43

MINISTRY OF EDUCATION AND SIENCE, YOUTH AND SPORTS

OF UKRAINE

Institute of higher education

DONETSK NATIONAL TECHNICAL UNIVERSITY

Department of electromechanics and theoretical fundamental of

electrical engineering

COURSE PROJECT

Theme: «Calculation and designing of power transformers»

Explanatory note on course project work

On the Subject „Electrical machines”

CP 6.050701-11-018.07.00.00.EN

Carrried out:

st. gr. EESAN-08 ____________________ Odoh Ifeanyi

(signature) (date)

Test: ______________________________ G.V. Demchenko

(signature) (date)

Supervisor:__________________________ G.V. Demchenko

(signature) (date)

Donetsk - 2011

Abstract

Course work contains 43 pages, 13 fig., 3 sources.

Object of development – power transformer with power of 160 kVA, with rated voltage of low voltage and high voltage windings U_1R=0.4 kV U_2R=6 kV,with regulation of voltage without excitation. The connection of windings is Y/Yo - O.

The purpose of this work is to design and to calculate the double-wound transformer with the beforehand given characteristics. The basic parameters and sizes of the transformer with flat magnetic system of a rod type (diameter of a core d = 0.18 m) are determined. The core is made from cold rolled steel of the trademark 3404 thickness 35 mm. The choice and account of windings is made. The winding of a high voltage is cylindrical multi-layer from a whole aluminum wire of the trademark АПБ with cross section S_wire2=8.81 mm². The winding of a low voltage is cylindrical multi-layer from a rectangular aluminum wire of the trademark АПБ with cross section 4x17 mm, S_el =0.671 mm².

The characteristics of U_SC, %; P_SC,kW; P₀, kW; I₀, % are determined; the excess of temperature of LV and HV windings is less Θ=65°С. The overall dimensions of the transformer and weight of constructional materials are determined.

transformer, winding, circuit, tank, yoke, radiator, convection, insulation, SHORT SIRCUIT, idling.

Contents

Page

LIST OF the CONDITIONAL INDICATION AND REDUCTION ……………… 5

introduction ……………..………………………………………………….…. 6

1 The CALCULATION of BASE ELECTRICAL QUANTITIES ……………….. 7

2 The CALCULATION OF BASE SCALES OF TRANSFORMER ……………..…8

3 CHOICE of the DESING and CALCULATION of WINDINGS …….…….. 12

3.1 Calculation of LV windings …………………………………………………….. 12

3.2 Calculation of HV windings …………………………………………………….. 15

3.3 Calculation of HV windings multi-layer cylindrical HV winding from

rectangular conductor ……………………………………………………………..… 15

4 DEFINITION of the characteristics of short circuit ………...... 19

4.1 Definition losses of short circuit for LV and HV windings …………………….. 19

4.2 Voltages of short circuit ………………………………………………………… 20

4.3 Mechanical forces in windings ………………………………………………….. 21

5 CALCULATION of TRANSFORMER MAGNETIS SYSTEM ……………….. 25

5.1 Design of magnetic system ……………………………………………………….25

5.2 Determination of the idling losses ………………………………………….…… 28

5.3 Determination of idling current …………………………………………...…….. 29

6 THERMAL COMPUTATUION of the TRANSFORMER …………………….. . 30

6.1Thermal calculation of the windings ……………………………………………. 31

6.2 Thermal calculation of the tank ………………………………………………… 32

6.3 Calculation of excess of temperature of windings and oil of the transformer ….. 36

7 Definition of weight of constructional materials and

oil of the transformer …………………………………………………… 38

8 The summary data of account of the transformer ………….40

conclusion ………………………………………………………………..……. 41

The list of the literature ……………………………………………..…. 42

appendix a……………………………………………………………………….. 43

APPENDIX B……………………………………………………………………….. 44