Showing papers in "IEEE Transactions on Energy Conversion in 1986"

Current Usage & Suggested Practices in Power System Stability Simulations for Synchronous Machines

Abstract: As a prelude to discussing some of the issues of prime interest to those concerned with the appropriate use of stability models, the Task Force A. INTRODUCTION believes the principal areas of interest for generator electrical modelling can be categorized This paper is being produced as a follow-up to the into four general areas (I) through (IV) noted Symposium on \"Synchronous Machine Modelling for below: (Only two of these areas, ie, II and III Power System Studies', (IEEE 83 TH0101-6-PWR). In will be covered in detail in this current paper). the symposium publication, discussed at the IEEE-PES Winter Power Meeting in 1983, the Joint Working (I) Short circuit, faults, and relay application Group, through a series of individual papers, gave studies. Parameters are required to obtain an overview of various approaches which have been initial R.M.S. current values or R.M.S. values used, or are currently being developed, to produce of current after subtransient currents have parameters for stability models. The complexities decayed. More complex studies can be possible in model availability were covered only performed including determination of dc offset briefly. Furthermore, the limitations in parameters values for specifying breaker ratings more obtained from data, obtained using either \"Standard\" precisely. methods, or using newly proposed methods, were not investigated or delineated in any depth. (II) Stability Studies (Large Disturbances, Non-Linear). Such analysis can include Another important factor, not given much treatment various types of time domain stability at the Symposium, was how saturation should be studies. Included are such examples as: treated in stability studies. It has been customary to consider a \"total\" saturation during the . First angular swing, no exciters, no initialization stage of stability studies, and also saliency (constant voltage behind a fixed during subsequent step by step calculations in time reactance). This approach, once common, is domain simulations. However, the application of now used infrequently for particular saturation factors to \"Unsaturated Models\" had not investigations of generating station been clearly demonstrated or fully justified in any stability limits. However, it is often used of the Symposium articles. Also the effects of to approximate the transient time-angle incremental changes in permeability (or saturation) response of machines or groups of machines have been covered in very few publications. The electrically remote from the principal area consideration of such effects in small signal or of investigation. The inertial effects of linearized stability analyses has been given limited such remote machines are important. recognition or study. First angular swing, with saliency The Joint Working Group feels that the above issues represented, both in the steady state and should be brought to the industries' attention, and transient state (constant field flux we welcome comments from both \"producers\" of linkages in the direct axis). This is an stability data, as well as from the many \"users\" of extension of the more commonly used approach such data. It is the Joint Working Group's described above. It is seldom used, since objective, in accordance with its scope, to the approximations made for the \"constant eventually produce a recommended set of Guidelines voltage\" approach provide acceptable results. for using various models in different types of stability studies, along with concordant procedures . Two or three time-angle rotor swings are for obtaining data for such models. often calculated principally of dominant

Application of Three-Dimensional Electromagnetic Analysis Methods to Electrical Machinery and Devices

Abstract: Electromagnetic field analysis methods have been effectively applied to Electrical machinery and devices over the last two decades as reported in the literature [1-10]. However, these methods have been limited to modeling the two-dimensional geometry of the machine or device and employing a single component vector or scalar potential function for the field solution. Electrical machine geometries are essentially three-dimensional and the potential solutions employed must yield all the three vector components of magnetic field and flux-density. Besides, with the increasing attention being focussed on energy efficient designs and reliability of apparatus in service, performance prediction and evaluation of design parameters such as end-leakage fluxes, inductances, time constants, losses, forces, torque etc., must be more accurately done than ever before. This paper reports on the development work done to date on three-dimensional modeling methods and their application to electrical machinery, and highlights some of the problems and opportunities for application of these techniques, for the manufacturing and utility industries. This project was partially funded by the Electric Power Research Institute, Palo Alto, California, under RP1288-1, ``Improvement in Accuracy of Prediction of Electrical Machine Constants.''