摘要
电力系统是国民经济的重要能源部门，而变电所的设计是电力工业建设中必不可少的一个项目。由于变电所的设计内容多、范围广、逻辑性强，因此要求要有较高的专业水平，并熟悉各种设计规程和设计原理，设计过程中要针对变电所的规模和形式，具体问题具体分析。本文是对大北60kv/10kv二次降压变电所提供的设计方案，设计分为两部分。
第一部分说明书中包括了对原始设计条件的分析，导线的选择，无功补偿静电电容器的选择，主变压器的选择，电气主接线的确定，短路计算，各种电气设备的选择与校验，高压配电装置的规划设计，防雷保护的规划设计。在设计和选择设备中都充分考虑到了可靠性，灵活性和经济性。另外，各种断路器、隔离开关、电流互感器型号的选择要与高压配电装置的布置联系在一起考虑。
计算书部分包括了计算变电所的最大负荷容量，无功补偿的计算，计算主变压器的容量，化简短路阻抗和计算短路电流，电气设备的校验，和防雷保护保护范围的计算。
本设计是有文字说明和图表解释的比较完整的二次降压变电所的设计方案。
关键词 电力系统，电气设备，变压器，继电保护
I
Abstract
The electrical power system is the national economy important energy department, but the transformer substation design is in the electric power industry construction an essential project. Because transformer substation design content many, scope broad, logical, therefore requests to have to have the high specialized level, and the familiar each design regulations and the principle of design, in the design process must aim at the transformer substation the scale and the form, concrete question concrete analysis. The content quite are many, the scope is broad, different voltage rank, different type, when heterogeneity load transformer substation design stresses the aspect is dissimilar. This book is about mishan 60/10KV Transformer Station Design of
Electric Portion. The design is divided into two parts.
The first part description includeddesigned conditional analysis to the originality,the choice of transmission line,static capacitor and main transformer,key diagram finalized,ect. high pressure in transformer substain, In all of the design the equipments choice in consideration of reliability, flexibility and economy. Moreover, all of the circuit breaker, disconnecting switch, electric current the choice of feeling machine model number want to go together with the decoration of giving or getting an electric shock the device with high pressure to contact to together consider with each other.
Calculations include the calculation of the maximum load capacity of substations, reactive power compensation, the calculation of main transformer capacity, a short way of calculating the impedance and short-circuit current, electrical equipment check, and the scope of protection lightning protection calculations.
The design is a text description and a chart to explain the relatively complete secondary step-down substation design.
Key words electrical power system, electrical equipment, transformer, relay
protection
II
目 录
摘要......................................................................................................................... I Abstract .................................................................................................................. II 第一篇 设计说明书............................................................................................... - 1 -
1 变电所设计原则............................................................................................ - 1 -
1.1 所址选择和所区规划.......................................................................... - 1 - 1.2 电气部分设计原则.............................................................................. - 1 - 2 10KV线路导线的选择.................................................................................... - 3 -
2.1 按经济电流密度选择导线经济截面积.............................................. - 3 - 2.2 选择导线截面积的步骤...................................................................... - 3 - 3 主变压器容量、台数和型式的选择............................................................ - 7 -
3.1 变压器选择的规定.............................................................................. - 7 - 3.2 主变压器容量和台数的选择.............................................................. - 7 - 3.3 变压器型式的选择.............................................................................. - 8 - 4 补偿电容器的选择...................................................................................... - 10 -
4.1 求出变压器的功率损耗.................................................................... - 11 - 4.2 补偿前平均功率因数计算公式........................................................ - 12 - 4.3 补偿容量的计算................................................................................ - 12 - 4.4确定电容器台数................................................................................. - 12 - 4.5补偿后总平均功率因数计算公式..................................................... - 12 - 5电气主接线方案设计................................................................................... - 13 -
5.1主接线设计的基本要求..................................................................... - 13 - 5.2主接线方案......................................................................................... - 14 - 5.3方案的比较与确定............................................................................. - 15 - 5.4主接线二次方案的说明..................................................................... - 15 - 6 短路电流的计算.......................................................................................... - 16 -
6.1 发生短路的原因和短路的定义........................................................ - 16 - 6.2短路的分类......................................................................................... - 16 - 6.3计算短路电流的目的......................................................................... - 16 - 6.4短路电流的计算过程......................................................................... - 17 - 7 电气设备的选择.......................................................................................... - 19 -
7.1 断路器的选择.................................................................................... - 19 - 7.2 隔离开关的选择................................................................................ - 21 - 7.3 互感器的选择.................................................................................... - 23 - 7.4避雷器的选择..................................................................................... - 27 - 7.5 高压开关柜的选择............................................................................ - 29 - 7.6母线的选择......................................................................................... - 33 - 8 继电保护...................................................................................................... - 36 -
8.1电力系统继电保护的作用................................................................. - 36 -
8.2 主变压器的保护................................................................................ - 36 - 8.3 线路保护............................................................................................ - 38 - 9 防雷保护...................................................................................................... - 40 -
9.1避雷针的装设原则及接地装置的要求............................................. - 40 - 9.2避雷针高度的计算............................................................................. - 40 -
第二篇 设计计算书............................................................................................. - 42 -
1 选择10KV输电线路导线 .......................................................................... - 42 -
1.1 选择机械制造厂出线架空线型号.................................................... - 42 - 1.3选择织布厂出线架空线型号............................................................. - 46 - 1.4选择标准件厂出线架空线型号......................................................... - 48 - 1.5 选择服装厂出线架空线型号............................................................ - 50 - 1.6选择粮食加工厂出线架空线型号..................................................... - 52 - 1.7选择汽水厂出线架空线型号............................................................. - 54 - 1.8选择化工厂出线架空线型号............................................................. - 55 - 2 选择主变压器的台数、容量、型号.......................................................... - 59 -
2.1 线路损耗的总功率............................................................................ - 59 - 2.2 线路所有负荷的总功率.................................................................... - 59 - 2.3计算变压器二次侧总功率................................................................. - 60 - 2.4选择变压器型号................................................................................. - 60 - 3 选择补偿电容器的容量、台数、型号...................................................... - 62 -
3.1 计算变压器功率损耗........................................................................ - 62 - 3.2 计算变压器高压侧功率.................................................................... - 62 - 3.3计算无功补偿前系统的功率因数..................................................... - 62 - 3.4 计算需要补偿的无功容量................................................................ - 63 - 3.5选择电容器......................................................................................... - 63 - 4 电气主接线方案设计.................................................................................. - 64 - 5 短路电流的计算.......................................................................................... - 65 -
5.1 画系统等值阻抗图............................................................................ - 65 - 5.2 求各元件等值电抗............................................................................ - 65 - 5.3计算各点发生短路时的短路电流..................................................... - 66 - 6 电气设备的选择.......................................................................................... - 69 -
6.1断路器的选择..................................................................................... - 69 - 6.2隔离开关的选择................................................................................. - 71 - 6.2.1 60KV侧隔离开关的选择 ............................................................... - 71 - 6.3电压互感器的选择............................................................................. - 72 - 6.4电流互感器的选择............................................................................. - 72 - 6.5避雷器的选择..................................................................................... - 74 - 6.6高压开关柜的选择............................................................................. - 75 - 6.7母线的选择......................................................................................... - 78 - 7 继电保护...................................................................................................... - 81 -
7.1变压器的保护..................................................................................... - 81 - 7.2线路保护设计..................................................................................... - 83 - 8 防雷保护设计.............................................................................................. - 85 -
8.1范围计算............................................................................................. - 85 -