Minimum Transmission Loss Research Articles

Optimized reactive silencers composed of closely-spaced elongated side-branch resonators.

This paper reports a theoretical study of the sound propagation in a rectangular waveguide loaded by closely-spaced elongated side-branch resonators forming a simple low-frequency broadband reactive silencer. Semi-analytical calculations account for the evanescent modes both in the main waveguide and side-branch resonators and for the viscothermal losses in the silencer elements. Reasonable accuracy is maintained in the evaluation of transmission, reflection, and absorption coefficients, while the calculation time is reduced by a few hundred times in comparison with the finite element method. Therefore, the proposed method is particularly suitable for optimization procedure. The lengths of the individual equally spaced side-branch resonators are optimized by a heuristic evolutionary algorithm that maximizes the minimum transmission loss (TL) over a pre-defined frequency range. Numerical results indicate that the minimum TL of the optimized silencers is reduced due to the destructive effect of the evanescent coupling from the resonators of the nearest side-branches. In the opposite, the TL increases linearly with the number of the side-branch resonators.

The Adaptive Chaotic Symbiotic Organisms Search Algorithm Proposal for Optimal Reactive Power Dispatch Problem in Power Systems

DOI : 10.26650/electrica.2019.18008 This paper presents an adaptive chaotic symbiotic organisms search algorithm (A-CSOS) for finding the solution of optimal reactive power dispatch (ORPD) problem which is one of the main issues of power system planning and operations. The most important advantage of symbiotic organisms search algorithm (SOS) is that is not need any particular algorithm parameters. However, the SOS algorithm has some features to be enhanced, like falling into local minima and sluggish convergence. A-CSOS algorithm with adding new and improved features like adaptivity and chaos to conventional SOS algorithm is proposed to solve ORPD problem. The ORPD problem is mainly focused on minimization of transmission loss (Ploss) and total voltage deviation (TVD). To determine the optimal set points of control variables including generator bus voltages, tap positions of transformers, and reactive power outputs of shunt VAR compensators is very crucial for minimization to Ploss and TVD. The proposed algorithm is implemented on IEEE 30-bus test power systems for ascertaining the performance of A-CSOS algorithm on ORPD problem. The results showed that the proposed approach is up to 10.39% better than many of which the latest algorithms in literature and encourage the researchers to implement A-CSOS algorithm to ORPD problem. Cite this article as: Yalcin E, Taplamacioglu MC, Cam E. “The Adaptive Chaotic Symbiotic Organisms Search Algorithm Proposal for Optimal Reactive Power Dispatch Problem in Power Systems”, Electrica, 2019; 19(1): 37-47.

Performance comparison of distributed generation installation arrangement in transmission system for loss control

Placing Distributed Generation (DG) into a power network should be planned wisely. In this paper, the comparison of having different installation arrangement of real-power DGs in transmission system for loss control is presented. Immune-brainstorm-evolutionary programme (IBSEP) was chosen as the optimization technique. It is found that optimizing fixed-size DGs locations gives the highest loss reduction percentage. Apart from that, scattered small-sized DGs throughout a network minimizes transmission loss more than allocating one biger-sized DG at a location.

Optimal Allocation of SVC for Enhancement of Voltage Stability limit and Minimization of Transmission losses in Power System using Particle Swarm Optimization

Optimal Allocation of SVC for Enhancement of Voltage Stability limit and Minimization of Transmission losses in Power System using Particle Swarm Optimization

Use of Genetic Algorithm on Optimal Power Flow: An Illustration of Transmission Line Loss Minimization

This paper presents the usefulness and effectiveness of Genetic Algorithm on solving Optimal Power Flow (OPF) problem formulation of a real world power system. Optimization is a broad concept that is generally directly or indirectly related to cost factor. In this case, transmission lines loss minimization is presented as the objective of optimization problem formulation keeping all other technical factors and parameters under operating constraints. Results of this study, presented in the Integrated Nepal Power System (INPS) transmission line network show that the Genetic Algorithm is effective method to optimize the power flow via assigned objective of transmission loss minimization in much quicker and effective way when compared to conventional Newton-Rapshon method.

Optimized reactive silencers with narrow side-branch tubes

This paper presents a theoretical study of the sound propagation in a waveguide loaded by an array of flush-mounted narrow side-branch tubes, forming a simple low-frequency reactive silencer. The individual tube-lengths and the distances between the adjacent tubes are optimized in order to maximize the minimum transmission loss over a given frequency range. The transmission properties of the silencer are calculated using the transfer matrix method, heuristic evolutionary approach is employed for the determination of the optimal parameters. The numerical results are validated against the finite element method simulation. A comprehensive parametric study is performed to demonstrate the optimized silencer performance as a function of the number of side-branch tubes, and the frequency range. It is shown that for the given frequency range, the minimum transmission loss of the optimized silencer increases linearly with the number of the side-branch tubes.

Spectroscopy analysis of mixed organic liquid detection with Ge20Se60Te20 glass-tapered fiber

In this study, the high-purity Ge20Se60Te20 glass was prepared by melt-quenching method and drawn into a bare glass fiber with a diameter of 450 μm. The minimum transmission loss of this fiber is approximately 3.4 dB/m at 5.9 μm. Then, the fibers were tapered into different waist diameters of 30, 50, 70, and 90 μm. Those tapered fibers were used as sensor for detection of mixed liquid containing different ratios of methanol (CH3OH) and dichloromethane (CH2Cl2) by fiber evanescent wave spectroscopy in situ. Finally, the sensing characteristics of the tapered fibers to the mixed liquid were simulated based on finite-element method. The simulation results were in good agreement with the experimental results.

Loss-Minimizing Generation Unit and Tie-Line Scheduling for Asynchronous Interconnection

Asynchronous interconnection of two power systems by high voltage direct current transmissions (HVDCs) is a judicious choice to enhance the reliability of system operation and evade some risks. As one of the pioneers of asynchronous interconnection, the southern China power system encounters the challenge of coordinating generation of the sending-end and demand of the receiving-end. The day-ahead generation unit and tie-line scheduling problem is formulated as a two-stage mathematical optimization, in which the first-stage problem minimizes the variance of the remaining load series of receiving-end and generates a near-optimal interarea power transmission schedule, whereas the second-stage problem decides the production level of generation units and power flow of HVDC tie-lines with the objective of minimizing transmission losses. In the second-stage problem, discrete characteristics of HVDC power profile is explicitly modeled, and a quadratic loss function derived from historical data is used to calculate the overall loss of each HVDC, which is then piecewise linearized to form a tractable mixed integer linear programming. Numeric experiments based on realistic data of China Southern Power Grid are carried out. The feasibility and effectiveness of the proposed method is verified through comparing the optimized generation and transmission schedules with original ones which are generated based on expert knowledge.

Loss Minimization in Optimal Reactive Power Planning (ORPP) Based on Whale Optimization Algorithm

The key of RPP is the optimal allocation of reactive power considering location and size. This paper presents the loss minimization in optimal reactive power planning (ORPP) based on Whale Optimization Algorithm (WOA). The objective is to minimize transmission loss by considering several load conditions at bus 3, bus 15 and bus 21. Reactive Power Scheduling (RPS) and Transformer Tap Changer Setting (TTCS) were set as the control variables. Validation was conducted on the IEEE 30 Bus RTS. Results from the study indicate that the proposed WOA can minimize transmission loss better than Evolutionary Programming (EP).

Hollow-core conjoined-tube negative-curvature fibre with ultralow loss

Countering the optical network ‘capacity crunch’ calls for a radical development in optical fibres that could simultaneously minimize nonlinearity penalties, chromatic dispersion and maximize signal launch power. Hollow-core fibres (HCF) can break the nonlinear Shannon limit of solid-core fibre and fulfil all above requirements, but its optical performance need to be significantly upgraded before they can be considered for high-capacity telecommunication systems. Here, we report a new HCF with conjoined-tubes in the cladding and a negative-curvature core shape. It exhibits a minimum transmission loss of 2 dB km−1 at 1512 nm and a <16 dB km−1 bandwidth spanning across the O, E, S, C, L telecom bands (1302–1637 nm). The debut of this conjoined-tube HCF, with combined merits of ultralow loss, broad bandwidth, low bending loss, high mode quality and simple structure heralds a new opportunity to fully unleash the potential of HCF in telecommunication applications.

Improvement of ORPD Algorithm for Transmission Loss Minimization and Voltage Control Using UPFC by HGAPSO Approach

The transmission losses are more dependent upon the voltages at various load conditions. The motive of research published in this paper is to propose a methodology to solve Optimal reactive power dispatch problem using two phase hybrid combination of Genetic algorithm and Particle Swarm Optimization algorithms. Optimal reactive power dispatch tackles network loss reduction, increased power transfer capability along with the voltage control at various buses by satisfying limitations on the dependent and independent control variables. Among all Flexible AC Transmission Systems Devices, unified power flow controller abbreviated as UPFC has been chosen for the analysis to control the power system because it was found to be the most efficient in empowering transmission network using reactive power injection. Therefore, most desirable placement and competency of UPFC has been worked out in the proposed research. Two-voltage source model of UPFC has been utilized for the analysis purpose. The UPFC control parameters are chosen to be the additional control parameters for the optimal reactive power dispatch calculations. The results are obtained by applying GA and PSO separately and finally, using the combination of Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). The simulation is carried out on standard IEEE-30 bus test system using MATLAB. The results obtained using GA, PSO and HGAPSO were compared, and it was found that HGAPSO results prove to be operative for the proposed optimal reactive power dispatch algorithm.

Population based evolutionary optimization techniques for optimal allocation and sizing of Thyristor Controlled Series Capacitor

During the last decade, the application of Flexible AC Transmission System (FACTS) devices in electrical power system increased due to their numerous advantages such as power transfer capability enhancement, reliability and security improvement and reactive power compensation. Although to obtain maximum advantage, their size and location should be optimal. Optimal position and size of Thyristor Controlled Series Capacitor (TCSC) in power system using evolutionary optimization techniques such as, Teaching Learning Based Optimization (TLBO), Artificial Bee Colony (ABC) and Particle Swarm Optimization (PSO) are presented in this paper. The minimization of transmission loss, the installation cost of TCSC and voltage deviation is considered as an objective function. To demonstrate the viability of the algorithms, it is validated on the IEEE 14 bus, IEEE 30 bus and Indian 75 bus systems. The results accomplish from TLBO are compared with the ABC and PSO to show the capability of the TLBO and its superiority over ABC and PSO.

Experimental Work for Using of Nanotechnology Coating to Minimize Transmission Losses by Reduction of Resistance

Experimental Work for Using of Nanotechnology Coating to Minimize Transmission Losses by Reduction of Resistance

Minimization of transmission loss using distributed generation approach

The goal of this work is to calculate the total loss in the system and minimize this loss by implementation of distributed generation (DG) technology. In this paper, load flow analysis method is followed to calculate the loss in the system in conjunction with the line flows. A simple 5 bus system with the main bus of the substation as the slack bus, three Plant generators at the generator bus and three load buses are taken for analysis. For loss minimization two distributed generators at two load buses are connected. One generator is a synchronous type model and the other is asynchronous type model. We searched for the most economical penetration level and the ratings of the distributed generators are decided by the magnitude of penetration power at each load bus. Using software, power system simulation for electrical (PSSE), the system with and without DG technology is modeled and the output from the PSSE is observed.

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

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

The impact of wind-power generation on the planning of regulating reserve

This doctoral thesis focuses on the efficient management of a power system with a large share of wind-power generation and on the methods for planning the operating reserve. The approach proposed in this research involves the use of data directly from the network’s dispatch center and the forecasting systems, as well as already existing day-ahead plans for wind and load power to determine the regulating reserve for the load frequency control (LFC). The same principle is used to find the optimal regulating reserve distribution (RRD) between the available generation units in the system for automatic generation control. It is developed using iterative power-flow computation with a reactive power correction and a stochastic search algorithm for transmission-loss minimization. Moreover, variations in the generation of individual wind-power plants (WPPs) from the plan are considered in the optimal RRD. A special focus of this research has been put on the Croatian power system due to the accessibility of relevant information and operating data. The obtained results of the testing with actual data from the Croatian power system indicate substantial savings in ancillary service costs for the LFC, while ensuring safe system operation. The considerable impact of variations from the plan for each individual WPP generation on the optimal RRD was also identified. Comparing the results for the daily sum of regulating reserves obtained with the proposed and the currently used approaches, the corresponding costs indicate a total saving of 21.2% for all 12 selected days in 2015 when using the proposed approach. In practice, a part of the reserve can be slow, i.e., with a lower unit price, thus the savings would be even higher. Furthermore, the obtained optimal RRD computed according to the proposed approach was compared with four commonly used RRDs in Croatia. The results obtained using the proposed approach indicate a decrease in the total transmission losses of between 1% and 2%. With a larger share of the generation from the WPPs and with more dispersed locations of the WPPs and regulating power plants a larger reduction in the transmission losses is expected.

Low-loss and single-mode tapered hollow-core waveguides optically coupled with interband and quantum cascade lasers

We report single-mode midinfrared laser beam delivery through a 50-cm-long tapered hollow-core waveguide (HCW) having bore diameter linearly increasing from 200 to 260 μm. We performed theoretical calculations to identify the best HCW-laser coupling conditions in terms of optical losses and single-mode fiber output. To validate our modeling, we coupled the HCW with an interband cascade laser and four quantum cascade lasers with their emission wavelengths spanning 3.5 to 7.8 μm, using focusing lenses with different focal lengths. With the best coupling conditions, we achieved single-mode output in the investigated 3.5 to 7.8 μm spectral range, with minimum transmission losses of 1.27 dB at 6.2 μm.

Flexible Transparent Conductive Films with High Performance and Reliability Using Hybrid Structures of Continuous Metal Nanofiber Networks for Flexible Optoelectronics.

We report an Ag nanofiber-embedded glass-fabric reinforced hybrimer (AgNF-GFRHybrimer) composite film as a reliable and high-performance flexible transparent conducting film. The continuous AgNF network provides superior optoelectronic properties of the composite film by minimizing transmission loss and junction resistance. In addition, the excellent thermal/chemical stability and mechanical durability of the GFRHybrimer matrix provides enhanced mechanical durability and reliability of the final AgNF-GFRHybrimer composite film. To demonstrate the availability of our AgNF-GFRHybrimer composite as a transparent conducting film, we fabricated a flexible organic light-emitting diode (OLED) device on the AgNF-GFRHybrimer film; the OLED showed stable operation during a flexing.

Solution of multi-objective optimal power flow using efficient meta-heuristic algorithm

An efficient meta-heuristic algorithm-based multi-objective optimization (MOO) technique for solving the multi-objective optimal power flow (MO-OPF) problem using incremental power flow model based on sensitivities and some heuristics is proposed in this paper. This paper is aimed to overcome the drawback of traditional MOO approach, i.e., the computational burden. By using the proposed efficient approach, the number of power flows to be performed is reduced substantially, resulting the solution speed up. In this paper, the generation cost minimization and transmission loss minimization are considered as the objective functions. The effectiveness of the proposed approach is examined on IEEE 30 and 300 bus test systems. All the simulation studies indicate that the proposed efficient MOO approach is approximately 10 times faster than the evolutionary-based MOO algorithms. In this paper, some of the case studies are also performed considering the practical voltage-dependent load modeling. The simulation results obtained using the proposed efficient approach are also compared with the evolutionary-based Non-dominated Sorting Genetic Algorithm-2 (NSGA-II) and the classical weighted summation approach.