变电所主接线设备选择二次继保护论文.doc

摘 要 机械工厂供电的是从电力系统取得电，经过合理的传输，变换，分配到工厂车间中的每一个用电设备上。随着工业电气自动化技术的发展工厂用电量的迅速增长，对电能的质量供电的可靠行以及技术经济指标等要求也日益提高。 工厂供电系统是由工厂总降压变电所（高压变电所），高压配电，车间变电所，低压配电及用电设备组成。Abstract The power supply system of the machinery factory aims to obtain the power from the power system, and distributing the power to each of the electrical equipments in machinery factory through reasonable transformation and transmission. With the development of machinery industrial’s electrical automation and the rapid growth of electricity consumption, power quality and the reliability of power supply are required increasing by the factory, so was the techno-economic indicators. The factory power supply system is consist of the total substation (high-voltage substation), high voltage distribution system, workshop substations, low voltage distribution system and electric equipment. The design of a large machinery factory power supply system was introduced in this paper, including choosing the voltage level of the incoming line; designing the main connection of the total substation; selecting the type of the main transformer and wokshop distribution transformers through the load calculation; performing the calculation of short current use per-unit value method and ohms method, then choosing the equipments for the factory power supply system, such as circuit breakers, disconnectors, current and voltage sensors and so on. It also introduces the design of secondary relay protection circuit simply. Detailed technical and economic comparison about high voltage side scheme of connection and equipments selection was introduced in this paper, striving to achieve economic reasonable and reliable. Whether the power supply system is designed perfect or not, not only affects the factory’s construction investment, operating costs and non-ferrous metal consumption, but also reflects the reliability of the power supply for the factory and production safety, it has close relationship with the economic efficiency, equipments