Optimal controllers design for voltage control in Off-grid hybrid power system

Generally, for remote places extension of grid is uneconomical and difficult. Off-grid hybrid power systems (OGHPS) has  renewable energy sources integrated with conventional sources. OGHPS is very significant as it is the only source of electric supply for remote areas. OGHPS under study  has Induction generator (IG) for wind power generation, Photo-Voltaic source with inverter, Synchronous generator (SG) for Diesel Engine (DE) and load. Over-rated PV-inverter has capacity to supply reactive power.  SG of  DE  has Automatic voltage regulator for excitation control to regulate terminal voltage. Load and IG demands reactive power, causes reactive power imbalance hence voltage fluctuations in OGHPS. To manage reactive power for voltage control, two control structures with Proportional–Integral controller(PI), to control  inverter reactive power and  SG excitation by automatic voltage regulator are incorporated.  Improper tuning of controllers lead  to oscillatory and sluggish response. Hence in this test system both controllers need to be tune optimally. This paper proposes novel intelligent computing algorithm , Enhanced Bacterial forging algorithm (EBFA) for optimal reactive power controller for voltage control in OGHPS. Small signal model of OGHPS with proposed controller is  tested for different disturbances. simulation results  are compared  with conventional  method , proved the effectiveness of EBFA

Reactive scheduling to treat disruptive events in the MRCPSP

Esta tesis se centra en diseñar y desarrollar una metodología para abordar el MRCPSP con diversas funciones objetivo y diferentes tipos de interrupciones. En esta tesis se exploran el MRCPSP con dos funciones objetivo, a saber: (1) minimizar la duración del proyecto y (2) maximizar el valor presente neto del proyecto. Luego, se tiene en cuenta dos tipos diferentes de interrupciones, (a) interrupción de duración, e (b) interrupción de recurso renovable. Para resolver el MRCPSP, en esta tesis se proponen tres estrategias metaheurísticas: (1) algoritmo memético para minimizar la duración del proyecto, (2) algoritmo adaptativo de forrajeo bacteriano para maximizar el valor presente neto del proyecto y (3) algoritmo de optimización multiobjetivo de forrajeo bacteriano (MBFO) para resolver el MRCPSP con eventos de interrupción. Para juzgar el rendimiento del algoritmo memético y de forrajeo bacteriano propuestos, se ha llevado a cabo un extenso análisis basado en diseño factorial y diseño Taguchi para controlar y optimizar los parámetros del algoritmo. Además se han puesto a prueba resolviendo las instancias de los conjuntos más importantes en la literatura: PSPLIB (10,12,14,16,18,20 y 30 actividades) y MMLIB (50 y 100 actividades). También se ha demostrado la superioridad de los algoritmos metaheurísticos propuestos sobre otros enfoques heurísticos y metaheurísticos del estado del arte. A partir de los estudios experimentales se ha ajustado la MBFO, utilizando un caso de estudio.DoctoradoDoctor en Ingeniería Industria

STATCOM Optimal Allocation in Transmission Grids Considering Contingency Analysis in OPF Using BF-PSO Algorithm

In this paper, a combinational optimization algorithm is introduced to obtain the best size and location of Static Compensator (STATCOM) in power systems. Its main contribution is considering contingency analysis where lines outages may lead to infeasible solutions especially at peak loads and it commonly can be vanished by load-shedding. The objective of the proposed algorithm is firstly to prevent infeasible power flow solutions without undesired load-shedding, which is critical in contingency analysis; and secondly to mitigate overall power losses and costs. Moreover, active and reactive powers generation costs are considered in the proposed objective function. Since there are various constraints such as lines outages number, cost and their duration that must be taken to account, Bacterial Foraging oriented by Particle Swarm Optimization (BF-PSO) algorithm combined with Optimal Power Flow (OPF) is used to solve and overcome the complexity of this combinational nonlinear problem. In order to validate the accuracy of the proposed method, two test systems, including IEEE 30 bus standard system and Azarbaijan regional power system of Iran, are applied in simulation studies. All obtained optimization results show the effectiveness of the suggested combinational method in loss and cost reduction and preventing load-shedding

Review: An Analysis of Different Population based Optimization Techniques used for Optimum Allocation and Sizing of Distributed Generations in Distributed Network

ABSTRACT: This Paper presents a review on the discussion of different types of population based Artificial intelligence optimization techniques used in the distributed generations in Distributed Networks. With the growing popularity of the Distributed Generations in the recent world it is required to determine the optimal location and size of the Distributed generations along with the reduction of the loss, improvement of Voltage Profile and reliability at lowest cost. For this different types of optimization techniques are used such as Firefly Algorithm, Genetic Algorithm, BFO, PSO, Artificial Bee Colony, Clonal Selection Algorithm, Ant Colony Optimization etc. This population based optimization techniques are more flexible and fast optimization methods

Performance Enhancement of Shunt APFs Using Various Topologies, Control Schemes and Optimization Techniques

Following the advent of solid-state power electronics technology, extensive usage of nonlinear loads has lead to severe disturbances like harmonics, unbalanced currents, excessive neutral current and reactive power burden in three-phase power systems. Harmonics lower down the efficiency and power factor, increase losses, and result in electromagnetic interference with neighbouring communication lines and other harmful consequences. Over the years, active power filter (APF) has been proven to be a brilliant solution among researchers and application engineers dealing with power quality issues. Selection of proper reference compensation current extraction scheme plays the most crucial role in APF performance. This thesis describes three time-domain schemes viz. Instantaneous active and reactive power (p-q), modified p-q, and Instantaneous active and reactive current component (i_d-i_q) schemes. The objective is to bring down the source current THD below 5%, to satisfy the IEEE-519 Standard recommendations on harmonic limits. Comparative evaluation shows that, i_d-i_q is the best APF control scheme irrespective of supply and load conditions. Results are validated with simulations, followed by real-time analysis in RT-Lab.In view of the fact that APFs are generally comprised of voltage source inverter (VSI) based on PWM, undesirable power loss takes place inside it due to the inductors and switching devices. This is effectively minimized with inverter DC-link voltage regulation using PI controller. The controller gains are determined using optimization technique, as the conventional linearized tuning of PI controller yield inadequate results for a range of operating conditions due to the complex, nonlinear and time-varying nature of power system networks. Developed by hybridization of Particle swarm optimization (PSO) and Bacterial foraging optimization (BFO), an Enhanced BFO technique is proposed here so as to overcome the drawbacks of both PSO and BFO, and accelerate the convergence of optimization problem. Extensive simulation studies and RT-Lab real-time investigations are performed for comparative assessment of proposed implementation of PSO, BFO and Enhanced BFO on APF. This validates that, the APF employing Enhanced BFO offers superior harmonic compensation compared to other alternatives, by lowering down the source current THD to drastically small values.Another indispensable aspect of APF is its topology, which plays an essential role in meeting harmonic current requirement of nonlinear loads. APFs are generally developed with current-source or voltage-source inverters. The latter is more convenient as it is lighter, cheaper, and expandable to multilevel and multistep versions for improved performance at high power ratings with lower switching frequencies. There can be different topologies of VSI depending on the type of supply system. With each topology, constraints related to DC-link voltage regulation change. For effective compensation, irrespective of the number and rating of DC-link capacitors used in any particular topology, voltages across them must be maintained constant with optimal regulation of DC-link voltage. Various topologies for three-phase three-wire systems (conventional two-level and multilevel VSIs) and four-wire systems (split-capacitor (2C), four-leg (4L), three H-bridges (3HB) and three-level H-bridge (3L-HB) VSIs) are analyzed and compared based on component requirements, effectiveness in harmonic compensation, cost and area of application

PLACEMENT OF DG AND CAPACITOR FOR LOSS REDUCTION AND RELIABILITY IMPROVEMENT IN RADIAL DISTRIBUTION SYSTEMS USING BFA

ABSTRACT This paper presents a methodology for determining the optimal location and capacity of Distributed Generator (DG) and capacitor in the radial distribution system in view of loss reduction and improvement in voltage profile and reliability. The overall objective function includes reliability index, power loss reduction, DG and capacitor investment cost and voltage deviation index. Customer and energy based indices i.e. SAIFI, SAIDI, CAIDI, AENS, and ASAI have been optimized by using the optimum values of failure rate. In this paper, the most recent Bacterial foraging algorithm (BFA) is used to find optimal location of single DG and capacitor in radial distribution systems. To evaluate the effectiveness of the proposed algorithm in finding best solutions, simulations are carried out with and without DG and capacitor installation on 10 bus and standard IEEE 33 bus radial distribution system. The obtained results are compared with binary particle swarm optimization algorithm (BPSO) for validation

Simulation of Network Maneuvers at Power Substantions

The purpose of this study is to simulate network maneuvers due to disruption in the distribution system. This research was conducted in the Daya substation from January to March 2019, transformer 20 MVA. To achieve the research goal, network maneuvers were carried out in accordance with the standard operation procedure (SOP) of PT. PLN by simulating the conditions before and after the maneuver under Digsilent. Based on the results of the study, it shows that there is a change in the loading value of several back-up feeders to cover consumers demand for day and night time