Maximum speed of turbogenerators at thermal power plants. Turbogenerator: purpose and principle of operation. Visualization system software

Introduction

Turbogenerators (TG) are the main type of generating equipment, providing over 80% of the total global electricity generation. At the same time, TG are the most complex type electric machines, which closely combine the problems of power, dimensions, electromagnetic characteristics, heating, cooling, static and dynamic strength of structural elements. Ensuring maximum operational reliability and efficiency of TG is a central scientific and technical problem. At the same time, despite the huge amount of work carried out over the past decades, issues of further development of the theory, development of more advanced technologies and designs of TG, calculation methods and research do not lose their relevance.

Turbogenerator - non-salient pole synchronous generator, the main function of which is to convert mechanical energy in work from a steam or gas turbine into electrical energy when high speeds rotor rotation (3000,1500 rpm). Mechanical energy from the turbine is converted into electric power using a rotating magnetic field, which is created by a direct voltage current flowing in the copper winding of the rotor, which in turn leads to the emergence of a three-phase alternating current and voltage in the stator windings. Depending on the cooling systems, turbogenerators are divided into several types: generators with air cooled, hydrogen cooled generators and water cooled generators. There are also combined types, for example, a hydrogen-water-cooled generator (HWG). Turbogenerator TVV-320-2 is designed to generate electrical energy at a thermal power plant with direct connection to steam turbine K-300-240 Leningrad Metal Plant or T-250-240 Ural Turbo Engine Plant.

Exercise

a) design and principle of operation of the electrical circuit in accordance with the specifications, scope of application;

b) winding diagram.

Select an option

a) selected according to table 1.1

Table 1.1

b) selected according to tables 1.2 and 1.3

Table 1.2

Table 1.3

Turbogenerators

2.1 Turbogenerator- a synchronous generator working in tandem with a turbine. The main function is to convert the mechanical energy of rotation of a steam or gas turbine into electrical energy. Rotor speed 3000, 1500 rpm. Mechanical energy from the turbine is converted into electrical energy through the rotating magnetic field of the rotor in the stator. The rotor field, which is created by a direct voltage current flowing in the copper winding of the rotor, leads to the occurrence of a three-phase AC voltage and current in the stator windings. The stronger the rotor field, the greater the voltage and current on the stator, i.e. more current leaking in the rotor windings. The voltage and current in the rotor windings are created by a thyristor excitation system or exciter - a small generator on the shaft of a turbogenerator. Turbogenerators have a cylindrical rotor mounted on two plain bearings, in a simplified form they resemble an enlarged generator passenger car. 2-pole (3000 rpm), 4-pole (1500 rpm as at the Balakovo NPP) are produced, therefore, they have high rotation speeds and problems associated with this. According to the methods of cooling the windings of a turbogenerator, they are distinguished: water-cooled (three waters), air-cooled and hydrogen-cooled (more often used at nuclear power plants).

Depending on the cooling system, turbogenerators are divided into several types: air-cooled, oil-cooled, hydrogen-cooled and water-cooled. There are also combined types, such as hydrogen-water-cooled generators. There are also special turbogenerators, for example, locomotive ones, which serve to power the lighting circuits and radio station of a steam locomotive. In aviation, turbogenerators serve as additional onboard sources of electricity. For example, the TG-60 turbogenerator operates on an aircraft engine taken from the compressor compressed air, providing drive for a three-phase alternating current generator 208 volts, 400 hertz, rated power 60 kVA*A.

Turbogenerator design

The generator consists of two key components - the stator and the rotor. But each of them contains big number systems and elements. The rotor is a rotating component of the generator and is subject to dynamic mechanical loads, as well as electromagnetic and thermal ones. The stator is a stationary component of the turbogenerator, but it is also subject to significant dynamic loads- vibration and torque, as well as electromagnetic, thermal and high-voltage. The initial (exciting) direct current of the generator rotor is supplied to it from the generator exciter. Typically, the exciter is coaxially connected by an elastic coupling to the generator shaft and is a continuation of the turbine-generator-exciter system. Although large power plants also provide backup excitation of the generator rotor. Such excitation occurs from a separate pathogen. Such pathogens direct current They are driven by their own three-phase alternating current electric motor and are included as a reserve in the circuit of several turbine units at once. From the exciter, direct current is supplied to the generator rotor by means of a sliding contact through brushes and slip rings. Modern turbogenerators use thyristor self-excitation systems.

Turbogenerator operation

Non-salient pole rotors (Fig. 10 and 11) are used in synchronous machines high power, rotating speed n = 1500÷3000 rpm. The manufacture of high-power machines with such rotation speeds with a salient-pole rotor design is impossible due to the mechanical strength of the rotor and the fastening of the poles and field winding.

Non-salient pole rotors have mainly synchronous generators designed for direct connection to steam turbines. Such machines are called turbogenerators. Turbogenerators for thermal power stations have a rotation speed of 3000 rpm and two poles, and for nuclear power plants- 1500 rpm and four poles. The turbine generator rotor is made of a massive solid steel forging. For the rotors of high-power turbogenerators, high-quality chromium-nickel or chromium-nickel-molybdenum steel is used. According to the conditions of mechanical strength, the rotor diameter at a rotation speed of 3000 rpm should not exceed 1.2-1.25 m. To ensure the necessary mechanical rigidity, the active length of the rotor should be no more than 6.5 m.

In Fig. 10 shows a general view, and in Fig. 11 - cross section of a two-pole rotor of a turbogenerator.

Grooves are milled on the outer surface of the rotor rectangular shape, in which the field winding coils are placed. The winding is not laid at approximately one third of the pole division, and this part forms the so-called large tooth, through which the main part of the generator's magnetic flux passes. Sometimes grooves are made in the large tooth to form ventilation ducts. Due to the large centrifugal forces acting on the excitation winding, it is secured in the grooves using non-magnetic metal wedges. Non-magnetic wedges reduce slot leakage magnetic fluxes, which can cause tooth saturation and reduce net flux. The grooves of the large tooth are closed with magnetic wedges. The frontal parts of the winding are secured with rotor bands. The rotor winding has class B or F insulation. The leads from the field winding are connected to the slip rings on the rotor. A central hole is drilled along the rotor axis along its entire length, which serves to examine the material of the central part of the forging and to relieve the forging from dangerous internal stresses. In Fig. Figure 12 shows a general view of the turbogenerator. In turbogenerators, the function of the damper winding is performed by the massive rotor body and wedges.

In addition to turbogenerators with a non-salient pole rotor, high-speed high-power synchronous motors - turbomotors - are produced.

Introduction

1. Technical data

2. Design and operation of the generator

3. Safety instructions

Conclusion

Bibliography

Introduction

Turbogenerators (TG) are the main type of generating equipment, providing over 80% of the total global electricity generation. At the same time, TGs are the most complex type of electrical machines, which closely combine the problems of power, dimensions, electromagnetic characteristics, heating, cooling, static and dynamic strength of structural elements. Ensuring maximum operational reliability and efficiency of TG is a central scientific and technical problem.

In the domestic turbogenerator industry, a huge contribution to the development of theory, development of issues of calculation, design and operation of TGs was made by many scientists, researchers, designers, among whom, first of all, it should be noted Alekseev A.E., Luther R.A., Kostenko M.P., Odinga A.I., Bergera A.Ya., Komara E.G., Efremova D.V., Ivanova N.P., Glebova I.A., Kazovsky E.Ya., Eremina M.Ya., Voldek A. .I., Gervais G.K., Vazhnova A.I. Among foreign experts, it should be noted E. Wiedemann, V. Kellenberger, V.P. Shuisky, G. Gotter.

At the same time, despite the huge amount of work carried out over the past decades, issues of further development of the theory, development of more advanced technologies and designs of TG, calculation methods and research do not lose their relevance.

A turbogenerator is a non-salient-pole synchronous generator, the main function of which is to convert mechanical energy in operation from a steam or gas turbine into electrical energy at high rotor speeds (3000-1500 rpm). Mechanical energy from the turbine is converted into electrical energy using a rotating magnetic field, which is created by a direct voltage current flowing in the copper winding of the rotor, which in turn leads to the generation of three-phase alternating current and voltage in the stator windings. Depending on the cooling systems, turbogenerators are divided into several types: air-cooled generators, hydrogen-cooled generators and water-cooled generators. There are also combined types, for example, a hydrogen-water-cooled generator (HW). The TVV-320-2 turbogenerator is designed to generate electrical energy at a thermal power plant in direct connection with the K-300-240 steam turbine of the Leningrad Metal Plant or T-250-240 of the Ural Turbomotor Plant.

1. Technical data

Nominal parameters of the generator at nominal pressure and temperatures of cooling media are given in table. 1.

Main parameters of cooling media

Hydrogen in the stator housing

Distillate in the stator winding

Process water in gas coolers

Process water in the stator winding heat exchangers

Overpressure process water there should be no more than the excess pressure of the distillate in the winding.

The permissible deviation is determined by the temperature of the distillate.

The highest permissible temperature of individual generator components and cooling media. Insulation of generator windings is class "B".

The highest permissible temperature of individual generator components and cooling media is indicated in table. 2.

*The temperature of the rotor winding is allowed to exceed the temperature of cold hydrogen by no more than 75.

Permissible temperature according to the resistance temperatures laid under the wedges of the stator winding, should not exceed 75 between the readings of the most and least heated resistance thermometers should not exceed 20 can be specified in agreement with the manufacturer for each specific machine after thermal tests.

Additional technical data

2. Design and operation of the generator

General functional diagram of work

The generator is designed with direct cooling of the stator winding with distilled water (distillate), and the rotor windings and stator core with hydrogen contained inside a gas-tight housing.

The distillate in the stator winding circulates under the pressure of the pumps and is cooled by heat exchangers located outside the generator.

Cooling hydrogen circulates in the generator under the action of fans mounted on the rotor shaft and is cooled by gas coolers built into the end parts of the generator housing.

Water circulation in gas coolers and heat exchangers is carried out by pumps located outside the generator.

The oil supply to the support bearings and shaft seals comes from the turbine oil system.

For emergency oil supply to the support bearings and shaft seals at the run-down of the unit, reserve tanks are installed outside the generator.

The generator is excited by a high-frequency inductor generator through semiconductor rectifiers.

Stator housing and foundation plates

The welded gas-tight stator housing consists of a middle part that carries the core with winding, and two end parts.

At the end parts there are winding frontal parts and gas coolers.

At the end part on the exciter side, the end terminals of the winding are installed - zero at the top, and linear at the bottom.

The mechanical strength of the housing is sufficient for the stator to withstand internal pressure in the event of a hydrogen explosion without residual deformation.

The outer stator shields are directly integrated with the internal shields, to which the fan shields are attached.

The fan shield halves are insulated from internal shields and among themselves.

The connectors of the shields are located in a horizontal plane.

There are special channels in the shields and in the rotor barrel through which the cooling gas enters the frontal parts of the rotor winding.

The gas tightness of the connections between the planes of the body and the outer panels is ensured by a rubber cord glued along the bottom of the grooves milled in the outer panels.

To get inside the body without dismantling the outer panels, a hatch is provided in its lower part.

Before installing the generator on the foundation, the stator rests on transport feet welded to the housing.

The stator is installed on the foundation using lifting arms, which are removed during transportation.

The basis for the generator and exciter are foundation slabs made of steel sheets. They are installed during installation on embedded slabs and permanent linings and filled with concrete.

Foundation studs are used to secure the generator to the foundation.

The base for the generator bearing is a box-type foundation slab.

Gas coolers

The heat generated in the generator is removed by four vertical coolers.

Each cooler consists of bimetallic, brass-aluminum tubes with rolled aluminum fins.

The tubes are rolled on both sides into tube sheets, to which chambers are bolted, sealed with rubber and connected by frames.

The coolers are inserted into the stator from above and rest on the end parts of the stator with their upper tube plates.

The lower chambers in relation to the stator housing are sealed with rubber in such a way that free thermal expansion of the coolers in the vertical direction is ensured.

Removable covers of the water chambers allow you to clean the tubes and monitor their condition without violating the tightness of the stator housing.

Pressure and drain pipes attached to the bottom covers.

To release air from upper chambers coolers are equipped with control drain pipes.

Each tube, passed through one of the cooling tubes and the lower chamber, ends in a flange welded to the chamber.

The flanges are connected to outlet pipes with taps, which must be constantly open during generator operation with a minimum of water draining into the drain.

Stator core

The stator core is assembled on wedges from segments of electrical steel 0.5 mm thick and is divided along the axis into packages by ventilation ducts.

The surface of the segments is covered with insulating varnish.

The stator core wedges are welded to the transverse rings of the housing.

The compressed stator core is tightened by pressure rings made of non-magnetic steel. The toothed area of ​​the outer packages is sealed with pressure fingers made of non-magnetic steel, installed between the core and pressure rings.

To dampen electromagnetic leakage fluxes from the frontal parts of the stator winding, copper screens are installed under the pressure rings.

To reduce the transmission of stop-period vibrations of the core to the housing and foundation, longitudinal slots are made in the stator wedges, which creates an elastic connection between the stator core and the housing.

Stator winding

The stator winding is three-phase, two-layer, with a shortened pitch, rod-type, with transposition of elementary conductors. The frontal parts of the winding are basket type. The winding rods are woven from solid and hollow elementary insulated conductors and secured in the grooves of the core with special wedges.

To cool the winding, distilled water passes through the hollow conductors.

At the ends of the rods, tips are soldered for supplying water to the hollow conductors. The tips are soldered to the rods hard solder type P Avg. The electrical connection of the rods is carried out with a copper clamp and wedges with soldering with soft solder of the POS type.

The beginnings and ends of the winding are brought out through the end terminals. The designation of linear and zero end terminals is indicated on the installation drawing included in the set of operational documentation.

To supply and drain cooling water from the stator winding, there are ring collectors mounted on insulators. The connection of the collectors with the winding rods is carried out by water connecting tubes made of insulating material. The cooling water in the winding passes through two rods, bars and terminals connected in series. To control the filling of the collectors with water and to bleed air from them, drainage tubes are installed at the upper points of the collectors, leading out from the stator housing.

During operation, the drain tubes must be open with minimal drainage to continuously remove air from the stator winding cooling system. Monitoring the permeability of the distillate in the stator winding rods is carried out by measuring the temperature with thermal resistances placed under the wedges in each groove of the stator core.

The rotor is made of a single forging of special steel, ensuring its mechanical strength in all operating modes of the generator.

The rotor winding is made of strip copper with a silver additive. Its cooling is carried out directly with hydrogen using a self-ventilation scheme with gas intake from the gap of the machine.

The duralumin wedges that hold the winding in the grooves have intake and outlet openings for cooling gas that coincide with the side channels milled into the coils.

The groove and turn insulation of the coils are made of pressed glass fiber coated with heat-resistant varnish. Contact rings, hot mounted on an intermediate bushing isolated from them, are installed behind the bearing on the exciter side.

The current supply rods, located in the central hole of the rotor, are connected to the winding and slip rings using insulated flexible tires and special insulated bolts, which have gland-type seals to ensure gas tightness of the rotor.

Rotor tires, made of special non-magnetic steel, have a hot-press fit on the centering sharpening of the rotor barrel.

The bandage ring is held against axial movements by a ring key and a nut screwed onto the nose of the bandage from the outside.

The frontal parts of the rotor winding are insulated from the bands and centering rings by insulating segments.

Support bearings

The generator support bearing installed on the exciter side is a riser type bearing and has a self-aligning ball bearing.

Bearing lubrication is forced. Oil is supplied under excess pressure from the turbine oil pressure line.

The bearing design provides for remote control of the temperature of the babbitt liner and drain oil using resistance thermometers. Visual control of oil drainage is carried out through the glass in the pipe.

A brush traverse is installed on the elongated part of the base of the bearing riser, which serves to supply excitation current to the rotor slip rings.

To eliminate bearing currents, this bearing is insulated from the foundation and from all oil pipelines.

On the rack of the traverse frame there is provision for installation of a brush insulated from the housing, which is used when measuring the insulation resistance of the rotor winding and to introduce protection against double short circuit of the rotor winding to the housing.

The turbine side generator support bearing is supplied by the turbine factory.

Shaft seals

To prevent hydrogen from escaping from the stator, two-chamber end-type shaft oil seals are installed on the outer shields of the generator. In this type of seal, the Babbitt-filled liner is constantly pressed against the thrust ring of the rotor shaft by the pressure of the clamping oil and follows all movements of the rotor along the axis.

The sealing oil, under a pressure exceeding the gas pressure in the generator, is supplied to the pressure chamber and from there, through holes in the liner, it enters an annular groove machined in the Babbitt fill of the liner. Then the oil fills the radial grooves and wedge bevels and, spreading in both directions from the annular groove, forms a continuous film during rotation, which prevents gas leakage from the generator housing.

The sealing and pressure oil chambers formed between the housing and the liner are sealed with rubber cords placed in annular grooves on the surface of the liner.

To protect the internal cavity of the stator from oil ingress, oil traps are installed on the outer shields between the shaft seal and the internal cavity of the stator, and additional cameras in fan shields.

To eliminate bearing currents, the seal housing and the oil trap on the exciter side are isolated from the outer shield and oil pipelines.

The required sealing and clamping oil pressure is provided by regulators included in the oil supply system.

Ventilation

The generator is ventilated according to closed loop. The gas is cooled by gas coolers built into the stator housing. The required gas pressure is created by two fans installed on the rotor shaft.

3. Safety instructions

At power plants equipped with hydrogen-cooled generators, follow departmental safety regulations.

When operating a hydrogen-cooled generator, hydrogen leaks to some extent into the atmosphere. The resulting gas mixture can ignite, and if it contains five or more percent hydrogen, it can explode.

To eliminate the possibility of fires and explosions during installation, during preparation for work and during operation, take measures to ensure that there are no unventilated volumes near the generator where hydrogen can penetrate.

When ventilating these volumes, exclude the possibility of hydrogen entering the units of the unit operating with sparking or having a high temperature.

Tolerance service personnel into the generator housing after it has been completely pushed out carbon dioxide and a chemical analysis of the air was carried out.

Conclusion

Currently, electricity is mainly generated by thermal, hydraulic and nuclear power plants. Of these, the predominant development was thermal power plants, which is explained as follows. The cost of electricity generated by hydroelectric power plants is significantly lower than the cost of electricity generated by thermal power plants. However, in terms of capital investment, hydroelectric power plants are several times more expensive than thermal power plants and they take longer to construct. long time. Therefore, increasing capacity to cover the ever-increasing needs for electricity is more feasible through the construction of thermal power plants. In this case, along with a faster increase in energy availability, the growth of labor productivity accelerates in all National economy, which has an additional impact on reducing the payback period for costs incurred. generator boiler circulation oil supply

The foregoing confirms the relevance of installing turbogenerators in boiler houses, mainly both to cover the boiler houses’ own needs and to supply electricity to external consumers.

Bibliography

1. Braimeister L.G., Pozdnyakov B.I., Teymurazyan Yu.V. and others. “Manual for the overhaul of the TVV-320-2 turbogenerator”, Moscow: SPO ORGRES, 1976.

2. Fedorov V.A., Smirnov V.M. "Experience in the development, construction and commissioning of small power plants", Moscow: Teploenergetika, No. 1, 2000.

3. Korennov B.E. "Replacing the ROU with a back-pressure turbine - an effective energy-saving enterprise for boiler houses and thermal power plants", Moscow: Industrial Energy, No. 7, 1997.

4. Bushuev V.V., Gromov B.N., Dobrokhotov V.I. and others. “Scientific, technical and organizational-economic problems of introducing energy-saving technologies”, Moscow: Teploenergetika, No. 11, 1997.

5. Khrilev L.S. "Main directions of development of district heating", Moscow: Teploenergetika, No. 4, 1998.

6. Dobrokhotov V.I. "Energy saving: problems and solutions", Moscow: Teploenergetika, No. 1, 2000.

Electrical energy driven by a steam or gas turbine. Typically this is a synchronous generator directly connected to the turbine of a thermal power plant (TPP). Since turbines used at thermal power plants operating on fossil fuels have the best technical and economic performance at high rotation speeds, turbogenerators located on the same shaft with the turbines must be high-speed (rotation speed 1500 or 3000 rpm).

The turbogenerator is a horizontal electric machine. Its field winding is located on the rotor with implicit poles, the three-phase operating winding is on the stator. The rotor, which experiences strong mechanical stress, is made from entire forgings of high-quality steel. According to strength conditions linear speed points of the rotor should not exceed 170-190 m/s, which limits its diameter to 1.2-1.3 m. The relatively small diameter of the rotor determines its relatively large length, which, however, is limited by the permissible deflection of the shaft and does not exceed 7.5 -8.5 m. Longitudinal grooves are milled on the surface of the rotor into which the turns of the field winding are placed. The winding is secured with wedges covering the grooves and massive bands made of non-magnetic steel covering the frontal (end) parts of the winding. The winding is powered by the exciter of electrical machines.

The turbogenerator stator consists of a housing and a core with slots for the winding. The core is made from several packages made from sheets of electrical steel 0.35-0.5 mm thick, coated with a layer of varnish. Leave between individual packages ventilation ducts 5-10 mm wide. The winding is secured in the grooves with wedges, and its frontal parts are secured on special rings located in the end part of the stator. The core is placed in a steel welded casing, closed at the ends with shields.

Turbogenerators of nuclear power plants have features related to the fact that the steam generated in nuclear reactor, has relatively low parameters. This makes it possible to produce a rotor with a diameter of up to 1.8 m. At the same time, the size of the rotor forging is limited by technological capabilities, maximum weight forgings reaches 140-180 tons. Turbogenerators with a power of up to 30 MW have closed system air cooling; with power over 30 MW air environment replaced with hydrogen with an excess pressure of about 5 kN/sq.m. The use of hydrogen as a coolant makes it possible to increase heat removal from cooled surfaces, since the heat capacity of hydrogen is several times higher than the heat capacity of air, and to increase the power of the turbogenerator. Coolant circulation is provided by fans located on the same shaft as the turbogenerator. Heat is removed from the surfaces of insulated conductors and steel cores. The heated coolant enters a special cooler. With hydrogen cooling, it is built into the turbogenerator and the entire cooling system is sealed. To intensify cooling when the turbogenerator power is over 150 MW, the hydrogen pressure in the system is increased to 300-500 kN/sq.m, and when the power is over 300 MW, internal cooling of the winding conductors with hydrogen or distilled water is used. With hydrogen cooling, the winding conductors are made with side cut-out channels, and with water cooling, hollow conductors are used. In large turbogenerators, cooling is usually combined: for example, the stator and rotor windings are cooled with water, and the stator core is cooled with hydrogen. An increase in turbogenerator power leads to a decrease specific consumption materials and to reduce the cost of its production per kW of power.

Most synchronous machines use reverse design diagram compared to, i.e., the excitation system is located on the rotor, and the armature winding is on the stator. This is explained by the fact that through sliding contacts it is easier to supply a relatively weak current to the excitation winding than current to the working winding. The magnetic system of a synchronous machine is shown in Fig. 1.

The field poles of a synchronous machine are located on the rotor. The pole cores of electromagnets are made in the same way as in DC machines. On the stationary part - the stator - there is a core 2, made of insulated sheets of electrical steel, in the grooves of which there is a working alternating current winding - usually three-phase.

Rice. 1. Magnetic system of synchronous machine

When the rotor rotates, a variable emf is induced in the armature winding, the frequency of which is directly proportional to the rotor speed. The alternating current flowing through the working winding creates its own magnetic field. The rotor and the field of the working winding rotate at the same frequency - . In the motor mode, the rotating working field carries along the magnets of the excitation system, and in the generator mode, vice versa.

Let's consider design of the most powerful machines - turbo and hydrogen generators. Turbogenerators are driven by steam turbines, which are most economical at high speeds. Therefore, turbogenerators are made with a minimum number of excitation system poles - two, which corresponds to a maximum rotation speed of 3000 rpm at an industrial frequency of 50 Hz.

The main problem of turbogenerator construction is to create a reliable machine under extreme electrical, magnetic, mechanical and thermal loads. These requirements leave an imprint on the entire design of the machine (Fig. 2).

Rice. 2. General form turbogenerator: 1 - slip rings and brush apparatus, 2 - bearing, 3 - rotor, 4 - rotor bandage, 5 - stator winding, 6 - stator, 7 - stator winding terminals, 8 - fan.

The turbogenerator rotor is made in the form of a solid forging with a diameter of up to 1.25 m and a length of up to 7 m (working part). Full Length forgings, taking into account the shaft, is 12 - 15 m. On the working part, grooves are milled into which the excitation winding is placed. This produces a two-pole cylindrical electromagnet without pronounced poles.

In the production of turbogenerators they use latest materials And Constructive decisions, in particular direct cooling active parts jets of cooling agent - hydrogen or liquid. To obtain greater power, it is necessary to increase the length of the machine, which gives it a very unique appearance.

Hydrogen generators (Fig. 3) differ significantly in design from turbogenerators. The efficiency of hydraulic turbines depends on the speed of the water flow, i.e. the pressure. It is impossible to create high pressure on lowland rivers, so turbine rotation speeds are very low - from tens to hundreds of revolutions per minute.

To obtain an industrial frequency of 50 Hz, such low-speed machines have to be made with a large number of poles. To accommodate large quantity poles, it is necessary to increase the diameter of the hydrogenerator rotor, sometimes up to 10 - 11 m.

Rice. 3. Longitudinal section of an umbrella-type hydrogenerator: 1 - rotor hub, 2 - rotor rim, 3 - rotor pole, 4 - stator core, 5 - stator winding, 6 - crosspiece, 7 - brake, 8 - thrust bearing, 9 - rotor bushing.

Creating powerful turbo and hydrogen generators is a complex engineering task. It is necessary to solve a number of mechanical, electromagnetic, thermal and ventilation calculations and ensure the manufacturability of the design in production. These tasks can only be accomplished by powerful design and production teams and companies.

Very interesting designs various types, in which systems with permanent magnets and reactive systems, i.e. systems in which the operating magnetic field interacts not with the excitation magnetic field, but with ferromagnetic salient poles of the rotor that do not have a winding.

But still, the main area of ​​technology where synchronous machines have no competitors today is energy. All generators at power plants, from the most powerful to mobile ones, are made on the basis of synchronous machines.

Rice. 4. Synchronous turbogenerator

As for, their weak point is the launch problem. By itself, a synchronous motor usually cannot accelerate. For this purpose it is equipped with a special starting winding, operating on the principle of an asynchronous machine, which complicates the design and the start-up process itself. Therefore, synchronous motors are usually produced for medium and high power.

Introduction

1. Technical data

2. Design and operation of the generator

3. Safety instructions

Conclusion

Bibliography

Introduction

Turbogenerators (TG) are the main type of generating equipment, providing over 80% of the total global electricity generation. At the same time, TGs are the most complex type of electrical machines, which closely combine the problems of power, dimensions, electromagnetic characteristics, heating, cooling, static and dynamic strength of structural elements. Ensuring maximum operational reliability and efficiency of TG is a central scientific and technical problem.

In the domestic turbogenerator industry, a huge contribution to the development of theory, development of issues of calculation, design and operation of TGs was made by many scientists, researchers, designers, among whom, first of all, it should be noted Alekseev A.E., Luther R.A., Kostenko M.P., Odinga A.I., Bergera A.Ya., Komara E.G., Efremova D.V., Ivanova N.P., Glebova I.A., Kazovsky E.Ya., Eremina M.Ya., Voldek A. .I., Gervais G.K., Vazhnova A.I. Among foreign experts, it should be noted E. Wiedemann, V. Kellenberger, V.P. Shuisky, G. Gotter.

At the same time, despite the huge amount of work carried out over the past decades, issues of further development of the theory, development of more advanced technologies and designs of TG, calculation methods and research do not lose their relevance.

A turbogenerator is a non-salient-pole synchronous generator, the main function of which is to convert mechanical energy in operation from a steam or gas turbine into electrical energy at high rotor speeds (3000-1500 rpm). Mechanical energy from the turbine is converted into electrical energy using a rotating magnetic field, which is created by a direct voltage current flowing in the copper winding of the rotor, which in turn leads to the generation of three-phase alternating current and voltage in the stator windings. Depending on the cooling systems, turbogenerators are divided into several types: air-cooled generators, hydrogen-cooled generators and water-cooled generators. There are also combined types, for example, a hydrogen-water-cooled generator (HW). The TVV-320-2 turbogenerator is designed to generate electrical energy at a thermal power plant in direct connection with the K-300-240 steam turbine of the Leningrad Metal Plant or T-250-240 of the Ural Turbomotor Plant.

1. Technical data

The nominal parameters of the generator at the nominal pressure and temperature of the cooling media are given in table. 1.

Main parameters of cooling media

Hydrogen in the stator housing

Distillate in the stator winding

Process water in gas coolers

Process water in the stator winding heat exchangers

The excess pressure of process water should not be greater than the excess pressure of the distillate in the winding.

The permissible deviation is determined by the temperature of the distillate.

The highest permissible temperature of individual generator components and cooling media. Insulation of generator windings is class "B".

The highest permissible temperature of individual generator components and cooling media is indicated in table. 2.

*The temperature of the rotor winding is allowed to exceed the temperature of cold hydrogen by no more than 75.

The permissible temperature according to the resistance temperatures laid under the wedges of the stator winding should not exceed 75 between the readings of the most and least heated resistance thermometers should not exceed 20 can be specified in agreement with the manufacturer for each specific machine after thermal tests.

Additional technical data