Turbogenerator Design Research Articles

Modeling of the Stress–Strain of the Suspensions of the Stators of High-Power Turbogenerators

In the submitted scientific work, the existing types of stator fastening design of turbogenerators and the main causes of the stressed state of the stator suspensions are considered. A detailed calculation of the complex stressed state of the turbogenerator stator suspension was carried out for a number of electrical sheet steels, taking into consideration the unevenness of the heat distribution along the horizontal axis of the unit. It is proposed that the calculation of the mechanical stress is carried out by means of the mechanical and thermal calculation, coordinated with the electrical one. The possibility of replacing steel 38Х2Н2ВА with steel 34CrNiMo6 and 40NiCrMo7 is indicated, subject to compliance with GOST 8479-70 for the same strength group.

Автоматизация проектирования турбогенераторов

Автоматизация проектирования турбогенераторов

Influence of Solid Rotor Steel on Dynamic Response and Losses of Turbogenerator With Loss of Excitation

The rotor of turbogenerator is made of solid steel, instead of laminated steel, for its high-speed rotation. The asynchronous torque resulting from the eddy current in the rotor core plays an important role in the asynchronous operation of turbogenerator after loss of excitation. On the other hand, the rotor loss and temperature rise restrict the operation of turbogenerator. The selection of solid steel is therefore a key factor that affects the operation limit and should be carefully considered in the design of turbogenerators. For a turbogenerator with the rotor core made of different solid steel, this paper presents time-stepping finite element calculation of the asynchronous performances and the experimental validation. The influences of different rotor solid steel on the dynamics, saturation, asynchronous operation ability, and rotor loss of turbogenerator with the loss of field are studied. The losses in different areas of rotor are calculated and compared. The results provide steel manufacturers and generator designers with the theoretic basis for improvement of the asynchronous operating ability of turbogenerator.

Peculiarities of Designing of Suspensions for Stators of High Power Turbogenerators

The analysis of existing designs of the stator fastening of Turbogenerators of various design versions is carried out. It is shown that the application of a spring suspension is the integral part of the design of Turbogenerators rated 100 MW and higher. The detailed calculation of the complex stressed state of the stators suspension of Turbogenerators manufactured at SE "PLANT "ELECTROTYAZHMASH" rated 200 MW and 250 MW with hydrogen and hydrogen-water cooling is submitted in the scientific work, taking into account the uneven thermal distribution along the horizontal axis of the aggregate for some number of electrical-sheet steels. The various types of the stator deformation caused by a number of forces are considered. It is proposed to carry out the calculation of mechanical stresses by iterative execution of mechanical and thermal calculations coordinated with electrical stresses. As limiting conditions for taking in to account of forces caused by temperature changes, the limiting conditions of the first kind were considered. At that, in the mechanical calculation, it is necessary to take into account the design peculiarities for each row of springs, taking into consideration the correction for temperature. The key factor is the difference between the calculated vibrations for a stand separately core and its installation in to the casing with suspension, depending up on the modulus of elasticity of the stacked up laminated core for electrical-sheet steels 3413, 3414 GOST21427.1-83, M270-50A. The possibility of changing of steel 38Х2Н2ВА to steel 34CrNiMo6 and steel 40NiCrMo7 is shown, provided that the GOST8479-70 complies with the same strength group.

Automated Prediction of Critical States of Turbogenerators During Thermal Expansion of a Rotor and a Stator Based on a Recurrent Neural Network

The present article is devoted to the development of a method and its software implementation for forecasting the critical states of a turbogenerator and its design elements that arise during starting-up & adjustment works and stopping a turbine. The method is based on a short-term prediction of the image of the spectrogram of vibrations during thermal expansion of the rotor and stator. The dependence of the increase in the vibration level in the spectrum with the failure of the turbogenerator design element is substantiated. The model takes into account the influence of thermal expansion on critical states. The technique of training a deep neural network is given in the classification of thermal influences on the level of vibration while a spectrogram receiving. For machine learning of a neural network in software, a recurrent autoencoder is used. The technique of operation is with a time sequence of spectrograms. To test the model is introduced the concept of semantic quality of clustering. Semantic quality, determined as the degree of correspondence between the information that can be extracted from the obtained cluster structure and the formalized presentation of the user. The interpretation of the results of the discovery of turbine generator defects is presented.

Analysis of complex fluid flow and temperature field in the turbogenerator end region with magnetic shield structure under underexcitation operation

The large electromagnetic losses and high temperature rise under underexcitation operation are the main issues of large turbogenerator design. In order to study the eddy current losses, fluid velocity, and temperature distribution in the turbogenerator end region with magnetic shield structure under underexcitation operation, three-dimensional transient electromagnetic field of a 1250 MW turbogenerator end region is investigated. The losses of end parts and stator end cores (heat source) are obtained under underexcitation operation. Velocity values of different inlets and pressure value of fan outlet (boundary condition) are determined by flow network calculation. Meanwhile, three-dimensional fluid and thermal fields are calculated. The distribution of fluid flow between magnetic shields is obtained. The temperature distribution of end parts and stator end cores in the end region of large turbogenerator is studied under underexcitation operation with 0.9 pf lead. Calculation results are compared with experiment data, which provides a reliable basis for the design and operation of larger turbogenerator.

Continuation of Prof. Władysław Latek’s research – revitalization of old power units

Abstract The research conducted by Prof. Władysław Latek (1916‒1991) has contributed greatly to development in turbogenerator design. The economical transformation taking place in Poland after 1991 initiated the process of revitalization of old power units in electric power stations. For the past 25 years, a team of scientists continuing the work on perfecting the turbogenerator design and design methods has been working in the Faculty of Electrical Engineering of Silesian University of Technology. The work of this team has led to proposing and implementing many modernization projects for turbogenerators operating in Polish power plants, as well as in power plants in European Union and Asian states. Numerous novel and innovative solutions have made it possible to significantly increase turbogenerator power, improve effectiveness of electrical energy production and reliability and safety of operation.

Numerical calculation for circulating current in stator transposition bars of large water-cooled turbo-generators

Accurate calculation of circulating current is one of the key problems for stator transposition bars in the design of turbo-generators. Aimed at limitation that analytical algorithm of circulating current could not reflect the local electromagnetic field distribution and difficulty that overlaps easily exist in solid modeling process of stator transposition bars, a simplified physical model of transposition bars is established. A three-dimensional (3-D) numerical method for circulating current in stator transposition bars of large water-cooled turbo-generators is investigated, which is combined with field-circuit coupling method. Taking stator bars less than 540° transposition with void model of a 600-MW water-cooled turbo-generator as the research object, the magnetic flux density distribution, current density distribution and circulating current distribution of transposition strands are obtained by numerical calculation. Compared with calculation results of the improved analytical algorithm, the correctness of the numerical calculation for circulating current is demonstrated, the calculation value difference for the maximum current of strands is obtained. The numerical calculation for circulating current will provide an appropriate basis for the reasonable calculation of local overheating of stator transposition bars and the design of safety margin for turbo-generators.

THE NUMERICAL FIELD ANALYSIS OF EXCITATION MODES AND OF THE DIFFERENT TYPES OF THE ARMATURE REACTION IN A POWERFUL TURBOGENERATOR

Principle and the numerical field analysis results of the different excitation modes and of the different types of the armature reaction of powerful turbogenerator are presented. A selection of the the magnetic field excitation factors in the idle mode, the rated load and short-circuit, as well as those specific modes that are characterized by longitudinal demagnetizing and magnetizing and more cross-reaction of the armature excitation of the magnetic field only the stator winding along the longitudinal and transverse axes of the rotor is shown. The principle, which allows by the results of the magnetic field calculation in each mode to determine the key electromagnetic values (magnetic flux and EMF) and the phase relationship between them and the currents is considered. The pictures of the magnetic fields are graphically presented in all modes, and the principle of the corresponding vector diagrams construction is also presented on the basis of calculation of these fields. In the original received vector diagrams it is possible to identify qualitatively and quantitatively the share and role of the magnetic field of the rotor and the stator magnetic field. The conducted research can be the basis for improving the system of study, analysis and design of turbogenerators and other electric machines because the considered method of analysis of magnetic fields is quite universal

Integrated Control System for Turbogenerator Design by Inverse Nyquist Array Method

This paper is concerned with the design, evaluation and testing of a Multivariable control scheme for a turbogenerator with fast turbine and excitation control.

SIMSYS - Computer Aid in the Design and Development of Turbogenerators

The paper introduces the need for a systematic problem-solving aid in turbogenerator design and development. Finite difference simulation is taken as the basic concept behind a special computer language to aid the problem-solving function. This language (SIMSYS) is described, together with some examples of its use in new turbogenerator development, and conclusions are drawn about the utility of such a system.