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Online Tuning of Power System Stabilizers Using Fuzzy Logic Network with Fuzzy C-Means Clustering Prediction: A Case Study
Mohammad Hajizade Kanafgorabi,
Ali Karami
Issue:
Volume 3, Issue 5, October 2014
Pages:
217-227
Received:
26 August 2014
Accepted:
16 September 2014
Published:
30 September 2014
Abstract: Power system stabilizers (PSS) has been widely used to enhance damping due to the electromechanical low frequency oscillations occurrence in power systems. In this paper, a new method is used for the online tuning of parameters of conventional power system stabilizers (CPSS) using fuzzy logic. Fuzzy logic enables mathematical modeling and computation of some nonlinear parameters of the system, which are usually derived empirically by utilization of expert knowledge rules. Various literatures has shown that fuzzy logic controller is one of the most useful methods for expert knowledge utilization. This type of controller is adaptive in nature and can be used successfully as a power system stabilizer. The design of fuzzy logic controllers is mainly based on fuzzy rules and input/output membership functions. Simple and efficient clustering algorithms allow data classification in distinct groups using distance and/or similarity functions. In the present paper, the optimum generation of fuzzy rules base using Fuzzy C-means (FCM) clustering technique is used. In fact, data are classified and the number of fuzzy rules which depends on convergence radius is determined. Finally, the performance of proposed FCM controller is compared with that of conventional controller. The active power, reactive power and bus voltages used as inputs to the fuzzy logic network based power system stabilizer and the parameters of the optimum stabilizer , i.e. gain factor as well as time constants of the lead/lag compensator, are the outputs of the proposed system. The design method has been successfully implemented on a single machine power system connected to an infinite bus over various operating conditions.
Abstract: Power system stabilizers (PSS) has been widely used to enhance damping due to the electromechanical low frequency oscillations occurrence in power systems. In this paper, a new method is used for the online tuning of parameters of conventional power system stabilizers (CPSS) using fuzzy logic. Fuzzy logic enables mathematical modeling and computati...
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Islanding Detection in Micro-Grids Using Sum of Voltage and Current Wavelet Coefficients Energy
Issue:
Volume 3, Issue 5, October 2014
Pages:
228-236
Received:
1 September 2014
Accepted:
24 September 2014
Published:
30 September 2014
Abstract: This paper presents wavelet based islanding detection in distributed generation (DG) interfaced to the microgrid. Also a new fast method is developed for islanding detection based on measuring the utility currents and voltages signals processed by discrete wavelet transform. These currents and voltages signals are measured before the main circuit breaker of microgrid network and their features extracted by discrete wavelet transform. These features are sum of wavelet coefficients energy and are used for distinguishing the islanding conditions from non-islanding ones. Because of changing in measuring point of currents and voltages signals from point of common coupling (PCC) in traditional methods to before the main circuit breaker in proposed method, this new method detects the islanding conditions faster than the other methods. The proposed method has been examined under various scenarios; including mains supply faults, various one, two, or three phases' grid faults, and changes of rate of produced energy on IEEE 1547 anti-islanding test system. The numerical studies show the feasibility and applicability of the proposed method with satisfactory results.
Abstract: This paper presents wavelet based islanding detection in distributed generation (DG) interfaced to the microgrid. Also a new fast method is developed for islanding detection based on measuring the utility currents and voltages signals processed by discrete wavelet transform. These currents and voltages signals are measured before the main circuit b...
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Predicting Heat Demand for a District Heating Systems
Issue:
Volume 3, Issue 5, October 2014
Pages:
237-244
Received:
31 August 2014
Accepted:
5 October 2014
Published:
20 October 2014
Abstract: Poland is one of the heaviest users of district heating systems in Europe, and those district heating systems are heated mainly by coal. Sustainable development of district heating systems in Poland including improving quality of environment, economic of heat production and security of heat supply is in close connection with increasing of energy efficiency. Heat production and heat distribution plays important role in national energy balance. Additional increasing of energy efficiency in district heating systems need detail forecasts for future heat consumption in scale of individual district heating system and for systems in whole country. Accurate forecast give possibility for increasing efficiency of heat production, decreasing fuel consumption and connected with it emission decreasing from combustion products to the atmosphere. Heat production efficiency can be optimized through the use of appropriate procedures for running heat sources alongside short-term heat demand forecasting combined with preparation for adjusting heat source work parameters to the predicted heat load for a few hours hence. The artificial neural networks model delivers good forecasting results. The accuracy of the results depends on the kind of network, its architecture, the size and type of input data as well as the forecasting period. Forecasting accuracy within a 3-5% margin of error is sufficient to steer heat source operations. Described forecasting methods can be use as a good tool to regulate district heating networks and heat sources.
Abstract: Poland is one of the heaviest users of district heating systems in Europe, and those district heating systems are heated mainly by coal. Sustainable development of district heating systems in Poland including improving quality of environment, economic of heat production and security of heat supply is in close connection with increasing of energy ef...
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Renewable Energy Sources and Turkey
Issue:
Volume 3, Issue 5, October 2014
Pages:
245-249
Received:
9 September 2014
Accepted:
30 September 2014
Published:
30 October 2014
Abstract: International economic competition is forcing countries for improving their technology. The main elements are knowledge and R&D for countries technological developments. However, the impulsion of development is “energy”. In this context, energy consumption is a one of the pointer for determine to development level of a country. Renewable energies are main sources of our energy consumption; the amounts of finite energy sources are decreasing so that countries are choosing renewable energy, especially in last 10-15 years. In this frame, renewable energy sources will have important potential for energy consumption in a near future. Renewable energy sources have huge advantages, such as not harming the environment, no risk on running out, able to produce with local resources on micro level, less dependency to out, without problem of supply-transport and demand security. In this study, renewable energy sources are firstly review on globally and also particularly Turkey taken in hand for potential analysis of natural energy. In this case, requirement is a new “strategy and policy of energy diversification”.
Abstract: International economic competition is forcing countries for improving their technology. The main elements are knowledge and R&D for countries technological developments. However, the impulsion of development is “energy”. In this context, energy consumption is a one of the pointer for determine to development level of a country. Renewable energies a...
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Development of Small Scale Screw Extrusion Machine for Production of Sawdust Briquettes in Rural Area in Indonesia
Anak Agung Putu Susastriawan,
Bambang Wahyu Sidharta
Issue:
Volume 3, Issue 5, October 2014
Pages:
250-253
Received:
8 September 2014
Accepted:
21 October 2014
Published:
30 October 2014
Abstract: Small scale screw extrusion machine is designed and tested for making compact sawdust briquettes in rural area in Indonesia. The extrusion machine is powered by 5,5 HP gasoline internal combustion engine. In this work, briquetting machine is used to produce sawdust briquettes which two different ratios of starch-sawdust. The ratios of starch to sawdust are 1:4 and 2:4. Sawdust briquettes have a length of 3 cm and 4 cm for both composition ratios. The performance of the machine is investigated in term of density changes of briquettes after three days. The density of sawdust briquettes just after extrusion process is compared with the density of sawdust briquettes after 3 days sunlight drying. The result shows that the extrusion machine is able to produce compact sawdust briquettes with different ratios of starch to sawdust. The result also indicates that 3 cm long sawdust briquettes which starch to sawdust ratio 2 : 4 has the lowest density changes and has the highest compressive strength.
Abstract: Small scale screw extrusion machine is designed and tested for making compact sawdust briquettes in rural area in Indonesia. The extrusion machine is powered by 5,5 HP gasoline internal combustion engine. In this work, briquetting machine is used to produce sawdust briquettes which two different ratios of starch-sawdust. The ratios of starch to saw...
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Assessment of Renewable Energy and Emissions from Domestic Sewage Treatment in Brazil
Fatima Aparecida de Morais Lino,
Kamal Abdel Radi Ismail
Issue:
Volume 3, Issue 5, October 2014
Pages:
254-260
Received:
25 September 2014
Accepted:
29 October 2014
Published:
10 November 2014
Abstract: With the growth of the world population, in recent decades, the generation of domestic sewage has increased. In Brazil about 28 million cubic meters of sewage are generated daily and needs to be collected and treated. This task has been one of the biggest challenges for municipal administrators. Disposition of domestic sewage without treatment is a risk to public health and environment. This paper presents scenarios for treatment of domestic sewage with energy recovery and minimization of environmental impacts based on the biodigestion and incineration with the objective of demonstrating to the public administrators the economic and environmental energy potential. The results show that the electrical energy from the biodigestion of sewage sludge is equivalent to the consumption of 1.5 million households and electricity resulting from incineration corresponds to consumption of 1.3 million homes while the emissions are about 0.875 MtCO2 per year compared to 3.585 MtCO2/year released in the biological treatment. In addition, in both processes of treatments, it is possible to recover half of the volume of wastewater for reuse. In this way, adequate treatment of domestic sewage can protect the environment from the drastic charges of sewage while being a source of energy and water, which are indispensable assets for maintenance of life on the planet.
Abstract: With the growth of the world population, in recent decades, the generation of domestic sewage has increased. In Brazil about 28 million cubic meters of sewage are generated daily and needs to be collected and treated. This task has been one of the biggest challenges for municipal administrators. Disposition of domestic sewage without treatment is a...
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Reducing Energy Consumption by Considering the “Wisdom of the Crowd”: USA and China Study
Ali Hashemi Araghi,
Ehssan Sakhaee
Issue:
Volume 3, Issue 5, October 2014
Pages:
261-265
Received:
2 November 2014
Accepted:
6 November 2014
Published:
20 November 2014
Abstract: Effective implementation of useful schemes that are readily accepted and implemented by a society for change require investigating the perceptions of problems and solutions as seen by a society, primarily those who are stakeholders and are most affected by change. This research aims to investigate the perceived problems and solutions of energy consumption in the two countries that contribute to the highest level of energy consumption in the world – namely China and the United States. The aim is to provide policy makers and government of better understanding the “wisdom of the crowd” when considering implementation for change – in this case reducing energy consumption in two separate societies.
Abstract: Effective implementation of useful schemes that are readily accepted and implemented by a society for change require investigating the perceptions of problems and solutions as seen by a society, primarily those who are stakeholders and are most affected by change. This research aims to investigate the perceived problems and solutions of energy cons...
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State Estimation of the Tanzanian Power System Network Using Non-Quadratic Criterion and MATLAB Environment
Issue:
Volume 3, Issue 5, October 2014
Pages:
266-276
Received:
12 November 2014
Accepted:
17 November 2014
Published:
21 November 2014
Abstract: Power system state estimation is an effective online tool for monitoring, control and for providing consistent database in energy management systems. This paper presents an algorithm for state estimation of the Tanzanian power system network using a non-quadratic state criterion. Equality and inequality constraints existing in a power system are included in formulating the estimation problem. Equality constraints are target values used in load flow analysis and are included in power system state estimation in order to restore observability to those parts of the power system network which are permanently or temporarily unobservable. Inequality constraints are limits such as minimum and maximum reactive power generation, transformer tap and phase-shift. The solution techniques used is primal-dual interior point logarithmic barrier functions to treat the inequality constraints. An algorithm is developed using the method and a program coded in MATLAB is applied in implementing the simulation. Computational issues arising in the implementation of the algorithm are presented. The simulation results demonstrate that the primal-dual logarithmic barrier interior point algorithm is a useful numerical tool to compute the state of an electrical power system network. The inequality constraints play essential role in enhancing the reliability of the estimation results. Also, it is expected that significant benefit could be gained from application of the constrained state estimation algorithm to the Tanzanian power system network.
Abstract: Power system state estimation is an effective online tool for monitoring, control and for providing consistent database in energy management systems. This paper presents an algorithm for state estimation of the Tanzanian power system network using a non-quadratic state criterion. Equality and inequality constraints existing in a power system are in...
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