Maksim Mashnikov

Faculty: Electrotechnical

Department: The Department of Mining Transport and Logistics

Speciality: Electromechanical Equipment of Power-Consuming Industries

Theme of master's work: Justification of parameters and development of recommendations for improvement explosion protected electrical equipment

Scientific supervisor: Aleksander Tkachuk

Summary of research and developments

Introduction

        To date, the coal industry of Ukraine is one of the most difficult in regard to ensuring safety.
        To avoid the likelihood of accidents all electrical equipment, used in mines, must be explosion-proof.

Topical issue

        Analysis of explosion protected electrical equipment showed that explosion-proof shell is the most common conception of explosion safety.

(Animated drawing, made in gif animator, the number of frames - 3, the number of repetitions - 7, volume 86 КБ)

        The concept implies that the electrical equipment is placed in a special shell with a small gap. This does not prevent contact of electrical circuits with an explosive mixture and the possibility of inflammation, but it is guaranteed that the shell constrains resulting from blast overpressure, and flash does not go beyond the restrictions of shell.
        However, this type of protection increases the weight and dimensions of electrical equipment, degrades the thermal regime.
        An urgent task is to develop recommendations for improvement explosion protected electrical equipment.

The aim and objectives

        The aim of this work is to develop recommendations for improving the consumer properties of explosion protected electrical equipment, such as reliability, usability, etc.
        To achieve the above objectives the following main tasks:

1.To do review and analysis of explosion-proof construction of electro equipment.
2.To do analysis of claims submitted to the constructions of explosion-proof electro equipment.
3.To Develop and to justify the rational design of explosion-proof transformer station.
4.To Develop and to justify the rational design of motor drives for mining machines.

Main results

        Currently applied explosion proof transformer substations which consist of the power transformer, which is the basic element of the substation, determining its basic dimensions, and explosion proof shell [1].
        Analysis of the design of explosion proof transformer substations showed that the main shortcoming of the conception of explosion proof - Explosion-proof shell, is its low fill factor, causing between a transformer and a shell are formed by air-filled space, which adversely affects the thermal conditions of the transformer, substantially increases the overall size and weight of the assembly substation.
        To resolve the above deficiencies were discussed option of a creating transformer with a cylindrical magnetic core, consisting of a package which contains winding and a package which closing the magnetic circuit.
        There was a preliminary comparative calculation of the transformer classical design, as currently applied, and the transformer of the proposed design. To do this, apply the same initial data:
Power transformer S = 4 кВА
Higher voltage U2 = 660 В
Low voltage U1= 133 В
Load losses Ро = 90 Вт
Loss of short-circuit Рк = 90 Вт

1. The diameter of the rod transformer

2. The average diameter of the channel between the windings

3. Height of winding

4. The active section of steel rod

5. Electromotive force coil

6. The number of turns of phase winding

7. The radial size of the winding LV

8. The inner diameter of winding LV

9. Outer diameter of coil LV

10. The radial size of winding HV

11. The inner diameter of winding HV

12. Outer diameter of winding HV

13. Height of a transformer with a cylindrical magnetic core

14. Outside diameter

15. The estimated length of the air gap

16. Stator current at rated load

17. The number of effective wires in the slot

18. Number of series-connected coils of one phase

        According to a calculation were drawn classic designs transformer and a transformer with a cylindrical magnetic core.

Fig. 1 - Drawing the classic design of the transformer and the transformer with a cylindrical magnetic core

Conclusion

        Clear from the figure that the proposed design of the transformer considerably less of the current. In addition, the transition to design a transformer with a cylindrical magnetic core will significantly reduce the mass of the entire substation, as well as facilitate the temperature regime due to absence of air-filled space between the transformer and the shell.

        Master's degree work is not yet completed. The fair copy of work can be got for an author or scientific supervisor after December, 2010.

References

1. Дегтярев В. В., Седаков Л. В. Руководство по ревизии, наладке и испытанию подземных электроустановок шахт - М.: Недра, 1989. - 614 с.
2. Нагорный М. А., Грушко В. М., Ковалёв А. П., Омельченко А. Н., Чернов И. Я. Трансформатор для взрывозащищенных комплектных трансформаторных подстанций // Взрывозащищенное электрооборудование: Сб. науч. тр. УкрНИИВЭ. - Донецк, 2008.
3. Тихомиров П. М. Расчет трансформаторов: Учебное пособие для вузов. - М.: Энергоатомиздат, 1986. - 528 с.
4. Копылов И. П. Проектирование электрических машин: Учебное пособие для вузов. - М.: Энергия, 1980. - 496 с.
5. Дзюбан В. С., Риман Я. С., Маслий А. К. Справочник энергетика угольной шахты - М.: Недра, 1983. - 542 с.