Voltage Flicker Parameters Estimation UsingShuffled Frog Leaping Algorithm (SFLA) andImperialistic Competitive Algorithm (ICA)

The Resource Constrained Project Scheduling Problem (RCPSP) is been studied under different kinds of constraints and limitations. In this paper, we are going to consider the discounted cash flows for project activities, and delay penalties which occur when the project make span exceeds its deadline as the objective function of the RCPSP. To solve the model, we will take advantage of three different meta-heuristic algorithms - Genetic Algorithm (GA), Imperialist Competitive Algorithm (ICA), and Shuffled Frog Leaping Algorithm (SFLA) - to achieve the optimal solution of the problem. The evaluation of the algorithms performance reveals that, in comparison with ICA and SFLA, GA performs better, especially in large-scale problems.

Chapter 10 - Constraint-based heuristic algorithms for software test generation

A clustering approach for EOS lumping — Using evolutionary-based metaheuristic optimization algorithms

Analytic Mode Decomposition and Windowed Three-Point Interpolated Chirp-Z Transform for Voltage Flicker Components Detection

Voltage flicker is an important power quality issue in power systems. Accurate modulation parameter estimation plays a crucial role in the voltage flicker measurement. This paper proposes an optimized matrix pencil-based method for the modulation parameter estimation. The voltage flicker signal model is transformed into a multifrequency model by considering the modulation component on the fundamental component as the combination of subharmonic and interharmonic. All components are first simultaneous estimated via the matrix pencil method. The modulation parameters are then estimated based on subharmonics and interharmonics near the fundamental. A precise model order determination method is designed to enhance the behavior of the proposed method under unknown noise levels. Finally, multiple simulation results validate the accuracy and efficiency of the proposed method.

One must be able to accurately measure voltage flicker levels and its frequency. This paper introduces a new application of the least error squares (LES) state estimation algorithm to measure voltage flicker and its frequency. We use a linear model of the flicker voltage magnitude, its phase angle and frequency deviation, and the system voltage magnitude and its phase angle. The proposed algorithm uses digitized samples of the voltage signal. Effects of data size, sampling frequency, and number of samples on the estimated parameters are studied.

The voltage flicker emission levels caused by electric arc furnace operation can cause objectionable disturbances in residential, incandescent lamp based light sources. Installation of a newly designed SPLC (smart predictive line controller) beta unit in the arc furnace power supply system of Co-Steel Lasco (46 kV, 100 MVA) reduced the flicker levels at the source. The paper presents the SPLC system description, details of installation, current and voltage fluctuation profiles, flicker measurements and operational benefits.

Voltage flicker has emerged as a major concern problem in the area of power quality. Amongst its effects, it is recognised that, in addition to the visual inconvenience, several types of electrical equipment can be strongly disturbed. This paper describes the voltage flicker phenomena, presenting its conception, definition, origin and methods of evaluation. Three procedures are considered: British, French and Standard. In addition to these theoretical contributions, this paper describes an instrument specially developed to provide a diagnostic of electrical system behaviour as long as voltage fluctuation is concerned. Experimental results associated with site measurements are also given to illustrate the developed prototype's performance.

Flickers and interharmonics have an inherent relationship. The magnitude of a voltage can fluctuate if it contains interharmonics. This paper investigates the amount of voltage fluctuation caused by two interharmonic components since interharmonics are often produced in pairs. The impact of the interharmonics on the flicker frequency and flicker magnitudes (expressed in the form of RMS and peak value fluctuations) is quantified. Analytical solutions to assess the impact are developed. One of the interesting findings of this work is that the two interharmonic components can be equivalenced into one interharmonic component that yields the same level of voltage fluctuation.

Available inverter-interfaced distributed generation in the distribution grid could be used for mitigation of voltage flicker. By providing reactive power within few cycles and compensating change in voltage they thereby improve the power quality. The theoretical performance of a generic PI control and a more detailed Q(V) control model for the mitigation of voltage flicker is investigated. For this analysis defined flicker levels are generated in the CIGRE European LV grid topology. A genetic algorithm is used to optimize the control parameters to obtain optimal flicker reduction for each defined voltage flicker level and its individual flicker frequencies as well as over its entire flicker frequency spectrum. Resulting flicker levels are compared to the results obtained from using standard parameters or with additional time delays. The comparison shows that ideally flicker reduction is possible to the extend of 77%. However, the more detailed model achieve mitigation only up to 17%.

This paper introduces a new technique based on the simulated annealing (SA) optimization algorithm to measure the voltage flicker magnitude and frequency. Moreover, the power system voltage magnitude, frequency and phase angle is estimated by the proposed technique. The problem is a highly nonlinear optimization problem in continuous variables. An efficient SA algorithm with an adaptive cooling schedule and a new method for variable discretization are implemented. The new algorithm minimizes the sum of the absolute value of the error in the estimated voltage signal, and does need any approximation in modeling the voltage signal, such as using Taylor's series expansion. Effects of sampling frequency as well as number of samples are discussed.

Reliable wave prediction plays a significant role in wave energy converter (WEC) research, but there are still prediction errors that would increase the uncertainty for the power grid and reduce the power quality. The efficiency and stability of the power take-off (PTO) system are also important research topics in WEC applications. In order to solve the above-mentioned problems, this paper presents a model predictive control (MPC) method composed of a prediction error compensation controller and a PTO optimization controller. This work aims to address the limitations of existing wave prediction methods and improve the efficiency and stability of hydraulic PTO systems in WECs. By controlling the charging and discharging of the accumulator, the power quality is enhanced by reducing grid frequency fluctuations and voltage flicker through prediction error compensation. In addition, an efficient and stable hydraulic PTO system can be obtained by keeping the operation pressure of the hydraulic motor at the optimal range. Thus, smoother power output minimizes grid-balancing penalties and storage wear, and stable hydraulic pressure extends PTO component lifespan. Finally, comparative numerical simulation studies are provided to show the efficacy of the proposed method. The results validate that the dual-controller MPC framework reduces power deviations by 74.3% and increases average power generation by 31% compared to the traditional method.

The dynamic characteristics of a new method of measurement intended for the measurement of sensor parameters are analyzed. The properties of the synergetic method of measurement are compared with those of traditional methods in precision —time coordinates. An evaluation of the prospects for the use of the synergetic method is supported by data from numerical experiments.

With the improvement in the anti-reconnaissance performance of the new system radar, the signals sent by the radar are more and more difficult to be detected, which brings new challenges to electronic reconnaissance. In order to find the enemy earlier, the receiver usually needs high sensitivity to detect weak signals. Therefore, according to the characteristics of airborne PD radar pulses, a method of PD radar parameter measurement based on non-coherent accumulation is proposed, which is of great significance to improve the receiver sensitivity. In this paper, the main peaks’ solution of PD Radar spectrum after non-coherent accumulation and the method of pulse parameter measurement are introduced in detail. Finally, the effectiveness of this method is verified by simulation experiments.

Because of Poor visibility, the hydraulic drive system usually to bring some troubleshooting difficult. In this paper, parameter measurement based fault diagnosis method, through quantitative analysis of system parameters and logical analysis, to achieve the accurate diagnosis of the hydraulic system failure, fault diagnosis with scientific accuracy and rapidity. The technology to significantly reduce the equipment assembly and disassembly work, reducing the skill level of maintenance personnel requirements of the more traditional method of fault diagnosis significantly improve the efficiency, the promotion should have practical value.