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本设计是机械厂机加工车间的低压配电系统及车间变电所供电系统。本文首先进行了负荷计算,根据功率因数的要求在低压母线侧进行无功补偿,进而确定对主变器容量、台数,从经济和可靠性出发确定主接线方案。其次,通过短路电流计算出最大运行方式和最小运行方式下的短路电流,确定导线型号及各种电气设备。最后根据本厂对继电保护要求,确定相关的保护方案和二次回路方案。
本设计采用需用系数法进行负荷计算,无功功率补偿采用低压侧电容并联补偿方法,这种方法能补偿低压侧以前的无功功率、经济效益比较好。根据机械加工车间用电特点和需求,主接线方案采用了高压侧无母线、低压侧单母线分段的主接线方案。根据干式变压器和油浸变压器在经济和安装条件对比,选择两台SC9-500/10系列干式变压器。
在仔细研究各负荷的实际数据,并严格按照国家规定,依照以上设计步骤设计本供电系统设计方案,以到达提高生产效益的目的。
关键词:低压配电系统;负荷计算;主接线;变电所;短路计算
Abstract
This design is the factory machining workshop of low voltage distribution system and
workshop substation power supply system. This paper conducted a load calculation,
according to the requirements of power factor in the low-pressure side of the bus reactive power compensation, and to determine the capacity of the transformer device, the number of units, starting from the economic and reliability to determine the main terminal program.Secondly, calculate the maximum short circuit current operation mode and minimum operating mode of the short circuit current to determine the wire type and variety of electrical equipment.Finally, according to the factory on protection requirements, identify relevant programs and secondary circuit protection program. This design uses the need coefficient method for the load calculation, reactive power compensation capacitor in parallel with low-pressure side of the compensation method, this method can compensate for low-voltage side of the previous reactive power, economic efficiency is better. According to machine shop characteristics and needs of electricity, the main connection schemes using non-bus high side, low side of the single-bus section of the Main Wiring.According to dry-type transformers and oil immersed transformers and installation conditions in the economy compared to select two SC9-500/10 series of dry-type transformers.
Only then carefully studies the factory the actual data, strictly stipulated according to the country, and only then may design an economy reliable power supply system through the above design procedure, thus arrives the enhancement production benefit the goal. Keywords: Low Voltage Distribution System; Load Calculation; Main Connection; Substation; Short circuit calculation
目 录
1 绪论 ............................................................................................................................... 1
1.1 设计背景、目的及意义 ..................................................................................... 1 1.2 设计内容 ............................................................................................................. 1 1.3 设计原则 ............................................................................................................. 1 2 负荷计算及无功补偿 ................................................................................................... 2
2.1 负荷计算 ............................................................................................................. 2
2.1.1 负荷计算的方法及其适用范围 ............................................................... 2 2.1.2 需用系数法 ............................................................................................... 2 2.1.3 负荷确定 ................................................................................................... 4 2.2 无功功率补偿 ..................................................................................................... 5
2.2.1 无功功率补偿概念 ................................................................................... 5 2.2.2 无功补偿提高功率因数的意义 ............................................................... 5 2.3 无功补偿容量计算 ............................................................................................. 6
2.3.1 无功功率补偿方式选择 ........................................................................... 6 2.3.2 无功补偿容量的确定 ............................................................................... 8 2.3.3 补偿容量计算 ........................................................................................... 8
3 变电所主接线方案设计及变压器选择 ..................................................................... 10
3.1 变电所主变压器台数和容量选择 ................................................................... 10
3.1.1 选择主变压器台数时应考虑下列原则 ................................................. 10 3.1.2 主变压器的确定 ..................................................................................... 11 3.2 总配变电所的主接线方案比较选择 ............................................................... 12 4 短路电流的计算及一次设备的选择原则 ................................................................. 14
4.1 短路计算 ........................................................................................................... 14
4.1.1 短路电流计算目的 ................................................................................. 14 4.1.2 采用三相短路电流计算为标准的原因 ................................................. 14 4.1.3 短路电流计算的方法步骤 ..................................................................... 14 4.1.4 短路电流计算 ......................................................................................... 15 4.2 一次设备选择 ................................................................................................... 16
4.2.1 概述 ......................................................................................................... 16 4.2.2 一次设备的选择原则 ............................................................................. 16 4.2.3 按短路情况校验电器的稳定性 ............................................................. 16 4.2.4 一次设备选择和校验 ............................................................................. 18
5 车间变电所高低压进出线选择 ................................................................................. 22
5.1 高压进线选择 ................................................................................................... 22 5.2 低压出线选择 ................................................................................................... 23 6 车间配电线路设计 ..................................................................................................... 25
6.1 车间配电线路结线方案 ................................................................................... 25 6.2 动力配电箱的选择 ........................................................................................... 25 6.3 刀开关的选择 ................................................................................................... 26 6.4 配电线路敷设方式 ........................................................................................... 26 7 二次回路方案的选择及继电保护整定 ................................................................... 26
7.1 概述 ................................................................................................................... 26 7.2 继电保护 ........................................................................................................... 27
7.2.1 继电保护的要求 ..................................................................................... 27 7.2.2 过电流保护 ............................................................................................. 27 7.2.3 电流速断保护 ......................................................................................... 28 7.3 变压器保护 ....................................................................................................... 28
7.3.1 概述 ......................................................................................................... 28 7.3.2 车间变电所的各分厂变压器保护 ......................................................... 28 7.3.3 降压变电所变压器保护 ......................................................................... 29 7.4 继电保护的选择和整定 ................................................................................... 29
7.4.1 继电保护的种类 ..................................................................................... 29 7.4.2 反时限过电流保护 ................................................................................. 29
8 防雷和接地 ................................................................................................................. 32
8.1 概 述 ................................................................................................................. 32 8.2 防雷和接地 ....................................................................................................... 32
8.2.1 防雷装置 ................................................................................................. 32 8.2.2 架空线路的防雷保护 ............................................................................. 32 8.2.3 车间变电所的防雷保护和接地装置的设计 ......................................... 33 8.2.4 电力系统的接地 ..................................................................................... 33 8.2.5 配电所公共接地装置的设计 ................................................................. 34
9 车间照明设计 ............................................................................................................. 35
9.1 光源分类 ........................................................................................................... 35 9.2 车间及各变电所光源的合理选择 ................................................................... 35 10 结论 ........................................................................................................................... 38 谢辞 ................................................................................................................................... 38 参考文献 ........................................................................................................................... 38 附录一 一车间负荷详细计算 ..................................................................................... 39 附录二 短路电流计算 ................................................................................................. 44 附录三 机加工一车间各配电线路的详细选择过程 ................................................. 46 附录四 主接线 ............................................................................................................. 52 附录五 一车间低压配电系统图 ................................................................................. 52 附录六 一车间电气设备配电布置图 ......................................................................... 52 附录七 一车间照明配电图 ......................................................................................... 52 附录八 变电所平面图、剖面图 ................................................................................. 52
1 绪论
1.1 设计背景、目的及意义
在工厂里,电能虽然是工业生产的主要能源和动力,但是它在产品成本中所占的比重一般很小(除电化工业外)。电能在工业生产中的重要性,并不在于它在产品成本中或投资总额中所占的比重多少,而在于工业生产实现电气化以后可以大大增加产量,提高产品质量,提高劳动生产率,降低生产成本,减轻工人的劳动强度,改善工人的劳动条件,有利于实现生产过程自动化。从另一方面来说,如果工厂的电能供应突然中断,则对工业生产可能造成严重的后果。
因此,如何正确地计算选择各级变电站的变压器容量及其它主要电气设备,这是保证企业安全可靠供电的重要前提。做好工厂供电工作对于发展工业生产,实现工业现代化,具有十分重要的意义。由于能源节约是工厂供电工作的一个重要方面,而能源节约对于国家经济建设具有十分重要的战略意义工厂供电工作要很好地为工业生产服务,切实保证工厂生产和生活用电的需要,并做好节能工作。根据该工厂的规模、负荷情况、供电条件、技术要求、自然条件,设计其总配变电所及配电系统。
1.2 设计内容
根据任务书的要求,本设计主要有以下内容:
(1) 车间的负荷计算及无功功率补偿; (2) 总配电所位置和型式的选择;
(3) 变电所主变压器台数和容量、类型的选择; (4) 变电所主结线方案的设计;
(5) 短路电流的计算,并进行一次设备的选择和校验; (6) 选择车间变电所高低压进出线;
(7) 选择电源进线的二次回路方案及整定继电保护; (8) 车间防雷保护和接地装置的设计; (9) 确定车间低压配电系统布线方案; (10)选择低压配电系统导线及控制保护设备。
1.3 设计原则
按照国家标准《工业和民用供配电系统设计规范》、《10KV及以下变电所设计规范》及《低压配电设计规范》等的规定,进行工厂供电设计必须遵循以下