A simple predictive method of critical flicker detection for human healthy precaution

Interharmonics and flickers have an interrelationship between each other. Based on International Electrotechnical Commission (IEC) flicker standard, the critical flicker frequency for a human eye is located at 8.8 Hz. Additionally, eye strains, headaches, and in the worst case seizures may happen due to the critical flicker. Therefore, this paper introduces a worthwhile research gap on the investigation of interrelationship between the amplitudes of the interharmonics and the critical flicker for 50 Hz power system. Consequently, the significant findings obtained in this paper are the amplitudes of two particular interharmonics are able to detect the critical flicker. In this paper, the aforementioned amplitudes are detected by adaptive linear neuron (ADALINE). After that, the critical flicker is detected by substituting the aforesaid amplitudes to the formulas that have been generated in this paper accordingly. Simulation and experimental works are conducted and the accuracy of the proposed algorithm which utilizes ADALINE is similar, as compared to typical Fluke power analyzer. In a nutshell, this simple predictive method for critical flicker detection has strong potential to be applied in any human crowded places (such as offices, shopping complexes, and stadiums) for human healthy precaution purpose due to its simplicity

AN INVESTIGATION OF THE RESPONSE OF INCANDESCENT LAMPS AND COMPACT FLUORESCENT LAMPS TO VOLTAGE FLUCTUATION

This thesis presents the results of tests that were performed on incandescent lamps and compact fluorescents lamps (CFLs) in order to observe their sensitivity to voltage fluctuations that can occur on a power system. The lamps tested were designed for use in a 120V, 60Hz system. They are models that are commonly available in the United States. In this research, the lamps in question were exposed to four separate tests. The first set of tests analyzed the response of each lamp to a series of long voltage fluctuations that were applied long enough to allow the light output from the lamps to reach a new steady state output. The second set of tests consisted of short duration voltage sags that were applied for only a few 60Hz cycles. The third set of tests consisted of non-rectangular voltage fluctuations that resemble those found in a real system. In the final tests, data was collected to propose a new flicker curve that is based on CFLs. In each test performed, the response of the CFL was shown to be superior to that of the incandescent lamp. In the long duration tests, the percentage reduction in light observed by the incandescent lamp was 4 to 6 times greater than that observed by the CFL. The light fluctuation of the CFL during the short duration tests was also shown to be less than that of the incandescent lamp. The drop and recovery times recorded indicated that the response of the CFL to the voltage fluctuation was much quicker than that of the incandescent. The non-rectangular tests provided confirmation that the trends observed in the previous tests apply to real conditions. The final tests performed provided data to propose a new flicker curve based on CFLs

DFT-based recursive group-harmonic energy distribution approach for power interharmonic identification

AbstractThe Discrete Fourier Transform (DFT) is still a widely used tool for analyzing and measuring both stationary and transient signals in power system harmonics. However, the misapplications of DFT can lead to incorrect results caused by some problems such as the aliasing effect, spectral leakage and picket-fence effect. The strategy of a DFT-based recursive Group-harmonic Energy Distribution (GED) algorithm is developed for system-wide harmonic/interharmonic evaluation in power systems. The proposed algorithm can restore individual dispersing spectral leakage energy caused by the DFT, and thus retrieve respective real harmonic/interharmonic value. Every distribution of energy minimizing iteration procedure for harmonic/interharmonic evaluation can be convergent fast, and therefore guarantee each harmonic/interharmonic magnitude and respective frequency approaches its actual value. Consequently, not only can high precision in integer harmonic measurement be retained, but also the interharmonics can be identified accurately, particularly under system frequency drift. A numerical example is presented to verify the proposed algorithm in terms of robust, fast and precise performance

The Impact of Connecting Distributed Generation to the Distribution System

This paper deals with the general problem of utilizing of renewable energy sources to generate electric energy. Recent advances in renewable energy power generation technologies, e.g., wind and photovoltaic (PV) technologies, have led to increased interest in the application of these generation devices as distributed generation (DG) units. This paper presents the results of an investigation into possible improvements in the system voltage profile and reduction of system losses when adding wind power DG (wind-DG) to a distribution system. Simulation results are given for a case study, and these show that properly sized wind DGs, placed at carefully selected sites near key distribution substations, could be very effective in improving the distribution system voltage profile and reducing power losses, and hence could  improve the effective capacity of the system.

An Analysis of Harmonic and Interharmonic Contribution of Electric Arc Furnace by Using Periodogram

Fast and accurate detection of the harmonic and interharmonic contribution of electric arc furnace (EAF) is crucial in identifying and to mitigate the undesired effects to the system.  In this paper, periodogram, a fast and accurate technique is introduced for the analysis of the contribution. Based on a rule-based classifier and the threshold settings that referred to the IEEE Standard 1159 2009, the analysis of the harmonic and interharmonic contribution of EAF are carried out successfully. Moreover, the impact of contribution is measured using total harmonic distortion (THD) and total non-harmonic distortion (TnHD). In addition, periodogram also gives 100 percent correct detection and able to analyze the contribution impact. It is proven that the proposed method is accurate, fast and cost efficient for analyzing the impact of harmonic and interharmonic of EAF

Distributed Generation and Its Impact on Power Quality in Low-Voltage Distribution Networks

This chapter is dedicated to review and investigate present approaches to power quality assessment in low-voltage (LV) networks with distributed generation (DG). Two complementary approaches are considered: firstly, origin of the emission limits requirement for the DG is searched in general electromagnetic compatibility (EMC) conditions used for the equipment and adopted to DG; secondly, rules and regulation of integration with a power system network is used in order to estimate the possible influence of DG on power quality in point of common coupling (PCC). An example of the regulation is control of reactive power consumption in function of active power generation known as cosφ (P) characteristic. This chapter constitutes the attitude that complementary approach brings improvement to the decision about the possible impact of DG in a power system network. It was shown that a combined approach allows to define a proposition of the limits of particular power quality parameters associated with the investigated node of LV network characterized by apparent short circuit power in the PCC (SkPCC). This combination brings desirable effect of criterion, making for integration of DG with LV networks. Mentioned attitude was investigated using a real case study of a photovoltaic (PV) system consisting of three independent one-phase subsystems. Estimated influence of the investigated PV on power quality parameters in the PCC was verified using real measurement. The measurement procedure allows to verify the real influence of the investigate DG on power quality in the PCC, however, the task in not easy due to problems of separation of the searched influence from the measurement background. One of the proposed approach is to affiliate changes of investigated power quality parameters with activities of the investigated DG, e.g., energy production. As it was presented in the case of influence of the investigated PV static voltage changes or total harmonic distortion in current in the PCC, a correlation index can be also implemented in order to classify the force of the common influence