Mechanical Repair Shop Design - Coursework

Contents

Introduction

1 General part of the project

1.1 Characteristics of electric power consumers

1.2 Description of single-line electrical circuit

2 Special part of the project

2.1 Calculation of electric lighting network

2.2 Calculation of electrical loads

2.3 Reactive power compensation

2.4 Transformer substation selection

2.5 Selection of electrical equipment to power supply diagram

2.6 Selection of wires and cables to power supply circuit

2.7 Calculation of grounding network

3 Economic part of the project

3.1 Calculation of power supply costs for mechanical repair shop

4 Safety measures

4.1 Technical measures ensuring safety of works

with voltage relief

Conclusion

List of literature

Introduction

Electric energy is widely used in all areas of the national economy and in everyday life. This is facilitated by its properties, such as versatility and ease of use; possibility of production in large quantities by industrial method and transmission over considerable distances.

In modern technology and the equipment of the industrial enterprises electric equipment role, i.e. sets of electrical machines, devices, devices and devices by means of which transformation of electric energy to other types of energy is made is big and automation of technological processes is provided.

The power of turbogenerators and hydrogenerators in a unit of equipment is steadily increasing. The industry has mastered the serial production of turbine generators with a unit power of 300 and 500 thousand kW, generators with a capacity of 800, 1000 and 1200 thousand kW and more with higher efficiency are manufactured. The length and voltage of transmitting high-voltage networks are growing. There are 1000, 1150 and 1500 kV lines.

Installation of electrical equipment of the modern enterprise is a complex set of works. These works include installation of: plant-wide and workshop transformer and distribution substations; air and cable transmission and distribution networks of large length and various voltages; lifting and transportation devices (elevators, cranes, electric trains, etc.); process electrical equipment, etc.

In modern conditions, the operation of electrical equipment requires deep and versatile knowledge, and the tasks of creating a new or modernizing the existing electrified technological unit, mechanism or device are solved jointly by technologists, mechanics and electricians. Requirements for electrical equipment are derived from process data and conditions. Electrical equipment cannot be considered in isolation from the technological and structural features of the electrified object, and vice versa. Therefore, for maintenance personnel, it is not enough to know only the electrical part, it is necessary to also know the mechanics and other systems in the equipment served .

Nowadays, more than 600 thousand km of overhead and cable lines with 35 kV voltage and 2 million km with 0.4... 20 kV voltage, more than 17 thousand substations with 35 kV voltage with a total capacity of about 575mn are operated in Russian power systems. kV * A.

In the near future, energy is faced with the task of worldwide development and use of renewable energy sources: solar, geothermal, wind, tidal, etc.; development of combined generation of electricity and heat for district heating of industrial cities.

1 General part of the project

1.1 Characteristics of electric power consumers

Consumers of electricity are a combination of machines, devices, power lines and auxiliary devices designed for the production, conversion, transmission and distribution of electric energy.

Consumers consider everything that is powered by electricity, that is, enterprises, household consumers, electrified transport, lighting cities and towns. They also include machines, lifting and transportation devices, compressors, fans, pumps, welding plants, transformers and various furnaces.

Electric receivers are classified by: voltage, current type, power, mode of operation.

By voltage, electric receivers are distinguished by low-voltage and high-voltage. Low-voltage - their voltage is up to 1000 V, and high-voltage - with a voltage of more than 1000 V. All electrical equipment in the workshop relates to low-voltage consumers, since all installations operate from the 220/380 Volt network.

By the type of current, electric receivers operating from:

- AC network of normal frequency 50 Hz;

- AC networks of increased or reduced frequency;

- DC network.

In the repair and mechanical workshop, all electric receivers operate from the AC network at a normal frequency of 50 Hz.

According to the power of electric receivers, there are: low power - up to 10 kW; average power - up to 100 kW.

According to operation mode electric receivers are divided into three groups:

A prolonged mode is a mode in which electric machines operate for a long time, without overheating. In this workshop, plants such as machines, heating chamber, fans, presses, ultrasonic baths operate in a long-term mode.

Intermittent mode is a mode in which working periods of operation alternate with periods of pauses, and the duration of the entire cycle does not exceed ten minutes. Various cranes operate in the workshop in this mode.

A short-term mode is a mode in which the working period is not so long that the temperatures of individual parts of the machine can reach a steady-state value, while the stopping period of the machine is so long that the machine manages to cool to ambient temperature. The proposed workshop does not have electric receivers operating in short-term mode.

According to the generality of the technological process, electric receivers can be divided into production mechanisms, general industrial plants, lifting and transportation equipment, converter plants, electric welding equipment, electric heating and electrolysis plants. Industrial plants (fans, compressors, pumps) occupy a significant place in the power supply system.

The reliability of the power supply consists in providing the enterprise with good quality electricity, that is, work should be carried out without disruption of the production plan and without emergency interruptions in the power supply. Electrical receivers of the repair and mechanical workshop belong to the second category of consumers, since a break in their power supply leads to mass underdelivery of products, downtime of workplaces and mechanisms.

1.2 Description of single-line electrical circuit

Power supply of the repair and mechanical workshop is carried out via two lines with 10 kV RP of cells 3 and 14.

Voltage is supplied to the high voltage input cabinet, which is equipped with load switches and with fuses and. Load switches are designed to disconnect transformers, and fuses and are protected from short-circuit currents.

A complete transformer substation is installed in the workshop, transformers and selected for a voltage that is reduced to a value.

Voltage from transformers is supplied to the low voltage input cabinet, which consists of input circuit breakers and, which serve to protect the switchgear buses, as well as from outgoing circuit breakers and, which serve to power electric receivers.

The sectional circuit breaker is designed to switch on and off the first and second bus sections.

Circuit breakers and protect capacitor units from short-circuit currents. KU are designed to compensate for reactive power.

From automatic switches, distribution points of RP 1,2,3,4 which are completed with lead-in automatic switches, and the departing automatic switches are powered: with RP1 - and for food of boards of lighting, with RP2 - - and with RP3 - - food is received by electroreceivers, with RP4 - and for food of emergency boards of lighting.

From automatic switches, food moves on buslines distributive ShS1,2,3 which are completed with lead-in automatic switches, and the departing automatic switches - from which power electroreceivers

Current transformers are designed to connect measuring instruments to them. Measuring instruments used in networks, these are ammeters and, voltmeters and, as well as meters of active and reactive power and.

And food receive ShchSU1 and ShchSU2 from automatic switches. Control station boards are designed for control of electric engines of plenum-exhaust ventilation.

To connect distribution points, busbars and electric receivers, AVVG cables with a section of 2.5 150 and PV3 wires with a section of 2.5 6 are used.

3. Organization of production.

Before starting the operation of electrical installations related to maintenance, performed with voltage removal, without voltage removal on current-carrying parts and in their vicinity, without voltage removal away from current-carrying parts under voltage, an organizational event is carried out - design of the work order

The order is issued to operational personnel immediately before the start of preparation of the workplace.

The work order is written out in two copies and filled under a copy. It is allowed to transfer the work order by telephone by the person issuing the work order to the senior person from the operational personnel of this facility or to the responsible manager. At the same time, the outfit is filled in three copies: one copy is filled by the person issuing the outfit, and two by the person receiving it by phone.

The number of orders issued simultaneously per responsible manager is determined in each case by the person issuing the order.

Admission to work at the same time is made directly at the workplace. Allowing, having checked the composition of the brigade and the qualifications included in the order of persons, explains to the brigade where the voltage is turned off, grounding is imposed, which parts are being repaired, which remain energized, draws the attention of the brigade to the special conditions of work, the boundaries of the workplace, and makes sure that everything stated by the brigade is understood. In installations with a voltage of up to 35 kV, the acceptor confirms the absence of voltage first by connecting the voltage indicator, and then by touching the hand.

The operating personnel shall not be entitled, without the knowledge of the responsible manager and the works manufacturer, to make changes to the installation scheme, which may change the safety conditions, except in emergency cases.

It is not allowed to remain alone at the site of work, including the manufacturer of work.

At the end of all work recorded in the order, the work place should be removed by the repair team and examined by the responsible leader, who, after the departure of the team, signs in the order and hands it over to the operational personnel.

All works carried out in electrical installations without work are performed by order of authorized persons with registration in the operational log or in the order of current operation with subsequent entry in the operational log.

A work order is of a one-time nature and is issued for only one job. The order is valid for one shift.

The order is transferred directly or by means of communication and recorded by the recipient in the operational log.

Operational personnel can perform small, short-term work in case of production need.

The experience of operation of electrical equipment and power grids at Russian enterprises shows that it is advisable to compile a single list of works performed in the electric farm of a particular enterprise. Such lists significantly help in the organization of safe work in the electric farm of the enterprise.

Safety of works performed with voltage shutdown is ensured by technical measures. At the site of works with voltage removal in electrical installations with voltage above 1000 V, the following shall be switched off: current-carrying parts on which work is carried out; unfounded current-carrying parts, to which people can approach.

In electrical installations with a voltage above 1000 V, on each side from where the switching device can supply voltage to the place of work, there must be a visible gap formed by disconnection or removal of buses and wires, disconnection of disconnectors, removal of fuses, as well as disconnection of separators and load switches, except for those where automatic shutdown is carried out by springs installed on the devices.

If the operation is carried out without the use of portable earthing, additional measures must be taken to prevent the erroneous supply of voltage to the place of work: removal of fuses, mechanical locking of the drives of disconnected devices, the use of insulating linings in choppers and automatic machines.

On the drives of disconnectors, separators, load switches and control keys, as well as on the bases of fuses with which voltage can be applied to the place of work, posters "Do not turn on People Work" are posted.

In electrical installations, before starting all types of works with voltage shutdown, it is necessary to check the absence of voltage in the work area. The check of the absence of voltage on the part of the electrical installation turned off for work is carried out by the permitting after hanging prohibition posters.

It is necessary to check the absence of voltage in electrical installations using the factory-made voltage indicator.

Short-term, non-overdue work to eliminate equipment malfunctions that can lead to an accident, as well as recovery operations in emergency cases, can be carried out without work, followed by recording in the operational log: operational personnel, at least 2 people at a voltage above 1000 V; repair personnel under the supervision of the operational, if the discharge and execution of the work may delay the elimination of the consequences of the accident.

The planned preventive repair system is a set of technical and organizational measures for the care, maintenance and repair of equipment, carried out as planned and of a preventive nature. The planned system is called because all the activities that make up its content are carried out according to the plan, within a predetermined time frame. It is called preventive because in addition to repair work it includes preventive measures that prevent accidents and breakdowns. These activities include: daily care, supervision of equipment and inter-repair maintenance - checking for accuracy, inspections, washing and oil change in crankcase systems.

Inspection is performed by OTC controllers together with repair locksmiths. The list of equipment and the frequency of inspection are established by the PPR bureau of the main power engineering department of the plant. Minor inaccuracies identified during the check are liquidated immediately.

Inspections are performed on schedule during off-hours. Problems detected during the inspection that interfere with the performance should be resolved during the inspection. Defects of equipment, which must be eliminated during the next repair, are entered in the punch list.

During the current repair, worn-out parts whose service life does not exceed the duration of the overhaul period are replaced. During the current repair, mechanisms are regulated to ensure equipment productivity and quality of processed parts.

During average repair, parts whose service life does not exceed the period between two average repairs are replaced. The average repair provides for the reconciliation of coordinates for returning to the machine the accuracy, power and performance provided for by GOST. With average repair, a simple unit is allowed within 0.6 days for each repair unit.

Overhaul provides for the replacement of all worn out parts, complete disassembly, adjustment. This is the most complex type of planned repair. During overhaul, simple equipment within one working day is allowed.

The main task of the PPM system is to extend the repair cycle and the overhaul period, reduce the time for repair work and reduce their cost. According to the PPM system, for each unit, depending on the conditions of its operation, the duration of the repair cycle and the overhaul period is established.

The repair cycle is considered the time between two overhauls, and for new equipment - the time from the beginning of operation to the first overhaul. The inter-repair period is the time between two regular repairs.