It should be noted that different kinds of equipment have different load-lives. On the average, the substation equipment has been worn out by about 40%. Requirements on reliability of the base facilities are standardized only in GOST 687–78 for ac circuit breakers rated for over 1000 V. The GOST 687–78 State Standard also includes requirements on the mechanical life evaluated in terms of parameter N specified for every kind of circuit breaker. For overhead transmission lines N is usually equal to 1000 on-off cycles .However, in t