Fault detection,location and classification of a transmission line

Neural Computing and Applications - Transient stability is very important in power system. Large disturbances like fault in a transmission line are a concern which needs to be disconnected as...     

A fast time–frequency transform based differential relaying scheme for UPFC based double-circuit transmission line

This paper presents a new differential relaying scheme for a mutually coupled, double circuit transmission line in presence of Unified Power Flow Controller (UPFC) in the line. The process starts at retrieving the three phase current signals at both ends of the transmission line synchronously and processing it though the time–frequency transform such as Fast Discrete S-Transform to derive the spectral energy content of the current signals. The differential spectral energy of current signals (difference between the spectral energy of the current signal at the sending and receiving ends, respectively) of the respective phases of transmission line is used to register the fault pattern. The proposed approach includes fault detection and classification along with identification of the fault section with respect to UPFC location in one of the double-circuit transmission line. The extensive test results indicate that the proposed differential relaying scheme is highly reliable in registering fault patterns in UPFC based transmission line including wide variations in operating parameters of the power network.     

Design, fabrication, and evaluation of a 5 F-5 V prototype of solid-state PANI based supercapacitor

A 5 F-5 V prototype of solid state supercapacitor based on polymer electrolyte (PANI) and XSPEEK composing of six single cells stacked in series has been fabricated. The scale-up from a small single cell to a larger stack prototype of a solid-state electrochemical supercapacitor is discussed in this paper. The developed prototype showed a higher series resistance than estimated in our previous study on individual cell supercapacitor. The fabricated prototype achieved a specific capacitance of 480 F/g. The assembled capacitor has been characterized by cyclic voltammetry, impedance spectroscopy and galvanostatic charging/discharging. The performances of the electrodes have been compared with that of the single cell electrodes of area 4 cm².     

Phase transition and electrical properties of gallium- and indium-doped Bi<Subscript>10</Subscript>Ti<Subscript>3</Subscript>W<Subscript>3</Subscript>O<Subscript>30</Subscript>

Polycrystalline samples of gallium- and indium-doped Bi₁₀Ti₃W₃O₃₀ (mixed-layer Aurivillius phase with the Ti⁴⁺ and W⁶⁺ distributed at random over the perovskite-like slabs) have been prepared by solid-state reactions, and their polymorphism and electrical properties have been studied. Doping with both In³⁺ and Ga³⁺ yields limited solid solutions and shifts the ferroelectric phase transition to lower temperatures. The heterovalent substitutions of In³⁺ and Ga³⁺ for Ti⁴⁺ and W⁶⁺ increase the oxygen vacancy concentration and, accordingly, the conductivity of the material relative to the undoped compound.     

Comparative performance analysis of Artificial Bee Colony algorithm in automatic generation control for interconnected reheat thermal power system

This study extensively presents the Automatic Generation Control (AGC) application of Artificial Bee Colony (ABC) algorithm. This algorithm is one of the new population based optimization algorithms which have been developed since 2005. In this study, the algorithm is applied to the interconnected reheat thermal power system in order to tune the parameters of PI and PID controllers which are used for AGC. The tuning performance of the algorithm is compared with that of Particle Swarm Optimization (PSO) algorithm through transient response analysis method. In addition to these, the robustness analysis is applied to the power system which is optimized by ABC algorithm so as to determine its response towards changing in the load and the system parameters, varied in the range of ±50%. The behavior of the system is also investigated with this analysis towards the different cost functions such as integral of absolute error (IAE), integral of squared error (ISE), integral of time weighted squared error (ITSE) and integral of time multiplied absolute error (ITAE). At the end of the study, it is seen that the ABC algorithm is successfully applied to the AGC in the application of interconnected reheat thermal power system, and it shows better tuning capability than the other similar population based optimization algorithm. Furthermore, it is also seen that the proposed system is robust and is not affected by changing in the load, the power system parameters and the cost functions.     

PIV study on the development of double-diffusive convection during the solidification effected by lateral cooling for a super-eutectic binary solution

The solidification of a binary solution occurs in a variety of industrial applications. The fundamental mechanism of the development of “double-diffusive convection” during solidification was one of the main subjects of study in the past. This study focused on the effect of the initial concentration of a super-eutectic aqueous ammonium chloride solution on the development of double-diffusive convection during the solidification process. Particle image velocimetry (PIV) technique was employed to measure the flow velocity and observe the morphological conditions associated with the solidification effected by cooling from the side wall. The transient temperature distribution within a test cell was also measured by using the designed experimental system. PIV measurement revealed that the flow structure was composed of a major circulation flow within the test cell for the binary solution with low-concentration and multiple layers of circulation flows developed in sequence in the melt of the test cell for the high-concentration binary solution. Test-cell images captured by CCD camera indicated the presence of more A-segregates within the mushy zone as the initial concentration of the binary solution increased. For the low-concentration binary solution, under circumstances of without or with very weak double-diffusive convection, transient temperature distribution presented thermal stratification within the test cell. However, strong double-diffusive convection resulted in intersection on temperature curves for the high-concentration binary solution.     

Comparison of model-free and model-based methods for time optimal hit control of a badminton robot

In this research, time optimal control is considered for the hit motion of a badminton robot during a serve operation. Even though the robot always starts at rest in a given position, it has to move to a target position where the target velocity is not zero, as the robot has to hit the shuttle at that point. The goal is to reach this target state as quickly as possible, yet without violating the limitations of the actuator. To find controllers satisfying these requirements, both model-based and model-free controllers have been developed, with the model-free controllers employing a Natural Actor-Critic (NAC) reinforcement learning algorithm. The model-based controllers can immediately achieve the desired motions relying on prior model information, while the model-free methods are shown to yield the desired robot motions after about 200 trials. However, in order to achieve this result, a good choice of the reward function is essential. To illustrate this choice and validate the resulting controller, a simulation study is presented in which the model-based results are compared to those obtained with two different reward functions.     

Cuckoo Search algorithm based load frequency controller design for nonlinear interconnected power system

A new optimization technique called Cuckoo Search (CS) algorithm for optimum tuning of PI controllers for Load Frequency Control (LFC) is suggested in this paper. A time domain based-objective function is established to robustly tune the parameters of PI-based LFC which is solved by the CS algorithm to attain the most optimistic results. A three-area interconnected system is investigated as a test system under various loading conditions where system nonlinearities are taken into account to confirm the effectiveness of the suggested algorithm. Simulation results are introduced to show the enhanced performance of the developed CS based controllers in comparison with Genetic Algorithm (GA), Particle Swarm Optimization (PSO) and conventional integral controller. These results denote that the proposed controllers offer better performance over others in terms of settling times and various indices.     

Tribological Behavior of Acrylic Acid–Modified Date Palm Leaf–Reinforced Polyvinyl Alcohol Composite

Most machine components are frequently exposed to tribological loadings during their service life. Hence, the tribological performance of materials is an essential element to be considered in the design of mechanical parts in addition to mechanical properties. Previously, authors have studied the mechanical properties of date palm leaf–reinforced polyvinyl alcohol composite. In the present investigation, an attempt has been made to investigate the tribological behavior of the composite under a multipass abrasion condition. The composite was prepared by reinforcing randomly oriented acrylic acid–modified date palm leaf fibers with varying weight percentages of 10, 20, 28, and 30%. The performances of the specific wear rate and wear weight loss were investigated as a function of applied loads and abrading distances. It was observed that 28 wt% is the optimum fiber loading to achieve maximum tribological properties similar to mechanical properties obtained from previous work. Scanning electron microscopy was used to understand the wear mechanisms of the composite at optimum fiber loading.