New Metaheuristic Algorithms for Reactive Power Optimization

Optimal reactive power dispatch (ORPD) is significant regarding operating the practice safely and efficiently. The ORPD is beneficial to recover the voltage profile, diminish the losses and increase the voltage stability. The ORPD is a complicated optimization issue in which the total active power loss is reduced by detecting the power-system control variables, like generator voltages, tap ratios of tap-changer transformers, and requited reactive power, ideally. This study offers new approaches based on Shuffled Frog Leaping Algorithm (SFLA) and Tree Seed Algorithm (TSA) to solve the best ORPD. The results of the approaches are offered set against the current results studied in the literature. The recommended algorithms were tested by IEEE-30 and IEEE-118 bus systems to discover the optimal reactive power control variables. It was observed that the obtained results are more successful than the other algorithms

An Improved Particle Swarm Optimization Algorithm Using Eagle Strategy for Power Loss Minimization

The power loss in electrical power systems is an important issue. Many techniques are used to reduce active power losses in a power system where the controlling of reactive power is one of the methods for decreasing the losses in any power system. In this paper, an improved particle swarm optimization algorithm using eagle strategy (ESPSO) is proposed for solving reactive power optimization problem to minimize the power losses. All simulations and numerical analysis have been performed on IEEE 30-bus power system, IEEE 118-bus power system, and a real power distribution subsystem. Moreover, the proposed method is tested on some benchmark functions. Results obtained in this study are compared with commonly used algorithms: particle swarm optimization (PSO) algorithm, genetic algorithm (GA), artificial bee colony (ABC) algorithm, firefly algorithm (FA), differential evolution (DE), and hybrid genetic algorithm with particle swarm optimization (hGAPSO). Results obtained in all simulations and analysis show that the proposed method is superior and more effective compared to the other methods

Effect of Neutral Grounding Protection Methods for Compensated Wind/PV Grid-Connected Hybrid Power Systems

The effects of the wind/PV grid-connected system (GCS) can be categorized as technical, environmental, and economic impacts. It has a vital impact for improving the voltage in the power systems; however, it has some negative effects such as interfacing and fault clearing. This paper discusses different grounding methods for fault protection of High-voltage (HV) power systems. Influences of these grounding methods for various fault characteristics on wind/PV GCSs are discussed. Simulation models are implemented in the Alternative Transient Program (ATP) version of the Electromagnetic Transient Program (EMTP). The models allow for different fault factors and grounding methods. Results are obtained to evaluate the impact of each grounding method on the 3-phase short-circuit fault (SCF), double-line-to-ground (DLG) fault, and single-line-to-ground (SLG) fault features. Solid, resistance, and Petersen coil grounding are compared for different faults on wind/PV GCSs. Transient overcurrent and overvoltage waveforms are used to describe the fault case. This paper is intended as a guide to engineers in selecting adequate grounding and ground fault protection schemes for HV, for evaluating existing wind/PV GCSs to minimize the damage of the system components from faults. This research presents the contribution of wind/PV generators and their comparison with the conventional system alone

A Load Flow Analysis Method for Kufa Cement Plant

The energy needs have been enlarged extremely. The electricity power generators are utilized and distributed in the national (local) grid. Many factors can affect on national distribution grid stability, such as load flow. It is utilized to evaluate various operating states for energy generation and distribution systems. In this article, six different generators are distributed in Kufa (Iraq) cement plant based on load flow balancing. Behinds, these distributed generators work under two modes, such that island mode and regular operation. The proposed modules are analyzed using Electrical Transient Analyzer Program (ETAP) software. The achieved analysis can help to reduce the distribution grid shutdown. Furthermore, the load balancing can be achieved at both modes. Load flow analysis takes consideration for the total energy demands and losses of the system separately in order to balance load and optimize operation. The results show that the buses’ voltage drop in island mode was more than the voltage drop when the local grid connected to the national grid. The problems of drop voltages and power factor were solved

Oxidative Stress Biomarkers in Urine of Patients with Hepatitis B and C

Objective: The aim of our study is to determine the role of oxidative stress biomarkers in hepatic damage in hepatitis B virus (HBV) and hepatitis C virus (HCV)-infected patients. Materials and Methods: Forty-eight patients with chronic hepatitis B, 15 patients with chronic hepatitis C and 30 healthy individuals as a control group were included in this study. Serum alanine-aminotransferase (ALT) and aspartate aminotransferase (AST) levels, urine oxidative stress biomarkers such as malondialdehyde (MDA) levels, superoxide dismutase (SOD-1) and catalase (CAT) activities were measured. Results: Urine MDA levels increased in patients with HBV and HCV compared to the control group. It was higher in HCV patients than HBV patients (p<0.001). Besides, while CAT and SOD-1 activities were decreased in the urine of patients with HCV, they increased in the urine of patients with HBV compared to controls (p<0.05). Furthermore, urine CAT ve SOD-1 activities in patients with HBV were statistically significantly higher than those of the HCV patients (p<0.001). Conclusion: Increase in urine MDA levels in hepatitis forms may be valuable in monitoring in viral hepatitis cases. Also, we thought that insufficiency of antioxidant barrier in patients with HCV may cause oxidative damage, so antioxidant treatment may useful and should be added to the combined therapy for these patients