Pump station power supply project

Contents

Introduction

General part

Source Data

Characteristics of the energy economy

Design and processing part

Calculation of electrical loads

Selection and calculation of transformers

Selection of power supply scheme

Calculation of short-circuit currents

Selection and calculation of electrical networks

Selection and calculation of electrical equipment

Calculation of grounding device

Selection of automation protection devices

Calculation of electric lighting

Reactive power compensation

Organizational and Economic Part

Occupational safety

Environmental protection

Fire safety

Conclusion

List of literature

Introduction

Pump stations are the most responsible structure in the water supply system, providing the necessary amount of water under the required head. Pump stations are rather difficult complex of the mechanical equipment, power stations (engines, power transformers and distributing devices), pipelines, fittings, instrumentations, the automation equipment and communication. The reliability of its operation and ease of operation depend on how well the pump station is designed and built.

When designing and building new pumping stations in relation to the given working conditions, design and construction organizations use a number of layout solutions tested by the experience of operating previously built stations.

Reliability of pump stations operation depends not only on the accepted design solutions or quality of construction and installation works, but also on how properly the station is operated, how accurately the established operation modes of pump units are maintained.

The safety and cost-effectiveness of the pump station, and hence the water supply and sewerage system, also depends on the accuracy of the operation of the operating personnel of the stations, including the dispatch service. Therefore, the operation of pump stations is of great importance in the development of operating modes for water supply and sewage systems.

The purpose of the thesis is to develop a power supply project for the pumping station of Uchalinsky Thermal Networks OJSC.

General part

1.2 Characteristics of the energy economy

The pumping station in Uchaly is a lowering pumping station and serves to pump water from the city's reverse heat supply system and further transit it to the UGOK boiler room, which supplies 50% of the city's population with heat.

All electrical receivers of enterprises according to the required degree of uninterrupted power supply in accordance with PUE are divided into 3 categories:

1) Electrical receivers are interrupted in the power supply of which is associated with a danger to the life of people, the marriage of products, damage to equipment and a long restoration of a complex technological process. In the mining industry, the first category includes: lifting plants, drainage plants, fire pumping plants, fan plants for mines and mines, heating plants for the area with difficult climatic conditions, central underground stations. All electric receivers must be provided with electric power from two independent power sources, and a break in power supply is allowed only for the time of automatic introduction of backup power supply to the ATS.

2) Electrical receivers interruption in power supply, which is associated with a significant decrease in output, downtime of workers, machinery and transport. In the mining industry, the second category includes: skip lifting machine, drilling machines, excavators, compressors, conveyor and electric locomotive transport, etc. For consumers of the second category, a break in power supply is allowed for the time of switching on the backup power supply by the duty personnel or the visiting operational team.

3) Unserviceable consumers include machines and mechanisms of auxiliary workshops, road lighting, warehouses, mechanical workshops. For them, it is allowed to interrupt the power supply for the time required for repair or replacement of the damaged power supply element, but not more than 1 day.

A break in the power supply of the pumps is unacceptable, as this can lead to a violation of the technological process, as well as lead to defrosting of pipelines in the winter. Therefore, in terms of uninterrupted power supply, pump units should be classified as consumers of the first category.

Lighting of the pump station and electric valves are also electric receivers of the first category. All other electric receivers belong to the second category.

Selection of protection and automation device

Relay protection is intended for disconnection by the circuit breaker of the protective element (interfacial K.Z., dangerous overvoltage, occurrence of excessive in magnitude and duration of overloads).

Main requirements for relay protection:

1) speed.

2) selectivity of protection action (selectivity).

3) sensitivity.

4) reliability - reliability.

In this section I select the type of protection of elements of electrical networks, I calculate and select current or voltage transformers, protection relays.

Current transformers designed to power current circuits of relay protection devices from short circuit shall meet the following requirements:

In order to prevent excessive protection actuations at short circuit outside the protected area, the error (full or current) of current transformers, as a rule, should not exceed 10%. Higher errors are allowed when using protections (for example, differential protection of tyres with braking), the correct action of which is provided by special measures at increased errors.

Current circuits of electrical measuring instruments (together with meters) and relay protection shall be connected, as a rule, to different windings of current transformers.

They can be connected to one winding of current transformers, provided that the requirements of 1.5.18 and 3.2.29 are met. At the same time, in the protection circuit, which according to the principle of action can work incorrectly in case of current disturbance

Circuits, switching on of electrical measuring instruments is allowed only through intermediate current transformers and provided that current transformers meet the requirements of 3.2.29 with the secondary circuit of intermediate current transformers open.

Protection using direct-acting relays, both primary and secondary, and protection at AC operating current is recommended, if possible, and leads to simplification and cheapening of the electrical installation.

As a source of AC operating current for protection against short circuit, as a rule, current transformers of the protected element should be used. Voltage transformers or auxiliary transformers may also be used.

Depending on the specific conditions, one of the following schemes should be used: with the dehunting of circuit breakers disconnection electromagnets, using power supplies, using charging devices with a capacitor.

Relay protection devices, which are taken out of operation according to the conditions of the network mode, selectivity of action or for other reasons, must have special devices for their removal from work by operational personnel.

2.8.3 Motor protection

Asynchronous motors of three-phase AC voltage up to 500 V at capacities from 0.05 to 400 kW are the most common type of electric motors.

Reliable and uninterrupted operation of electric motors is ensured primarily by their proper selection according to their rated power, mode of operation and form of execution. It is also important to comply with the necessary requirements and rules when compiling an electrical circuit, selecting ballast equipment, wires and cables, installing and operating an electric drive .

Depending on the nature of possible damages and abnormal operation modes, several of the main most common types of electrical protection of asynchronous motors are distinguished.

Protection of asynchronous motors against short circuits

Short circuit protection disconnects the engine when short circuit currents appear in its power (main) circuit or in the control circuit.

Short circuit protection devices (fuses, electromagnetic relays, circuit breakers with electromagnetic release) operate almost instantaneously, i.e. without time delay.

Asynchronous motors overload protection

Overload protection protects the engine from unacceptable overheating, in particular with relatively small but prolonged heat overloads. Overload protection should be used only for motors of those operating mechanisms that may have abnormal load increases in case of process disturbances.

Overload protection devices (temperature and heat relays, electromagnetic relays, circuit breakers with a thermal disconnector or with a clock mechanism), when an overload occurs, disconnect the engine with a certain time delay, the greater the less overload, and in some cases, with significant overloads, and instantly.

Protection of asynchronous motors against voltage reduction or loss

Protection against voltage decrease or loss (zero protection) is performed with the help of one or several electromagnetic devices, acts to shut down the engine when the power supply is interrupted or the mains voltage drops below the set value and prevents the engine from spontaneous switching on after the power supply break is eliminated or normal mains voltage is restored.

Electric devices used for motor protection

Electrical protection devices can carry out one or more types of protection at once. Thus, some circuit breakers provide short circuit and overload protection. Some of the protection devices, such as fuses, are single-action devices and require replacement or recharging after each operation, others, such as electromagnetic and thermal relays, are multiple-action devices. The latter differ in the method of returning to the ready state on devices with self-return and with manual return.

In this case, electromagnetic starters are used to protect the motors.

Payroll of employees

Wages are the form of remuneration for work and the basis for stimulating work. Its magnitude depends on:

1) from the results of the economic activity of the enterprise;

2) from the personnel policy of the enterprise;

3) from unemployment in the region;

4) from the action of trade unions.

Conclusion

In this diploma project of power supply of the pumping station, I determined that the station belongs to the 1st category of consumers. Calculated electrical loads according to the method of installed power, determined the radial power supply scheme. According to these calculations, I selected the 6kV transformer corresponding to all parameters, and checked it according to the condition of reliable operation. Then he chose the compensating devices and determined the short-circuit currents. After calculating the loads, I determined the section and cable tag. Then, according to the currents received, he chose electrical equipment - circuit breakers and fuses, as well as high-voltage switches. I also calculated the resistance of the grounding circuit and determined the number of electrodes. He chose relay protection, calculated the electric lighting of the workshop room.

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