Search

Eccentricity in salient poles synchronous generators (SPSG) is a failure mode that requires particular attention due to its possible catastrophic consequence. To diagnose it, specialists have focused on the frequency spectrum of the stator current, obtained from the Fast Fourier Transform (FFT). Other techniques, such as transient current analysis, flux and vibration have proven to be valuable sources of information. The paper aims to illustrate the state of the art on the diagnosis of eccentricity in SPSG and proposes a new state variable for the diagnosis of this failure mode with the asset in service. As a result of the work on the technology and the theoretical research carried out, it is concluded that it is possible to diagnose the eccentricity of the electric generator from the behavior of the neutral current of the machine in operation. [ABSTRACT FROM AUTHOR]

Copyright of Revista CIENCIA UNEMI is the property of Universidad Estatal de Milagro (UNEMI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

That the electromagnetic torque is who mainly brakes the mechanical power applied by the primary motor it is professionally of total knowledge, but anything practical it is made to reduce its negative effect, because this is accepted for more than one century like something inherent to the electric generator, it is certain that this you cannot avoid, but it is practical and theoretically possible to minimize its noxious effect. Modifying the main magnetic circuit of the synchronous generator is possible to minimize the antagonistic torque electromagnetic, main cause of the enormous consumption mechanic energy of the generator synchronous commercial necessary today; in the present its validity is demonstrated like potential way to saving of primary energy by means of parameters in the physically measured practice, as well as mathematically using equations, theorems and laws of the electric engineering; we continue developing new variants in our University. [ABSTRACT FROM AUTHOR]

This paper presents the theory and methodology for the adjustment of the negative sequence current protection function (PF) ANSI 46 of a synchronous generator with poles and poles, for a multifunctional relay SIEMENS 7UM62 that uses for its logic of decision the curve of time of heating allowed of the machine before the increase of the magnitude of negative sequence Also the consequences and the damages that can be caused by the excess of current of negative sequence circulating by the stator of the generator are explained. In addition, its functional diagram is illustrated by identifying its input signals: data (settings), analog and binary signals; It also describes in detail its decision process and exit signals. This logical diagram was divided into 3 sub-diagrams to identify the causes that originate their outputs: alarms, startup, firing or blocking, this way of illustrating the process by stages allows greater clarity, since the explanation process is more didactic than the one presented by the manufacturer in the manual. As an example of an illustration, the calculations of the adjustment criteria of the ANSI 46 PF applied to a salient pole generator from Unit 1 of the Salvajina Hydroelectric Plant are presented in detail. This protection function protects the machine by heating load imbalance and asymmetric faults. [ABSTRACT FROM AUTHOR]

This paper presents the state of the art on system identification applied to excitation systems. First, general overviews about system identification and excitation systems for synchronous generators are presented, highlighting the unique characteristics imposed by the excitation systems in an identification process. Then, a bibliographic classification method based on the excitation system characteristics was designed, which provides a results matrix condensing the topics addressed by more than 40 reviewed publications. From the results analysis the state of the art in excitation system identification was established, and open research areas in the topic were recognized. [ABSTRACT FROM AUTHOR]

In this work, a black-box model for the estimation of the rotor angle of a synchronous generator is developed by using voltage and current measurements at the terminals. The model is based on neural networks of the multilayer perceptron (MLP) type. From time-domain simulations for a basic power system, which consists of a generator connected to an infinite bus bar, voltage and current records are collected, which are used as a database to train and validate the neural network that is proposed for the estimation of the rotor angle. It is found that the neural-network based model adapts itself very well to the classic model of the generator, exhibiting a mean square error of 1x10-10. The results show the validity of the estimation method and foster its potential use for stability studies of the synchronous generator. [ABSTRACT FROM AUTHOR]

In this paper, we make an evaluation of the complete ground-fault protection of the stator of synchronous generators by use of the subharmonic injection method. Firstly, we describe two approaches for the complete protection of the stator: the third harmonic method and the method of subharmonic injection. Secondly, we analyze the error in the determination of the ground-fault resistance for an 11.4 kV synchronous generator from the consideration of various operating conditions. This error is related to the type of voltage transformers being used, the occurrence of signal noise, the digitalization process, and variations in the numerical values of the required parameters. Lastly, we show that the subharmonic injection method is very useful for the determination of the ground-fault resistance and performs well for the complete protection of the stator. [ABSTRACT FROM AUTHOR]