Volume 3 Issue 6
Authors: Solomon Nunoo; Edward Kofi Mahama
Abstract: This paper investigates the use of internet-based Supervisory Control and Data Acquisition (SCADA) system to monitor power transformer parameters remotely and to investigate into how personnel can have access to their system regardless of their location. There are several parameters that can be monitored for efficient operation of a power transformer, although temperature, voltage, load and bushing condition are considered in this work because they are the major cause of transformer failure. In carrying out this work, the software and hardware components required to carry out the remote monitoring function was considered. Means of preventing hackers from getting access to the network have been considered. The implementation of the monitoring system will help to save running cost by optimising maintenance schedule and reduce risk of failure to the power transformer.
Keywords: Internet-based SCADA, Automation, Power Transformers, Remote Monitoring, Maintenance Optimisation, SCADA Security
Authors: Xianwei Hu; Menglan Duan; Haitao Zhang; Mingchen Ni
Abstract: Subsea production system, being of high value to deep water oil and gas production, has become more and more important recently. Simultaneously, issues related to its safety and reliability is hotly disputed by engineers and scholars. Based on fuzzy fault tree, risk analysis of oil and gas leakage is successfully completed. Through the construction of fault tree, qualitative analysis is conducted, obtaining minimum cut sets and cut-sets importance. Moreover, quantitative analysis, based on theory of fuzzy sets, is employed, through which failure probability, probabilistic importance and critical importance have been figured out. The above-mentioned results serve as a good reference to avoid oil and gas leakage in subsea production system.
Keywords: Subsea Production System, Oil/Gas Leakage, Risk Analysis, Fuzzy Fault Tree Analysis, Fuzzy set theory
Authors: Xing Luo; Jihong Wang; Hao Sun
Abstract: IIn comparison to hydraulic and electrical actuators, the significant drawback of pneumatic actuators is low energy conversion ability which is due to the open-circuit structure in nature. This paper represents a hybrid pneumatic-electrical system for the purpose of recycling exhaust compressed air energy from existing pneumatic actuator outlets to generate electricity. A proper control strategy is developed to manage the actuator system operation and to ensure the energy recovery work well. The pneumatic-electrical system mathematical model and the simulation results are presented. The laboratory experimental tests are described. The system energy efficiency is also analyzed. The simulated and experimental studies demonstrate that the whole system operated by the designed controller can successfully recover exhaust compressed air energy under appropriate working conditions.
Keywords: Pneumatic Actuators; Electrical Systems; Energy Recovery; Mathematical Modelling; Process Control
Authors: Dang Quoc Thong; Bach Quoc Khanh; Vu Van Thang
Abstract: Recently, the restructuring of electricity market and the development of technology have been enhancing the application of distributed generators (DGs) and renewable energy resources. Hence, the planning of distribution systems (PDS) for competitive electricity markets (CEMs) has encountered impacts which need to be investigated. This paper proposes a novel approach for optimazing distribution system planning in CEMs with the presence of DGs. The proposed model can determine equipment sizing and timeframe required for upgrading power network in order for utilities to purchase electric energy from electricity markets. Besides, the problems of DG system development (Optimal DG displacement, sizing, technology selection and installation period) in distribution planning to meet the demand growth will be solved. The model uses the objective function that minimizes the total cost of network (feeders and transformers) upgrading, new DGs installation, distribution systems operating, and electric energy purchasing from CEMs. The proposed model is tested using a 33 bus 22 kV radial feeder. The calculation is programmed in GAMS environment.
Keywords: Distributed Generator (DG); Planning of Distribution System (DS); Competitive Electricity Markets (CEM)
Authors: Alexander Bolonkin
Abstract: The current flight passenger-transport and cargo systems have reached the peak of their development. In the last 30 years there has been no increase in speed or reductions in trip costs. The transportation industry needs a revolutionary idea, which allows jumps in speed and delivery capability, and dramatic drops in trip price. The author offers a new idea in transportation in which trip (flight) time practically does not depend on distance, and vehicle load capability doubles and has a driving engine that is located on the ground and can use any cheap source of energy. The author develops the theory and provides computations for project which contains five subprojects united the common idea: acceleration of the air vehicle on ground and continuation of flight by inertia (high speed catapulting). The initial speed is 290 – 6000 m/s, the range is 50 -10000 km (short, average, and long distances). Short transport system has range 50-70 km, for example: city – sub-city, strait and air bridges such as across the Straits of Gibraltar 16 km, the English Channel 40 km, Bering Straits 100 km (Russia–America), Sakhalin–Asia 20 km, Russia–Japan, etc. The long distance has range up 10000 km such as New York-Paris 5838 km, Washington-London 7373 km, San-Francisco – Tokyo 8277 km, San-Francisco – Vladivostok (Russia) 8377 km, New York – Moscow 7519 km, Moscow – Beijing 5800 km, Moscow – Tokyo 7487 km, New York – Berlin 6392 km, and so on. The offered catapult system having length of 400 km can be used as the space launch system which decreases the space launch cost in hundreds of times. That also may be used as the new conventional high speed (up 1000 km/h) transport system between cities. That will be significantly cheaper than used MagLev (Magnetic Levitation) systems, because suspending of the vehicle used the conventional wing. The offered system may be also used for the mass launch of bombs (projectiles) in war.
Keywords: Air Catapult Transport; Air Kinetic Transport; New Passenger and Cargo Transport; Catapult Aviation; New Space Launch System; New Suspending High Speed Ground System; Cattran; Skimplane
Authors: Ciprian -Mircea Neme?
Abstract: The increased integration of wind power into the electric power systems brings new challenges for effective their planning and operation. The Weibull distribution is a widely used distribution, especially for modelling the random variable of wind speed. In the paper, the authors present a comparative analysis of some methods for estimating the Weibull parameters. Results for a real-world database are presented in a study case. The techniques require historical wind speed data, collected over a certain time interval, to establish the parameters of the wind speed distribution for that particular location.
Keywords: Wind Speed Data; Wind Energy; Probability Density Function; Weibull Distribution
Authors: Shuichi Torii; Cheng Chen
Abstract: The present study is to produce the high calorific fuel using sewage sludge. Consideration is given to the effects of implication water rate of sewage sludge, temperature, and vacuum pressure on the optimum production condition and the high calorific fuel. In order to reduce the initial moisture content of sewage sludge, the vacuum drying method which is modified here is employed. It is found from the study that the lower implication water rate causes the higher caloric fuel and the maximum calorific value developed here is similar to that of woody pellet for reference. This application will accelerate the reuse and reduce of sewage sludge.
Keywords: Biomass; Sewage Sludge;High Calorific Fuel; Decompression; Moisture
Authors: Andres Feijoo; Jose Luis Pazos; Daniel Villanueva
Abstract: Asynchronous wind turbines (WT) have been among the most used type of converters in wind energy plants. Conventional asynchronous WTs were installed during the first years of wind energy research, but doubly-fed induction generator (DFIG) WTs and other types have also been added for current and future use. So, the massive presence of such machines in electrical networks means it is important to develop dynamic and steady-state models to describe their behaviour. This paper presents a review of steady-state models of asynchronous WTs for the load flow analysis (LF) that have been presented in recent years. A large number of conventional asynchronous WTs can still be found in electrical systems in many different countries all over the world. This fact constitutes a reason for the authors not to overlook them when studying the operation of such systems. In addition, there has been some discussions about these models over the last few years.
Keywords: Asynchronous Wind Turbine; Load Flow Analysis; Newton-Raphson