Contents

Abstract .......................................................................................................................................... II Introduction ..................................................................................................................................... 1 1 The choice of electrical main wiring scheme ............................................................................... 1 1.1 Electrical main wiring design ................................................................................................ 1 1.1.1 Design principle of main wiring ..................................................................................... 1 1.1.2 Main wiring design requirements ................................................................................... 1 1.1.3 Main wiring scheme ....................................................................................................... 2 1.1.4 Source ............................................................................................................................. 4 1.1.5 Plan ................................................................................................................................. 5 1.2 Determination of electrical main wiring scheme .................................................................. 5 1.2.1 Reliability comparison of main wiring scheme .............................................................. 5 1.2.2 The flexibility of main wiring scheme ........................................................................... 7 1.2.3 Economic comparison of main wiring schemes ............................................................. 7 1.2.4 Determination of main wiring scheme ........................................................................... 7 2 Determination of transformer ....................................................................................................... 8 2.1 The main transformer capacity and number and type selection ............................................ 8 2.1.1 Selection of main transformer ........................................................................................ 8 2.2 Volume, number and types of transformer used in the choice of ........................................ 10 2.2.1 By determine the number and capacity of transformers .............................................. 10 2.2.2 Lead connection mode ................................................................................................. 11 2.2.3 Variable selection used ................................................................................................. 11 3 Calculation of short-circuit current ............................................................................................ 11 3.1 The purpose of short-circuit current calculation ................................................................. 11 3.2 General rules for calculation of short-circuit current .......................................................... 12 3.2.1 Basic situation of calculation ....................................................................................... 12 3.2.2 Connection mode .......................................................................................................... 12 3.2.3 Computational capacity ................................................................................................ 12 3.2.4 Short-circuit type .......................................................................................................... 12 3.2.5 Short-circuit calculation point ...................................................................................... 12

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3.3 Calculation of short-circuit current ..................................................................................... 12 3.3.1 Select the short-circuit point ........................................................................................ 12 3.3.2 Drawing equivalent network diagram .......................................................................... 12 3.3.3 Calculation ................................................................................................................... 12 4 Selection and verification of equipment..................................................................................... 16 4.1 The principle and regulations of equipment selection ......................................................... 16 4.1.1 General principles for equipment selection .................................................................. 16 4.1.2 The relevant provisions of the choice of equipment .................................................... 17 4.2 Wire selection and verification ............................................................................................ 17 4.2.1 Wire selection ............................................................................................................... 17 4.2.2 Calibration of wire ....................................................................................................... 19 4.3 Selection and verification of circuit breaker ....................................................................... 19 4.3.1 Technical conditions for selecting circuit breakers ...................................................... 19 4.3.2 Choice of type and type of circuit breaker ................................................................... 21 4.3.3 Selection and verification of circuit breaker ................................................................ 21 4.4 Isolation switch selection and verification .......................................................................... 22 4.4.1 Isolation switch selection and calibration principle ..................................................... 22 4.4.2 Isolation switch selection and verification ................................................................... 23 4.5 Selection and verification of transformer ............................................................................ 24 4.5.1 The choice of voltage transformer................................................................................ 24 4.5.2 The choice of current transformer ................................................................................ 24 4.5.3 Calibration of current transformer ................................................................................ 25 4.6 Selection and verification of arrester .................................................................................. 26 4.6.1 Type .............................................................................................................................. 26 4.6.2 Metal oxide arrester selection principle ....................................................................... 26 5 Design of power distribution equipment inside and outside the house ...................................... 27 5.1 Distribution equipment design requirements ...................................................................... 27 5.1.1 Basic requirements for distribution equipment ............................................................ 27 5.1.2 Distribution device security clearance ......................................................................... 28 5.2 Distribution equipment selection and layout ....................................................................... 28

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5.2.1 Selection principle of distribution equipment outside the house ................................. 28 5.2.2 Outdoor distribution equipment selection .................................................................... 30 5.2.3 10kV power distribution device selection .................................................................... 30 6 Lightning protection and grounding system design ................................................................... 29 6.1 Lightning protection system ................................................................................................ 29 6.1.1 Hx=11m protection range ............................................................................................. 29 6.1.2 Hx=7m protection range............................................................................................... 30 6.2 Substation grounding device ............................................................................................... 31 6.2.1 Earthing device requirements ....................................................................................... 31 6.2.2 Grounding flat size requirements ................................................................................. 31 6.2.3 Earthing device selection ............................................................................................. 31 7 Substation general layout ........................................................................................................... 31 7.1 Overall planning .................................................................................................................. 31 7.2 General layout ..................................................................................................................... 31 7.2.1 Main contents of total plane layout .............................................................................. 31 7.2.2 Basic principles of general layout ................................................................................ 31 Reference ....................................................................................................................................... 33 Thank ............................................................................................................................................. 34 Appendix ....................................................................................................................................... 35

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110KV降压变电站一次系统设计

摘要：本文是对110kV 变电站电力系统进行总体分析，然后进行计算和初步设计，确定了变电站电气一次系统主接线的形式。该变电站设有两台主变压器，站内主接线分为 110kV、35kV 和 10kV 三个电压等级。本次设计进行了电气主接线的设计和选择、短路电流计算、主要电气设备选择及校验（包括断路器、隔离开关、互感器、避雷器等）、各电压等级配电装置设计、防雷保护接地系统设计和变电站总体布置。本设计以《电力工程电气设计手册》、《35～110kV高压配电装置设计规范》等规范规程为依据，设计的内容符合国家有关经济技术政策，所选设备全部为国家推荐的新型产品，技术先进、运行可靠、经济合理。

关键词：一次系统 变压器 短路电流 设计

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