Saša Vlahinić

Indices for Harmonic Distortion Monitoring of Power Distribution Systems

Among different power quality parameters, the voltage total harmonic distortion is important and often-analyzed category. Different indices have already been suggested to measure and to monitor both the current and the voltage distortion in power systems, but harmonic site characterization still cannot be performed in satisfactory way. The state of the harmonic distortion is difficult to predict due to variability and a large number of unknown, such as detailed consumer and system characteristics. In this paper a new index describing the total harmonic distortion in current measurements, total rated distortion (TRD), is suggested in order to simplify and standardize harmonic current measurements. Another index representing the increase of harmonic voltage distortion with TRD, equivalent harmonic impedance zeq, is proposed as an efficient way of characterizing a particular site. Finally, extensive harmonic measurements of a real distribution system were performed to prove the usefulness of the proposed indices.

Monitoring cerebral processing of gustatory stimulation and perception using emotiv epoc

The affective and cognitive states of the user can be effectively monitored by electroencephalography (EEG). The human taste stimulation and perception produces changes in the EEG signals of the brain at several subdivisions of insula, orbitofrontal cortex and anterior cingulate cortex. In this work we propose a method which can be used to monitor these signals elicited by taste stimulation and perception using a simple gaming EEG device. Emotion elicited by taste recall is stronger than stimulus elicited emotion will be re-established but with a gaming EEG device. The results are presented for a number of subjects and obtained using the research edition of the gaming EEG headset.

A simple measurement for harmonic source localization

A simple measurement is proposed for source identification and characterization. Power transformer is proposed as a point to perform the measurements in a cheap and practical way. Simulation has been undertaken to confirm validity of the proposed method. The procedure for the load characterization, outlined in this paper, has been tested in real power distribution system to establish the contribution of the certain industrial customer to the harmonic distortion. In contrary to previous assumption, it has been found out that the analyzed customer is not dominant source of distortion and is only partially responsible for the harmonic distortion at the PCC.

Brain computer interface communicator: A response to auditory stimuli experiment

This paper describes a communication system, designed to help people with disabilities to communicate with others. In this case, it is built on Event Related Potentials (ERP) which occur as a response to stimuli. The stimuli are auditory answers to the asked questions, where one of the stimulus is the correct answer. The stimulus which is the possible correct answer is the target stimulus and other stimuli are considered as non-targets. The only reliable information available is the onset of the stimuli, based on this information the spatio-temporal pattern for the target and non-targets is expected to be uncorrelated to the ongoing brain activity and with each other. This allows us to train the spatial filter coefficients for the know targets, so that it can use this trained dataset to correctly classify targets. Results are obtained by optimizing the spatial filter parameters prior to classification, and the classification results are analyzed for several healthy participants.

Noise improvement using SC filters

In this paper noise analysis of three different filter designs is performed. Voltage noise spectral density and RMS noise voltage in simply designed active RC, noise optimized active RC and switched capacitor (SC) filter design are calculated for fifth order Chebyshev low pass filter, with a cut-off frequency fc=3.4kHz, and pass-band ripple αmax=-0.5dB. All three designs are realized as a cascade of two second order sections and one first order section. All filter analysis has been performed using MATLAB and SPICE program tools. Through the analysis it is shown that SC based filter has significantly lower noise when compared with active RC based filter.

The effect of IEC grouping algorithms on the measurement uncertainty of harmonic distortion indices

The influence of noise on the measurement uncertainty of different harmonic indices calculated according to IEC grouping algorithms is analyzed in this paper. The results of a previously published paper are extended to cases where the input noise is superimposed on to the harmonic signal. Probability density functions (pdf) of the harmonic indices are obtained by means of numerical integration and are used for assessment of the statistical properties of the output noise. The values of the offset errors and standard deviations are compared to uncertainties obtained by applying the uncertainty propagation law, as indicated by The Guide to the Expression of Uncertainty in Measurement (GUM).