摘要:由于经济的发展和现代工业建设的崛起，供电系统的设计也越来越全面、越来越系统化，工厂用电量也在迅速地增长，因此对电能质量、技术经济状况、供电的可靠性等指标的要求也日益提高，从而对供电设计也要求更完善、全面。城市供电系统的核心部分是变电站。因此，设计和建造一个安全、经济的变电站，是十分重要的。

　　　本变电站设计除了注重变电站设计的基本计算外，对于主接线的选择与论证等都作了充分的说明，其主要内容包括：变电站主接线方案的选择，进出线的选择；变电站主变压器台数、容量和型式的确定；短路点的确定与短路电流的计算，电气设备的选择（断路器，隔离开关，电流互感器，电压互感器，避雷器）；配电装置设计和总平面布置；防雷保护与接地系统的设计。同时按照电力系统相关的图纸要求绘制了两张图纸，包括：电气主接线图和电气总平面布置图。

关键词 降压变电站；电气主接线；电气设备；电气总平

Abstract:With the development of economy and the rise of modern industrial building,power supply system designs also more and more comprehensive,more systematic,plant growth rapidly,so the power quality,technical and economic conditions,power supply reliability requirements are also increasing,thus the power supply design also requires more perfect,comprehensive.The core part of the city power supply system of the substation.Therefore,the design and construction of a security,economic substation,is very important.

　　　The substation design in addition to focus on the basic calculation of substation main wiring design, for the selection and demonstration have been fully described, its main content includes: the choice of main wiring scheme of substation, out line choice; Determination of substation main transformer number, capacity and type; calculation of short-circuit point and short-circuit current, the choice of electrical equipment (circuit breaker, isolating switch, current transformer, voltage transformer, arrester); power distribution equipment design and layout; lightning protection and grounding system design.At the same time, according to the power system related drawings drawn two drawings, includes: the main electrical wiring diagram and electrical general layout plan.

Keywords  Step-down substation Main electrical connections Electrical equipment   Electrical sheet arrangement