Calculation method of electrical parameters of internal fault circuit of turbo generator

1 The structure characteristics of the hidden-pole turbo generator Compared with the pole-step generator, the old-pole turbo generator has the following characteristics: 3. The air gap is uniform. If the influence of the stator and rotor on the cogging is not considered, the air gap permeability Is a constant, ie. The rotor excitation winding is a distributed excitation winding + a concentrated excitation winding of a 1-pole hydro-generator. Correspondingly, the self-inductance and the mutual inductance calculation with other circuits are different from the salient-pole synchronous motor. In addition to the laminated structure, it is usually an integral capability. Large turbo generators are usually equipped with a full-length damping magnetic pole full-length damping or a complete full-length damping system on the rotor. In this case, the damping system and solid must be considered. The combined effect of the rotor thirst.

These flashing factors have determined that the calculation of the parameters of the turbine generator circuit has its characteristics of white body. The magnetic path magnetic field method and the magnetic field numerical method are respectively used to discuss the circuit resistance and part of the inductance parameters of the stator and rotor. The calculation can be referred to the relevant literature. The text is no longer explained. The magnetic circuit of the magnetic circuit is used to calculate the electrical parameters of the circuit. The magnetic circuit is used to calculate the loop inductance, which is called the road. It is based on the following idea between the two coils. The mutual inductance is proportional to the magnetic permeability of the path through which the coil intersects the sense flux in the unit current, that is, the air gap main mutual inductance of the 4th and 7th coils is the air gap magnetic difference per unit area. The magnetic permeability coefficient is studied as a winding function, which is the coordinate established on the rotor at a mechanical angle, and the winding function of the two-wire or the path and the air-gear permeability coefficient are known from the direct axis of the rotor. It is possible to derive the air gap main inductance between the two lines in accordance with Equation 2, and the main inductance plus the leakage inductance is the total inductance between the two coils or the loop. The method can consider the effects of the harmonics of the air gap magnetic field. Air gap main inductance between stator circuits.

The inductance between the single stator of the 21 stator is constant because the air gap of the turbo generator is uniform, and the magnetic permeability coefficient thereof is constant. Therefore, the numbers and the numbers are known from the equations 16 and 17 of the literature 3. The 5 sense between the coils is the force 9 for the leakage flux of the corresponding slot and the leakage of the end leakage is the main inductance of the air gap; the number is the line, the number of 7; the household is the pole log; the pole distance; left It is the short-distance coefficient of the moxibustional harmonics; 1 is the stator slot angle, and the electrical angle can be used in the formula 2 of the mountain literature 3, after considering the secondary harmonics of the train, the single coil of the stator and the main inductance of the seven air gaps It is also known that the mutual inductance between the single coils of the turbine generator stator is independent of the rotor position. 22 The self-inductance of the excitation winding is known from the motor knowledge. The radial groove of the rotor body surface of the hidden pole turbine generator is opened. The field winding is placed in the groove on both sides, and the line; 1; is formed into a so-called concentric distributed excitation winding. In order to make the waveform of the excitation magnetic potential close to the sine, the winding is not placed in the middle portion of the magnetic pole, which is called the definition of the large tooth of the rotor. Turning real, the number of slots is 7, and the number of turns is stone, then the indexing ratio = 22 stone for the difference of the sign of the 4 rotor position angle, here the rotor indexing ratio is recorded as the rotor in each slot The number of turns of the coil is equal, the rotor potential waveform is a function of the indexing ratio, and is a stepped waveform, usually for convenience. For analysis, approximately trapezoidal waves are used instead. Correspondingly, the winding function is also a trapezoidal wave, the function of the giant foot of the turbo generator is 1 in the winding function, the middle ordinate is placed on the axis of the large tooth, the number of coils is 4, and the number of coils is 4; The number of parallel branches is 1 and 2, and the self-inductance of the excitation winding of the turbo generator is the inductance of the main magnetic field. And there are 2.3 damper loops between the inductor rotor equivalent resistance system is divided into slot 槐 齿 极 ,, pseudo-surface damper winding, different closed loop, and consider the rotor thirst effect to consider adjacent tendon and part The damper end ring constitutes a damper circuit, and the inductance of the damper circuit 1 and 2 is the number of turns of the damper circuit; the electrical angles of the damper circuits 1 and 2 are respectively turned to the center line of the straight axis; moxibustion is damping When the loops 1 and 2 speak the subharmonic short-distance ratio when 1 = jade, =1, the formula 8 is the self-inductance of the damping loop. When all the subharmonics are counted, the self-inductance of the damping loop 1 is damped. The mutual inductance between loops 1 and 2 is as simple as 2.4. The inductance between the excitation winding and the damping circuit is the mutual inductance. Therefore, when all the subharmonics are taken into account and the damping circuit is located in the rotor slot, the excitation is performed. The conciseness of the mutual inductance between the winding and the damping circuit 1 is.

In the same way, when all the subharmonics are taken and the damping circuit 1 is located at the pole surface portion, the simple relationship between the excitation winding and the damping circuit is the line between the 1st line and the field winding of the fixed-level group. Sense 26 stator single coil and the damping circuit between the inductance of the stator winding of the first coil and the damping circuit 1 mutual inductance is the wheel generator circuit inductance is a series of algebraic form, shape 3 magnetic field numerical method The loop electrical parameters are firstly divided into the grid of the whole machine by using the parameterized limit element 1 grid generation software to calculate the permeability distribution of the turbine generator during normal operation. Keeping the permeability distribution unchanged, a coil or loop 1 is turbulent. The distribution of the field at this time is calculated by the finite element method. And using the flux linkage method to calculate the chain and the other coils of the cross-link or the flux linkage of the road 1 and get the self-inductance and mutual inductance 2 is the magnetic field distribution of the single damping circuit of the Qiao 3 post 2 turbo generator. Each of the large teeth is made up of 2 pole surface damping circuits, etc., and the magnetic flux is rapidly attenuated from the equivalent line with turbulence, and the mutual inductance between the equivalent damping circuits is also changed with the equivalent circuit. The spatial distance increases and the speed is reduced. After the separation of the circuit, the feeling is very small. The calculation results of the electrical parameters of the 4 steam turbine generator circuit are calculated by the above two methods. The circuit electrical parameters of the 302 steam turbine generator under no load, the main parameters of the generator are The outer diameter of the stator is 卞1=22, which is equivalent to a few sands. , =, other parameters, the design of the machine is the inductance between the first coil and the first coil of the stator. Because the stator and rotor of the turbo generator are smaller than the fire turbine, it is much smaller. The influence of the spatial distance on the stator inductance value is not the stator line of the large-scale hydro-generator bright excitation winding, and the mutual inductance varies with the rotor position angle. 4 From this, the variation waveform has a cycle of dragons and basically has a cosine variation. It also indirectly shows that the normal analytical formula is quite accurate for the influence of the 5th core magnetoresistance, so the loop parameters calculated by the magnetic field numerical method are more in line with the meaning of the object, the magnetic path magnetic permeability method; the magnetic field numerical method has no damping circuit. Mutual mutual inductance, magnetic path magnetic permeability method; magnetic field numerical method mutual inductance with rotor position angle 7 relationship between the two methods of comparison and conclusions of the two parameters calculation methods have their own advantages and disadvantages. Magnetic path magnetic method magnetic path magnetic method; magnetic field numerical method of each harmonic amplitude of the mutual inductance between the loops can be considered because of the effect of the air gap magnetic field harmonics and current NO wave which have a large influence on the internal fault of the fixed winding 1 And the calculation is small. It is a fast and effective method to obtain the generator winding loop parameters. However, the magnetic path magnetic conduction method calculates the core magnetoresistance to the air gap according to the magnetic circuit on the fundamental wave, and the internal fault circuit of the stator winding has a great influence on the air gap harmonic magnetic field. Inductance calculation will cause a fixed error magnetic field numerical method. Several lamps can consider the superiority of the core cogging nonlinear cogging effect and air gap harmonics, and help to improve the accuracy of the loop parameters after the internal fault of the stator winding of the generator. It can be seen from the calculation results of the circuit parameters of 302 large steam turbine generators in Muwen. The magnetic field numerical method is more in line with the physical principle than the magnetic path magnetic conduction method, and correspondingly simulates the internal fault current of the stator. The results are also more reasonable. This part of the content will be issued but the computer hardware requires high magnetic field numerical method, the programming is more complicated, and the required motor parameters are more than the magnetic path magnetic conduction method. In practical applications, the calculation method of the electrical parameters of the motor can be selected according to the saturation degree of the core of the motor, and the calculation parameters of the motor are provided by the design department.

Thank you very much.

Magnetic field magnetic field method numerical method 15 Yuan Yaxiang, Sun Wenyu 38, 8 called, 1. Optimization Xiao Yuan, male, doctoral student, is currently engaged in short-term optimal scheduling research of hydropower systems.

Yuan Yan, male, Ph.D., is currently engaged in the application research in hydropower systems.

Quan Xianyu, male, professor, is mainly engaged in the economic operation of hydropower systems.

4 Tu Liming, Hu Minqiang 1 gold, buckle. The loop parameters of the fractional-slot winding hydro-generator are calculated by the finite element method.

5 Tu Liming 1 叩. Synchronous generator stator winding internal fault analysis method and its application research PhD thesis (3) XIANG Shanxian Tu Liming, male, Ph.D., mainly engaged in the research and development of electrical main equipment fault simulation and protection devices.

Hu Minqiang, male, professor, doctoral tutor, is mainly engaged in the teaching and research work of large-scale motor design and operation of motor physics and electrical fault diagnosis.

1 cylinder Jingde, Wang Xiang 5 lines, Li Fahai; 3. Pei. 16,33!3.161 tower, 13. Analysis of AC motor and its system, Xian 10鳕3.06 grab 13870, Beizu Tsinghua University Press Beijingf

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