{"title":"Enhanced Energy Saving Performance in Composite Trigeneration Systems","authors":"G. Chicco, P. Mancarella","doi":"10.1109/PCT.2007.4538524","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538524","url":null,"abstract":"Small-scale cogeneration prime movers (below 1 MWJ such as microturbines and internal combustion engines can be effectively coupled to absorption chillers fed by cogenerated heat and/or electric heat pumps fed by cogenerated electricity. Such trigeneration or Combined Cooling Heat and Power (CCHP) systems potentially boast significant energy saving characteristics with respect to the traditional separate generation of electricity (from large power plants), heat (in boilers) and cooling power (in electric chillers). In this paper, a specific high-efficiency composite scheme, in which a cogeneration prime mover, an absorption chiller, and an electrical heat pump are combined all together, is illustrated and discussed. The performance of this system is assessed through the Trigeneration Primary Energy Saving (TPES) indicator, previously introduced by the authors. Performance maps for equipment available on the market are drawn, through which it is possible to evaluate the plant energy performance at every operating point. Sensitivity studies are provided to point out the influence of the different variables and parameters on the plant performance characteristics.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"131 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115203379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fuzzy Logic-Based AVC Relay for Voltage Control of Distribution Network with and without Distributed/Embedded Generation","authors":"S. Salman, Z.G. Wan","doi":"10.1109/PCT.2007.4538647","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538647","url":null,"abstract":"Voltage control is considered one of the basic operational requirements of electrical power systems both at distribution and transmission levels. The most popular voltage control equipment includes On-Load Tap Changer (OLTC) transformer controlled by Automatic Voltage Control (AVC) relay, which is mostly used in 11 kV networks. In recent years, a growing number of distributed/embedded generators are connected to distribution networks. Conventional AVC relay usually equipped with compounding whose setting are chosen to compensate for the voltage drop along the feeder(s) emanating from source substation. However, the integration of Distributed/Embedded generators (DGs/EGs) including wind farms into distribution systems causes voltage regulation problems due to the interference with the performance of AVC relay. Therefore, the development of a new voltage control scheme of supply system with DGs/EGs is required. This paper presents an attempt to design an AVC relay based on Fuzzy Logic. The structure of the proposed Fuzzy Logic based-AVC relay is presented and the results that show its performance with and without integrated distributed generation into distribution network are also presented and discussed.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"258 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116209122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Muyeen, M. Ali, R. Takahashi, T. Murata, J. Tamura, Y. Tomaki, A. Sakahara, E. Sasano
{"title":"Blade-Shaft Torsional Oscillation Minimization of Wind Turbine Generator System by Using STATCOM/ESS","authors":"S. Muyeen, M. Ali, R. Takahashi, T. Murata, J. Tamura, Y. Tomaki, A. Sakahara, E. Sasano","doi":"10.1109/PCT.2007.4538314","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538314","url":null,"abstract":"In this paper, blade and shaft torsional oscillations of wind turbine generator system (WTGS) are analyzed when a network disturbance occurs in the power system. Many studies have been reported so far about the shaft torsional oscillations of synchronous generators. Though a large number of wind generators are going to be connected with the existing network, the blade-shaft torsional oscillations of WTGS have not been reported so far sufficiently. In this paper, damping control of blade-shaft torsional oscillations of WTGS by using a voltage source converter (VSC) based STATCOM/BESS (battery energy storage system) topology is proposed. The six-mass drive train model of WTGS is used in the simulation analyses for the sake of precise analysis. Both symmetrical and unsymmetrical faults are considered as a network disturbance in the analyses. Simulation results clearly show that the proposed STATCOM/BESS can significantly decrease the blade and shaft torsional oscillations of WTGS. The simulations have been done by PSCAD/EMTDC.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116213276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Graphical Modeling for Selecting Input Variables of Short-term Load Forecasting","authors":"H. Mori, E. Kurata","doi":"10.1109/PCT.2007.4538466","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538466","url":null,"abstract":"This paper proposes a Graphical Modeling method for selecting input variables of short-term load forecasting in power systems. Short-term load forecasting plays a key role to smooth operation and planning such as economic load dispatching, unit commitment, etc. In addition, the deregulated power market players require more accurate prediction models for short-term load forecasting to maximize a profit and minimize the risk As a result, it is of importance to focus on the relationship between input and output variables. In this paper, a graphical modeling method is used to determine the appropriate input variables of ANN (artificial neural network) model in short-term load forecasting. It has advantage that more effective input variables are selected because of excluding the pseudo-correlation that gives more errors to the predicted value. The proposed method is tested for real data of short-term load forecasting.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122343997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Short Circuit Studies in Transmission Networks Using Improved Fault Model","authors":"V. Terzija, D. Dobrijević","doi":"10.1109/PCT.2007.4538581","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538581","url":null,"abstract":"Accuracy of short circuit analysis depends on the fault modelling. This paper addresses the implementation of a new fault model consisted of a serial connection of the tower footing resistance and arc resistance. In existing approaches the value of the arc resistance at the fault location must be known in advance, or it is totally neglected from the consideration. The fault current and arc resistance are mutually dependent, so the short circuit analysis cannot be performed directly. A new solution for this problem is the use of an iterative procedure, calculating fault current and arc resistance iteratively. The new method presented in this paper calculates short circuit currents and arc resistance simultaneously. Results of fault analysis and arc resistance calculation in two test network are presented and discussed in the paper.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122660692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Reconfigurable Phase Shifting Transformer for Analog Computation","authors":"J. C. Jiménez, A. S. Leger, C. Nwankpa","doi":"10.1109/PCT.2007.4538408","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538408","url":null,"abstract":"This paper focuses on the development of a phase shifting transformer model designed for a previously proposed method of analog power flow computation. Prior research in this field has modeled generators, loads and transmission lines. Accurate analog models of power system components are required in order to realize an analog computation engine for power systems. Analog computation is an area of continued interest and has certain advantages over traditional digital computation. Among the advantages are physically realizable solutions and significantly faster computation times. The transformer model proposed here provides a more accurate depiction of the network and captures the behavior of phase shifting transformers. The transformer is modeled in analog form. The model is constructed and verified via software simulation.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"100 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122614095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Stochastic, Computational and Convergence Aspects of Distribution Power Flow Algorithms","authors":"E. Haesen, J. Driesen, R. Belmans","doi":"10.1109/PCT.2007.4538528","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538528","url":null,"abstract":"This paper discusses uncertainties in distribution system analysis. Special emphasis lies with distributed generation (DG) units. Both backward-forward sweeps and Newton-Raphson based current injection updates are discussed. A first class of stochastic modeling is of probabilistic nature. In analytic probabilistic methods a linearization of the power flow equations is applied. Non-linearities are respected in numerical Monte Carlo analysis when using the appropriate convergence criteria. The second class uses qualitative uncertainty descriptions in boundary and fuzzy power flow methods. Correlation of loads and DG is always a crucial aspect. These aspects are elaborated with regard to robust methodologies for setting benchmarks of DG performance based on stochastic programming and evolutionary algorithms.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123922354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Configuration of a Large Scale Analog Emulator for Power System Analysis","authors":"A. S. Leger, C. Nwankpa","doi":"10.1109/PCT.2007.4538409","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538409","url":null,"abstract":"This paper provides a systematic approach to configure a large scale analog emulator for power system analysis. Historically this involved magnitude and time scaling of parameters and consisted of many trials and errors. A recently developed remotely reconfigurable analog power system emulator contains operational transconductance amplifiers and thus has limited linear operating ranges. Scaling of the power system parameters is critical to ensure accurate results and keep the analog hardware operating in linear regions. The configuration method proposed here determines analog hardware gains along with magnitude and time scaling parameters to ensure the analog hardware properly emulates the power system in a systematic manner which could be automated via software and remote control of the hardware. An example is provided for a single machine infinite bus system.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"30 9","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114023964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Houwing, R. Negenborn, P. Heijnen, B. de Schutter, H. Hellendoorn
{"title":"Least-cost model predictive control of residential energy resources when applying μmCHP","authors":"M. Houwing, R. Negenborn, P. Heijnen, B. de Schutter, H. Hellendoorn","doi":"10.1109/PCT.2007.4538355","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538355","url":null,"abstract":"With an increasing use of distributed energy resources and intelligence in the electricity infrastructure, the possibilities for minimizing costs of household energy consumption increase. Technology is moving toward a situation in which households manage their own energy generation and consumption, possibly in cooperation with each other. As a first step, in this paper a decentralized controller based on model predictive control is proposed. For an individual household using a micro combined heat and power (muCHP) plant in combination with heat and electricity storages the controller determines what the actions are that minimize the operational costs of fulfilling residential electricity and heat requirements subject to operational constraints. Simulation studies illustrate the performance of the proposed control scheme, which is substantially more cost effective compared with a control approach that does not include predictions on the system it controls.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124297516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On the Computation of underground Electromagnetic Fields Generated by Lightning: A Comparison between Different Approaches","authors":"A. Mimouni, F. Delfino, R. Procopio, F. Rachidi","doi":"10.1109/PCT.2007.4538413","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538413","url":null,"abstract":"This paper deals with the evaluation of lightning electromagnetic fields inside a finitely conducting ground. We present a comparison between three different approaches that have been adopted by researchers dealing with lightning electromagnetic effects. The first is the Cooray Formula in which, the equations of lightning generated electromagnetic fields below the ground surface are connected to surface fields that can easily be determined. The second approach recently proposed by Delfino et al. consists of numerically evaluating the exact field expressions. Finally, the third approach is based on a numerical solution of Maxwell's equations using the finite difference time domain (FDTD) method. Two different values for the ground conductivity, namely 0.01 S/m and 0.001 S/m are considered in the computations. The adopted model for the return stroke is the modified transmission line model with exponential decay (MTLE). The results obtained using Delfino et al. algorithm and those obtained using FDTD are virtually identical. It is also shown that the Cooray formula is able to reproduce with a very good accuracy the underground fields, especially for their early- time response.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124063299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}