MXPA00003037A - An electric power plant - Google Patents

Abstract

An electric power plant comprises at least one electric machine (2, 4, 6, 8) of alternating current type designed to be connected directly to a distribution or transmission network and comprising at least one electric winding. The winding of the machine comprises at least one electric conductor, a first layer with semiconducting properties surrounding the conductor, a solid insulating layer surrounding the first layer and a second layer with semiconducing properties surrounding the insulating layer. Auxiliary power means (10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40) are arranged to provide the requisite auxiliary power. The procedure in such a plant is also described.

Description

ELECTRICAL POWER PLANT TECHNICAL FIELD The present invention relates to an electric power plant comprising at least one electric machine of the type of alternating current designed to be directly connected to a distribution network or transmission network and comprising at least an electric winding The invention is also concerned with processes in such a plant.

BACKGROUND OF THE INVENTION The electric machine included in the plant according to the invention can be a rotary electric machine such as a synchronous machine, dual feed machine, cascade of asynchronous static current converter, external pole machine or synchronous flow machine or a stationary machine such as a transformer or a reactor. In order to connect the machines of this type to distribution or transmission networks, in the following so-called power networks, transformers have so far been used to adjust the voltage to the level of the network, that is to the range of 130-400 KV. The generators that have a nominal voltage of up to 36 KV are described by Paul R. Sietler "36 KV Generators REF .: 32960 Arise from Insulation Research", Electric World, October 15, 1932, pages 524 - 527. These generators comprise windings of high voltage cable in which the insulation is divided into different layers with different dielectric constants. The insulating material used consists of several combinations of the three mica-mica sheet, varnish and paper components. It has now been found that, by manufacturing the aforesaid winding of the machine from an insulated high-voltage electrical conductor with a solid insulation of a type similar to that used in power transmission cables, the voltage of the machine can be be increased to such levels that the machine can be directly connected to any power network without the use of intermediate transformers. Thus the transformer can be omitted. A typical operating range for these machines is 30 to 800 KV. In conventional generators the auxiliary power for starting and for putting the machines into operation, as well as for station requirements such as operation pumps and flood gates as well as for heating and lighting purposes, is taken via transformers from the terminals of the generator, then the terminal voltage is less than 25 KV. Figure 1 shows a simplified study diagram for the distribution of auxiliary power in a power station according to known technology. Four alternative supply routes to a bar used as an auxiliary power distribution bar 200 are illustrated. Two generators Gl, G2 are thus connected to a power network, each via its own transformer: 202, 204. Branchings to auxiliary power transformers 206, 208 are located outside the circuit breakers 210, 212 of the generator. The auxiliary power is thus diverted by means of these auxiliary power transformers 206, 208 to the auxiliary power distribution bus 200. The figure also shows a diesel generator 218 and supply of the local distribution network, for example at 220, which provides two more supply alternatives to the auxiliary power distribution bus 200. The distribution of the auxiliary power of the auxiliary power distribution bus 200 is then effected via the alternating current distribution busbars 222 and the direct current distribution busbars 224, as described hereinafter. Figure 2 shows a modification of the auxiliary power distribution illustrated in Figure 1, also with four supply alternatives. Two of the supply alternatives include generators 226, 228 with extra stator windings for the generation of auxiliary power and excitation 230, 232 and 234, 236 respectively. In both embodiments according to Figures 1 and 2, the switching between several supply alternatives comprises a temporary voltage interruption in the auxiliary power distribution bus 200. In conventional plants, as well, auxiliary power is often taken from the generator terminals via transformers, the terminal voltage is then less than 25 KV. The typical auxiliary power voltages are 400v - 690v, 3.3 KV, 6.6 KV, 6 KV - 10 KV. Thus, the terminal voltage of the generator is frequently transformed to one or more of these discrete levels via at least one transformer for the auxiliary power. An auxiliary power equipment for heating and lighting, for example, frequently requires a voltage of 380-220v, in which case the power system comprises at least one local power transformer to reduce the voltage of the generator voltage to this voltage. of auxiliary power. Alternatively, an auxiliary power winding can be arranged in the power transformer to carry out this reduction. Both of these alternatives for auxiliary power generation require extra equipment either in the form of an extra transformer or a complicated power transformer construction, thus increasing the space required and also making the power plant more expensive. The problems mentioned above are accentuated in electrical machines with a terminal voltage in the range of 36 - 800 KV. The object of the present invention is thus to provide an electrical power plant comprising at least one electrical machine of the alternating current type which can be connected directly to distribution networks or transmission networks, such a power plant also comprises power means auxiliaries that allow the required auxiliary power to be provided in a simple manner.BRIEF DESCRIPTION OF THE INVENTION This object is obtained with an electric power plant of the type described in the introduction, having the aspects defined in claim 1. The insulating conductor or high voltage cable used in the present invention is flexible and is of type described in more detail in WO 97/45919 and WO 97/45847. The insulated conductor or cable is further described in WO 97/45918, WO 97/45930 and WO 97/45931.

Thus, in the device according to the invention, the windings are preferably of a type corresponding to cables having solid, extruded insulation, such as those currently used for power distribution, such as XLPE cables or cables with EPR insulation. Such a cable comprises an internal conductor composed of one or more strands, an inner semiconductor layer surrounding the conductor, a solid insulating layer surrounding this semiconductive layer and an outer semiconductor layer surrounding the insulating layer. Such cables are flexible, which is an important property in this context since the technology for the device according to the invention is based mainly on winding systems in which the winding is formed from cables that are bent during assembly. The flexibility of an XLPE cable normally corresponds to a radius of curvature of approximately 20 cm for a cable of 30 mm in diameter and a radius of curvature of approximately 65 cm for a cable of 80 mm in diameter. In the present application, the term "flexible" is used to indicate that the winding is flexible at a radius of curvature of the order of 4 times the diameter of the cable, preferably 8 to 12 times the diameter of the cable. The winding must be constructed to retain its properties even when it is bent and when subjected to thermal or mechanical stresses during operation. It is vital that the layers retain their adhesion to each other in this context. The material properties of the layers are decisive here, particularly their elasticity and relative coefficients of thermal expansion. In an XLPE cable, for example, the insulating layer consists of crosslinked low density polyethylene and the semiconductor layers consist of polyethylene with mixed soot and metal particles. Changes in volume as a result of temperature fluctuations are completely absorbed as changes in the radius of the cable and thanks to the comparatively slight difference between the coefficients of thermal expansion in the layers in relation to the elasticity of these materials, the radial expansion it can be carried out without loss of adhesion between the layers. The combinations of materials summarized above should be considered as examples only. Other combinations that satisfy the specified conditions and also the condition of being semiconductors, that is, having a resistivity in the range of 10"1 - 106 ohm-cm, for example 1-500 ohm-cm or 10-200 ohm-cm , also falls naturally within the scope of the invention The insulating layer may consist for example of a solid thermoplastic material such as low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP), polybutylene (PB) , polymethylpentane (PMP), crosslinked materials such as crosslinked polyethylene (XLPE) or rubber (rubber) such as ethylene propylene rubber (EPR) or silicon rubber.The inner and outer semiconductive layers may be of the same basic material but with particles of conductive material such as mixed soot or metal powder The mechanical properties of these materials, particularly their coefficients of thermal expansion, are affected relatively little in case of soot or dust of metal is mixed in or not at least in the proportions required to obtain the necessary conductivity according to the invention. Thus, the insulating layer and the semiconductor layers have substantially the same coefficients of thermal expansion. An ethylene-vinyl acetate / nitrile copolymer rubberPolylimp polyethylene, ethylene-acrylate copolymers and ethylene-ethyl acrylate copolymers can also be suitable materials for semiconductor layers. Although different types of materials are used as a basis in the various layers, it is desirable that their coefficients of thermal expansion are of the same order of magnitude. This is the case with the combination of the materials listed above.

The materials listed above have a relatively good elasticity, with an E modulus of E < 500 MPa, preferably < 200 MPa. The elasticity is sufficient so that any minor differences between the coefficients of thermal expansion for the materials in the layers are absorbed in the radial direction of the elasticity in such a way that cracks or other damages do not appear and in such a way that the layers are not released each. The material in the layers is elastic and the adhesion between the layers is at least of the same magnitude as the weakest of the materials. The conductivity of the two semiconductor layers is sufficient to substantially equalize the potential along each layer. The conductivity of the outer semiconductor layer is sufficiently large to contain the electric field in the cable, but small enough so as not to give rise to significant losses due to currents induced in the longitudinal direction of the layer. Thus, each of the two semiconductor layers essentially constitutes an equipotential surface and the winding composed of these layers will substantially enclose the electric field therein.

Of course, there is nothing to prevent one or more additional semiconductor layers from being arranged in the insulating layer. According to an advantageous embodiment of the plant according to the invention, at least two adjacent layers of the winding of the machine have coefficients of thermal expansion substantially equally large. The damages due to the formation of cracks or the like in the insulating layer are thus avoided. According to another advantageous embodiment of the plant according to the invention, such layers are arranged to adhere to each other even when the insulated conductor is bent. This ensures good contact between the layers from start to finish. According to an advantageous embodiment of the machine according to the invention, the auxiliary power means comprise at least one auxiliary power source which is connected to an auxiliary power distribution bar for auxiliary power distribution, via component equipment. electronic power to keep the voltage in the auxiliary power distribution bar constant, the electronic power equipment is provided with a direct voltage intermediate link to which a backup voltage can be connected if necessary. A battery is appropriately connected to the direct voltage intermediate link to supply a predetermined backup voltage to the direct voltage intermediate link if its voltage level falls below the predetermined level. This reinforcement of the direct voltage intermediate link allows it to be treated with temporary overloads without the ordinary supply source being overloaded. The voltage and frequency can thus be maintained in the auxiliary power distribution bar even in the case of temporary interruptions in the ordinary supply. Thus, the equipment of electronic components of power can be used in conjunction with power supplies, such as synchronous / asynchronous generators with frequency and constant or variable voltage, as well as in conjunction with transformers with appropriate levels for the secondary voltage. The auxiliary power distribution bar can also be powered from a plurality of parallel power supplies. According to another advantageous embodiment of the plant according to the invention, the electronic power component equipment is arranged for an optional control of the power flow from the auxiliary power generator to the auxiliary power distribution bar or a power bar. distribution of auxiliary power to the auxiliary power generator or alternatively of the auxiliary power winding in a multiple winding machine to the auxiliary power distribution bar or from the auxiliary power distribution bar to the auxiliary power winding in a multiple winding machine . A) Yes, the equipment for the generation of auxiliary power can also be used for the electrical delay of the electric machine until it stops. This is a considerable advantage with respect to the known technology in which electric delay is only possible at 5-10% of the starting speed, after which mechanical braking is required. Thus, none of such mechanical braking equipment is required in accordance with the present invention. According to still another advantageous embodiment of the plant according to the invention, if the electric machine is a synchronous machine, the field winding of the auxiliary power generator can be short-circuited and its stator side can be fed with a Three-phase voltage having a phase position and a frequency, such that the auxiliary power generator operates as an asynchronous machine with a rotation direction for a maximum braking torque. This asynchronous operation continues until the machine reaches rest. According to further advantageous embodiments of the plant according to the invention, the field winding of the auxiliary power generator can be short-circuited and at least one winding of the stator can be fed with a direct current. In this case, a static frequency changer or a separate thyristor current converter for a single quadrant operation is preferably arranged to feed the stator winding with direct current. According to yet another advantageous embodiment of the plant according to the invention, an auxiliary power generator is designed with a number of poles suitable for frequency adaptation. The auxiliary power distribution bar can then have multiple inputs, for example a directly connected input and an input via one or more frequency changers. The double inputs allow switching between alternative power supplies without any voltage interruption in the busbar.

BRIEF DESCRIPTION OF THE DRAWINGS To explain the invention in more detail, embodiments of the plant according to the invention, selected by way of example with reference to figures 3-22 of the accompanying drawings, will now be described, in which: 1 and 2 show diagrams of study of the auxiliary power distribution in a power station according to the known technology, Figure 3 shows a circuit diagram for an embodiment of the electric power plant according to the invention, with several auxiliary power sources for supplying an auxiliary power distribution bar via a direct voltage intermediate link, Figure 4 shows in more detail one of the examples of Figure 3 for obtaining auxiliary power, Figure 5 shows several alternatives to excite a electrical machine in the plant according to the invention, Figure 6 illustrates a principle solution for obtaining pot auxiliary encia in a case with several parallel power supplies, Figure 7 shows a modification of the mode of Figure 6, in the. which other source of supply is added in the form of a grounding transformer with an extra secondary winding, Figure 8 shows in more detail an example of the output circuit of the electronic power components equipment in the modes illustrated in the previous figures Figure 9 shows a mode in which the auxiliary power is generated by an auxiliary power generator, which can also be used for the electrical delay of the electric machine, Figure 10 illustrates a mode that has several possible inputs to the bar auxiliary power distribution, Figure 11 shows a mode that has auxiliary power distribution with various voltage levels, Figures 12 and 13 show two examples of the short-circuiting of the field winding of the auxiliary power generator during the delay , Figure 14 shows a modality of the plant according to the invention, in which a generator of Separate auxiliary power is used for the start of the static frequency changer, Figure 15 shows a modality in which a separate auxiliary power winding is used to start the static frequency changer of a synchronous machine, Figure 16 shows a modality of the plant according to the invention in which a separate auxiliary power winding is used to start the frequency changer of a synchronous machine and in which the voltage adjustment is carried out with the aid of a three-winding transformer, Figure 17 shows an embodiment having two generators with common frequency changing equipment, Figure 18 illustrates a principle solution for the auxiliary power distribution in a plant embodiment according to the invention having generators with variable speed, Figure 19 shows a schematic, perspective view of a section taken diametrically through s of a stator in a rotary electric machine in an electric power plant according to the invention, Figure 20 shows a cross-sectional view through an insulated conductor used for windings in machines in the electric power plant in accordance with The present invention, Figure 21 schematically shows a sector of a rotary electric machine in the electric power plant according to the invention. and Figure 22 shows a sector of the stator corresponding to a tooth step of the radial sector in Figure 21.

DESCRIPTION OF THE PREFERRED MODALITIES Figure 3 shows a circuit diagram for an embodiment of the electric power plant according to the invention, comprising a variety of electric machines of the alternating power type, such as generators 2,4,6 and a transformer 8, constructed in accordance with the invention for direct connection to a high voltage busbar, commonly in the range of 40-400 KV, via a circuit breaker 9 connected to the power network. The generator 2 is designed with a separate auxiliary power winding 10 for connection via power electronic component equipment to an auxiliary power distribution bar which commonly falls at a voltage of 400 v. The electronic power component equipment comprises an input stage 12 in the form of a rectifier 12, which is connected between the auxiliary power winding 10 and a direct voltage intermediate link 14. Between the direct intermediate voltage link 14 and the auxiliary power distribution bar is an output stage 16 in the form of an inverter and a transformer 18. The input stage 12, the direct voltage intermediate link 14 and the step 16 The outputs are in principle a static frequency changer with a constant direct voltage intermediate link. The generator 4 is provided with a bypass terminal that is connected via the transformer 20 and the input stage 22 to the direct voltage intermediate link 14 for the auxiliary power bypass. The generator 6 is arranged to drive a separate auxiliary power generator 24 which in turn is connected to the direct voltage intermediate link 14 via an input stage 26. As another example of an auxiliary power source, a transformer 8 of The ground connection is shown connected directly to the busbar and provided with an extra secondary winding 28 for auxiliary power extraction. The secondary winding 28 is connected to the direct voltage intermediate link 14 via an input stage 30. A backup circuit in the form of a battery 32 is connected to the direct voltage intermediate link 14 via a semiconductor rectifier 34 which locks the circuit during the normal operation and a resistor 36. If the ordinary supply sources for the input stages 12, 22, 26, 30 are limited to keep the output voltage of the static frequency changers constant to a temporary overload and temporary cuts in the supply , the backup circuit 32, 24, 26, is put into operation and maintains the constant voltage in the direct voltage intermediate link 14. This prevents the supply source (s) from being overloaded to a temporary overload or interruptions. The backup circuit 32, 34, 36 thus serves to reinforce the direct voltage intermediate link 14. In solutions of the system having multiple inputs in parallel, such as the supply of the direct voltage intermediate link 14 shown in Figure 3, it is also It can include equipment for the distribution of the load. At the maximum current allowed at the input the output voltage levels at the input stages 12, 22, 26, 30, that is, the voltage on the direct voltage intermediate link 14, must be less than the voltage level of the backup of backup circuit 32, 34, 36 which is then connected. The auxiliary power distribution bar may also have several parallel inputs, that is, a diesel-driven generator 38 and an external power supply connected via the transformer 40, also as the input 16, 18 of the direct voltage intermediate link 14. Figure 4 shows more clearly an embodiment with an electric machine in the form of a synchronous machine 42 having a winding 44 of extra auxiliary power. The voltage of the auxiliary power winding 44 is rectified in the input stage 46 of the power electronic component equipment. The direct voltage intermediate link of equipment 48 of electronic power components acquires a voltage value dependent on the ULS load, which is displayed as a constant voltage U minus a voltage drop dependent on the load? URL on the resistor Rl and the inductance L. The direct voltage intermediate link 50 also constitutes a backup circuit in the form of a battery 52, a semiconductor rectifier 54 and a resistor 66, connected as described above with reference to Figure 3. At the maximum allowable current, Imax, in the supply circuit 58 of the auxiliary winding 44, the ULS voltage level in the intermediate link 50 of direct voltage is less than the level of the backup voltage UB of the backup circuit 52, 54, 56, after which it is connected via the semiconductor rectifier 54. The backup circuit is kept charged via the resistor 56 and the circuit is blocked during normal operation by means of the semiconductor rectifier 54. If the voltage and frequency are constant, the input stage 46 can be formed via a traditional diode bridge and the voltage drop dependent on the delta URL load is obtained with the help of the resistor Rl and the inductance L. In system solutions in which the supply voltage can vary in level and in frequency, the input stage 46 is real preferably raised with the aid of controllable semiconductor elements and the ULS voltage level in the direct voltage intermediate link 50 is adjusted to the current operating situation by means of voltage controlled current control. The maintenance charge of the battery 52 in the backup circuit is carried out using conventional equipment for charging batteries and the semiconductor rectifier can be replaced with a thyristor switch, for example having ignition circuit for the controlled activation of the backup circuit. The conversion and voltage filtering of the harmonic content is presented in the output stage of the electronic power component equipment 48, which comprises an attenuator 60 and transformer 62, as described in more detail with reference to FIG. 8. The distribution of Auxiliary power typically comprises an alternating voltage distribution bar 64 and one or two direct voltage distribution bars 66, 68. The direct voltage distribution bars 66, 68 are powered by the battery 70, 72 and by the inverter 74, 76. The inverter 74, 76 can be powered from the alternating voltage distribution bar 64 or from the intermediate link 50 of the equipment 48 of electronic power components. Figure 5 shows a modality similar to that shown in Figure 2, with a different supply alternative for the excitation of the machine 42. The auxiliary auxiliary power winding 44 is used as the source of supply for the excitation. It is then important that the field winding 74 of the machine 42 or the supply field be galvanically separated from the supply source of the excitation equipment. The excitation can be carried out with the aid of conventional static current converter equipment, a separate synchronous machine or permanent magnet generator 76 or supply of the auxiliary power distribution bar 64 which is used in place of the power winding 44 assistant. Alternatively, the excitation can be obtained from the direct voltage intermediate link 50 with the help of a pulsed connection 78 with galvanic isolation of input and output. The type of supply selected for the excitation of the machine 42 depends mainly on the desired excitation force. The supply of the auxiliary power distribution bar 64 is not normally chosen in cases where strong excitation is desired. Figure 6 shows a modality similar to that of Figures 2 and 3, in which the auxiliary power is supplied to the direct voltage intermediate link 50 by means of several parallel inputs 58, 78, 80. Two alternatives for the excitation of the machine 42 are illustrated in the figure, that is, of the auxiliary power winding 44 and the direct voltage intermediate link 50. If redundancy is required, it is recommended that two alternatives be used for excitation. In the modality shown in figure 6Thus, the electronic power component equipment comprises several parallel input stages 58, 78, 80. If galvanic separation is required between the supply sources, a transformer is added to each input stage. The voltage regulation, individual, controlled by the current, of each input stage is required if the current limitation is necessary for the protection of one or more sources of supply. In this mode, the input circuits of the various supply sources are fed with a variable voltage and frequency level. Figure 7 shows another embodiment having several inputs parallel to the direct voltage intermediate link 50, as in Figure 6, one of these input sources comprises a grounding transformer 82 with extra secondary winding 84. The primary objective of the transformer 82 to ground is to obtain an artificial zero point for the ground connection of the system in order to eliminate the third circulating harmonic currents during the operation of one or more parallel generators 42, 68, 88 and to limit the point current zero in case of external failures. The figure shows two alternatives for the supply of transformer 82, ALT 1 or ALT 2, respectively. In ALT 1, the supply is via the direct voltage intermediate link 50, while in ALT 2, the auxiliary power distribution bar 90 is supplied directly from the secondary winding 84 of the grounding transformer 82. In this case, the voltage of the secondary winding 84 must be adapted to the voltage of the bus 90 of auxiliary power. Figure 8 shows in more detail one embodiment of the main circuit of the power electronic component equipment, comprising input stages connected between a supply source and the direct voltage intermediate link 50, which acts as a collection point. As described above, a backup circuit consisting of the battery 52, the semiconductor rectifier 54 and the resistor 56 is connected to the direct voltage intermediate link 50 and an output stage is connected between the direct voltage intermediate link 50 and the auxiliary power distribution bar, for voltage conversion and harmonic filtering. The input stages, proposed mainly to rectify the voltage of the supply source and the output stage, designed to reverse the voltage, are known per c and therefore are not described in detail. Figure 9 shows an embodiment of the plant according to the invention in which the equipment for generating auxiliary power can also be used for the electrical delay of the machine, the operation of the braking effect to a standstill. The plant thus comprises an electric machine 92 with brushless excitation and an auxiliary power generator 94 also with brushless excitation. The auxiliary power generator 94 is connected to an auxiliary power distribution bar 98 via a static frequency changer 96. Other sources of supply, such as an external source in 100 or a diesel generator 102 can also be connected to the bar of distribution 98 of auxiliary power. A common rotational drive equipment 104 is provided for the excitation of the machine 92 and the auxiliary power generator 94. This excitation apparatus comprises a permanent magnet generator 106 and rectifying elements such as thyristor bridges 108, 110 for supplying the field windings 112, 114 of the generators 92, 94. The bridges 108, 110 of the thyristor are controlled from stationary control 116, each via its own unit for wireless communication. Each communication unit comprises a stationary transmitter and / or receiver unit 118 connected to the control means 116 and a receiver and / or transmitter unit 120 applied on the rotary drive equipment. In figure 9, a connection 122 is also indicated between the machine 92 and the control means 116 in such a way that the output voltage of the machine 92 can be controlled by controlling the excitation. A connection 124 is also indicated for measuring the network voltage, which is necessary to phase the machine 92. In this embodiment, the equipment for generating auxiliary power comprises the frequency changer equipment 96 for operation in multiple quadrants and can be used for the electrical delay of the machine 92. The braking effect is obtained by short-circuiting the field winding 114 of the auxiliary power generator 94 and feeding its stator side with a three-phase voltage having a phase position and a frequency which allow the auxiliary power generator 94 (synchronous machine) to function as an asynchronous machine with rotation direction for maximum braking torque. The asynchronous operation can continue until the machine 92 reaches a complete rest. This is described in more detail later herein with reference to Figure 12.

The braking effect can also be obtained by short-circuiting the field winding 114 of the auxiliary power generator 94 and feeding the winding of its stator with direct current, as described in more detail hereinafter with reference to the figure 13. Decisive as to how the auxiliary power generator 94 can be used for the delay is how long it can be overloaded without damage. Figure 10 shows an example of several possibilities of input to the auxiliary power distribution bar 126. In addition to an external supply source 128 and the diesel generator 130, for example, two generators 132, 134 are shown which share common frequency changer equipment 136, which may in turn be connected to the auxiliary power generators 132, 134 (via the transformer 138) to the auxiliary power distribution bar 126. Thus, the supply via the frequency changer 136 or by the directly connected supply of the auxiliary power generators 132, 134, also as alternative supplies 128, 130 They're possible. Figure 11 shows an embodiment with auxiliary power distribution having several voltage levels. The generators 140, 142 can thus be directly connected to a level of 6 KV and via the transformers 144, 146 with extra secondary lines, directly with the auxiliary power distribution bar 150 or via the frequency changer equipment 148. The bar auxiliary power distribution commonly falls at 0.4 KV and feeds direct voltage distribution bars 156, 158, via converters 152, 154 as described above. However, other voltage levels or even several voltage levels are also possible. Figure 12 illustrates more clearly the principle for short-circuiting the field winding 162 of the auxiliary power generator during the delay operation. The field winding 162 is thus connected to the excitation module 164 via a thyristor short circuit 166 comprising two opposite directed thyristors 168, 170 with their ignition circuits 172, 174. The stator side of the generator 160 is supplied with alternating voltage via the frequency changer 176 with a phase position and frequency such that the machine operates as an asynchronous machine with rotation direction for maximum braking torque. Figure 13 shows an alternative mode in which the generator 160 is supplied with direct voltage on the stator side of a thyristor converter 178. This results in countercurrent braking, in which the braking effect is carried out with direct voltage. Figure 14 shows an embodiment of the plant according to the invention in which a separate auxiliary power generator G2 is used as the starter motor. The auxiliary power generator G2 is driven by the electrical machine Gl that is connected directly to the power network. The auxiliary power distribution bar 240 commonly falls at a voltage of 0.4 KV and has three input alternatives, that is, a Gd diesel generator, an input from an external supply source 241 via a T2 transformer and the power generator separate auxiliary G2 which is connected to the auxiliary power distribution bar 240 via a CT transformer for voltage adjustment. At the moment when the machine Gl is going to start, the circuit breakers CB1, CB2 and CB5 are open. A voltage is applied to the auxiliary power distribution bar 240 via one of such supply alternatives Gd, 241. During the time for the first stage of the starting process, the CB4 circuit breaker is closed and the circuit breaker CB5 is open, which means that the FC frequency changer is directly connected to the auxiliary power generator G2. During the time for the second stage of the boot process, the circuit breaker CB4 is open and the circuit breaker CB5 is closed. During the starting process, the excitation equipment EXC of the auxiliary power generator G2 is fed from the auxiliary power distribution bar 240 via the transformer T3. When the machine Gl has been put in phase in the operation of the motor, the switching to ordinary excitation is presented and the voltage is applied to the auxiliary power distribution bar 240 of the external network by means of powering via the machine Gl and the generator of auxiliary power G2. Circuit breaker CB1 is closed and the other auxiliary systems can be started. Figure 15 shows an alternative embodiment of the plant according to the invention, in which an auxiliary power winding 242, separated from the machine Gl at start-up, is used. In a manner similar to the embodiment described in Figure 14, the auxiliary power distribution bar 240 has three input alternatives, of which one supply source is the auxiliary power winding 242 separated from the machine Gl supplying the bar of 240 auxiliary power distribution via the TI transformer for voltage adjustment. The starting process is the same as in the mode shown in Figure 14 and when the machine Gl has been phased in the operation of the motor, the commutation to the ordinary excitation is presented by the excitation equipment EXC and the voltage is applied on the auxiliary power distribution bar 240 of the external network by means of the machine Gl and its auxiliary power winding 242. When the synchronous machine Gl has been phased it can have the following simultaneous modes of operation: a mode of synchronous motor for driving a turbine part, for example, in air or vacuum, a synchronous compensator mode for generating reactive power to maintain the voltage and a transformer mode for reducing and transmitting the active and reactive power to the busbar auxiliary power. Figure 16 shows a modification of the embodiment of Figure 15, in which a transformer 244 with three windings is connected to the auxiliary power winding 242 of the machine Gl. The auxiliary power distribution bar 240 is supplied via the secondary winding of the three winding transformer 244 and the transformer 243, while the other secondary winding of the three winding transformer 244 is used for the excitation of the machine Gl. The start-up process, also as the normal operation, is carried out in a similar manner as in the embodiment according to Figure 15. Figure 17 shows a modality of the plant according to the invention, with two machines or generators 246 , 248 that has FC common frequency changer equipment for start-up. Each generator 246, 248 comprises an auxiliary auxiliary power winding 250, 252 for supplying the auxiliary power distribution bar 254 in a similar manner as in the embodiment of FIG. 15. The auxiliary power systems can be connected to the power switch CB7 circuits and the auxiliary power windings can be separated from the respective auxiliary power distribution bar 254 with the help of circuit breakers CB1, CB4 respectively. The figure also shows parts of turbine STl and ST2 connected to machines 246, 248 via couplings Cl, C2 respectively. In other aspects, the function of the mode shown in Figure 17 is the same as that of the mode shown in Figure 15. Figure 18 illustrates yet another principle for the auxiliary power distribution when the speed of the machines 256, 258 in the plant is variable. A voltage is applied in the auxiliary power distribution at the station level via one of four alternative input routes, that is, either from the 256 machine or the 258 machine or from a 260 diesel generator or from a supply source external 262. At the start of the machine 258, voltage is temporarily applied in the auxiliary power distribution for the machine 258 via the auxiliary power distribution for the station level, after which the ordinary input of the machine 258 is opened before the voltage application. After the start and accumulation of voltage, switching to ordinary excitation is presented, that is, the machine 258 produces its own auxiliary force. The constant speed is maintained to drive the pump and the like after the variation in the voltage and frequency of the supply network, with the help of integral motors 264. Direct voltage and alternating voltage distribution bars are connected to the distribution of auxiliary power at the station level as described above. The priority given to the alternative voltage distribution bar is supplied via frequency changers 266, 268 via the constant direct voltage intermediate link 270 and battery backup 272 as described above. Various modifications of the modalities shown and described above by way of example are feasible within the scope of the invention. Thus, the auxiliary power generator and the machine can be excited with the help of static exciters or brushless exciters with diode rectifiers. In addition, the adaptation and coupling between auxiliary power generators and auxiliary power distribution bars can be realized naturally in several different ways. The start-up methods and principles may vary from one plant to another and in some cases the frequency changer may be supplied for starting from a separate source of supply, possibly from a separate diesel generator. The conductors in other equipment for auxiliary power generator can also be used for electric braking, as well as for starting the frequency changer of the machines. Figure 19 shows a part of an electric alternating current machine of the type included in the plant according to the invention. The rotor has been removed to reveal the construction of stator 1 more clearly. The main parts of the stator 1 are a frame 25 of the stator, a core 3 of the stator, comprising the teeth 27 of the stator and a rear part of the stator defining an external rear portion 5. The stator also comprises a stator winding 29 formed from an insulated conductor and placed in a space 7 also called slot, formed as a bicycle chain, see figure 21, formed between the individual stator teeth 27. In Figure 21, winding 29 of the stator is only indicated by its conductor. As is evident from Figure 19, winding 29 of the stator forms a coil end package 31 on each side of stator 1. Figure 21 also reveals that the insulated conductor is graduated or staggered in various dimensions depending on its radial position in the stator. In larger conventional machines, the stator frame 25 often consists of a welded steel plate construction. In large machines, the core 3 of the stator, also called the laminated core, is generally made of a 0.35 mm plate divided into stacks with an axial length of approximately 50 mm spaced from each other by 5 mm ventilation ducts that form divisions. However, the ventilation ducts are removed in a machine of the type included in the plant according to the present invention. In large machines, the construction of each laminated stack is obtained by stacking die-cut plate segments 9 of an appropriate size together with a first layer and placing each subsequent layer transversely to build a complete plate-like part of a core 3 of the stator. The parts and partitions are held together by pressure rods 33 which are pressed against pressure rings, pressure handles or pressure segments, not shown. Only two pressure rods are shown in Figure 19. Figure 20 shows a cross section through an insulated conductor designed for use in the windings in the machine or machines in the plant according to the present invention. The insulated conductor 11 comprises a plurality of strands 35 having a circular cross section and consisting of copper (Cu), for example. These strands 35 are arranged in the middle part of the insulated conductor 11. A first semiconductor layer 13 is arranged around the strands 35. An insulating layer 37, for example XLPE insulation is arranged around the first semiconductor layer 13. A second layer semiconductor 15 is arranged around insulating layer 37. The insulated conductor is flexible and retains this property throughout its service life. Such three layers are constructed in such a way that they adhere to each other even when the insulated conductor is bent. The insulated conductor has a diameter in the range of 20-250 mm and a conductive area in the range of 80-3,000 square mm. Figure 21 schematically shows a radial sector of a machine with a segment 9 of the stator 1 and a pole 39 of the rotor on the rotor 17 of the machine. It can also be seen that the winding 29 of the stator is arranged in the space 7 formed as a bicycle chain, formed between the individual stator teeth 27. Each tooth 27 of the stator extends radially inwardly from the outer rear portion 5. Figure 22 shows a sector corresponding to a tooth pitch of the radial sector in Figure 21, with the winding 29 of the stator in the slot 7, this is It does in three stages with the innermost stage, seen in radial direction, which has the smallest diameter and the outermost stage, seen in radial direction, which has the largest diameter. Each stage is provided with four winding turns. The slot 7 has a bottom 41 at its outermost radius and a top 21 at its innermost radius. The embodiment in Figure 22 shows an auxiliary power winding 43 arranged in a channel 23 located in connection with the bottom 41 of the slot through which the auxiliary power winding 43 runs. In addition, the channel 23, with its auxiliary power winding 43 is located radially in relation to the winding 29 of the stator. The full auxiliary power winding is obtained by an appropriate number of slot 7 which are provided with channels 23 in the bottom 20 of the slot, such that an appropriate number of turns of the winding are obtained, depending on the desired auxiliary power voltage. . The location shown in Figure 22 offers advantages with respect to the winding assembly. This location also provides less losses in the extra winding and ensures that the leakage reactance for the main winding does not increase. The auxiliary power winding is constructed in the same way as the main winding but with considerably fewer turns, which provides a lower terminal voltage. The power output of the auxiliary power winding is within the range of about KW or up to about 25% of the total output of the machine. Thus, the auxiliary power winding is the smallest winding with respect to the power and is therefore placed at the bottom of the slot 7. The auxiliary power voltage for the station requirement is determined at certain values, for example 400 V - 690 V - 3 KV, 3 KV - 6.6 KV or 10 KV. However, depending on the parameters of the main design of the generator construction, it may not be possible to obtain these specific voltage levels and consequently the auxiliary power winding is sized to approach as closely as possible to these values, in such a way that a transformation to these values can be obtained with a relatively simple transformer. The modality of an auxiliary power winding shown in Fig. 22 constitutes only one possible solution of the location of the winding. The winding can also be placed at the top 21 of the slot or somewhere else along the slot. A slot can also be provided with more than one winding turn. It is not necessary that each slot be provided with an auxiliary power winding. Instead of this, every second slot or every third slot can be provided with the winding. Many modifications of the modalities may therefore be selected within the scope of the invention, depending on the design parameters of the generator and the auxiliary power voltage desired for the requirements of the station. The common denominator for all modes is that the generator is provided with a stator winding of the high voltage type and that the auxiliary power winding is located in or near the slot. "In or near" to the slot means that the space 7 of the slot communicates with the channel 23 for the auxiliary power winding 43. Thus, the stator comprises at least one winding system that acts as an auxiliary power winding. consisting of insulated solid conductors of the type described above, placed and arranged in such a way as to link sufficient magnetic flux to ensure that the induced voltage is appropriate for direct connection to a distribution network or transmission network, this is commonly 36 KV - 800 KV It is noted that, in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (60)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. An electric power plant comprising at least one of the following types of electric machines, for example a rotary electrical machine of the current type alternatively, a transformer or a reactor designed to be directly connected to a distribution network or transmission network and comprising at least one electrical winding, characterized in that the winding of the machine comprises at least one electrical conductor, a first layer with semiconductor properties surrounding the conductor, a solid insulating layer surrounding the first layer and a second layer with semiconducting properties surrounding the insulating layer and also because the auxiliary power means are arranged to provide the required auxiliary power.
2. 2. A plant according to claim 1, characterized in that the potential in the first layer is substantially equal to the potential over the conductor.
3. 3. A plant according to claim 1 or claim 2, characterized in that the second layer is arranged to form a substantially equipotential surface surrounding the conductor.
4. 4. A plant according to claim 3, characterized in that the second layer is connected to a predetermined potential.
5. 5. A plant according to claim 4, characterized in that the predetermined potential is ground potential.
6. 6. A plant according to any of the preceding claims, characterized in that at least two adjacent layers of the winding of the machine have substantially equal large thermal expansion coefficients.
7. A plant according to any of the preceding claims, characterized in that the conductor comprises a plurality of strands, at least some of which are in electrical contact with each other.
8. A plant according to any of the preceding claims, characterized in that each of the three layers is firmly joined to adjacent layers along substantially all of its contact surface.
9. A plant according to any of the preceding claims, characterized in that the layers are arranged to adhere to each other even when the insulated conductor is bent.
10. 10. An electrical power plant comprising at least one of the following types of electrical machines, for example a rotary electric machine of the alternating current type, a transformer or a reactor designed to be directly connected to a distribution network or network transmission and comprising at least one magnetic core and at least one electrical winding, characterized in that the winding is formed of a cable comprising one or more current carrying conductors, each conductor has a diversity of strands, an inner semiconductor layer provided around each conductor, an insulating layer of solid insulating material provided around the inner semiconductor layer and an outer semiconductor layer provided around the insulating layer and in that the auxiliary power means are arranged to provide the required auxiliary power.
11. 11. A plant in accordance with the claim

    10, characterized in that said cable comprises a lining.
12. 12. A plant according to any of claims 1-11, characterized in that the electric machine is a rotating electric machine and because the stator is provided with at least two windings designed for different voltages, one such winding is arranged as a auxiliary power winding to generate auxiliary power.
13. 13. A plant according to claim 12, characterized in that the auxiliary power winding comprises at least one electrical conductor, a first layer with semiconductive properties surrounding the conductor, a solid insulating layer surrounding the first layer and a second layer with semiconducting properties surrounding the insulating layer.
14. 14. A plant according to claim 12 or claim 13, characterized in that a winding of the stator is dimensioned for voltages in the range of 36 KV - 800 KV, while the auxiliary power winding is dimensioned for voltages in the range of 400 V - 20 KV.
15. 15. A plant according to any of claims 12-14, characterized in that the auxiliary power winding is dimensioned to supply voltages within one of the following discrete voltage ranges: 380-420 V, 650-725 V, 3.1- 3.5.KV, 6.2 -7.0 KV or 9.5 -10.5 KV.
16. 16. A plant according to any of claims 12-14, characterized in that the auxiliary power winding is sized to supply an arranged voltage to be transformed to a voltage within one of the following discrete voltage ranges: 380-420 V , 650 - 725 V, 3.1 -3.5 KV, 6.2 -7.0 KV or 9.5 - 10.5 KV.
17. 17. A plant according to any of claims 12-16, characterized in that the auxiliary power winding is a three-phase winding.
18. 18. A plant according to any of claims 12-17, characterized in that the auxiliary power winding is placed at the bottom of a groove formed between two adjacent teeth of the stator.
19. 19. A plant in accordance with the claim

    18, characterized in that the auxiliary power winding is placed in an extra space of the winding in the stator, oriented radially in relation to the winding of the stator.
20. 20. A plant in accordance with the claim

    18 or claim 19, characterized in that the auxiliary power winding is placed in each slot in the stator.
21. 21. A plant according to any of claims 1-11, characterized in that the electric machine is a generator and because the auxiliary power means comprise a bypass terminal in the winding of the generator to derive auxiliary power to form a power source. assistant.
22. 22. A plant according to any of claims 1-11, characterized in that the auxiliary power means comprise as an auxiliary power source an auxiliary power generator, such as a synchronous machine or permanent magnet generator, driven by the electric machine. .
23. 23. A plant according to claim 22, characterized in that the auxiliary power generator is provided with at least one winding comprising at least one electrical conductor, a first layer with semiconductive properties surrounding the conductor, a solid insulating layer surrounding the first layer and a second layer with semiconductor properties surrounding the insulating layer.
24. 24. A plant according to any of claims 1-11, characterized in that the auxiliary power means comprise as an auxiliary power source an extra secondary winding of a grounding transformer connected to a busbar for several generators.
25. 25. A plant according to any of claims 1-11, characterized in that at least one of the windings of a grounding transformer connected to a busbar for several generators is provided with a bypass terminal to extract auxiliary power.
26. 26. A plant in accordance with the claim

    24 or 25, characterized in that at least one of the windings of the transformer comprises at least one electrical conductor, a first layer with semiconducting properties surrounding the conductor, a solid insulating layer surrounding the first layer and a second layer with semiconducting properties surrounding the insulating layer.
27. 27. A plant according to any of the preceding claims, characterized in that the auxiliary power means comprise at least one auxiliary power source which is connected to an auxiliary power distribution bar for the auxiliary power distribution, via the power equipment. Electronic power components to keep the voltage in the auxiliary power distribution bar constant, the electronic power component equipment is provided with a direct voltage intermediate link to which a backup voltage can be connected if necessary.
28. 28. A plant according to claim 27, characterized in that a battery is connected to the direct voltage intermediate link to supply a predetermined backup voltage to the direct voltage intermediate link if its voltage level falls below the predetermined level.
29. 29. A plant in accordance with the claim

    27 or claim 28, characterized in that the equipment of electronic power components comprises an input stage for rectifying the alternating voltage obtained from the auxiliary power source for the generation of a direct voltage in the intermediate link in the electronic power equipment.
30. 30. A plant according to claim 29, characterized in that the input stage comprises a diode bridge.
31. 31. A plant according to claim 29, characterized in that the input stage and an output input included in the electronic power equipment each comprise a converter equipment.
32. 32. A plant in accordance with the claim

    29, characterized in that the input stage is designed to generate a direct voltage in the intermediate link, with a voltage level dependent on the load.
33. 33. A plant according to claim 32, characterized in that the input stage comprises a resistor and an inductor to produce a voltage drop dependent on the load.
34. 34. A plant according to claim 33, characterized in that the input stage is designed in such a way that, when the maximum allowable current is supplied, the voltage in the direct voltage intermediate link drops below the backup voltage.
35. 35. A plant according to any of claims 27-34, characterized in that a plurality of generators with extra windings for generating auxiliary power are connected in parallel to the direct voltage intermediate link, each via its own input stage in the equipment. auxiliary electronic
36. 36. A plant according to any of claims 27-35, characterized in that the auxiliary power distribution bar can be fed from additional sources, such as external supply sources or generators driven by diesel engines.
37. 37. A plant according to any of claims 27-36, characterized in that at least one alternating voltage distribution bar and at least one direct voltage distribution bar for distributing auxiliary power are fed from a battery and the auxiliary power distribution bar via a converter or from the intermediate link of the. equipment of electronic components of power.
38. 38. A plant according to claim 12 or claim 13, characterized in that the rotary electric machine is arranged to be energized from the auxiliary power winding.
39. 39. A plant according to any of claims 27-37, characterized in that the electric machine is arranged to be excited with the help of a pulsed circuit, the input and output are galvanically separated and the input is connected to the voltage intermediate link. direct.
40. 40. A plant according to claim 22 or claim 23, characterized in that the auxiliary power generator is connected to an auxiliary power distribution bar and because an integral motor is arranged to maintain constant the speed of the auxiliary power generator when there are variations in the voltage and / or frequency of the supply network.
41. 41. A plant in accordance with the claim

    22 or claim 23, characterized in that the equipment of electronic power components is arranged for the optional control of the power flow from the auxiliary power generator to the auxiliary power distribution bar or from the auxiliary power distribution bar to the generator of auxiliary power.
42. 42. A plant according to claim 41, wherein the electric machine is a synchronous machine, characterized in that the field winding of the auxiliary power generator can be short-circuited and that its stator side can be supplied with a three-phase voltage having a phase position and a frequency, such that the auxiliary power generator operates as an asynchronous machine with a rotation direction for a maximum braking torque.
43. 43. A plant according to claim 41, wherein the electric machine is a synchronous machine, characterized in that the field winding of the auxiliary power generator can be short-circuited and that at least one winding of the stator in the auxiliary power generator it can be fed with a direct current.
44. 44. A plant according to claim 43, characterized in that a frequency changer or a separate thyristor current converter for a single quadrant operation is arranged to feed with direct current at least one stator winding of the power generator. assistant.
45. 45. A plant according to any of claims 41-44, characterized in that the auxiliary power generator is designed with a suitable number of poles for frequency adaptation.
46. 46. A plant according to claim 12 or claim 13, characterized in that the electronic power equipment is arranged for an optional control of the power flow of the auxiliary power winding to the auxiliary power distribution bar or the power bar. distribution of auxiliary power to the auxiliary winding.
47. 47. A plant according to claim 46, wherein the electric machine is a synchronous machine, characterized in that the field winding of the machine can be short-circuited and because its auxiliary winding can be powered with a three-phase voltage that has a phase position and a frequency in such a way that the synchronous machine operates as an asynchronous machine with a direction of rotation for a maximum moment of braking torque.
48. 48. A plant according to claim 46, wherein the electric machine is a synchronous machine, characterized in that the field winding of the machine can be short-circuited and that at least one of its auxiliary windings can be powered with current direct
49. 49. A plant according to claim 46, wherein the electric machine is a synchronous machine, characterized in that a frequency changer or a separate thyristor current converter for a single quadrant operation is arranged to feed a winding with current. of auxiliary power in the machine.
50. 50. A plant according to any of claims 27-37, characterized in that the electric machine is arranged to be energized from a separately driven auxiliary power generator.
51. 51. A plant according to any of claims 17-21, 22 or 23, characterized in that an auxiliary power generator or generator with auxiliary power winding is connected to an auxiliary power distribution bar and because the actual loads are connected to integral motors, the speed is kept constant when there are variations in the voltage and / or frequency of the supply network.
52. 52. A plant according to any one of claims 1-24, characterized in that the machine with auxiliary power winding, connected to an auxiliary power distribution bar, can be driven in three simultaneous operating modes, ie, one mode of synchronous motor for driving a turbine part in air or vacuum, a synchronous compensator mode for generating reactive power to maintain the voltage in the external network and a transformer mode for transmitting power to the auxiliary power distribution bus.
53. 53. A plant according to any of claims 1-24, characterized in that the machine with separate auxiliary power generator, connected to an auxiliary power distribution bar, can be driven in three simultaneous modes of operation, i.e. a mode of synchronous motor for driving a turbine part in air or vacuum, a synchronous compensator mode for generating reactive power to maintain the voltage in the external network and a transformer mode for transmitting power to the auxiliary power distribution bus.
54. 54. A process in an electric power plant comprising at least one rotating electric machine of the alternating current type designed to be directly connected to a distribution network or a transmission network and comprising at least one electric winding, characterized because the winding of the machine is formed of at least one electrical conductor, a first layer with semiconductor properties surrounding the conductor, a solid insulating layer surrounding the first layer and a second layer with semiconducting properties surrounding the insulating layer and because that auxiliary power is generated with the help of an extra winding in the stator.
55. 55. A process in an electric power plant comprising at least one electric machine of the alternating current type in the form of a generator, designed to be directly connected to a distribution network or a transmission network and comprising at least one electrical winding, characterized in that the winding of the machine is formed of at least one electrical conductor, a first layer with semiconducting properties that the conductor surrounds a solid insulating layer surrounding the first layer and a second layer with semiconducting properties surrounding the insulating layer and because the auxiliary power is derived from a bypass terminal in the winding of the generator.
56. 56. A process in an electric power plant comprising at least one electrical machine of the alternating current type designed to be directly connected to a distribution network or a transmission network and comprising at least one electrical winding, characterized in that the winding of the machine is formed of at least one electrical conductor, a first layer with semiconducting properties surrounding the conductor, a solid insulating layer surrounding the first layer and a second layer with semiconducting properties surrounding the insulating layer and because a Separate auxiliary power generator is driven by electric machine.
57. 57. A process in an electric power plant comprising at least one electric machine of the alternating current type designed to be directly connected to a distribution network or a transmission network and comprising at least one electric winding, also as a grounding transformer connected to a busbar designed for several generators, characterized in that the winding of the machine is formed of at least one electrical conductor, a first layer with semiconductive properties surrounding the conductor, a solid insulating layer which surrounds the first layer and a second layer with semiconductor properties surrounding the insulating layer and because the auxiliary power is extracted from an extra secondary winding of the grounding transformer.
58. 58. A process in an electric power plant comprising at least one electric machine of the alternating current type designed to be directly connected to a distribution network or a transmission network and comprising at least one electric winding, also as a grounding transformer connected to a busbar designed for several generators, characterized in that the winding of the machine is formed of at least one electrical conductor, a first layer with semiconducting properties surrounding the conductor, a solid insulating layer surrounds the first layer and a second layer with semiconductor properties surrounding the insulating layer and because the auxiliary power is derived from a branch terminal of a transformer winding.
59. 59. A process in an electric power plant comprising at least one rotary electric machine of the alternating current type designed to be directly connected to a distribution network or a transmission network and comprising at least one electric winding, also as an auxiliary power generator connected to an auxiliary power distribution bar, characterized in that the winding of the machine is formed of at least one electrical conductor, a first layer with semiconducting properties surrounding the conductor, a solid insulating layer surrounding the first layer and a second layer with semiconductor properties surrounding the insulating layer and because the power flow is optionally controlled from the auxiliary power generator to the auxiliary power distribution bar or from the auxiliary power distribution bar to the power generator assistant.
60. 60. A process in an electric power plant comprising at least one synchronous machine designed to be directly connected to a distribution network or a transmission network and comprising at least one electric winding, characterized in that the winding of the machine is formed of at least one conductor, electric, a first layer with semiconducting properties surrounding the conductor, a solid insulating layer surrounding the first layer and a second layer with semiconducting properties surrounding the layer insulation and because the field winding of the machine is short-circuited and an auxiliary winding of the machine is fed with a three-phase voltage having a phase position and a frequency such that the machine operates as an asynchronous machine with an address of rotation for a maximum torque of braking torque.

    PLANT OF ELECTRICAL POWER

    SUMMARY OF THE INVENTION An electric power plant is described which comprises at least one electric machine (2, 4, 6, 8) of the alternating current type designed to be directly connected to a distribution network or a transmission network and which it comprises at least one electrical winding. The winding of the machine comprises at least one electrical conductor, a first layer with semiconductor properties surrounding the conductor, a solid insulating layer surrounding the first layer and a second layer with semiconductor properties surrounding the insulating layer. Auxiliary power means (10, 12, 14, 16, 18, 20, -22, 24, 26, 28, 30, 32, 34, 36, 38, 40) are arranged to provide the required auxiliary power. The procedure in such a plant is also described.