机械工厂变配电所的设计 毕业设计.doc

兰州交通大学毕业设计（论文） - PAGE IV - - PAGE I - 摘 要 机械工厂供电的目的是从电力系统取得电能，经过合理的传输，变换，分配到机械工厂车间中的每一个用电设备上以供使用。随着机械工业电气自动化技术的发展以及工厂用电量的迅速增长，使工厂对电能的质量，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），高压配电系统，车间变电所，低压配电系统及用电设备组成。本设计对一个大型机械工厂的供电系统进行设计，主要包括进线电压等级的选择；总降压变电所主接线的设计；通过负荷计算确定主变压器及各车间配电变压器的型号；用标幺值法及有欧姆法进行了短路计算，进而对总降压变电所、高压配电线路、车间变电所及低压配电线路中的电气设备进行选择与校验，例如断路器、隔离开关、电流互感器、电压互感器。本文也对二次保护回路进行了简单设计。 本设计在确定高压侧接线方案及对高压侧设备选择时进行了较为详细的技术经济比较，力求达到经济合理可靠。因为供电设计是否完善，不仅影响工厂的基本建设投资、运行费用和有色金属消耗量，而且也反映到工厂供电的可靠性和工厂的安全生产上，它与企业的经济效益、设备和人身安全等是密切相关的。 关键词：变电所；主接线；设备选择；二次继电保护 - PAGE III - 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