# Calculation Method of Internal Fault Circuit Parameters of Steam Turbine Generator

1 Structural features of the hidden-pole turbine generator Compared with the polar-step generator, the old-pole turbine generator has the following features: 3. Uniform air gap, regardless of the influence of the stator and rotor on the slot, the air gap permeability Is a constant, ie. The rotor field winding is a distributed field winding + centralized excitation winding of a 1-pole hydroelectric generator. Accordingly, the self-inductance and the calculation of the mutual inductance with other circuits are different from that of the salient-pole synchronous motor. The rotor is small except In addition to the lamination structure, the overall capability is usually a large-scale turbine generator usually equipped with an end damping groove on the rotor, a full-length damping pole or a full-length damping system in full length. In this case, the damping system and solid must be considered. The combined effect of the thirsty rotor.

These wolframs have determined that the calculation of the parameters of the turbine generator circuit has its own characteristics. The magnetic circuit magnetic susceptibility method and the magnetic field numerical method are respectively used to discuss the resistance of the stator and rotor of each stator circuit and the part of the circuit. The calculations can be found in the relevant literature, and the article no longer interprets the magnetic circuit of the magnetic circuit. 2 The calculation method of the magnetic circuit of the magnetic circuit uses the magnetic circuit magnetic conductance method to calculate the loop inductance, which is the so-called path method. It is based on the following idea between the two coils. The mutual inductance is proportional to the magnetic flux of the path through which the coil crosses the sense magnetic flux generated when the coil passes a unit current, that is, the air gap primary inductance of the fourth and the seventh coils is the air gap magnetic difference per unit area. The magnetic permeability is called the winding function, which is the coordinate established on the rotor with the mechanical angle, and the origin of the rotor is taken as the coordinate origin. If the winding function and air gap permeability of the two wires or paths are known. It is possible to educe equation 2 to derive the main inductance of the air gap between the two wires. This part of the main inductance plus the leakage inductance is the total inductance between the two coils or the loop. This method can consider the effects of various harmonics of the air gap magnetic field. Air-gap main inductance between stator loops.

21 Inductance Between Stator Single Coils Because the turbine generator has an even air gap and its permeability is constant, it can be known from Equation 16 and Equation 17 in Reference 3 that number and number are. No. 5 between the coil sense, for the nine corresponding to the leakage magnetic flux leakage and the end of the magnetic leakage leakage from the main inductance of the air gap; Huan, the number of lines, 7; households for the pole logarithm; for the pole pitch; left Is the short-range coefficient of the moxibustion subharmonic wave; 1 is the stator slot pitch angle, and the electric angle can be used in formula 2 of the mountain bibliography 3, and after one row considers the subharmonics, the stator single coil and the seven air gap primary inductors The concise formula is 1 also knows that the mutual inductance between the stator coils of the turbine generator is independent of the rotor position. 22 The self-inductance of the excitation winding is known from the knowledge of electrical machinery. There is a radial slot on the surface of the rotor of the hidden-type turbine generator. Excitation winding placed in the two sides of the slot, and the line; 1; the formation of the so-called concentric distributed excitation winding In order to make the excitation magnetic potential waveform close to sine, in the middle of the pole does not put the winding, called the rotor tooth definition If the number of slots is 7 and the number of slots is 7 and the number of divisions is stone, then the index ratio is equal to 22 stones. In order to distinguish between the four rotor position angles, the rotor indexing ratio is recorded in each slot of the rotor. The number of turns of the coil is equal, then the rotor magnetic force waveform is a function of the graduation ratio, and is a staircase 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 is the winding function of the opposite polarity of the turbine generator in 1, the middle ordinate is placed on the axis of the large tooth, the number of coils, strokes = 4 households; for the excitation winding The number of parallel branches from 1 and 2 can be obtained from the induction inductance of the excitation winding of the turbine generator as the inductance of the main magnetic field of the gap. There are 2.3 Inductances between the damping loops The rotor equivalent damping system is divided into slotted tooth pole faces, pseudo pole face damper windings, different closed loops, and approximately considers the rotor thirst effect that adjacent tendons and sections The damping end loop constitutes the damping loop, then the inductance of the damping loop 1 and 2 is the number of turns of the damping loop; the damping angles of the damping loops 1 and 2 along the center line of the leading straight axis; the moxibustion is respectively the damping When the short-distance ratios of loops 1 and 2 are 1 = jade, =1, equation 8 is the self-inductance of the damping loop. When all the sub-harmonics are counted, the damping of loop 1 is self-inductance. The simple mutual inductance between loops 1 and 2 is 2.4. The inductance between the excitation winding and the damping loop The mutual inductance between the excitation winding and the damping loop 1 is such that excitation is accounted for when all the subharmonics are accounted for and the damping loop is located in the rotor slot. The simplicity of the mutual inductance between the winding and the damping circuit 1 is.

In the same way, when all the sub-harmonics are considered and the damping loop 1 is located on the polar surface, the mutual inductance between the excitation winding and the damping loop is the same as that of the Shanghai-class group No. 1 between rolling and field windings. Sense 26 Inductance between stator single coil and damping circuit The mutual inductance between stator coil and damping circuit 1 of the stator winding is algebraic expression in which the inductance of the wheel-generator circuit is in the form of an infinite number, and the magnetic field method of type 3 is calculated. The electrical parameters of the loop are firstly applied to the parameterization storage limit element 1 grid generation software to split the entire grid to calculate the permeability distribution of the turbine generator during normal operation. Keeping the permeability distribution constant, one coil or loop is turned on. The distribution of the field is calculated by the finite element method. And use the magnetic chain method to calculate the magnetic field distribution of the single damping circuit of Qiaoyouyou 2 turbo generator when the current flows through the chain and crosses the other chain or the magnetic flux of road 1 and obtains the self-inductance and mutual inductance 2 . Eight pole-damping loops are used on each big tooth, and the magnetic flux is rapidly attenuated outward from the belt's equivalent line. The mutual inductance between the equivalent damping loops is also equivalent to that of the equivalent circuit. The distance between space increases and it rapidly decreases. , After a little circuit, the sense is very small. In the calculation results of the electric parameters of the 4 turbine generator circuit, the above two methods are used to calculate the electric parameters of the 302 turbine generator at no load. The main parameters of the generator are: The outer diameter of the stator is = åž 1 = 22, and the number of phases is æ²™. ,,,,,,,,,,,,,,,,,,,,,,, Other parameters, inductance, inductance between the first coil and the seventh coil of the stator, because the stator diameter of the stator of the turbine generator is much smaller than that of the fire type turbine generator, therefore, The effect of space distance on the value of stator inductance is that there is no stator winding of the large excitation generator's next excitation winding, and the mutual inductance varies with the rotor position angle. From this, the change waveform takes a dragon as a period and basically changes as a cosine. It also indirectly shows that the normal analytical formula is quite accurate in the influence of the 5th-phase iron core magnetic reluctance, so the loop parameters calculated by the magnetic field numerical method are also more in line with the meaning of physical properties, the magnetic flux permeability method; the magnetic field numerical method has no damping loop. The mutual inductance, the magnetic permeability method; magnetic field numerical method of mutual inductance with the rotor position angle 7 of the relationship between the two methods of comparison and conclusions The two parameters have their advantages and disadvantages. Magnetic circuit magnetic method magnetic circuit magnetic method; magnetic field numerical method The mutual harmonic amplitude of the circuit between the loop because it can be considered in the fixed winding çºŸ1 internal fault when the air gap magnetic field harmonics and the effect of the current harmonic , And the calculation is small. It is a quick and effective method for obtaining the parameters of the generator winding loop. However, the magnetic circuit magnetic permeability method reduces the magnetic resistance of the core to the air gap according to the magnetic circuit on the fundamental wave. The internal fault circuit of the stator winding has a great influence on the effect of the air gap harmonic magnetic field. Inductance calculation will cause a certain error. The magnetic field numerical method can consider the superiority of the core reluctance non-linear cogging effect and air-gap harmonics and other factors, and it helps to improve the accuracy of the loop parameters after the stator internal winding fault. From the calculation results of the loop parameters of 302 large-scale turbo-generators by Muwen, it can be seen that the magnetic field numerical method is more in line with the physical sense than the magnetic circuit magnetic conductance method, and accordingly the internal fault current simulation of the stator hunger hunger is simulated. The results are also more reasonable. This part of the content of the text but the magnetic field numerical method requires high computer hardware, programming is more complex, the required motor parameters than the magnetic circuit magnetic method more. In practical applications, the corresponding circuit electrical parameter calculation method can be selected according to the calculation accuracy requirements of the parameters of the saturation degree of the operating condition of the motor core and the motor parameters provided by the design department.

Thank you very much.

Magnetic field magnetic method magnetic field numerical method 15 Yuan Yaxiang, Sun Wenyu 38, 8 is called, 1. The optimization of Yuan Xiaohui, male, doctoral student, is currently mainly engaged in the short-term optimal scheduling of hydropower systems.

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

Quan Xianyi, male, professor, is mainly engaged in research on the economic operation of hydropower systems.

4 Tu Liming, Hu Minqiang 1 gold, buckle. Calculation of the loop parameters of the fractional slot winding turbine generator using the finite element method.

5 Slaughter 1 dawn. The analysis method and application of the internal fault of the stator windings of synchronous generators. Research Doctoral Dissertation (3) Yanshan Xian Tuming, male, Ph.D., is mainly engaged in research and development of fault simulation and protection devices for electrical main equipment.

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

1 Jingde Jingde, Wang Xiang 5 lines, Li Fahai; 3. Pei. 16,33, 3.161 Tower, 13. Analysis of AC motors and their systems, Xian 10é³•3.06, 13870, Beizuo Tsinghua University Press Beijingf