摘要
由于国内人民生活水平的提高,科技不断地进步,控制不断地完善,从而促使变电所设计技术在电气系统领域占据主导权,也使得110kV变电所被广泛应用。在变电所系统设计领域中,110kV变电所成为目前一处亮丽的风景线,因为其设计资源众多,开发经验丰富,最重要的是成本较低,控制在用户可承受的范围内,因此变电所设计逐渐成为世界各国关注的重点。随着变电所系统领域的不断革新,数量越来越大,逐渐成为研究的重点方向,因此新一代的我们要认真去钻研变电所控制系统的构成。
本次设计是我们的毕业设计,本次设计的变电所的类型为地区变电所,是为了满足市区生产和生活的要求,根据老师给出的设计资料和要求,结合所学的基础知识和文献资料所做的。通过本设计,对以前所学的知识加强了理解和掌握,复习巩固专业课程学习的相关内容并进行课题实践,锻炼、培养对110kV变电所的设计能力。从总体上掌握了电力工程设计的过程,并熟悉了-些设计方法,为以后从事电力工程设计工作打下一定的基础。
根据110kV变电所为研究方向,根据变电所的原始数据设计其电气接线图、变压器选型 、负荷计算、短路电流计算、继电保护方案设计以及防雷接地设计等相关研究。
关键词:变电所;电气主接线;短路电流计算;一次设备;防雷保护
Abstract
Firstly, this paper analyzes the load development trend according to the parameters of the system, circuit and all loads given in the task book. The establishment of the clarified the necessity from the aspects of load growth, and then through the proposed generalization of substation and line direction, and through the analysis of load data, safety, economy and reliability into consideration, determine the 110 kv station of the electric main wiring, then on the main transformer was determined by the load calculation and power supply scope sets, capacity and model number, At the same time, the capacity and type of transformer used in the station are also determined. Finally, according to the calculation results of the maximum continuous working current and short circuit, the selection of high-voltage fuses, isolation switches, busbars, insulators, voltage transformers and current transformers is carried out, thus completing the design of 110kV electric primary part.
This design is our graduation design, the type of substation design for the regional substation, is in order to meet the requirements of urban production and life, according to the design data and requirements given by the teacher, combined with the basic knowledge and literature. Through this design, I have strengthened my understanding and mastery of the knowledge I have learned before, reviewed and consolidated the relevant contents learned in professional courses and carried out subject practice, so as to exercise and cultivate my design ability of 110kV substation. Master the process of power engineering design on the whole, and familiar with some design methods, for the future engaged in power engineering design work to lay a certain foundation.
According to the 110kV substation as the research direction, according to the original data of the substation design of its electrical wiring diagram, transformer selection, load calculation, short-circuit current calculation, relay protection scheme design and lightning protection grounding design and other related research.
Key words: Substation; Main electrical connection,Short-circuit current calculation,Primary equipment,Lightning protection
目录
1 绪论.................................................................................................. 1
1.1 概述........................................................................................ 1
1.2 变电所电气部分技术的现状................................................ 2
1.3 变电所设计的任务及原则.................................................... 3
1.4 课题的研究内容及章节安排................................................ 4
2 电力系统及其发电厂电气设计...................................................... 5
2.1 电力系统的构成.................................................................... 5
2.2 电力系统的基本要求............................................................ 5
3 发电厂电气主接线设计.................................................................. 7
3.1 变电所主接线的要求及原则................................................ 7
3.1.1 设计要求...................................................................... 7
3.1.2 设计原则...................................................................... 8
3.2 110kV侧电气主接线的选择................................................. 8
4 变压器的选择................................................................................ 12
4.1 主变压器的选择.................................................................. 12
4.1.1 主变压器容量和台数的确定.................................... 12
4.1.2 主变压器型式的确定................................................ 12
4.1.3 主变压器保护............................................................ 13
4.2 站用变压器的选择.............................................................. 14
4.2.1 站用变压器的台数确定............................................ 14
4.2.2 站用变压器容量的确定............................................ 14
5 短路电流的计算............................................................................ 16
5.1 短路电流计算的目的.......................................................... 16
5.2短路电流计算....................................................................... 16
5.2.1各元件电抗计算及等值电路图................................. 16
5.2.2 110kV 母线侧短路电流的计算................................ 17
6 电气设备的选择.......................................................................... 19
6.1 电气设备选择的一般原则.................................................. 19
6.2 载流导体的选择.................................................................. 19
6.3 断路器和隔离开关的选择.................................................. 20
6.4 电流互感器的选择.............................................................. 22
6.5 电压互感器的选择.............................................................. 23
7 结束语.......................................................................................... 24
参考文献............................................................................................ 25
致 谢............................................................................................ 27
1 绪论
1.1 概述
常见的变电所在对电能的接受和发送,降压和升压转换,电流的方向等方面进行控制,高压和低压电网的连接也是通过变压器来转换的。变电所的设计规划在电力系统的整体设备中是至关重要的,要实现电网的稳定运行和供电,不影响用户和发电厂之间电量转换的关系。
日常中的变电所主要用途在于转换电压,将发电厂输出的高压电进行降压处理,转换成用户可以直接使用的220V低压电,发电厂端的变电所主要是用来将发电厂输出的电进行升压转换,其一是为了方便进行远程传输,除此之外能够有效地降低传输线上的电阻等产生的消耗;另外一种使我们经常见的降压变压器,主要是将电缆中的高压线通过降压处理传输给用户使用,达到220V电压。针对不同的状况,变压器进行升压和降压的程度完全不同,因此变电所的种类多种多样,例如在进行远距离传输时,电压将会升至千伏以上,甚至达到更高;当为近距离传输时,电压会升至一千伏左右,经过降压变压器转换后,将高压电转换成220V用户电。
变电所电气部分技术的现状
电力行业的快速发展直接影响着我国的社会经济发展,我们只要将电力设备保证稳定运行,才能完成城镇化的发展目标。相比国外而言,我国的电网设备的发展革新相对较晚,现如今在一线大中城市的变电所已经跟换为最新的设备,然而在相对比较落后的偏远地区还在使用比较老旧的变电所设备,并且变电所需要人为操作;而在发展比较先进的地区,变电所基本实现无人化,交流电输出逐渐转换成比较稳定的直流电输出。国外的变电所设计发展相对比较先进,已基本实现无人化,正在向直流电方向普及。同时,全世界科学家及电力事业工作者逐渐将数字智能变电所作为研究发展的方向。
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