VICARED: A Neural Network Based System for the Detection of Electrical Disturbances in Real Time

The study of the quality of electric power lines is usually known as Power Quality. Power quality problems are increasingly due to a proliferation of equipment that is sensitive and polluting at the same time. The detection and classification of the different disturbances which cause power quality problems is a difficult task which requires a high level of engineering knowledge. Thus, neural networks are usually a good choice for the detection and classification of these disturbances. This paper describes a powerful system for detection of electrical disturbances by means of neural networks

Considerations on the non-active power using geometric algebra

Several approaches have been developed to define the non-active power concept under nonsinusoidal situations in electrical systems. Nevertheless, these contributions do not provide a complete and satisfactory solution to the non-active power reversibility between frequency domain and time domain. This paper presents a non-active power multivector concept, based on an original vector space frequency-domain approach that bridges the gap between both domains. The suggested correspondence can provide a convenient descriptive language to reconcile Fryze’s instantaneous non-active power with Budeanu´s deactive-power

Wavelet and Neural Structure: A New Tool for Diagnostic of Power System Disturbances

The Fourier transform can be used for analysis of nonstationary signals, but the Fourier spectrum does not provide any time-domain information about the signal. When the time localization of the spectral components is needed, a wavelet transform giving the time-frequency representation of the signal must be used. In this paper, using wavelet analysis and neural systems as a new tool for the analysis of power system disturbances, disturbances are automatically detected, compacted, and classified. An example showing the potential of these techniques for diagnosis of actual power system disturbances is presented

Instantaneous current vectors in polyphase systems: two compensation concepts

6 páginas, 9 figuras, 24 referencias.-- Trabajo presentado al Modern Electric Power Systems (MEPS) International Symposium, celebrado del 20-22 de septiembre 2010, en Wroclaw, Polonia.According to the target of minimal line losses and a power factor equal to one, the present work studies two concepts of instantaneous compensation of nonactive current which are generally applied to polyphase systems. The analysis is defined both on the basis of the instantaneous value concept, for arbitrary voltage and current waveforms, and on the basis of the average value concept, for steady-state and periodic conditions. Results of using these concepts for instantaneous compensation are compared by simulation.Peer reviewe

Reviewing concepts of instantaneous and average compensations in polyphase systems

According to the target of minimal line losses and a power factor that is equal to one, this paper studies two concepts of instantaneous compensation of nonactive current which are generally applied to polyphase systems. The analysis is defined both on the bases of the instantaneous-value concept, for arbitrary voltage and current waveforms, and the average-value concept, for steady-state and periodic conditions. The results of using these concepts for instantaneous compensation are compared by simulations.Peer Reviewe

Strategies of instantaneous compensation for three-phase four-wire circuits

When the voltage source is not balanced for three-phase four-wire circuits, instantaneous compensation for the instantaneous reactive power does not eliminate the neutral current on the source side. In fact, when the zero-phase voltage of the source exists, none of the present compensation strategies can guarantee the instantaneous elimination of the neutral current in three-phase four-wire systems. Two approaches are distinguished in this paper for instantaneous compensation. The first eliminates the instantaneous reactive current, thus neutral current can still flow. The second eliminates the instantaneous pseudo-reactive current, so that the neutral current component is compensated. In the latter case, a new control strategy is designed to avoid instantaneous power flowing through the compensator. It provides flexibility in compensating for the neutral current in a three-phase four-wire system including the zero-sequence voltage. Finally, simulated and experimental results are obtained to confirm the theoretical properties and show the compensator performance.Peer Reviewe

Identification of instantaneous current components in three-phase systems

The theory of electric power for three-phase systems has been based on both the instantaneous value concept and the average value concept (mainly developed in the frequency domain). In the former, two orthogonal current vectors have been considered as the suppliers of the active and reactive power components, which are transferred between source and load. In the latter, active, reactive, scattering, unbalanced, and nonlinear currents are identified as the suppliers of the corresponding power components. Under stationary and periodic conditions, the authors demonstrate the identification of instantaneous current components defined by both concepts. Balanced or unbalanced loads with sinusoidal or nonsinusoidal phase voltages are considered.Peer Reviewe

Medidor de potencia activa, potencia reactiva; valores eficaces de tensión e intensidad y factor de potencia de señales sinusoidales o no sinusoidales

Referencia OEPM: P0463618.-- Fecha de solicitud: 27/10/1977.-- Titular: Consejo Superior de Investigaciones Científicas (CSIC).Medidor de potencias activas y reactivas, tensiones, intensidades y factor de potencia por cálculo analógico.Peer reviewe

Influencia del fotoperiodo en el desarrollo de plantas jovenes de olivo

7 pag., 1 figuras, 3 tabla y 3 referencias. -- Trabajo presentado en el III Congreso Nacional de Química. Sevilla (España). Sevilla, 20-22, Febrero, 1980. Vol. 1: Química agrícola.The influence of three photoperiods 6, 12 and 18 hr on the development of young olive plants is studied. The 12 hr one, gave the best growth, highest number, size leaves and chlorofile content,followed by 18 hr and then 6 hr photoperiods. The nutritive status showed also differences, but shorter than those related to the parameters before indicated.Peer reviewe