EA003265B1 - Rotating power system stabilizer - Google Patents

Abstract

1. Power system stabiliser comprising a rotating electrical main machine (2,2'), windings (14) of a stator (12) are connected to the electric power network terminals, a current converter (18,18') connected to it a voltage source, the current converter (18,18') is also connected to the alternating current windings (16) of the rotor, whereby electric power is exchanged via the power line terminals by changing the rotational speed of the rotor (10). 2. Power system stabiliser according to claim 1, characterised in that the voltage source is a voltage source, which is independent of the power lines. 3. Power system stabiliser according to claim 1 or 2, characterised in that the voltage source is a regulating machine (20,20'). 4. Power system stabiliser according to claim 1,2 or 3, characterised in that the regulating machine (20,20') and the main machine (2,2') has a common shaft (22). 5. Power system stabiliser according to claim 4, characterised in that the current converter (18') is arranged at the static parts of the main machine and connected to the rotor windings (16) of the main machine via brushes (30) and slip rings (32). 6. Power system stabiliser according to claim 4, characterised in that the regulation machine (20) and the main machine (2) are brushless and in that the current converter (18) is arranged co-rotating at the shaft (22) of the rotor. 7. Power system stabiliser according to any of the claims 1 to 6, characterised by a flywheel arranged at the shaft (22) of the electrical main machine. 8. Power system stabiliser according to any of the claims 1 to 7, characterised by a driving means arranged for applying a force to the shaft (22) of the electrical main machine. 9. Power system stabiliser according to any of the claims 1 to 8, characterised by a load means arranged for collecting of the driving force of the shaft (22) of the electrical main machine. 10. Power network comprising power lines and a shunt stabiliser (84, 84A, 84B) of a parallel type according to claim 1. 11. Power network according to claim 10, characterised in that the voltage source is a voltage source, which is independent of the power lines. 12. Power network according to claims 10 or 11, characterised in that the voltage source is a regulating machine (20,20'). 13. Power network according to claims 10 to 12, characterised in that the regulating machine (20,20') and the main machine (2,2') has a common shaft (22). 14. Power network according to claim 13, characterised in that the current converter (18') is arranged at the static parts of the main machine and connected to the rotor windings (16) of the main machine via brushes (30) and slip rings (32). 15. Power network according to claim 13, characterised in that the regulation machine (20) and the main machine (2) are brushless and in that the current converter (18) is arranged co-rotating at the shaft (22) of the rotor. 16. Method for stabilising of the voltage in a power system comprising transmitting of electric power between a power line and a rotating electrical main machine (2,2'), characterised by regulating the, by the electrical main machine (2,2') emitted/received, electric power by changing of the rotational speed of the electrical main machine. 17. Method according to claim 16, characterised in that the step of regulation comprises providing of a rotor current through rotor windings (16) at the electrical main machine (2,2'); controlling of amplitude, phase and frequency of the rotor voltage for achieving of required amplitude, phase and frequency of the voltage over stator windings (14) at the electrical main machine (2,2'). 18. Method according to claim 17, characterised in that the regulation power of the rotor winding of the main machine is provided by a regulation machine (20,20'). 19. Method according to claim 18, characterised in that a shaft of the regulation machine (20,20') is mechanically driven by a shaft (22) of the electrical main machine (2,2'). 20. Method according to any of the claims 16 to 19, characterised by sensing of current/voltage of the power line for detecting of disturbances in its amplitude, virtual value, phase or frequency; whereby the regulation takes place based on at least one of the detected disturbances. 21. Method according to claim 20, characterised by sensing of the temperature of the stator windings (14) of the main machine; whereby the regulation takes place based also on the stator temperature. 22. Method according to claim 20 or 21, characterised by sensing of the temperature of the rotor windings (16) of the main machine; whereby the regulation takes place based also on the rotor temperature. 23. Method according to claim 22, characterised in that the regulation step during a limited time gives electric powers that exceed rated power, valid for continuous operation, for the electrical main machine (2,2'). 24. Method according to any of the claims 16 to 23, characterised by transferring of control information between the stationary and rotating parts of the main machine. 25. Method according to any of the claims 16 to 24, characterised by transforming the voltage over the stator windings (14) of the main machine to a suitable network voltage.

Description

The present invention relates generally to stabilizers in energy systems and to methods of stabilization. More specifically, the invention relates to stabilizers containing rotating electrical machines, and to methods for controlling such devices.

The level of technology

Ideally, the power system should be a “bus” to which various producers and consumers of electricity can be connected at any time to supply / consume the necessary power. In practice, the power system does not meet these ideal rules, since there are restrictions on the amount of power supplied / consumed in various places and on the amount of power that can be transferred between different parts of the power system.

A power system is usually called a power supply network in which energy is transmitted through a 3-phase high-voltage AC transmission line. However, there may be DC connections between non-synchronous AC networks or internal connections between two points (nodes) on the AC network.

Often, in power systems, power limits do not depend on the thermal load capacity of the components included in the network, but are determined for reasons of stability and reliability. The system must be stable, that is, large or small perturbations in its work must be extinguished, and the system must return to a steady state. In addition, the power system must withstand the shutdown of large producers and / or consumers without causing instability or failure, leading to the failure of the power system.

In addition, the power system must operate within certain predetermined voltage limits. Some devices, such as transformers and motors, are designed to work in specified voltage ranges. The AC mains voltage is controlled by controlling the reactive power balance in this network. With a shortage of reactive power or with an unfavorable distribution of reactive power between the places of its generation and use in the network in some cases it is not possible to keep the voltage constant, and as a result there is a so-called voltage avalanche, as a result of which the network fails.

In addition to energy conversion, synchronous machines are used as synchronous compensators that are not connected to another driving machine or mechanical load and therefore do not perform any energy conversion. These machines rotate synchronously with the frequency of the power system and are able to supply / consume reactive power.

In addition, they contribute to the stability of the power system under disturbances, since the magnetization of the machine can be controlled, and the synchronous compensator increases the short-circuit power in the power system. The ability of the synchronous machine to stabilize the operation of the power system by modulating the active power is limited by the fact that this active regulated power must be generated from magnetic energy concentrated in the air gap of the machine, or from the energy of the rotating mass due to a short-term change in the rotation frequency when the load angle changes.

An asynchronous generator is an asynchronous machine in which the rotor winding is supplied through slip rings from a current transducer connected to the same power system as the stator poles of the machine. These machines are used primarily in pumping power plants. There are several advantages: among other things, the efficiency of the power plant increases, and when pumping, you can use the so-called load tracking, that is, by pumping you can adjust the power taken from the network. Such machines are operated in several places in Japan and are described in the work of Takao Ki'tagk c1. a1. Eekshppy apy yuiash1e gekropke syatas1eppkok o! 400 Μ \ ν ay) ry1 riesray for a young man and £ 11 £ from Oika 11, oo. 2, 1996, pp. 376-384. In addition, by feeding a DC inductor into the rotor, it can be used as a synchronous machine. However, it should be borne in mind that this may cause thermal overload in one of the phases if the total magnetizing current constantly passes through it.

An asynchronous generator can be used to increase the stability of the network, since with disturbances or faults in the network, it can quickly regulate the active power supplied to the network from the machine. Unlike the synchronous machine, it is possible to regulate the active and reactive power independently. Improving the sustainability of the power system increases the efficiency of network utilization, as it allows the transmission of more power. This is described in 1ai O. O) etye e1. a1. The United States of America by the United States of America Nuigo Masiyek ίη Ek1aY1kyyy YEGCogkk, Rgos. o £ nuytoro ^ et w! o Fe iH! Seišu - III (Nuytoro ^ et '99), Otypiep, Aikyta, 1999, pp. 559-567. Another advantage of asynchronous generators is that the operating power of the current transducer is small compared to the total operating power of the machine and usually at operating power plants is 15-30%.

The problem with the use of modern asynchronous generators is that when disturbances occur in the operation of the power system, the frequency converter connected to the power system will be quickly disconnected. Therefore, the machine is sensitive to failures in the power system. This is especially true when the part of the converter that is connected to the power system requires reactive power for switching, especially when the converter is a down converter, where the power in the network must also be highly symmetrical for the phases. In US patent No. 4812730 and 4870339 described various ways of controlled stabilization of alternating voltage in the stator of the machine in case of emergency disconnection of the corresponding power system. It is absolutely necessary to preserve the magnetization of the machine so that it can be correctly phased when the supply voltage is restored from the power system.

The term "flexible AC transmission systems" refers to several different power electronics nodes that are used to regulate the flow of energy and the distribution of voltage in a power system. The definition given by the Institute of Electrical and Electronics Engineers (ΙΕΕΕ) states that flexible AC transmission systems are "AC transmission systems that include electronic-based power regulators and other static regulators designed to increase controllability and increase energy throughput."

Simplified, components of flexible AC transmission systems can be described as devices that in most cases contain powerful electronic valve elements (thyristors and transistors) designed to quickly and accurately change the voltage, current, impedance and / or phase angle at the connection points ( nodes) with which this component is connected, or between them. Since the introduction of these components allows you to control the flow of energy, they can be used to increase the capacity of the energy system between different areas or points. In addition, the introduction of such components can reduce energy losses during transmission in the transmission system due to a better distribution of energy flow between the various transmission paths.

Components of flexible AC transmission systems can be connected to the power system using parallel connections, serial connections, or a combined series-parallel connection.

Parallel-connected units are mainly used for input / output of reactive power, and the components of power electronics are used to quickly regulate the input / output of reactive power. One example is a static reactive power compensator, which consists of parallel-connected reactors (coils) and capacitors, where power electronics are used to control the generation / consumption of reactive power in a unit. This is usually accomplished by controlling the amount of current through the reactors. If full controllability is desired, that is, at ± 100% of power, in a static reactive power compensator unit, then the power electronics nodes should be designed for the total reactive power of the unit. However, a static reactive power compensator creates harmonics, and therefore filtering is necessary. In addition, the ability of a static reactive power compensator to inject reactive current into a power system decreases with decreasing voltage, that is, when the need is often maximum. However, the “static synchronous compensator” (8TATSOM) does not have this drawback, since parallel-connected capacitors and reactors are not part of the reactive power generation / consumption circuit. Reactive power is generated directly in the power electronic valve elements, and in fact the unit operates as a synchronous compensator with no rotating mass and with controlled and limited short-circuit power. However, all reactive power must pass through the current converter, so the latter must be designed for full power.

The serially used elements used in power transmission consist mainly of capacitors and are mainly used to compensate for the line reactance, thus reducing its “electrical length”. A series-connected capacitor introduces a voltage that is shifted in phase by 90 ° relative to the current in the line. The amplitude of the applied voltage can be controlled, for example, using a series capacitor controlled by a thyristor.

The universal energy flow regulator consists of two current transducers, one of which is connected in series, and the other parallel to the transmission system. Therefore, a universal energy flow regulator can regulate reactive power, which can be entered in parallel with the power line, as well as an adjustable voltage, which can be entered sequentially, as a result of which both amplitude and voltage phase can be controlled. Thus, the universal energy flow regulator can simultaneously and independently control both active and reactive energy flow in the transmission line and, therefore, combines the functions of power control and voltage regulation. The universal energy flow regulator is a flexible tool for managing energy flows, but requires, however, the use of circuits with expensive current transducers.

Flexible AC transmission systems are very dynamic, which allows them to be used to improve the dynamic characteristics of the power system. In addition, they are able to compensate for the asymmetry that occurs during operation, for example, when the voltage of different phases is different. A brief overview of the various components of flexible AC transmission systems and their use, as well as the level of modern technology is given in the article by K. Ogypit C1. a1. GAST8 - ro \\ sgGi1 kuk1s 1115 ίο g Deh111 ro \ ssg Ιπιηκιηίκκίοη. ABB KeU1e ^, Νο. 5.1999, pp. 4-17.

For all components of flexible AC transmission systems, it is generally true that they traditionally contain no energy storage device worth mentioning. The energy stored in capacitors and reactors is very limited compared to the operating capacity of the unit, and therefore these elements cannot contribute or take active power from the grid. This can be realized, for example, by connecting the energy source to a static synchronous compensator on the side of the DC terminals. At existing experimental power plants, either batteries (energy storage battery — BE8) or superconducting coils (superconducting magnetic energy storage — 8ME8) are used as energy storage devices. In article Υ. Myash e1. a1. Arryssayop ο £ 8uregbis 11th Madie! Epegdu Georges шο 1шргое Ро \ усг 8ук1еш Эупат1с РегЮттапсе, 1ЕЕЕ Тгпкас1юп5 іп Ρο \\ όγ 8у51етк, νοί. 3, Νο. 4, Szetzieg 1988, pp. 1418-1425, it is shown how such an element can be used to increase the stability of a power system. The drawbacks of both the battery energy storage device and the superconducting magnetic energy storage device are that the current converter must be designed for full power, and the energy storage devices are expensive, and that some types of batteries contain heavy metals and other materials that are harmful to the environment. .

To achieve the desired result, the placement of various types of compensators in the power system is very important. For good performance when stabilizing electromechanical oscillations, parallel-type reactive compensators should be placed between generators or groups of generators, for example, at an equal electrical distance between these two generators (or groups of generators). However, in order to improve the balance of reactive power in the power system, these units should be placed close to or within areas of high load. To achieve stabilization, parallel-connected units that are capable of regulating active power, for example, an asynchronous generator, should be installed close to other power generators.

For all power electronic converters, it is usually true that their overload capacity is limited by short “thermal” time constants. For example, a current converter can withstand overload for only a very short time. Therefore, the current converter must be rated for the maximum current and voltage load.

The power grid, much of which is related to the energy of non-thermal stations, such as hydroelectric power stations or wind power stations, may experience large seasonal or daily changes in energy flow. Thus, there is a need for stabilizers that can compensate for reactive and / or active power and, thus, be used in various operating conditions that occur in the power system.

A specific embodiment of the rotating electrical machine, where the high-voltage stator winding is made on the basis of a cable, is described in the application GSO 97/45919. In this case, there is no need to use any transformer to connect to the high-voltage network. Machines with a stator winding of this type are characterized by the fact that the current density in the stator conductors is very low and cooling essentially takes place over the stator packet, at ground potential. With a suitable choice of area and / or protection of the rotor windings, such a machine can generate very high reactive power for some time - for tens of minutes or even several hours. The protection design, where the rotor temperature is limited by a relay permanently installed in the device, is described in the GSO 98/34312 application.

A common problem with known stabilizers is the difficulty of creating sufficient reserves of energy. The cost and complexity of the design of high-capacity stabilizers are very high, so they often prefer to use smaller stabilizers, and in the event of a serious emergency, turn off parts of the power system. Another common problem of the known stabilizers is the impossibility of their flexible use to compensate for both reactive and active power.

Summary of Invention

Thus, the general aim of the present invention is to create such stabilizers for energy systems that are capable of greater energy storage. Another common goal of the present invention is to create stabilizers that are smaller, simpler, and more versatile than known stabilizers.

The above objectives are achieved using the devices and methods set forth in the claims. In general terms, the invention relates to a rotating stabilizer for an energy system, comprising a main machine in the form of an asynchronous machine with a phase rotor. To change the amount of stored energy, the rotor speed can be changed. The stabilizer for the energy system is characterized in that the stator of the main machine is connected to the power system, the rotor winding of the main machine is connected to the current converter, and the current converter takes the active power from the voltage source, which is preferably independent of the power system. Preferably, the voltage source is formed by a rotating electrical regulating machine having a common shaft with an asynchronous machine. The current transducer is designed to control and adjust the generated / consumed reactive power of the main machine. A current transducer regulates the current in the rotor winding, thereby controlling the magnetization and power conversion in the machine. Preferably, the current transducer is mounted on a common shaft of the main machine and the regulating machine.

To increase the energy storage capacity of the rotor, the shaft of the stabilizer of the energy system can be connected with a flywheel. The stabilizer of the energy system, first of all, must ensure the damping of oscillations in electrical networks during and after disturbances and, thus, increase the dynamic stability of the system, and therefore it is actively functioning only for short periods of time. The stabilizer of the energy system, made in accordance with the present invention, may experience an overload for precisely such small periods of time, therefore it is possible to keep its nominal power, and hence the cost, low. Using direct temperature control in the stator and / or rotor windings, it is possible to temporarily overload the main electric machine when transmitting large powers, which significantly exceed the rated power, without risk of causing any damage in the machine.

The stabilizer of the energy system can be used in several ways. It can be used as a parallel-connected element of the power system, where, during disturbances and in emergency situations in the power system, it stabilizes by supplying / consuming active and reactive power. The selection / supply of active power is carried out by changing the rotational speed of the rotor of the machine, in which the mechanical energy is accumulated due to the moment of inertia of the rotor. In normal operation, the rotating stabilizer of the energy system can compensate for reactive power, in which case it acts mainly as a rotating synchronous compensator. In addition, the stabilizer of the energy system can be used as a power converter; In this case, the machine, in addition to the functions described above, converts mechanical energy into electrical or electrical energy into mechanical energy by connecting the shaft of the power stabilizer with a turbine or mechanical load, respectively.

Usually the stabilizer of the energy system rotates close to the synchronous frequency of rotation. Thus, the active electrical power that flows from the current transducer to the rotor winding / from the rotor winding is only a small part of the active electrical power that the power system stabilizer supplies / receives from the power system. Therefore, a rotating asynchronous machine forms an active power amplifier for a current transducer associated with the rotor of the machine.

In addition, the invention relates to a method for stabilizing an energy system, including as basic operations the transmission of electrical power between a power line and a main rotating machine and the adjustment of this electrical power by changing the rotational speed of the main machine.

The device and method of the present invention have many advantages. Rotating stabilizer, in contrast to static compensators, has a large energy storage device in the form of a rotating shaft, and this storage device can be used for short-term reception and supply of active power to ensure the attenuation of power fluctuations in the power system. With a brief overload of the machine, its parameters can be significantly better. Energy storage can be improved by using a flywheel, which, however, leads to an increase in cost. In contrast to the known rotating compensators, the proposed rotating stabilizer can compensate when an asymmetry occurs (negative sequence system). When used as a reactive compensator of a parallel type, the machine can withstand a significant overload of reactive power within a limited time, for example, 5-60 minutes, and the allowable limits of variation of the insulation temperature can be used to control by measuring the temperature of the rotor and / or stator windings. In addition, a machine with a high-voltage cable winding is characterized by a higher thermal time constant, i.e. the period of time when the machine is not in thermal equilibrium increases. During this period, the load can be further increased. The ability to withstand overload leads to the fact that the rated power of the machine can be reduced. The internal emf of a rotating stabilizer can, in principle, be controlled even in case of power failures, as long as the regulating machine can supply energy to the current converter. Thus, the machine can be controlled input of active and / or reactive power during short-term failures in the power system. Thus, the machine is characterized by a controlled short-circuit power. The rotor winding design may provide for frequency-dependent resistance in order to increase the ability of the machine to withstand large disturbances in the network. For example, unlike static compensators, a machine can be used at a power station as a combined transducer and compensator for damping vibrations associated with both electrical networks and water flows.

Brief Description of the Drawings

Other objects and advantages of the invention will be better understood from the following description with reference to the accompanying drawings, where FIG. 1a schematically illustrates an energy system stabilizer made in accordance with the present invention and comprising a transformer, but without connection with a driving machine or load;

in fig. 1b schematically illustrates an energy system stabilizer made in accordance with the present invention and containing high-voltage cable windings, but without connection to a driving machine or load;

in fig. 2a schematically illustrates an energy system stabilizer made in accordance with the present invention, comprising a transformer and connected to a driving machine or load;

in fig. 2b schematically illustrates an energy system stabilizer made in accordance with the present invention, comprising high-voltage cable windings and connected to a driving machine or load;

in fig. 3 schematically illustrates a first embodiment of a stabilizer according to the present invention comprising a brushless host machine;

in fig. 4 schematically illustrates a first embodiment of a stabilizer according to the present invention comprising a main machine with brushes;

in fig. 5a shows the equivalent circuit of one phase of the main machine shown in FIG. 3;

in fig. 5b shows the converted equivalent circuit corresponding to the circuit shown in FIG. 5a;

in fig. 6 shows a vector diagram of the operating situation when a stabilizer made in accordance with the present invention operates as a synchronous compensator in a stationary mode;

in fig. 7 shows the position of the stator flow relative to the winding axes of the stator and rotor windings;

in fig. 8 shows a block diagram of the stabilizer control in a stator-oriented system in which the current converter is connected to the rotor of the main machine;

in fig. 9a is a graph of power fluctuations between a power system stabilizer made in accordance with the present invention and a power system;

in fig. 9B is a plot of rotational frequency deviations occurring in a stabilizer made in accordance with the present invention with power fluctuations shown in FIG. 9a;

in fig. 10 shows a graph of non-periodic power fluctuations between the stabilizer of the energy system, made in accordance with the present invention, and the power system;

in fig. 11 schematically illustrates a power system with a single power generation site and a single load site;

FIG. 12 schematically illustrates a power system with two sections of electricity generation and one load section, where the stabilizer is connected to one of the electricity generation sections;

in fig. 13 schematically illustrates a power system with two sections of electricity production and one load section, where the stabilizer of the energy system is connected to the load section;

in fig. 14 shows how the voltage and power stabilization system shown in FIG. 8 may be extended to perform active and reactive power control; and in FIG. 15 shows the sequence of operations for the stabilization method according to the present invention.

Detailed description

As mentioned above, the preferred embodiment of the invention is a stabilizer for an energy system, made in the form of a rotating electric machine (main machine), where the stator winding is connected in parallel to the energy system. The rotor winding is a multi-phase AC winding, powered by a current transducer. In addition, the current transducer is connected to another rotating machine (regulating machine) mounted on the same shaft with the main machine.

First, it will be briefly described how the stabilizer is connected to the power grid and what powers can be controlled to stabilize the power grid. The following describes the energy-carrying parts of the rotating stabilizer, that is, the stator and rotor of the main machine and the regulating machine, as well as a current transducer that is connected between the regulating machine and the rotor winding of the main machine. Then, the stabilizer control methods and control methods of its operation and their implementation using sensors and digital control units installed in the rotor and / or the stator of the machine are described. In conclusion, the methods for actuating the stabilizer and using it in the power system are described in more detail.

AC machines are usually designed to convert power, that is, they work either as motors or as generators. In these cases, the shaft of the machine is associated with a mechanical load or a driving machine.

As shown in FIG. 1a according to the first embodiment of the present invention, the main machine of an energy system stabilizer is, in principle, an asynchronous machine 2, in which the stator winding is a 3-phase alternating current winding connected to the power system 1 via a transformer 3 and connecting means 4. FIG. 1a, the main machine is not connected to any driving machine (“primary engine”) or mechanical load, and, consequently, its possible exchange of power with the power system consists of the following components.

A: The stabilizer can, in a stationary mode, supply reactive power to the grid or consume it from the grid. This value can quickly change from a stationary value 01 to a new stationary value 02. The maximum power is determined by the stationary thermal limitations for the main machine.

AO: This value reflects the possibility of a stabilizer under conditions of disturbance in operation or failure for a limited time to supply / absorb reactive power, which may exceed the stationary value allowed by thermal limitations. This is discussed in more detail below.

AR: This value reflects the ability of the machine for a limited time to supply / absorb active power, which differs from the power on the shaft, by changing the shaft rotation frequency. In this case, the energy can be taken from the rotating mass by reducing the rotational speed or added to the rotating mass by increasing the rotational speed. This is discussed in more detail below.

In the embodiment of the invention shown in FIG. 1b, the main machine of an energy system stabilizer is an asynchronous machine 2 ', in which the stator winding is a winding of a high-voltage cable. In this case, the winding through the connecting means 4 is directly connected to the power grid, without using a transition transformer. FIG. 1b the main machine is also not connected with any driving machine ("prime mover") or with mechanical load, and therefore its possible energy exchange with the power system is similar to that described above in connection with FIG. 1a

As shown in FIG. 2a, the stabilizer may be connected to a load or a driving machine 5. A driving machine supplies mechanical energy to the shaft (“prime mover”). On the contrary, the mechanical load takes the mechanical energy from the shaft of the stabilizer. The driving machine may be, for example, a turbine (water, steam or gas turbine), an internal combustion engine (a piston engine or a Stirling engine) or an electric engine. The mechanical load may be a pump, an electric generator or a brake. If such a machine is connected to the stabilizer shaft, it is able, separately from the previously mentioned quantities, to permanently supply or receive active power from the power system, that is, to operate as a generator or engine.

FIG. 2b shows an asynchronous machine with a high-voltage cable winding associated with a load or a driving machine 5. This design, like the one described above, makes it possible to supply active power to the power system or to consume this power from it.

FIG. 3 shows one embodiment of an energy system stabilizer according to the present invention. Here, the main machine 2 is an asynchronous machine with a phase rotor 10. The stator 12 of the main machine has a 3-phase winding 14 connected via a transformer 3 to the power grid. In principle, the rotor winding 16 may have several phases: two or more. The synchronous rotation frequency, which is set by the 3-phase winding 14 in the stator 12, is determined by the frequency of the power system and the number of poles of the winding 14. The rotational speed of the rotor 10 can vary relative to this frequency when alternating current flows in the winding 16 of the rotor of the main machine 2. This current is supplied from the converter 18 current. The frequency of this current is determined by the difference between the synchronous frequency of rotation and the frequency of rotation of the rotor, as well as the number of poles in the machine. The regulating machine 20 is mounted on the same common shaft 22. In this example, the regulating machine 20 is a synchronous machine in which the armature winding 24 is located in the rotor 26. Therefore, the current converter 18 rotating in the same direction can transfer energy between the rotor 26 of the regulating machine and the rotor 10 of the main machine. When the main machine 2 rotates at a synchronous speed, all the electricity in the stator is converted into mechanical energy in the rotor (if losses are neglected). Therefore, in this case no active electrical power is supplied to the rotor winding 16. When the machine 2 rotates asynchronously, some of the power of the stator 12 due to induction associated with a change in the rotational speed will be transferred from the winding 16 of the rotor. Therefore, this electrical energy must be supplied to the winding 16 of the rotor from the current converter 18. Thus, the current converter 18 provides for magnetization of the main machine 2 and supply / receipt of regulating power (active power) to the winding / from the rotor winding 16 to the main machine 2 / from the main machine 2. The task of the regulating machine 20 is to function as a voltage source for the current converter 18 to magnetize the host machine 2 and convert the regulating energy into mechanical energy on the common shaft 22; while it alternately works as an engine or generator. In a preferred embodiment of the present invention, the regulating machine 20 acts as a synchronous machine. The regulating machine 20 may have a different number of poles than the main machine 2, so that the frequency in it may be higher. The regulating machine 20 provides DC power to the excitation windings 34 in the stator 28. In normal operation, they are powered through a rectifier 42 connected to the same three-phase lines as the stator windings 14 of the main machine through a transformer 44. When the voltage drops in the power system, which is connected, or when other interruptions in the operation of the power system, the excitation winding of the regulating machine can be powered by the backup battery 65 or the regulating machine can have permanent magnets. In the first case, the converter will perform the role of uninterruptible power supply (LRZ).

FIG. 5a shows the equivalent circuit of a single phase of the main machine. In this example, the active resistance of the rotor and stator windings is neglected. X _m denotes the magnetization reactance, X _ъ - the leakage reactance of the stator winding and X |, 1 <- the leakage reactance of the rotor winding. 1 _m indicates the magnetizing current, 1 _h current through the stator windings and 1 _{to the} current through the rotor windings, 8 indicates the rotor slip relative to the synchronous frequency of rotation of the stator flow. The stator is shown as a generator and the rotor as an engine.

In normal mode, the stabilizer of the energy system rotates at a frequency that is close to synchronous. From the equivalent circuit it can be seen that the voltage in the rotor winding is small, since the slip 8 is very small. If the stabilizer is driven into rotation with a frequency lying within the frequency range, for example ± 10% of synchronous, the fraction of active power that must be fed to the winding 16 of the rotor will not exceed 10% of the power of the main machine. This means that the power supplied to the current converter is small relative to the total power of the main machine (and thus the stabilizer). In addition, the current transducer should provide magnetization of the main machine of the stabilizer, which means that the power of the current transducer should be slightly higher. Therefore, the power of the regulating machine is determined by the maximum control power and the required reactive power of the current converter.

FIG. 4 shows an alternative embodiment of the present invention. Basically, it is similar to the previously described embodiment, so the description of the common parts is omitted. In this embodiment, the armature winding 24 'of the regulating machine 20' is located in the stator 28. The current converter 18 'is stationary and is connected to the rotor winding 16 of the main machine 2 by means of brushes 30 and slip rings 32. Accordingly, the excitation winding 36 of the regulating machine 20 is located in the rotor 26 and receives current from the rectifier via brushes 38 and slip rings 40.

FIG. 5b shows a converted equivalent circuit diagram of an asynchronous machine with wound rotor, wherein X _m denotes the resistance of the magnetization, X _z - leakage resistance and the stator winding _and X _<- leakage resistance of the rotor winding. Their sum is the reactance of the stator winding and X denotes _A. The amplitude and phase of the current C of the rotor refers to the stator side of the machine.

FIG. 6 shows a vector diagram of the operating situation when the stabilizer functions as a synchronous compensator in the stationary mode. No mechanical driving machines or loads are connected to the shaft. In this case, the limit of the maximum delivered stationary reactive power is usually determined by the heat load in the rotor. Therefore, the main dimensions of the machine are usually determined by the need to create the necessary magnetomotive force in the rotor.

If the stabilizer works as a reactive power compensator, the expression for the rotor current can be obtained from FIG. 5b:

^I γ of ^'l m ^l m

From this expression it follows that the need for magnetization (rotor current of 1 _K ) is the smaller, the greater the resistance X _{m of} magnetization. On this basis, the machine must have a high magnetization resistance with a small stator reactance. It is clear that, compared with the known synchronous compensator, made on the basis of a known synchronous machine, the need for a magnetomotive force becomes less than is usually required in a known synchronous machine. Among other things, it depends on the requirements for stability in case of disturbances in the power system. Since the current converter 18 connected to the rotor winding 16 can control the rotor current in amplitude and phase, the flow through the rotor and stator in such a machine will not become asynchronous. Therefore, in such a machine, no synchronization loss occurs, as in a known synchronous machine, and stability requirements can be reduced, thus reducing the need for a magnetomotive force in the rotor compared to the known synchronous compensator. This means that the stabilizer for compensating reactive power in stationary mode can be made smaller in comparison with the known synchronous machine. This follows from the fact that it is the rotor that determines the size of the machine, and the losses in the rotor can be reduced by reducing the current density in the rotor winding.

Malfunctions in the power system, such as a short circuit or a ground fault, usually lead to a malfunction of the power system. In the event of a fault, the currents in the power system increase, and the voltages drop. The greatest changes occur near the location of the fault. During such a failure, the torque balance in the synchronous machines changes in the energy system, since the moment of the electrical load changes, while the mechanical moment remains approximately unchanged. Transients in the power system are very complex, so, for example, it may be desirable, while the malfunction persists, to supply reactive power to the network in order to maintain the best balance of torque. In other cases, this is undesirable because the currents in the location of the fault will become too large. In this case, it is possible, on the contrary, to require the limitation of both active and reactive power (current) supplied to the fault site. Since the current converter 18 shown in FIG. 3, powered by the regulating machine 20, the fault will not affect the current supply to the current converter 18. Therefore, the current converter 18 can, while the fault condition in the power system continues, supply the rotor winding 16 with the desired current and voltage. Thus, if the fault condition continues, the input reactive power from the stabilizer can be controlled.

As mentioned above, in a known asynchronous generator, if the voltage in the power system is too high and / or if the asymmetry is too large, the current converter will shut down. On the contrary, in a stabilizer made in accordance with the invention, the short-circuit power is controlled during the entire time the fault is maintained. In addition, in the well-known synchronous compensator, you can only control the short-circuit current, after which the transition process will come to an end. In addition, the dynamics of the synchronous machine control is limited due to the large time constant of the excitation winding. The combination of the voltage of the excitation winding and the internal voltage of the machine can be considered as a first-order system with a characteristic time constant. This time constant is the transient reactance of the machine when the stator poles are open and is essentially determined by the excitation winding. In the literature, it is referred to as T ' _a0 . For large synchronous machines, its value is 1-8 s. Since the main machine in a rotating stabilizer is an asynchronous machine, the rotor winding is an alternating current winding, unlike a synchronous machine. It has a greater time constant and, in addition to changing the amplitude of the current, allows for a change in its phase.

To further increase the stability of the stabilizer to faults and to increase its damping capacity, the rotor winding 16 can be designed so that its internal resistance increases with the frequency of the current. This is achieved by using a leakage flow in the rotor to create a current bias, that is, the current in the rotor winding 16 is not evenly distributed over its cross section, but is concentrated from the part of the winding 16 that is located closer to the air gap in the machine. This effect grows with frequency.

Usually the line where there is a fault is disconnected. If the rotating stabilizer was connected to the power line that was disconnected, then it will no longer be connected to the power grid. As a rule, the power management system attempts to perform a fast switch, in which the line is first disconnected. Therefore, it is important that the stabilizer be able to behave similarly to a conventional synchronous generator, that is, it could be connected back to the network in phase mode. The stabilizer according to the present invention has its own separate power system in the rotor, including the rotor winding 16 in the main machine 2, the current converter 18 and the regulating machine 20. Since the regulating machine 20 does not lose magnetization, when the external power system is disconnected, the kinetic energy of the rotating parts can be used for magnetizing the system and supplying power directly to the rotor of the main machine. Magnetisation of the regulating machine does not require high power, and, as noted earlier, it can be secured by supplying energy from the backup battery 65 or using a regulating machine 20 with permanent magnets. Even if the external power system is turned off for some time (in the worst case, by a few minutes), the voltage in the master machine 2 of the stabilizer can be adjusted for such a frequency and phase correction so that the automatic connection can be made. When it is detected that a disconnection has occurred, it is possible to make the stabilizer control system (described in detail below) produce the reference value of the stator flux, for example, so that the stabilizer rotates at the same speed as before the fault.

FIG. 6 that when the stabilizer works as a compensator near its nominal power, an increase in the active power of the DR or the reactive power of the DL can easily lead to an overload of the machine. Currently, the nominal capacity is usually set according to the recommendations of the manufacturer, possibly with some margin. In addition, manufacturers' recommendations usually refer to stationary situations where it is assumed that the ambient temperature, etc., is higher than normal. In addition, manufacturers themselves usually provide recommendations with some margin. Thus, at present, for most electric machines and transformers, there are usually some thermal boundaries within which an electrical machine can be overloaded, at least temporarily. In order to prevent the main machine from breaking down in such a situation, the temperature in the rotor and / or stator windings can be monitored during operation using temperature sensors. FIG. 3, the main machine has a temperature sensor 60 mounted in the rotor winding 16 and a temperature sensor 64 mounted in the stator winding. Similarly, in the machine shown in FIG. 4, there are also temperature sensors 60, 64. This allows for a limited period of time to operate outside the nominal parameters of the machine, as shown in FIG. 6

This means that, compared with the known parallel type compensators, the ability of the proposed stabilizer to supply / consume reactive power in a short time can be effective, but cheaply increased far beyond the rated power of the stabilizer. In a static reactive power compensator, this is impossible, and the entire structure must be designed for peak power. Therefore, overloading is unacceptable. In a static synchronous compensator, the full reactive power must be supplied via an electronic energy converter. It allows only minor overloads. This means that the entire structure must be designed for peak power. On the contrary, in the stabilizer for an energy system made in accordance with the present invention, only the frequency converter should be designed for increased rotor power. Since the total power of this converter is low compared to the full power of the stabilizer, the costs are significantly reduced.

In addition, the stabilizer is capable of supplying active power to the grid or consuming active power from it. This can be done by changing the frequency of rotation of the stabilizer and / or in the presence of a driving machine / mechanical load connected to the stabilizer. First, we describe an embodiment of the invention in which the machine does not contain a driving machine or a mechanical load connected to the shaft, which corresponds to the systems shown in FIG. 1a and 1b.

The energy stored in the rotating parts of the stabilizer is mainly determined by the moment of inertia and rotational speed. For electric cars, it is often expressed in terms of the time constant H for the inertia of the machine:

wherein 1 - the moment of inertia of the machine, ω ₀ - nominal frequency of mechanical rotation (rad / s) and δ _Ν - power machine. Then N corresponds to the amount of energy stored in rotating parts at the nominal speed of rotation, relative to the power of the machine. For large electric cars, typical values of this value are 2-8 s.

FIG. 9a is a graph of the output power P of an energy system stabilizer. The power varies between P ₀ and -P ₀ , but the average power is zero. When the power oscillates sinusoidally, as shown in FIG. 9a, converted energy A! during one half period is equal to (2 / n) RT, where P is the maximum active power, and T is the oscillation period. During the next half period, the same energy A ₂ will be converted again, but now in the opposite direction. The rotational speed of this process will vary, as shown in FIG. 9b. The typical period of energy oscillations caused by oscillations on the pole ring, depending on the speed of oscillation of the frequency of rotation of synchronous machines is 0.5-2 s. Then for the sinusoidal power changes shown in FIG. 9a, the amount of required stored energy is between 0.32P and 1.3P. In articles Υ. Myash c1. a1. ArrNsayoi Got 8irresoi Bisyid Madie! Heyhdu 81tade Yu 1shrtoue Po \ teg §u81esh Puiash1s RegGogshaise. 1ЕЕЕ Ттаизасйоик ои Ро \ tag §у81еш8, Wo1. 3, oo. 4, Aug. 1998, pp. 1418-1425, and I. Cashea e1. a1. Acoue-Ro / Ueg 81aShkheg5 Gog MiShshasYie Ro \ Zuyep Tag: SyaNeideh aiB RtkresB, 1EEE Ttaikasjoik oi Ro \ Teg Zuietk, Wo1. 13, oo. 4, Looper 1998, considers the amount of energy that needs to be stored depending on the power of the stabilizer. It is shown that even with the accumulation of energy E <P, where E is the stored energy measured in joules, and P is the power measured in watts, it is possible to ensure sufficient attenuation of oscillations in the power system. Now suppose that the rotation frequency variations are ± 10% of the synchronous rotation frequency. This means that approximately 20% of the rotational energy can be used to stabilize; those. in this example, the constant inertia H must be in the order of magnitude 1.6-6.5 s. If the stabilizer does not have enough natural moment of inertia, it can be increased in a cost-effective way using flywheels in the stabilizer. This is schematically shown in FIG. 3 position 72. The most effective such a tool for high-speed rotating machines, because at higher speeds you can accumulate more energy in the flywheel of the same size. As we know from the article Kashga e1. a1. Barde-8caile Asyue-Loab MoBiyoioi Gog Aidlee 81aYiuyu 1trouteyiG, 1EEEE Tgaikasioiz oi Ro \ tag 8u51et5, Wo1. 14, oo. 2, Maw 1999, pp. 582590, it is usually necessary to modulate active power by only 5%. This means that a power of 1000 MW in a transmission line can be stabilized by modulating a power of 50 MW. Thus, the rotating stabilizer provides a cost-effective energy storage device with a capacity of E, which is close to P in order of magnitude, and considering that the stabilizer made in accordance with the present invention can withstand considerable overload, it is clear how much more stabilizer is compared to its nominal electric power. . Only the current transducer connected to the rotor windings of the main machine should be designed for increased power, but the power of this converter is only a small part of the stabilizer power.

For cases where the oscillation frequency is so low that the need for power control becomes large compared to the power itself, mechanical loads can be used. FIG. 4, a brake 70 is mounted on the rotor shaft 22. This brake 70 can be used to absorb too high rotational energies. This further enhances the flexibility of the stabilizer, allowing the average power output from the power system to be non-zero and, if necessary, allowing to get rid of excess energy using the brake 70. If necessary, the brake 70 can be equipped with cooling devices that allow the brake 70 to be used constantly for a few minutes.

FIG. 10 shows another time dependence for the active power P released from the stabilizer of the energy system. Power varies non-periodically, but each time this power is controlled according to needs. The frequency of rotation of the stabilizer of the energy system also varies non-periodically as a result of the presence of energy flows. Similar to the situation discussed above, the integral of the power curve corresponds to the energy that is supplied to the energy system. As long as this integral remains less than the allowed variation in the rotational speed of the stabilizer, energy must neither flow into or out of the stabilizer. However, if the power fluctuations are too large, it is necessary that the driving machine or the load is connected to the stabilizer shaft, changing its rotational frequency within small limits.

FIG. 3 also shows the main parts of the control and monitoring systems. The stationary control unit 48 is designed to supply control signals through the control connection 52 to the rectifier 42. The rectifier 42 supplies the appropriate magnetizing current to the excitation winding 34 of the regulating machine. Similarly, the rotating control unit 46, which rotates together with the common shaft 22 and, thus, with the rotor 10 of the main machine, is designed to supply the appropriate control signals through the control connection 66 to the current converter 18. Thus, the current converter 18 supplies to the rotor winding 16 of the main machine a current of the corresponding phase, amplitude and frequency. The following describes in detail how this control is performed. The rotating control unit 46 further comprises communication means 54 for wirelessly communicating with the communication means 54 in the fixed control unit 48. Thus, control blocks 46 and 48 can exchange information. Both control blocks 46, 48 comprise processor devices 47, 49 for processing signals and data.

Rotating together with the rotor control unit 46 is connected to a temperature sensor 60, from where it receives data on the temperature of the rotor winding. In addition, there is a sensor 58 for measuring the current / voltage in the rotor winding of the main machine and a sensor 62 for measuring the current / voltage in the winding of the regulating machine, which are connected to the control unit 46 and monitor the current and / or voltage in the rotor windings 16 and the current and / or voltage between the regulating machine 20 and the current converter, respectively.

Similarly, the fixed control unit 48 is connected to a temperature sensor 64 for measuring the temperature of the stator winding. In addition, the sensor 50 is connected to the control unit 48 for measuring the current and / or voltage in the stator 12 of the main machine. Having information about the parameters of the transformer 3, this sensor 50 indirectly perceives the state of the power system. Alternatively, the sensor 51 may be installed on the power system side with respect to the transformer 3, i.e., the power station where the stabilizer is installed, for direct measurements anywhere in this power station. However, due to high voltages, this usually requires more expensive technical solutions. Thus, sensor 50 or sensor 51 can detect disturbances in the power system, for example, associated with rms phase and / or voltage amplitudes and / or rms phase and / or current amplitudes and their frequencies.

In this way, data on electrical and thermal parameters can be obtained, and this data is transmitted between control units 46, 48, preferably via wireless communication. Therefore, the required operational information can be received into the rotating control unit 46, on the basis of which the rotor current is controlled in the usual way by means of the current converter 18.

FIG. 4 shows the corresponding control blocks 46, 48. Here, the rotating control unit 46 is mainly responsible for collecting data from the temperature sensor 60 and the sensor 58. This data is processed in the processor unit 47 and transmitted wirelessly to the fixed control unit 48. The fixed control unit 48 is responsible for controlling both the rectifier 42 and the current converter 18 ′.

Thus, the stabilizer in FIG. 3 contains an integrated control and monitoring system that includes a stationary 49 and 47 rotating digital processors with brushless digital communication elements 54, 56 and sensors 50, 51, 58, 60, 62, 64 for measuring and monitoring current parameters. Processors 47 typically operate as a master / slave system, with the slave processor 47 being the slave. Essentially, the stationary processor 49 controls the power conversion, measurement and control of quantities related to the stator 12 of the electric machine, and communicates with other external control and monitoring systems . The main task of the rotating processor 47 is to control the current converter 18 by controlling the rotation of the shaft of the electric machine, as well as measuring and controlling values related to the rotor 10 of the machine.

Rotating processor 47 is programmed so that with repeated and serious violations in the means 54, 56 wireless digital communication, he is able for some time to control and monitor the operation of the stabilizer autonomously.

The host machine can be controlled according to the same rules that are commonly used for asynchronous generators. The stabilization method can be based on the so-called α-β-transformation, in which the system of equations of the machine dynamics and physical currents and voltages in the rotor and stator is converted to a system consisting of fictitious rotor and stator windings, oriented in some way relative to the flow in the stator. It can be shown that one component of the rotor current controls the torque and thus the active power P, while the other component controls the pole voltage of the stator and, thus, the reactive power O. The structure of such a regulator is shown in FIG. 8, where 91 is the voltage regulator or reactive power regulator, and 92 is the active power regulator. The current regulator is indicated at 90. Stress and _{hypertension,} and _{br, c,} and served on the transmitter modulator. A more detailed description is available in the work of 1Ai O. C) egbe c1. a1. Sopzez. Iepsez about £ 1p! Gobistd Absolute Single Reboob Nubgo (A8H) η EDYYANsb Ro \ usg ΝοΙ \ uogkz, Proc. о £ Р8СС'99, Wo1. 1, pp. 150-156, №g \ ueshap υηίν. £ og Tkkpo1odu apb 8s1epse, Tgopbkepp. 1999. When the stabilizer is connected to the turbine and works as a generator, the rotational speed is controlled by a turbine having its own control system. Examples of such a configuration are given in the work of T. Ki \ uabaga eE a1. Esschp about the buzpayu gesropze eGastelezbzzz about £ 400 M \ u at the most important of all the rytreb from the igogada ish1 £ og oeka ^ asy ros ue 81abop, ΙΕΕΕ Tgapszyyopz o Epegda Co ^ ezüp, Uo1. 11, Νο. 2, 1996, pp. 376-384.

The on and off times for a current transducer connected to the rotor can be calculated as shown in FIG. 7. The flow position (( ₈ ) of the stator relative to the windings υ _{3 of the} stator can be found in several ways, for example, by installing sensors in the air gap of the machine or by integrating the measured stator voltage. Integration of the measured rotational speed allows determining the position υ of the rotor relative to the stator. Thus, it is possible to calculate υ _Γ and the components α and β of the rotor current can be converted into real phase currents in the rotor. The rotational speed of the machine can, for example, be measured / calculated by integrating the voltage on the regulating machine.

Measuring voltage in a high-voltage device is expensive because it requires measurement equipment that is connected to high-voltage conductors and, therefore, must be isolated to protect against high-voltage voltages. For electric machines with high-voltage stator windings, it is too expensive to equip the machine with own voltage transformers for measuring voltage at the poles, while current measurement is cheaper because it does not require galvanic coupling. Usually, the measurement of the voltage at the poles of the machine is necessary for its phasing in the power system, if the machine will operate as a generator. Voltage is always measured on the bus because it is necessary for phasing other lines, machines, etc. The stabilizer made in accordance with the present invention can be phased relative to the external power system and without the need to measure the voltage at the poles of the machine. Data on the measured voltage, relative to which the machine must be phased, is transmitted, for example, to a stationary computer. This computer then calculates the position of the stator flow so that the voltage is in phase with the measured voltage. Then, controlling the amplitude, frequency and phase of the rotor current, generate such a voltage at the output of the machine, which is in phase with the measured one. This is an undoubted advantage compared with the known devices, since there is no need for any special voltage transformers for phasing. Since dynamic processes in an electric machine occur much faster than in a machine driving it, it does not have to work with a constant rotational speed that coincides with a synchronous one, since the difference between the synchronous rotational speed and the real frequency of rotation of the stabilizer can be compensated by controlling the frequency of the currents in the rotor . For a synchronous machine, this is not possible.

Due to the presence of a rotating digital control unit and a communication line between the rotor and the stationary parts of the stabilizer, you can take advantage of the control system in the rotor, even if a large amount of signal processing is required. Partial discharges in the insulation, when their intensity becomes too large, can destroy the insulation and lead to breakdown. In the work of A. KNeibe b1. a1. Soiyiyoik 0i-1she Rajya1 E | ksNagde Moiyoyid OG Ro \\ sg Oeiega! Ogk, 1996 Aipia1 Faith - Sophegepsa oi E1es1psa1iiki1a! Yi aib O1elec (r1 RdNioteaa, p. 166166), and, when you’re going to be control the intensity of partial discharges in the stator winding of an AC rotary machine. In the presence of a rotating digital control unit, a similar system can also be used to control the insulation in the rotor.

A rotating stabilizer made in accordance with the present invention is flexible to use. To illustrate this, consider how it is used in the power system. FIG. 11 depicts a power system comprising mainly one electric power generation section 80 and a load section 82. For effective stabilization of power fluctuations between these areas there may be switching means 84 A, 84B connected to the power grid. The active power control will be most effective when the switching means are located close to the manufacturer 88, such as means 84A, or the consumer 86 active power, such as means 84B. Then the stabilizer can be placed either on the power generation section 80 80, or on the load section 82. If stabilizer 84A is placed in power generation section 80, it can additionally be used as a power converter by connecting it to a turbine. If the stabilizer 84B is placed on the load section 82, it may additionally work, for example, as a synchronous compensator. Its ability to withstand overload leads to the fact that when there is a danger of an avalanche of stress, it can experience a significant overload during a critical period, usually 1-30 minutes.

Power fluctuations in power supply networks can occur as a result of poorly suppressed attenuation of low-frequency (for example, from 0.1 to 2 Hz) oscillations between the rotors of the generators. There are two main groups of problems associated with fluctuations that occur either between different areas (interregional), or more local (intraregional). The introduction of a power system stabilizer in generators can actively contribute to the quenching of power fluctuations. If we consider the power fluctuations between areas, most of the damped torque occurs due to the modulation of loads in the power supply network.

Attenuation of (interregional) oscillations is carried out by increasing the attenuation for the given types of oscillations, which is ideally carried out using braking torque proportional to the deviation of the speed of the machine. Two practical options for stabilization by controlling the magnetization of electrical machines are modulating electrical or mechanical torque. In practice, better damping can be achieved if the stabilizer of the energy system is allowed to give an additional signal to the machine magnetization system. The input signals for the stabilizer of the energy system may contain, for example, signals of deviation of the speed of rotation of the rotor shaft, the frequency at the generator terminals or the integral of the electrical power.

The placement of devices for stabilization of the power system is a complex topic, which in each case requires a detailed analysis. However, on the basis of simplified models one can understand how to try to use different devices. Some indications are given in the article of T. 8tey, S. Lpbeg88oi Iishtd NUES 1o Eatr Roete g OksShayoik, ΙΕΕΕ Tgaikasyoik oi Roete g Oejuegu, Wo1. 8, oo. 2, LRG 1993, pp. 620-627. Devices that are basically capable of modulating active power should be placed close to consumers or active power generators, and devices that can basically modulate reactive power should be placed at an electrical midpoint between manufacturers and consumers of active power. According to the above article, the mains frequency is a suitable input for controlling the modulation of active power, and the derivative of the voltage amplitude is a suitable input for controlling the modulation of reactive power.

The instantaneous value of the active electrical power at the output of the main machine of the stabilizer can be calculated, for example, by multiplying the measured instantaneous values of current and voltage relating to one phase. Reactive power at the output of the main machine of the stabilizer can be calculated by measuring the rms values of current and voltage, as well as the phase shift between current and voltage related to the same phase.

FIG. 14 shows how, for this purpose, the system shown in FIG. 8. The signals DI and Δω are processed in separate filters / signal processors, which are denoted by their transfer functions C _p and C _and . Then these devices produce a signal ΔΟ. which is a short-term change in the stationary reference value for the voltage / reactive power of the stabilizer, and a signal ΔР, which is a short-term change in the reference value for the active power of the machine.

FIG. 12 depicts a power system with two sections 80A and 80B of electricity generation and one load section 82. Now suppose that these sections 80A and 80B of electricity production are subject to daily and / or seasonal changes. If section 80A belongs to a hydroelectric power station with large water resources, then it will dominate in the winter period. Then the energy will flow mainly from the power generation section 80A to the load section 82. The power generation section 80B may relate, for example, to hydroelectric power stations located on rivers. The performance of such power plants is maximum at high water, for example in the spring. Then the energy will mainly flow from the power generation section 80B to the load section 82. If stabilizer 84 is installed in the section 80B, then it can be used for the above-described power changes. When the power generation section 80A dominates, stabilizer 84 will be able to supply reactive power to the power grid, achieving optimum voltage distribution in it. In case of malfunctions, the stabilizer can temporarily supply regulated reactive power ΔΟ, smoothing out the active power fluctuations between the power generation section 80A and the load section 82. When the power generation section 80B dominates, it is possible to modulate the active power, as shown in FIG. 11, smoothing the oscillations of the active power between the electric power generation section 80B and the load section 82.

FIG. 13 shows a power system with two dominant power generation 80C, 80Ό sections that supply more load section 82 with electricity. Here stabilizer 86 can be used stationary as a synchronous compensator and supply reactive power to load section 82, temporarily supply reactive power ΔΟ to dampen oscillations between two sections 80C, 80Ό of electricity production and temporarily supply the active power ΔР to damp oscillations between the load section 82 and one of the sections 80C and 80Ό and electricity. An example of such inclusion is given in article Ι. Cateta her a1. Harde-8saile Asyue-Loi Moiuyayoi £ og Aidile 81aYiuyu 1trgouei1, ΙΕΕΕ Tgaikasyoik oi Roete ZuChep, Wo1. 14, oo. 2, Maw 1999, pp. 582-590.

FIG. 15 shows a flow chart that simplifies the control method according to the present invention. The process begins at step 100. At step 102, power is transferred from the main stabilizer machine to the power grid or from the power system to the main stabilizer machine. At step 104, this energy transfer is controlled. Adjustment is performed by changing the speed of the main machine. This operation is completed by feeding the current of the corresponding frequency, phase and amplitude through the rotor windings of the main machine. The process ends at step 106.

Specialists in this field of technology it is clear that in the present invention can be performed various changes and modifications that are within the scope of the invention, which are defined by the claims. For example, you can use a different type of current source instead of a rotating regulating machine. In order for the stabilizer to maintain satisfactory parameters in the event of faults in the power system, this voltage source must be independent of the power system. The voltage source may contain, for example, any energy storage device or a separate machine. A single machine can be of any type that provides the required currents and voltages to control the rotor of the main machine. It may also have a shaft that is separated from the main machine, although some exceptional features of the machine will not be provided.

Claims (25)

1. The stabilizer of the energy system containing the main rotating asynchronous electric machine (2, 2 '), the windings (14) of the stator (12) which are made with the possibility of connection to the power line, a current converter (18, 18') and a voltage source connected to it moreover, the current Converter (18, 18 ') is also connected to the windings (16) of the rotor to ensure the exchange of electric power with the power line by changing the rotational speed of the rotor (10). 2. The stabilizer according to claim 1, characterized in that the voltage source is independent of power lines. 3. The stabilizer according to claim 1 or 2, characterized in that the voltage source is a regulating machine (20, 20 '). 4. The stabilizer according to any one of claims 1 to 3, characterized in that the control machine (20, 20 ') and the main machine (2, 2') have a common shaft (22). 5. The stabilizer according to claim 4, characterized in that the current converter (18 ') is located on the fixed parts of the main machine and connected to the windings (16) of the rotor of the main machine through brushes (30) and slip rings (32). 6. The stabilizer according to claim 4, characterized in that the control machine (20) and the main machine (2) are brushless, and the current transducer (18) is made rotating together with the rotor shaft (22). 7. The stabilizer according to any one of claims 1 to 6, characterized in that a flywheel is installed on the shaft (22) of the main electric machine. 8. The stabilizer according to any one of claims 1 to 7, characterized in that it contains a driving means for applying force to the shaft (22) of the main electric machine. 9. The stabilizer according to any one of claims 1 to 8, characterized in that it contains load means for absorbing the driving force of the shaft (22) of the main electric machine. 10. A power system including power lines and a stabilizer (84, 84A, 84B) of a parallel type according to claim 1. 11. The power system of claim 10, wherein the voltage source is independent of power lines. 12. The power system according to claim 10 or 11, characterized in that the voltage source is a regulating machine (20, 20 '). 13. The power system according to any one of paragraphs.10-12, characterized in that the control machine (20, 20 ') and the main machine (2, 2') have a common shaft (22). 14. The power system according to item 13, wherein the current transducer (18 ') is located on the fixed parts of the main machine and connected to the windings (16) of the rotor of the main machine through brushes (30) and slip rings (32). 15. The power system according to item 13, wherein the control machine (20) and the main machine (2) are brushless, and the current transducer (18) is made rotating together with the rotor shaft (22). 16. A method of stabilizing voltage in a power system, comprising transmitting electric power between a power line and a rotating main electric machine (2, 2 '), characterized in that the electric power supplied or received by the main electric machine (2, 2') is controlled by changes in the rotational speed of its rotor. 17. The method according to p. 16, characterized in that the regulation includes ensuring the flow of rotor current through the windings (16) of the rotor of the main electric machine (2, 2 '); controlling the amplitude, phase and frequency of the rotor voltage to achieve a given amplitude, phase and frequency of the voltage across the stator windings (14) in the main electric machine (2, 2 '). 18. The method according to 17, characterized in that the regulating power of the rotor winding of the main machine is provided with the help of a regulating machine (20, 20 '). 19. The method according to p. 18, characterized in that the shaft of the control machine (20, 20 ') is driven into mechanical rotation by the shaft (22) of the main electric machine (2, 2'). 20. The method according to any one of paragraphs.16-19, characterized in that the current / voltage in the power line is measured to detect perturbations of its amplitude, current value, phase or frequency, and the regulation is carried out on the basis of at least one of the detected perturbations . 21. The method according to claim 20, characterized in that the temperature of the stator windings (14) of the specified main machine is measured, and the regulation is also based on this stator temperature. 22. The method according to claim 20 or 21, characterized in that FIG. 1a FIG. 1b Fig. 2a measures the temperature of the rotor windings (16) of the specified main machine, and regulation is also carried out based on this rotor temperature. 23. The method according to item 22, wherein the regulation for a limited time gives an electric power that exceeds the rated power of the main electric machine (2, 2 ') for continuous operation. 24. The method according to any one of paragraphs.16-23, characterized in that it includes the transmission of control information between the stationary and rotating parts of the main machine. 25. The method according to any one of paragraphs.16-24, characterized in that it includes converting the voltage across the windings (14) of the stator of the host machine into a voltage suitable for the power system.