Robust state feedback controller design of STATCOM using chaotic optimization algorithm

In this paper, a new design technique for the design of robust state feedback controller for static synchronous compensator (STATCOM) using Chaotic Optimization Algorithm (COA) is presented. The design is formulated as an optimization problem which is solved by the COA. Since chaotic planning enjoys reliability, ergodicity and stochastic feature, the proposed technique presents chaos mapping using Lozi map chaotic sequences which increases its convergence rate. To ensure the robustness of the proposed damping controller, the design process takes into account a wide range of operating conditions and system configurations. The simulation results reveal that the proposed controller has an excellent capability in damping power system low frequency oscillations and enhances greatly the dynamic stability of the power systems. Moreover, the system performance analysis under different operating conditions shows that the phase based controller is superior compare to the magnitude based controller

Application of Multi Objective HFAPSO algorithm for Simultaneous Placement of DG, Capacitor and Protective Device in Radial Distribution Network

In this paper, simultaneous placement of distributed generation, capacitor bank and protective devices are utilized to improve the efficiency of the distribution network. The objectives of the problem are reduction of active and reactive power losses, improvement of voltage profile and reliability indices and increasing distribution companies’ profit. The combination of firefly algorithm, particle swarm optimization and analytical hierarchy process is proposed to solve the multi-objective allocation problem. The proposed method is implemented on IEEE 69-bus and also an actual 22-bus distribution systems in Tehran-Iran. Test results approve the effectiveness of the proposed method for improved reliability and network performance of the distribution network

A Novel Multi-Level Cascade Inverter with Reduced Switching Devices to Connect Renewable Energy Sources to the Grid

Multi-level inverters (MLIs) have now become an essential component for medium and high power applications with medium voltage levels. Low switches multi-level inverters are very popular due to their high efficiency, low cost, and easy control for output with higher levels. In this paper, a new multi-level inverter structure based on a switched DC voltage source is proposed by reducing the number of switches for single-phase applications. The proposed structure can be used in grid-connected applications, such as grid connections for renewable energy sources. The proposed structure is developed with a higher number of levels at the output using a smaller number of devices. The proposed topology can also be used in symmetric and asymmetric configurations. Two switching methods including pulse width modulation (PWM) switching and ladder switching based on selective harmonic elimination (SHE) have been used to generate the output voltage. Comparative studies with multilevel inverters were presented recently to show the advantage of the proposed structure in terms of reducing the number of devices. Simulation and experimental results are presented to confirm the performance of the proposed topology. In addition, the performance of the proposed multilevel structure for energy transfer from renewable sources to the low-power grid has also been investigated

Coordinated flexible energy and self-healing management according to the multi-agent system-based restoration scheme in active distribution network

This study presents the optimal model of the coordinated flexible energy and self-healing management (C-FE&SH-M) in the active distribution network (ADN) including renewable energy sources (RESs), electric vehicles (EVs) and demand response program (DRP).The flexible energy management (FEM) is extracted using coordination between the RESs, EVs and DRP. The self-healing method (SHM) is related to multi-agent system-based restoration process (MAS-based RP) that finds the optimal restoration pattern at the fault condition according to the different zone agents (ZAs) distributing along with the network. This method minimizes the difference between energy cost and flexibility benefit related to the FEM part and difference between the number of switching operation and priority loads restored based on the SHM part. Also, this problem subjects to power flow equations, RESs and active loads constraints, restoration process formulation and system operation limits. Stochastic programming is used to model the uncertainty of loads, energy prices, RESs and EVs. Hereupon, the suggested strategy is implemented on the 33-bus radial distribution network and it is solved by the crow search algorithm (CSA). Ultimately, the obtained results imply the high flexibility and security of the operation, incorporating the proposed strategy, and delineate the optimal restoration scheme for the ADN.© 2021 The Authors. IET Renewable Power Generation published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.M. Shafie-khah acknowledges FLEXIMAR-project (Novel marketplace for energy flexibility), which has received funding from Business Finland Smart Energy Program, 2017-2021. J.P.S. Catalão acknowledges the support by FEDER through COMPETE 2020 and by FCT, under POCI-01-0145-FEDER-029803 (02/SAICT/2017).fi=vertaisarvioitu|en=peerReviewed

Degradation of Organophosphorus Pesticides in Water during UV/H2O2 Treatment: Role of Sulphate and Bicarbonate Ions

Abstract: The photodegradation of two organophosphorus pesticides, malathian and diazinon, by sulfate radicals and bicarbonate radicals in aqueous solution were studied. The effect of the operational parameters such as pH, salt concentration, water type, H2O2 concentration and initial concentration of pesticides was studied. Gas chromatography mass spectroscopy (GC-MS) was used for analyses of pesticides. When salt effect was studied, it was found that sodium bicarbonate was the most powerful inhibitor used, while sodium sulfate was the weakest one. The highest degradation in UV/H2O2 process for malathion was found in alkaline condition and for diazinon in acidic condition. The photodegradation in all waters used in this work exhibited first order kinetics. Photodegradation rate in distilled water was higher than real water. The degradation of pesticides increased with increasing of H2O2 concentration

Organophosphorous Pesticides in Surface Water of Iran

Abstract This research aims to evaluate the presence and distribution of pesticides in Babolrood River of Mazandaran Province in Iran. Mean diazinon levels in surface water ranged from 77.6 to 101.6 lg L-1 with maximum level of 768.9 lg L-1 and mean malathion levels ranged from 55.7 to 75.9 lg L-1 with maximum level of 506.6 lg L-1 . The residues of malathion and diazinon pesticides in all of the stations, 2 weeks after spraying, were more than allowed limits

Dizajn PWMSC regulatora za prigušenje elektromehaničkih oscilacija

Pulse Width modulated based Series Compensator (PWMSC), a newly FACTS device, can modulate the impedance of a transmission line through the variation of the duty cycle of a train of pulses with fixed frequency, resulting in improvement of system performance. In this study, a current injection model of PWMSC is proposed and incorporated in the transmission system model. The purpose of the work reported in this paper is to design an oscillation damping controller for PWMSC to damp low frequency oscillations. We have used the residue method to the linearized equations of the power system for multiple operating conditions and obtained a generalized form which is suitable for different damping controller input-output channels and therefore suitable for different control devices. The case study results show that the proposed controller is very effective to mitigate the power system critical modes of oscillation.Pulsno-širinski modulirani serijski kompenzator (PWMSC), novi FACTS uređaj, modulira impendanciju prijenosne linije putem promjene popunjenosti niza signala s konstantnom frekvencijom, što rezultira poboljšanim svojstvima. U ovome radu predložen je model ubrizgavanja struje u PWMSC-u koji je nadodan u model prijenosa. Cilj ovoga rada bio je dizajnirati oscilatorni regulator prigušenja za PWMSC u svrhu prigušenja niskih frekvencija oscilatora. Korištena je metoda reziduala na linearizirani model energetskog sustava za različite uvjete te je dobivena općenita forma pogodna za ulazno-izlazne kanale regulatora prigušenja pogodna za različite upravljačke ulaze. Analiza pokazuje da je regulator učinkovit kod ublažavanja kritičnih oscilacija energetskog sustava

Enhancing the Resilience of Operational Microgrids Through a Two-Stage Scheduling Strategy Considering the Impact of Uncertainties

This article deals with the stochastic scheduling of a microgrid (MG) to balance the economical and resilience metrics. In the proposed model, the MG resilience indices are integrated into the economic criteria to ensure the resilience of MG operation alongside the main MG actors' profit/loss. The MG fragility index, recovery efficiency index, MG voltage index, and lost load index are considered in the proposed planning model. Further, to make the results more realistic, the uncertainties associated with energy price and wind production, alongside with planning of energy storage systems and electric vehicles parking lots are considered. To achieve a better solution for the security-constraint operation of MG, AC network equations are included in the system modeling. Finally, a large-scale MG based on the IEEE-33 bus testbed is utilized to evaluate the effectiveness of the proposed stochastic scheduling program

Genetic algorithm based studying of bundle lines effect on network losses in transmission network expansion planning

Transmission network expansion planning (TNEP) is a basic part of power system planning that its task is to minimize the network construction and operational cost, while meeting imposed technical, economic and reliability constraints. Recently, many methods have been introduced for solution of the static transmission network expansion planning (STNEP) problem. However, in whole of them, the effect of bundle lines on network losses has not been investigated. For this reason, in this paper, STNEP problem is being solved considering the effect of bundle lines on the network losses in a transmission network with different voltage levels using decimal codification genetic algorithm (DCGA). Finally, the effectiveness of proposed idea is tested on an actual transmission network of the Azerbaijan regional electric company, Iran. The results analysis reveals that bundle lines have important effect on the network losses in STNEP problem. Moreover, considering the bundle lines in a power system with various line voltage levels are caused the operational costs is decreased in addition to reduce of the total expansion costs. Thus, the effect of bundle lines on the network losses is caused the total expansion costs (expansion cost of lines and substations) are calculated more exactly and therefore the transmission expansion planning is optimized