电气毕业论文--35kv变电所设计.doc

电气毕业论文--35kV变电所设计

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摘要：近年来，我国电力系统发展很快，交流750kV系统已于2005年10月在大西北电网投入运行，±800kV系统也在规划建设当中。与此同时，世界各国都把电能消费占总能源消费的比重和电力系统的发展速度，作为衡量国家经济发展和现代化水平的标志，所以发展电力是当今世界每个国家的重点。电力工业已经成为国民经济中具有社会公益性和发展先行性的国民经济基础行业，关系着国家工业生产命脉，是实现国家经济发展现代化的战略重点。可以说，电气化就是现代化的象征，没有电气化就没有现代化。
技术进步不仅能够推动行业的发展，而且能够促进技术自身的发展。电力系统的快速发展，同时也促进的电力系统各组成的设计与建设、系统维护与运行、电力设备制造和检测、监测监控与综合自动化等技术的不断进步。其中，作为电力系统中的一个重要组成部分，作为电力传输的枢纽和媒介，各级变电所正受到广大电气开发人员的关注。如何根据系统要求、负荷要求，并结合环境等各方面的条件来设计变电所，以实现高效率、低损耗的电能运输，这需要我们不断进行探索。
35kV变电所现在虽然在用电量大的城市和经济发达的沿海城市已不再扩建,但由于它具有投资少、见效快、建设周期短、安装、运行、维护、检修技术力量较容易解决等特点,在广大的农村地区这种供电方式仍将长期存在,主要对35kV变电所主系统设计的探讨。本设计根据某某城镇的电力负荷资料，进行了该城镇35kV降压变电所的初步设计。设计中先对负荷进行了统计与计算，选出了所需的主变型号，然后根据负荷性质及对供电可靠性要求拟定主接线设计，考虑到短路对系统的严重影响，设计中进行了短路计算。设计中还对主要高压电器设备进行了选择与计算，如断路器、隔离开关、电压互感器、电流互感器等。此外还进行了防雷保护的设计和计算，提高了整个变电所的安全性。
关键词：变电所 短路计算 整定保护 防雷措施

The design of a 35kV transformer substation
Abstract：In recent years, China's electric power system has developed rapidly. An AC 750kV system was grid into operation in Northwest, October, 2005.A ± 800kV system also be planned to build as soon as possible. At the same time, most countries around the world regard the proportion that Energy consumption proportion of total energy consumption and the pace of development of the power systems as a symbol to measure the level of national economic development and modernization. As a result, the development of power is the focus of every country in the world today. Power industry has become a basic industry of the national economy with social welfare and leadship of the national economy, influencing the national industrial production lifeline. It has become a strategic focus to achieve national economic modernization. It can be also said that electrification is a symbol of modern. There will be no modernization without electrification.
Technological advances can not only promote the development of the industry but also to promote the development of technology itself. The rapid development of the power system promotes the development of design and construction in the various components of the power system, system maintenance and operation, manufacturing and testing of power equipments and monitoring and control and integrated automation. Different levels of substation draw the majority of positive attention from electrical developers as an important part in the power system as well as hub and media in power transmission. How to design a substation according to the system requirements and load requirements combined with other aspects of environmental conditions in order to achieve high efficiency, low loss power transport, this requires us to continue to explore.
35kV substation is no longer to expanded in the cities of large electricity demand and economically developed coastal cities. However, in the vast rural areas, this power supply will exist for a long time because of the feature less investment, short construction period, easy installation, operation, maintenance and repair technology. Preliminary design of 35kV substation buck has been done based on certain information about power load of a small town. The first process of the design is selecting the required transformer model based on statistics and calculates of all loads. Than I make the main wiring design according to the nature of the load and reliability requirements. Designs contain short-circuit calculation; taking serious impacts on the system by short-circuit into account. Than, do some selection and calculation of main high-voltage electrical equipment ,such as breaker，disconnections ,voltage transformer and current transformer. It also conducted a lightning protection design and calculation, improves the security of the entire substation.
Key words: Transformer substation Short-circuit calculation Tuning protection Lightning protection

目  录

第一章 绪论 1
第二章 原始资料 3
1.1系统情况 3
第三章 变压器的选择 5
3.1 主变台数的选择 5
3.2 调压方式的选择  5
3.3 容量的选择 5
3.4 主变阻抗的选择   7
3.5 主变冷却方式的选择   7
3.6 是否选用自耦变压器   7
3.7 变压器各侧电压等级的选择   7
3.8 相数、绕组数和绕组连接方式的选择   8
3.9 变压器电压绕组材料的选择   8
3.10 主变压器保护    8
第四章 电气主接线设计 10
4.1 基本要求和原则 10
4.2 母线接线的选择 10
4.2.1 35kV侧 10
4.2.2 10kV侧 12
4.3 中性点接线方式 13
第五章 短路电流计算 15
5.1 短路的概念 15
5.2 短路电流计算的目的 15
5.3 短路电流计算的基本原理 15
5.3.1 基本假设 15
5.3.2 计算方法和步骤 16
5.4具体计算过程 16
5.4.1 负荷计算 16
5.4.2 短路电流计算 17
第六章 电气设备的选型与保护 20
6.1电气设备选择的重要性 20
6.2电气设备选择的一般条件 20
6.2.1 按正常工作条件选择电气设备 20
6.2.2 按短路情况校验热稳定性和动稳定性 21
6.3 相关电气设备的选择 22
6.3.1断路器、隔离开关 22
6.3.1.1 35kV侧断路器、隔离开关 22
6.3.1.2 10kV侧断路器、隔离开关 25
6.3.2熔断器 27
6.3.2.1 35kV侧熔断器 28
6.3.2.2 10kV侧熔断器 28
6.3.3 限流电抗器 29
6.3.4 电力线路 31
6.3.4.1 母线的选择及校验 31
6.3.4.2 输电线路的选择及校验 37
6.3.5  互感器 39
6.3.5.1 互感器的配置 39
6.3.5.2 电流互感器的选择和校验 40
第七章 继电保护 45
7.1 概述 45
7.2 继电保护的基本条件 45
7.3 本系统故障分析 46
7.3.1 系统线路主要的故障 46
7.3.2 电力变压器的故障 46
7.3.3 变压器的不正常情况 46
7.4 本变电所继电保护配置 46
7.4.1 35kV线路继电保护配置 46
7.4.2 10kV线路继电保护配置 46
7.4.3 主变压器继电保护配置 47
7.4.3.1 主保护 47
7.4.3.2 后备保护 48
第八章 防雷保护 49
8.1 变电所防雷概述 49
8.2 避雷针的选择 49
结论与展望 52
致谢 53
参考文献 54
附录I  变电所所需电气设备型号及具体参数 55
附录II 变电所电气部分主接线 58