Mechanical assembly workshop of ESN and EO

Contents

Contents

Introduction

1. General part

1.1 Initial data for the exchange rate project

1.1.1 Characteristics of the designed object

1.3. Environment and building area

1.4. Process

1.5. Room classification by explosion-fire-electrical safety

2. Design part

2.1 ESN reliability category and ESN circuit selection

2.2. Calculation of electrical loads of the workshop

2.3 Calculation of compensating devices (CP) and transformer selection

2.4. Calculation and selection of protection devices

2.3.1 Selection of switches

2.5. Selecting How to Lay the Supply and Distribution Network

2.6. Selection of ESN lines

2.7. Calculation of short-circuit currents

2.8 Check of ESN elements of the characteristic line by short circuit currents and voltage loss

3. Conclusion

4 List of literature

Appendix A

Appendix B

Appendix B

Appendix D

Introduction

The increase in the level of electrification of energy production and efficiency is based on the further development of the energy base, the continuous increase in electric energy. The increase in the efficiency of the joint use of thermal and hydraulic stations is based on the accelerated development of the OS of the country, which also unites the Urals, Kazakhstan and the regions of Western Siberia in addition to the European part of the former USSR. To transfer large flows of electric energy from these areas to the European part of the country, 1150 kV AC and 1500 DC ultra-high voltage transmission lines are being built. At present, with the presence of powerful power plants, combined into electric systems with high reliability of electricity supply, the construction of power plants continues in many industrial enterprises. The need for their construction is due to the great distance from energy systems, the need for thermal energy for production needs and heating, the need for backup power for essential consumers. Design of power supply systems is carried out in a number of design organizations. As a result of the generalization of the design experience, power supply issues of enterprises received the form of standard solutions. Currently, methods have been developed for calculating and designing workshop networks, choosing the capacity of workshop transformers, determining workshop loads, etc. In this regard, the issues of training highly qualified personnel who can successfully solve the issues of designing electricity supply and practical tasks are of great importance.

A power supply system is a complex of devices for the production, transmission and distribution of electric energy.

Power supply systems of industrial enterprises provide electric power to industrial consumers. The main consumers are electric drives of various machines and mechanisms, electric lighting, electric heating devices, including electric furnaces.

The operation of industrial electric drives and other consumers, both during design and during operation, must be in strict compliance, both with individual receivers and with a complex of electric drives that ensure the operation of complex mechanisms.

Operation of electric power receivers depends on its quality. The quality of the electric power, and in particular the deviation of the voltage, causes a change in the speed of the electric drives, which in turn causes a decrease or increase in the productivity of industrial mechanisms. With large deviations in the speed of the mechanisms, it is possible to scrap the product, as well as reduce the amount of product and even completely stop its production.

The impact of the power supply system on the production process is very large. Suffice it to say that the production process is largely determined by the indicators of the industrial power supply system and electric drives, which ensure the normal operation of the entire industrial enterprise.

Due to the above, specialists in the field of electric drive should be sufficiently fully informed about the influence of the industrial power supply system on the operation of electric drives of production mechanisms. In turn, specialists in the field of industrial power supply should also be sufficiently informed about the possible impact of the power supply system on the operation of industrial electric drives, for example, in the case where the engine start itself may take place and when it should be strictly prohibited .

Due to the above, in the interests of the normal operation of industrial production, it is necessary to have a sufficiently complete knowledge of the set of issues of electricity supply - electric drive for future engineers of industrial enterprises .

Unfortunately, the required knowledge is not always available to electric drive specialists, and the design of electric drives is carried out almost in isolation from power supply systems .

An example of this is the failure to take into account the quality of electric energy when creating electric drives, for example, voltage deviation, frequency deviation, voltage variation span, voltage and current sinusoidity, not symmetry. In most cases, when designing electric drives, power breaks are also not taken into account (long and short-term during the operation of automation - ATS, APV, etc.).

The lack of awareness of electric power engineers about the measures that should be taken with poor-quality electricity forces them to make unsustainable decisions. For example, in the presence of asymmetry in the transformer-receiver power supply system, the issue is solved by introducing a special symmetrical device between the transformer and the receiver, which practically doubles the power of the supply device and dramatically increases the losses in the supply system. At the same time, if you install a transformer with a different winding connection circuit instead of a symmetrical device, you can limit the additional power by only 5-6% and sharply reduce the power consumption for excessive losses.

General part

1.1.1 Characteristics of the designed object

In this course project, a power supply plan for the mechanical assembly shop site is being developed.

The design includes:

selecting motors corresponding to the environment conditions;

selection of power supply circuit and distribution of shop network;

calculation of electrical loads, selection of number and power of power transformers;

selection of protective devices in 0.4 kV networks;

cable selection and equipment check for short-circuit currents.

grounding selection;

Indoor environment is non-explosive.

The section of the mechanical assembly shop (MPS) is designed to release the front axle and the rear axle of trucks. The workshop is an integral part of the production of a machine-building plant. UMC provides for production, auxiliary office and household premises.

By the degree of explosion, the room does not belong to such, since the technological process is not associated with explosive substances.

UMC receives power supply (ESN) from its own workshop transformer substation (TP), located at a distance of 1.5 km from the deep input substation (PGV) of the plant. Input voltage 6, 10 or 35 kV.

PGV is connected to the power system (ESN) located at a distance of 8 km.

Electric power consumers (EE) belong to ESN reliability category 2 and 3.

The number of working shifts is 2.

Soil near the shop - clay with a temperature of +5 wasps. The frame of the building is built of blocks-sections with a length of 8 and 6 m each.

The size of the workshop is A × B × H = 50 × 30 × 9 m.

1.3. Environment and building area

The section of the mechanical assembly workshop is a building with dimensions of 50 × 30 × 9 m, built of reinforced concrete blocks - sections 6 and 8 m each.

By the degree of explosion, the room does not belong to such, since the technological process is not associated with explosive substances.

Since in the room there are conductive floors and it is possible to simultaneously touch the equipment housing and metal structures of the building, these conditions make the workshop a particularly dangerous room .

The air temperature inside the building does not exceed + 20 ° С.

The environment in the workshop is not aggressive .

1.4. Process

The section of the mechanical assembly shop (MPS) is designed to release the front axle and the rear axle of trucks. The workshop is an integral part of the production of a machine-building plant.

UMC provides for production, auxiliary office and household premises.

Design part

2.1 ESN reliability category and ESN circuit selection

All electrical receivers on reliability of power supply are divided into three categories (6, paragraph 1.2.18.):

Electric receivers of category I - electric receivers, the interruption of power supply of which can entail: danger to people's lives, significant damage to the national economy; damage to expensive basic equipment, mass scrap of products, disorder of complex technological process, disruption of functioning of critical elements of public utilities. From the composition of electric receivers of category I, a special group of electric receivers is distinguished, the uninterrupted operation of which is necessary for accident-free shutdown of production in order to prevent the threat to people's lives, explosions, fires and damage to expensive basic equipment.

Electrical reception of category II - electric receivers, the interruption of power supply of which leads to mass underdelivery of products, mass downtime of workers, mechanisms and industrial transport, disruption of the normal activities of a significant number of urban and rural residents.

Category II electric receivers are allowed to be powered by one HV, including with a cable insert, if it is possible to carry out emergency repair of this line for a period of not more than 1 days. Cable inserts of this line must be made by two cables, each of which is selected by the longest current of the HV. Power supply of category II electric receivers is allowed along one cable line consisting of at least two cables connected to one common set.

If there is a centralized reserve of transformers and the possibility of replacing the damaged transformer for a period of not more than one day, power supply of category II electric receivers from one transformer is allowed.

For category II electric receivers in case of failure of power supply from one of the power sources, power supply interruptions are allowed for the time required for switching on the backup power supply by the actions of the duty personnel or the field operational team.

According to PUE, electric receivers of category II are recommended to be provided with electricity from two independent, mutually redundant power sources.

Electrical reception of category III - all other electrical receivers that are not suitable for the definitions of categories I and II.

For electric receivers of category III, power supply can be carried out from one power source, provided that the power supply breaks necessary for repair or replacement of the damaged component of the power supply system do not exceed 1 days. Electrical receivers of training workshops in relation to ensuring the reliability of power supply on assignment belong to electrical receivers of categories II and III.

Electromechanical workshop by ESN reliability category belongs to consumers of categories 2 and 3. In order to save money and due to the fact that during repair there will be no mass underdelivery of products, we select a transformer substation with a single transformer and a main power supply circuit according to (2.5.7 .):

The main supply circuits are widely used not only to power many electric receivers of a single process unit, but also a large number of relatively small receivers that are not connected to a single process. Such consumers include metal cutting machines in metal machining shops and other consumers distributed relatively evenly over the area of the shop.

Backbone diagrams make it possible to avoid the use of a bulky and expensive switchgear or shield. In this case, it is possible to use the circuit of the transformer line unit, where current conductors (bus conductors) manufactured by industry are used as the supply line. Backbone diagrams made by busbars provide high reliability, flexibility and versatility of workshop networks, which allows technologists to move equipment inside the workshop without significant alterations of electrical networks.

To supply a large number of electric receivers of relatively small power, relatively evenly distributed over the area of ​ ​ the workshop, schemes with two types of main lines are used: supply and distribution. Supply or main lines are connected to the busbars of transformer substation cabinets specially designed for main circuits. The distribution lines to which the electric receivers are directly connected are powered by the main supply lines or directly from the buses of the complete transformer substation (PTS), if the main lines are not used.

As few individual electric receivers as possible are connected to the main supply lines. This improves the reliability of the entire power system.

The disadvantage of the backbone circuitry is that when the backbone is damaged, all the electric receivers supplied from it are simultaneously disconnected. This disadvantage is felt when there are some large consumers in the workshop that are not connected to a single continuous process.

SHPA - 1 feeds via line switch

electric receivers No. 1,2,3,4,5,6,9,10,11,12,13,14;

SHPA - 2 feeds via line switch

electric receivers No. 16.17.18.19.20.21.24.25.26.27.28.

SHPA - 3 feeds via line switch

electric receivers No. 7,8,15,22,23,30,29,31.

Conclusion

The design of ESN and EO of the press section of the workshop has been developed.

TM25010/0.4 transformer is selected as power transformer.

To compensate for reactive power, a capacitor unit 2 * CC was calculated and adopted 2-0,415-40

Protection devices, distribution point and power supply lines are calculated and selected. For the characteristic line, short circuit currents are calculated to check the protection devices, and check the circuit for compliance with voltage losses.

Transformer load factor is: Kz = 0.57