Minimum Transmission Loss Research Articles

Comparison of infiltration rates in the dry riverbed of the Colorado River Delta during environmental flows

Water has been over-allocated all over the world; natural rivers have been over-exploited and regulated to manage storage and distribute the water to thirsty cities and agricultural lands. The Colorado River is no exception to this trend. It is one of the most regulated rivers in the world; the once mighty Delta that formed from the river has become a few hectares of native trees surrounded by agriculture lands and houses. At the border between Mexico and the U.S., the last of the Colorado’s water is diverted, so that the last 160 kilometers of natural stream channel no longer carry regular flows and the river doesn’t reach the sea. Because of this, the first binational environmental water allocation between Mexico and the United States was initiated (termed Minute 319) and two environmental flows were agreed upon.Those separate flow events provided an opportunity to investigate streambed infiltration under very different hydrographs, a “base flow” and a “pulse flow”. In this work, we evaluate the infiltration process using heat as a tracer and compare these point measurements to a saturated/unsaturated 2-D numerical model of a cross-section of the river. Heat tracer analysis showed that in both events, infiltration was high at the start and then decreased over time, from a maximum of 0.60md−1 during the pulse flow and 1.60md−1 during base flow. Monte Carlo analyses for the pair of temperature sensors at each event showed that uncertainty is greater at higher vertical fluxes; therefore greater during base flow (0.4md−1) and lower at pulse flow (0.2md−1). The total volume infiltrated during 6 and 8days of the pulse and base flows (March 25–30 and September 7–14, respectively) was 151,714m3 and 307,610m3, respectively. In contrast, the 2-D numerical model showed 241,780m3 and 125,295m3 across the cross-section in a 500m longitudinal distance of the river channel, during the pulse flow and base flow, respectively. In both models, the flux was highest during the initial days of each event. These results suggest that for future environmental flows focused on longitudinally reconnecting the river in conditions similar to those presented in this study, the minimization of channel transmission losses could be achieved through lower, consistent flows. However, this would not lead to reconnection of surface water and groundwater and therefore propagation of the wetting front laterally, which benefits restoration areas.

Seismic attenuation in Jati area, Lower Indus Basin, Pakistan

Reduced amplitude and distorted dispersion of seismic waves caused by attenuation, especially strong attenuation, always degrade the resolution of migrated images. To improve seismic imaging, attenuation must be compensated. This study addresses the factors causing seismic attenuation in Jati Block. Jati Block lies in Lower Indus Basin, Pakistan, approximately 25 mi north of the offshore Indus. Method used for Q factor is empirical equation method. Q factor correlation indicates that there are three major zones of attenuation in Jati block, i.e., zone I (surface to top Khadro), zone II (Upper Goru Formation), and zone III (Lower Goru Formation). Lowest Q value is in zone I, followed by zone II and zone III, respectively. Commonly, Khadro Formation (Basalt) of Paleocene and saucer-shaped igneous intrusion is considered as sources of attenuation. However, surprisingly, Khadro Formation of Paleocene and saucer-shaped igneous intrusion is zone of minimum attenuation and causes minimal transmission loss. Anisotropy analysis is performed to determine cause of attenuation within these zones. Thomson anisotropic parameters are computed for vertical wells using Backus averaging algorithm. These parameters are calibrated using sonic scanner data available for one well. Correlation of Q factor curve with mud log suggests that loose, unconsolidated sands and sand-shale layering are sources of attenuation within zone I. Attenuation in this zone is mostly due to fluid motion relative to the framework of loosely packed grains. Major lithology of Upper Goru Formation is marl. It is a slow formation, and in this formation, P wave loses energy to the formation in what is known as leaky P mode (sonic logging) and is dispersive (seismic). Epsilon (Ɛ) value is greater than almost 0.02 throughout Lower Goru Formations, indicating that this formation is strongly anisotropic. Fluctuation of epsilon (Ɛ) in Lower Goru Formation also suggests that this formation is causing layer-induced anisotropy. This layer-induced anisotropy in Lower Goru Formation added by dispersive and slow nature of Upper Goru Formation causes rapid attenuation.

Application of swarm intelligent techniques with mixed variables to solve optimal power flow problems

This paper proposes a new swarm based evolutionary algorithm called LBEST PSO with dynamically varying sub-swarms (LPSO DVS). Swarm based algorithms are meta-heuristic search methods whose mechanics are inspired by the collaborative behaviour of biological populations. The performance of four swarm based algorithms, i.e., particle swarm optimisation (PSO), fuzzy adaptive particle swarm optimisation (FAPSO), fitness distance ratio particle swarm optimisation (FDRPSO) and LPSO DVS are also compared with genetic algorithm (GA) and improved GA when applied to the power system optimal power flow (OPF) problem. OPF optimises the power system operating objective function, while satisfying the set of system operating constraints. The objective functions considered in this OPF problem are fuel cost (FC) minimisation, voltage stability enhancement index (VSEI) minimisation, transmission loss minimisation (LM) and voltage deviation (VD) minimisation. Simulation results for the IEEE 30 bus system are presented and the comparison is made among the numerical results obtained using the different evolutionary algorithms.

Optimal Power Flow with Reactive Power Compensation for Cost and Loss Minimization on Nigerian Power Grid System

One of the concerns of power system planners is the problem of optimum cost of generation as well as loss minimization on the grid system. This issue can be addressed in a number of ways; one of such ways is the use of reactive power support (shunt capacitor compensation). This paper used the method of shunt capacitor placement for cost and transmission loss minimization on Nigerian power grid system which is a 24-bus, 330kV network interconnecting four thermal generating stations (Sapele, Delta, Afam and Egbin) and three hydro stations to various load points. Simulation in MATLAB was performed on the Nigerian 330kV transmission grid system. The technique employed was based on the optimal power flow formulations using Newton-Raphson iterative method for the load flow analysis of the grid system. The results show that when shunt capacitor was employed as the inequality constraints on the power system, there is a reduction in the total cost of generation accompanied with reduction in the total system losses with a significant improvement in the system voltage profile.

Minimizing Transmission Loss in Smart Microgrids by Sharing Renewable Energy

Renewable energy (e.g., solar energy) is an attractive option to provide green energy to homes. Unfortunately, the intermittent nature of renewable energy results in a mismatch between when these sources generate energy and when homes demand it. This mismatch reduces the efficiency of using harvested energy by either (i) requiring batteries to store surplus energy, which typically incurs ∼ 20% energy conversion losses, or (ii) using net metering to transmit surplus energy via the electric grid’s AC lines, which severely limits the maximum percentage of renewable penetration possible. In this article, we propose an alternative structure where nearby homes explicitly share energy with each other to balance local energy harvesting and demand in microgrids. We develop a novel energy sharing approach to determine which homes should share energy, and when to minimize system-wide energy transmission losses in the microgrid. We evaluate our approach in simulation using real traces of solar energy harvesting and home consumption data from a deployment in Amherst, MA. We show that our system (i) reduces the energy loss on the AC line by 64% without requiring large batteries, (ii) performance scales up with larger battery capacities, and (iii) is robust to different energy consumption patterns and energy prediction accuracy in the microgrid.

A Multi-objective Hybrid Heuristic Approach for Optimal Setting of FACTS Devices in Power System Operation

<p>Improvement of power system performance in terms of increased voltage profile and decreased transmission loss is becoming one of the challenging tasks to the system operators under open access environment. Apart from traditional power flow controlling devices, use of Flexible AC Transmission System (FACTS) devices can give an attractive solution for the operation and control of deregulated power system. The type, size, location and number of FACTS devices are to be optimized appropriately in order to get the targeted benefits. In this paper, two FACTS devices, Thyristor Controller Phase Shift Transformer (TCPST) and Interline Power Flow Controller (IPFC) are selected to obtain the required performance such as improvement of voltage profile and loss minimization. To search the optimal location and optimal rating of the selected FACTS devices, a hybrid algorithm which formulated with Particle Swarm Optimization (PSO) and Gravitational Search Algorithm (GSA) is proposed. At the first step, the optimization problem is solved for finding the optimal location of FACTS devices using PSO with an objective of voltage profile maximization and later GSA is implemented to optimize their parameters with an objective of transmission loss minimization. The proposed method is implemented on IEEE 30-bus test system and from the simulation results it can be proved that this technique is well suited for real-time application. </p><p align="center"><strong><br /></strong></p>

Optimal reactive power dispatch by improved GSA-based algorithm with the novel strategies to handle constraints

Optimal reactive power dispatch (ORPD) is well known as a complex mixed integer nonlinear optimization problem where many constraints are required to handle. In the last decades, many artificial intelligence-based optimization methods have been used to solve ORPD problem. But, these optimization methods lack an effective means to handle constraints on state variables. Thus, in this paper, the novel and feasible conditional selection strategies (CSS) are devised to handle constraints efficiently in the proposed improved gravitational search algorithm (GSA-CSS). In addition, considering the weakness of GSA itself, the improved GSA-CSS (IGSA-CSS) is presented which employs the memory property of particle swarm optimization (PSO) to enhance global searching ability and utilizes the concept of opposition-based learning (OBL) for optimizing initial population. The presented GSA-CSS and IGSA-CSS methods are applied to ORPD problem on IEEE14-bus, IEEE30-bus and IEEE57-bus test systems for minimization of power transmission losses (Ploss) and voltage deviation (Vd), respectively. The comparisons of simulation results reveal that IGSA-CSS provides better results and the improvements of algorithm in this work are feasible and effective.

A Two-Stage Hybrid Optimization Approach to Improve Transmission System Performance using FACTS Controllers under Open Access Environment

The Flexible AC Transmission System (FACTS) controllers have been resolved many technical issues which emerged with deregulated environment. One of such issues is transmission system performance improvement under open access. In this paper, two FACTS controllers, Thyristor-Switched Series Capacitor (TSSC) and Unified Power Flow Controller (UPFC) are selected to improve the system performance. At the first stage, the generation schedule under competitive electricity market dispatch model is obtained and at the second stage, the impact of the selected FACTS controllers is analyzed while executing various power transactions. A two-stage hybrid optimization approach using Gravitational Search Algorithm (GSA) and Particle Swarm Optimization (PSO) algorithm is adopted to find out the optimal location and parameters of FACTS controller to achieve the required objectives like voltage stability index maximization as well as transmission loss minimization. For case studies, standard IEEE 30 bus test system is used and the simulation results obtained have been validating for real-time adaptability of this proposed method.

CFD study on aerodynamic power output of a 110 kW building augmented wind turbine

Building augmented wind turbine (BAWT) has been studied numerically. BAWT is a new technology trend to combine wind turbine with building and it has several advantages compared with the conventional stand-alone wind turbine such as minimization of electrical transmission loss and construction cost for the distributed power source and by using existing building. In this paper, a 110kW horizontal axis wind turbine blade is designed and CFD analysis is carried out with various reference wind speed and flow angle for the 110kW BAWT. The results show that aerodynamic power output of 110kW BAWT is higher than that of 110kW stand-alone wind turbine due to the concentration effect caused by the wind speed acceleration between buildings. Also this kind of advantage appeared in flow angle between −30° and 15°. Due to the fixed rotational direction of the wind turbine, the effect of flow angle shows asymmetric nature. It is also shown that to exceed Betz limit of 0.593 is possible by the effect of buildings similar to the ducts and shrouds. The results of this study can be applied to the research and development of various BAWT and enhancement of energy efficiency of wind turbine.

Cost effective scheme for OLT in next generation passive optical access network based on noise free optical multi carrier

We propose a cost-effective multi-carrier generation technique which minimizes the passive optical access network (PON) costs. In this study replacement of laser array with multi-carrier source at optical line terminal (OLT) side in PON is addressed. With 25-GHz frequency spacing, the generated optical multi-carriers exhibit good tone to noise ratio (TNR) i. e. above 20dB, and least amplitude difference i. e. 1.5dB. At the OLT, multi-carriers signal based multiplexed differential phase shift keying (DPSK) data from all the channels each having 10Gbps for downlink is transmitted through 25km single mode fiber. While the transmitted information is retrieved at optical network unit (ONU), part of the downlink signal is re-modulated using intensity modulated (IM) on-off keying(OOK) for upstream transmission at 10-Gbps. Simulation results are in good agreement with the theoretical analysis, showing error free transmission in downlink and uplink with 10Gbps symmetric data rate at each channel. The received power, both for uplink and downlink transmission, is adequate for all channels at BER of 10−9 with minimum power penalties. Power budget is calculated for different splitting ratios showing excellent system margins for any unseen losses. The proposed setup provides a cost-effective way minimizing transmission losses, and providing greater system's margin in PON architecture.

Multiobjective optimal power flow using a fuzzy based grenade explosion method

The aim of this paper is to solve the multiobjective optimal power flow (MOPF) problem using a new metaheuristic that is the grenade explosion method. The MOPF problem is formulated by assuming that the decision maker may have a fuzzy goal for each of the objective functions. Six objectives are considered which are: the minimization of generation fuel cost, the improvement of voltage profile, the enhancement of voltage stability, the reduction of emission and the minimization of active and reactive transmission losses. The proposed approach has been tested on the IEEE 30-bus test system. The obtained results show the effectiveness of the proposed method.

Guiding 2.94 μm using low-loss microstructured antiresonant triangular-core fibers

We introduce a new simple design of hollow-core microstructured fiber targeted to guide mid-infrared light at a wavelength of 2.94 μm. The fiber has a triangular-core supported via silica-glass webs enclosed by a large hollow capillary tube. The fiber specific dimensions are determined by the anti-resonant guiding mechanism. For a triangular-core with side length 100 μm, the fiber has a minimum transmission loss 0.08 ± 0.005 dB/m and dispersion 2.3 ps/km/nm at the operational wavelength of 2.94 μm.

Chaotic krill herd algorithm for optimal reactive power dispatch considering FACTS devices

Conventionally, optimal reactive power dispatch (ORPD) is described as the minimization of active power transmission losses and/or total voltage deviation by controlling a number of control variables while satisfying certain equality and inequality constraints. This article presents a newly developed meta-heuristic approach, chaotic krill herd algorithm (CKHA), for the solution of the ORPD problem of power system incorporating flexible AC transmission systems (FACTS) devices. The proposed CKHA is implemented and its performance is tested, successfully, on standard IEEE 30-bus test power system. The considered power system models are equipped with two types of FACTS controllers (namely, thyristor controlled series capacitor and thyristor controlled phase shifter). Simulation results indicate that the proposed approach yields superior solution over other popular methods surfaced in the recent state-of-the-art literature including chaos embedded few newly developed optimization techniques. The obtained results indicate the effectiveness for the solution of ORPD problem of power system considering FACTS devices. Finally, simulation is extended to some large-scale power system models like IEEE 57-bus and IEEE 118-bus test power systems for the same objectives to emphasis on the scalability of the proposed CKHA technique. The scalability, the robustness and the superiority of the proposed CKHA are established in this paper.

Unified power flow controller based reactive power dispatch using oppositional krill herd algorithm

In power system, minimizing the power loss in the transmission lines and/or minimizing the voltage deviation at the load buses by controlling the reactive power is referred as optimal reactive power dispatch (ORPD). This paper presents an improved evolutionary algorithm based on oppositional krill herd algorithm (OKHA) for obtaining optimal steady-state performance of power systems. This article also proposes the effect of UPFC location in steady-state analysis and to demonstrate the capabilities of UPFC in controlling active and reactive power flow within any electrical network. To verify the effectiveness of KHA and OKHA, two different single objective functions such as minimization of real power losses and improvement of voltage profile and a multi-objective function that simultaneously minimizes transmission loss and voltage deviation have been studied through standard IEEE 57-bus and 118-bus test systems and their results have been reported. The study results show that the proposed KHA and OKHA approaches are feasible and efficient.

Optimal Power Flow Using an Improved Electromagnetism-like Mechanism Method

In this article, an improved version of the electromagnetism-like mechanism is developed and proposed to find the optimal solution for the optimal power flow problem in a power system. To show the effectiveness of the developed method, it has been demonstrated on standard IEEE 30-bus and IEEE 57-bus test systems for seven different objectives that reflect fuel cost minimization with generators that may have either convex or non-convex fuel cost characteristics, voltage profile improvement, voltage stability enhancement, and active and reactive power transmission losses minimization. The results obtained using the improved version of the electromagnetism-like mechanism method are compared with those obtained using different methods reported in the literature. Considering the quality of these results, the proposed method is a quite promising alternative approach for solving optimal power flow problems.

PV-WT Based Distribution Generator Location Minimizing Transmission Loss in Pool/Bilateral Electricity Market Model

In this paper, analysis has been carried out for transmission loss minimization with the integrated hybrid PV and Wind turbine in the power system network. For obtaining the power output from the PV and Wind turbine, a probabilistic model for the solar irradiation and wind has been considering using Beta and Weibull distribution function. A Mixed Integer Nonlinear Programming (MINLP) approach has been utilized for determining optimal location and number of distributed generators considering minimization of transmission loss. The analysis has been carried out with constant PQ load and Zip load model. The impact of different load models has been studied. The analysis has been carried out for IEEE24 bus test system in pool/bilateral electricity market model.

Application of Swarm Intelligent Techniques with Mixed Variables to Solve Optimal Power Flow Problems

This paper proposes a new swarm based evolutionary algorithm called LBEST PSO with dynamically varying sub-swarms (LPSO DVS). Swarm based algorithms are meta-heuristic search methods whose mechanics are inspired by the collaborative behaviour of biological populations. The performance of four swarm based algorithms, i.e., particle swarm optimisation (PSO), fuzzy adaptive particle swarm optimisation (FAPSO), fitness distance ratio particle swarm optimisation (FDRPSO) and LPSO DVS are also compared with genetic algorithm (GA) and improved GA when applied to the power system optimal power flow (OPF) problem. OPF optimises the power system operating objective function, while satisfying the set of system operating constraints. The objective functions considered in this OPF problem are fuel cost (FC) minimisation, voltage stability enhancement index (VSEI) minimisation, transmission loss minimisation (LM) and voltage deviation (VD) minimisation. Simulation results for the IEEE 30 bus system are presented and the comparison is made among the numerical results obtained using the different evolutionary algorithms.

Krill Herd Algorithm Based Real Power Generation Reallocation for Improvement of Voltage Profile

Present-day Electric Power Systems are driven under much stressed circumstances when compared to the past and creating a developing need for accuracy, flexibility, and reliability in the areas of Transmission, Distribution and Electric Power Generation. In all stages of power system, voltage stability problems are increasing more and more. So, the only alternate solution for these problems is proper placement and sizing of UPFC. The paper presents the Placement and Tuning of UPFC for a multi-objective function consisting of minimization of transmission losses, load voltage deviation. Here L-index is used to place the UPFC in a specified location i.e., weakest bus, critical line and the weak area of the system. In this paper, a newly developed meta-heuristic algorithm named Krill Herd (KH) is introduced to solve multi-objective problem of optimization. Simulation is carried on IEEE 14-bus system and the results have been compared with the Genetic algorithm with and without UPFC.

Comparison of EPSO, PSO and EP Approaches in Transmission Loss Minimization in Power System Network

The paper presents a comparison of Computational Intelligence techniques are Evolutionary Programming Swarm Optimization (EPSO), Particle Swarm Optimization (PSO), Evolutionary Programming (EP) to optimal placement and sizing of Static Var Compensator. The technique has been implemented to minimize the transmission loss and improve the voltage profile of the system. Simulation performed on standard IEEE 118-Bus RTS and indicated that EPSO a feasible to achieve the objective function.

Optimal Placement of TCSC For Enhancement of Power System Stability Using Heuristic Methods: An Overview

Flexible Alternating Current Transmission Systems (FACTS) represents a vast development in the area of power system operation and control. As we know that under heavily loaded conditions our power system is at high risks of consequent voltage instability problem. This paper gives an overview about application of series connected Flexible alternating current transmission system (FACTS) for improvement of power system performance like transfer stability, secure voltage profile and reduce the system losses etc. FACTS devices require huge capital investment. Therefore, heuristic techniques are used for optimal location and sizing of series FACTS controllers like Genetic Algorithm (GA), Particle Swarm Optimization (PSO) etc. These techniques are used to solve the optimization problem. This paper gives details of optimal placement and sizing of FACTS devices based on different evolutionary techniques which is used for minimization of transmission loss, enhancement of stability of power system. In this study one of the FACTS devices is used as a scheme for enhancement of power system stability.Proper installation of FACTS devices also results in significant reduction of transmission loss. In this review,TCSC is selected as the compensation device.