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  Subjects -> ENGINEERING (Total: 2160 journals)
    - CHEMICAL ENGINEERING (186 journals)
    - CIVIL ENGINEERING (168 journals)
    - ELECTRICAL ENGINEERING (93 journals)
    - ENGINEERING (1165 journals)
    - ENGINEERING MECHANICS AND MATERIALS (355 journals)
    - HYDRAULIC ENGINEERING (55 journals)
    - INDUSTRIAL ENGINEERING (57 journals)
    - MECHANICAL ENGINEERING (81 journals)

ELECTRICAL ENGINEERING (93 journals)

Actuators     Open Access  
Advances in Electrical Engineering     Open Access   (Followers: 5)
Advances in Microelectronic Engineering     Open Access   (Followers: 2)
Advances in Signal Processing     Open Access   (Followers: 2)
American Journal of Electrical and Electronic Engineering     Open Access   (Followers: 12)
American Journal of Sensor Technology     Open Access   (Followers: 1)
APSIPA Transactions on Signal and Information Processing     Open Access   (Followers: 6)
Archives of Control Sciences     Open Access   (Followers: 2)
Archives of Electrical Engineering     Open Access   (Followers: 9)
Atom Indonesia     Open Access   (Followers: 1)
Bulletin of Electrical Engineering and Informatics     Open Access   (Followers: 9)
Circuits, Systems, and Signal Processing     Hybrid Journal   (Followers: 8)
Computers & Electrical Engineering     Hybrid Journal   (Followers: 9)
Current Trends in Signal Processing     Full-text available via subscription   (Followers: 2)
Electric Power Components and Systems     Hybrid Journal   (Followers: 8)
Electric Power Systems Research     Partially Free   (Followers: 13)
Electrical and Electronic Engineering     Open Access   (Followers: 12)
Electrical and Power Engineering Frontier     Open Access   (Followers: 10)
Electrical Engineering     Hybrid Journal   (Followers: 15)
Electrical Engineering and Automation     Open Access   (Followers: 2)
Electrical Engineering in Japan     Hybrid Journal   (Followers: 7)
Electrical, Control and Communication Engineering     Open Access   (Followers: 8)
Emerging and Selected Topics in Circuits and Systems     Hybrid Journal   (Followers: 4)
EURASIP Journal on Advances in Signal Processing     Open Access   (Followers: 7)
Ferroelectrics     Hybrid Journal   (Followers: 2)
Ferroelectrics Letters Section     Hybrid Journal   (Followers: 1)
Frequenz     Hybrid Journal   (Followers: 3)
Frontiers of Electrical and Electronic Engineering     Hybrid Journal   (Followers: 6)
IEA Electricity Information     Full-text available via subscription   (Followers: 6)
IEEE Access     Open Access   (Followers: 6)
IEEE Electrical Insulation Magazine     Full-text available via subscription   (Followers: 9)
IEEE Signal Processing Magazine     Full-text available via subscription   (Followers: 36)
IEEE Transactions on Control of Network Systems     Hybrid Journal  
IEEE Transactions on Dielectrics and Electrical Insulation     Hybrid Journal   (Followers: 5)
IEEJ Transactions on Electrical and Electronic Engineering     Hybrid Journal   (Followers: 9)
IET Control Theory & Applications     Hybrid Journal   (Followers: 11)
IET Electric Power Applications     Hybrid Journal   (Followers: 9)
IET Electrical Systems in Transportation     Hybrid Journal   (Followers: 6)
IETE Journal of Education     Open Access   (Followers: 2)
Ingeniería Electrónica, Automática y Comunicaciones     Open Access  
Integrated Ferroelectrics: An International Journal     Hybrid Journal   (Followers: 1)
International Journal of Advanced Electronics and Communication Systems     Open Access   (Followers: 5)
International Journal of Advances in Telecommunications, Electrotechnics, Signals and Systems     Open Access   (Followers: 3)
International Journal of Electrical and Computer Engineering     Open Access   (Followers: 10)
International Journal of Electrical Engineering Education     Full-text available via subscription   (Followers: 6)
International Journal of Electrical Power & Energy Systems     Open Access   (Followers: 11)
International Journal of Emerging Electric Power Systems     Hybrid Journal   (Followers: 5)
International Journal of Monitoring and Surveillance Technologies Research     Full-text available via subscription   (Followers: 4)
International Journal of Nano Devices, Sensors and Systems     Open Access   (Followers: 5)
International Journal on Communication     Full-text available via subscription   (Followers: 9)
International Journal on Control System and Instrumentation     Full-text available via subscription   (Followers: 10)
International Journal on Electrical and Power Engineering     Full-text available via subscription   (Followers: 10)
International Journal on Signal and Image Processing     Full-text available via subscription   (Followers: 3)
International Transaction of Electrical and Computer Engineers System     Open Access  
International Transactions on Electrical Energy Systems     Hybrid Journal   (Followers: 7)
J3eA     Open Access   (Followers: 2)
Journal of Control, Automation and Electrical Systems     Hybrid Journal   (Followers: 5)
Journal of Electrical and Computer Engineering     Open Access   (Followers: 7)
Journal of Electrical and Computer Engineering Innovations     Open Access   (Followers: 2)
Journal of Electrical and Electronics Engineering Research     Open Access   (Followers: 4)
Journal of Electrical Bioimpedance     Full-text available via subscription   (Followers: 2)
Journal of Electrical Engineering     Open Access   (Followers: 8)
Journal of Electrical Engineering & Electronic Technology     Hybrid Journal   (Followers: 2)
Journal of Electrical Systems and Information Technology     Open Access  
Journal of Field Robotics     Hybrid Journal   (Followers: 3)
Journal of Micro-Bio Robotics     Hybrid Journal   (Followers: 1)
Journal of Microwaves, Optoelectronics and Electromagnetic Applications     Open Access   (Followers: 7)
Journal of Power Technologies     Open Access   (Followers: 2)
Journal of the Society for Information Display     Hybrid Journal   (Followers: 1)
Journal of Zhejiang University SCIENCE C     Hybrid Journal  
Jurnal Infotel     Open Access  
Jurnal Nasional Teknik Elektro     Open Access   (Followers: 1)
Majlesi Journal of Electrical Engineering     Open Access  
Micro and Nano Systems Letters     Open Access   (Followers: 4)
Nanotechnology Development     Open Access   (Followers: 3)
Oil, Gas, Coal and Electricity - Quarterly Statistics - Electricite, charbon, gaz et petrole - Statistiques trimestrielles     Full-text available via subscription   (Followers: 9)
Photovoltaics, IEEE Journal of     Hybrid Journal   (Followers: 7)
Recent Patents on Electrical & Electronic Engineering     Full-text available via subscription   (Followers: 2)
Recent Patents on Telecommunications     Full-text available via subscription   (Followers: 1)
Research & Reviews : Journal of Embedded System & Applications     Full-text available via subscription   (Followers: 1)
Russian Electrical Engineering     Hybrid Journal   (Followers: 4)
Scientific Journal of Electrical Engineering     Open Access   (Followers: 5)
SID Symposium Digest of Technical Papers     Hybrid Journal   (Followers: 2)
Sustainable Energy, Grids and Networks     Hybrid Journal  
Sustainable Energy, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Synthesis Lectures on Electrical Engineering     Full-text available via subscription   (Followers: 1)
Telematique     Open Access  
TELKOMNIKA : Indonesian Journal of Electrical Engineering     Open Access   (Followers: 9)
Trends in Electrical Engineering     Full-text available via subscription   (Followers: 2)
Turkish Journal of Electrical Engineering and Computer Science     Open Access   (Followers: 1)
Universal Journal of Electrical and Electronic Engineering     Open Access  
Wireless Engineering and Technology     Open Access   (Followers: 2)
Електротехніка і Електромеханіка     Open Access  
Journal Cover   Sustainable Energy, IEEE Transactions on
  [SJR: 2.826]   [H-I: 24]   [8 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1949-3029
   Published by Institute of Electrical and Electronics Engineers (IEEE) Homepage  [176 journals]
  • IEEE Transactions on Sustainable Energy society information
    • Abstract: Provides a listing of board members, committee members and society officers.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
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    • Abstract: This page or pages intentionally left blank.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Table of Contents
    • Pages: 658
      Abstract: Presents the table of contents for this issue of the publication.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • IEEE Transactions on Sustainable Energy
    • Abstract: Provides a listing of the editors, board members, and current staff for this issue of the publication.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Blank page
    • Abstract: This page or pages intentionally left blank.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Uncertainty-Based Design of a Bilayer Distribution System for Improved
           Integration of PHEVs and PV Arrays
    • Authors: ElNozahy; M.S.;Salama, M.M.A.;
      Pages: 659 - 674
      Abstract: Recent years have seen increased interest in green technologies such as photovoltaic (PV) electricity and plug-in hybrid electric vehicles (PHEVs). Such technologies, however, have been found to be detrimental to distribution networks. This paper introduces a novel distribution system architecture that can better accommodate the expected growth in PV electricity and PHEVs. In the proposed architecture, the distribution system becomes a bilayer system composed of the traditional ac layer that serves existing system loads, plus an embedded dc layer that interfaces with PV arrays and PHEVs. A bidirectional converter interconnects the two layers and controls the power flows between them. This paper presents the key design and operational aspects of the proposed architecture, with consideration of different uncertainties inherent in the system. To this end, a probabilistic benchmark has been developed for modeling these uncertainties and for use with the sizing and scheduling of different system components. Monte Carlo (MC) simulations confirmed the technical and economic merit of the proposed design methodology.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Robust Optimal Power Management System for a Hybrid AC/DC Micro-Grid
    • Authors: Hosseinzadeh; M.;Salmasi, F.R.;
      Pages: 675 - 687
      Abstract: Hybrid ac/dc micro-grid is a new concept decoupling dc sources with dc loads and ac sources with ac loads, while power is exchanged between both sides using a bidirectional converter/inverter. This necessitates a supervisory control system to split power between its different resources, which has sparked attention on the development of power management systems (PMSs). In this paper, a robust optimal PMS (ROPMS) is developed for a hybrid ac/dc micro-grid, where the power flow in the micro-grid is supervised based on solving an optimization problem. Satisfying demanded power with maximum utilization of renewable resources, minimum usage of fuel-based generator, extending batteries lifetime, and limited utilization of the main power converter between the ac and dc micro-grids are important factors that are considered in this approach. Uncertainties in the resources output power and generation forecast errors, along with static and dynamic constraints of the resources, are taken into account. Furthermore, since uncertainties in the resources output power may result in fluctuations in the dc bus voltage, a two-level controller is used to regulate charge/discharge power of the battery banks. Effectiveness of the proposed supervisory system is evaluated through extensive simulation runs based on dynamical models of the power resources.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Distributed Generation Allocation on Radial Distribution Networks Under
           Uncertainties of Load and Generation Using Genetic Algorithm
    • Authors: Ganguly; S.;Samajpati, D.;
      Pages: 688 - 697
      Abstract: This paper presents a distribution generation (DG) allocation strategy for radial distribution networks under uncertainties of load and generation using adaptive genetic algorithm (GA). The uncertainties of load and generation are modeled using fuzzy-based approach. The optimal locations for DG integration and the optimal amount of generation for these locations are determined by minimizing the network power loss and maximum node voltage deviation. Since GA is a metaheuristic algorithm, the results of multiple runs are taken and the statistical variations for locations and generations for DG units are shown. The locations and sizes for DG units obtained with fuzzy-based approach are found to be different than those obtained with deterministic approach. The results obtained with fuzzy-based approach are found to be comparatively efficient in working with future load growth. The proposed approach is demonstrated on the IEEE 33-node test network and a 52-node Indian practical distribution network.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Employment of Kernel Methods on Wind Turbine Power Performance Assessment
    • Authors: Skrimpas; G.A.;Sweeney, C.W.;Marhadi, K.S.;Jensen, B.B.;Mijatovic, N.;Holboll, J.;
      Pages: 698 - 706
      Abstract: A power performance assessment technique is developed for the detection of power production discrepancies in wind turbines. The method employs a widely used nonparametric pattern recognition technique, the kernel methods. The evaluation is based on the trending of an extracted feature from the kernel matrix, called similarity index, which is introduced by the authors for the first time. The operation of the turbine and consequently the computation of the similarity indexes is classified into five power bins offering better resolution and thus more consistent root cause analysis. The accurate and proper detection of power production changes is demonstrated in cases of icing, power derating, operation under noise reduction mode, and incorrect controller input signal. Finally, overviews are illustrated for parks subjected to icing and operating under limited rotational speed. The comparison between multiple adjacent turbines contributes further to the correct evaluation of the park overall performance.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Optimal Bidding Strategy of a Strategic Wind Power Producer in the
           Short-Term Market
    • Authors: Ting Dai;Wei Qiao;
      Pages: 707 - 719
      Abstract: Wind energy is a clean and renewable energy source which is rapidly growing globally. As the penetration level of wind power grows, the system operators need to consider wind power producers as strategic producers whose bidding behaviors will have an impact on the locational marginal prices. This paper proposes a bilevel stochastic optimization model to obtain the optimal bidding strategy for a strategic wind power producer in the short-term electricity market. The upper level problem of the model maximizes the profit of the wind power producer, while the lower level problem represents the market clearing processes of both day-ahead and real-time markets. The uncertainties in the demand, the wind power production, and the bidding strategies of the strategic conventional power producers are represented by scenarios in the model. The conditional value at risk of the selected worst scenarios is included in the objective function for managing the risk due to uncertainties. Using the duality theory and Karush-Kuhn-Tucker condition, the bilevel model is transferred into a mixed-integer linear problem. Case studies are performed to show the effectiveness of the proposed model.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Generation Dispatch Techniques for Remote Communities With Flexible Demand
    • Authors: Clavier; J.;Bouffard, F.;Rimorov, D.;Joos, G.;
      Pages: 720 - 728
      Abstract: Remote communities are typically isolated from the main electricity grid and require local generation, most often relying on expensive resources (especially diesel) to supply their load. The economic and logistical aspects are such that there is value in exploring different approaches to reduce the consumption of diesel and to increase the energy input from local renewables. In this paper, we focus on using the virtual storage capabilities of the demand side to perform diesel generation optimization. Specifically, we revisit the economic dispatch (ED) problem by adapting it to the presence of flexible demand. We compare three different formulation approaches: 1)where demand is reallocated heuristically to shave the peak; 2)where the reallocation is itself optimized; and 3)that attempts to optimize the overall efficiency of the diesel units. A case study based upon a remote microgrid shows that flexible demand can decrease diesel fuel consumption in an economically meaningful manner, which is still significant given the costs associated with the purchase and haulage of diesel to these small communities.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Optimal Sizing of a Vanadium Redox Battery System for Microgrid Systems
    • Authors: Nguyen; T.A.;Crow, M.L.;Elmore, A.C.;
      Pages: 729 - 737
      Abstract: The vanadium redox battery (VRB) has proven to be a reliable and highly efficient energy storage system (ESS) for microgrid applications. However, one challenge in designing a microgrid system is specifying the size of the ESS. This selection is made more complex due to the independent power and energy ratings inherent in VRB systems. Sizing a VRB for both required power output and energy storage capacity requires an in-depth analysis to produce both optimal scheduling capabilities and minimum capital costs. This paper presents an analytical method to determine the optimal ratings of VRB energy storage based on an optimal scheduling analysis and cost-benefit analysis for microgrid applications. A dynamic programming (DP) algorithm is used to solve the optimal scheduling problem considering the efficiency and operating characteristics of the VRBs. The proposed method has been applied to determine the optimal VRB power and energy ratings for both isolated and grid-connected microgrids, which contain PV arrays and fossil-fuel-based generation. We first consider the case in which a grid-tie is not available and diesel generation is the backup source of power. The method is then extended to consider the case in which a utility grid tie is available.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Real-Time Dispatchability of Bulk Power Systems With Volatile Renewable
           Generations
    • Authors: Wei Wei;Feng Liu;Shengwei Mei;
      Pages: 738 - 747
      Abstract: The limited predictability and high variability of renewable generations has brought significant challenges on the real-time operation of bulk power systems. This paper proposes the concept of real-time dispatchability (RTDA) of power systems with variable energy resources, which focuses on investigating the impact of operating constraints and the cost of corrective actions on the flexibility of real-time dispatch. RTDA is the largest region in the uncertainty space, such that all the elements in it will not cause infeasibility while deploying a corrective action. This paper proposes a closed polyhedral form of RTDA. Moreover, an adaptive constraint generation algorithm is proposed to compute the boundaries of RTDA. Three potential applications are suggested. Case studies on the IEEE 118-bus system illustrate the RTDA concept and demonstrate the validity and efficiency of the proposed method in practical applications.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Probabilistic Modeling of Multisite Wind Farm Production for
           Scenario-Based Applications
    • Authors: Le; D.D.;Gross, G.;Berizzi, A.;
      Pages: 748 - 758
      Abstract: The deepening penetration of wind resources introduces major challenges into power system planning and operation activities. This is due to the need to appropriately represent salient features of wind power generation from multiple wind farm sites such as nonstationarity with distinct diurnal and seasonal patterns, spatial and temporal correlations, and non-Gaussianity. Hence, an appropriate model of multisite wind power production in systems with integrated wind resources represents a major challenge to meet a critical need. In this paper, we aim at defining a new methodology to improve the quality of generated scenarios by means of historical multisite wind data and effective deployment of time series and principal component (PC) techniques. Scenario-based methodologies are already available in power systems, but sometimes lack in accuracy: this paper proposes a methodology that is able to capture the main features of wind: it can both characterize spatio-temporal properties and be used to reduce size of data sets in practical applications without using any simplifying assumption. Extensive testing indicates good performance in effectively capturing the salient wind characteristics to provide useful models for various problems related to multisite wind production, including security assessment, operational planning, environmental analysis, and system planning. An application to security assessment is presented.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Impacts of High Penetration of DFIG Wind Turbines on Rotor Angle Stability
           of Power Systems
    • Authors: Edrah; M.;Lo, K.L.;Anaya-Lara, O.;
      Pages: 759 - 766
      Abstract: With the integration of wind power into power systems continues to increase, the impact of high penetration of wind power on power system stability becomes a very important issue. This paper investigates the impact of doubly fed induction generator (DFIG) control and operation on rotor angle stability. Acontrol strategy for both the rotor-side converter (RSC) and grid-side converter (GSC) of the DFIG is proposed to mitigate DFIGs impacts on the system stability. DFIG-GSC is utilized to be controlled as static synchronous compensator (STATCOM) to provide reactive power support during grid faults. In addition, a power system stabilizer (PSS) is implemented in the reactive power control loop of DFIG-RSC. The proposed approaches are validated on a realistic Western System Coordinating Council (WSCC) power system under both small and large disturbances. The simulation results show the effectiveness and robustness of both DFIG-GSC control strategy and PSS to enhance rotor angle stability of power system.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • A Switched PV Approach for Extracted Maximum Power Enhancement of PV
           Arrays During Partial Shading
    • Authors: Elserougi; A.A.;Diab, M.S.;Massoud, A.M.;Abdel-Khalik, A.S.;Ahmed, S.;
      Pages: 767 - 772
      Abstract: This paper proposes a switched photovoltaic (PV) approach to enhance the extracted maximum power from a PV array during partial shading conditions. The proposed system is simple and cost effective. However, it may provide lower power enhancement compared to other existing solutions, which makes it more suitable for domestic applications. For assessing the proposed switched PV-based system, a detailed numerical comparison between the extracted power from the proposed system and other existing technologies has been presented for the same operating conditions. Simulation and experimental results show the possibility of enhancing the PV arrays extracted output power during partial shading with the proposed system.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • LatchingDeclutching Control of Wave Energy Converters Using
           Derivative-Free Optimization
    • Authors: Zhe Feng;Kerrigan; E.C.;
      Pages: 773 - 780
      Abstract: We consider predictive control of a wave energy converter (WEC) that can switch between three modes: power generation; declutched with no power generation; or latched with zero velocity. We propose a formulation that turns the optimal control problem into a small dimensional discrete optimization problem, where the only decision variables are bounds on the latching time and power take-off (PTO) time, whereas the objective function is computed from the trajectory of a hybrid system with linear dynamics in each sample interval. The optimization problem is solved using a novel derivative-free algorithm that exploits the quantization of the decision variables in order to reduce the number of function evaluations. Two closed-loop formulations are also studied within a receding horizon implementation: the first one uses past wave information and can double the energy generation compared to the uncontrolled case, while the second formulation uses predictions of future waves and is able to result in a further increase in energy generation. The benefits of codesigning the physical system and controller is compared to the sequential approach of first optimizing the physical system without control, followed by controller design.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Robust Look-Ahead Power Dispatch With Adjustable Conservativeness
           Accommodating Significant Wind Power Integration
    • Authors: Zhigang Li;Wenchuan Wu;Boming Zhang;Bin Wang;
      Pages: 781 - 790
      Abstract: Robust look-ahead power dispatch is an effective and secure approach to account for uncertainties in wind power. Based on the robust look-ahead power dispatch model proposed in our previous work, in this paper, we focus on coping with adjustable uncertainty sets to reduce the conservativeness of robust dispatch (RD). Robust look-ahead power dispatch with adjustable uncertainty sets is formulated using robust optimization (RO) and is transformed into biconvex programming. Several strategies exploiting different levels of uncertainty information are developed to adjust the conservativeness by varying the desired confidence level. Monte Carlo simulations are carried out to compare the performance of the proposed approaches with another popular strategy. Test results show that the proposed method is effective in reducing the conservativeness of RD and ensuring system security with controllable risk. Experiments on large-scale benchmark systems show the scalability of the proposed method.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Support-Vector-Machine-Enhanced Markov Model for Short-Term Wind Power
           Forecast
    • Authors: Lei Yang;Miao He;Junshan Zhang;Vittal; V.;
      Pages: 791 - 799
      Abstract: Wind ramps introduce significant uncertainty into wind power generation. Reliable system operation, however, requires accurate detection and forecast of wind ramps, especially at high penetration levels. In this paper, to deal with the wind ramp dynamics, a support vector machine (SVM)-enhanced Markov model is developed for short-term wind power forecast, based on one key observation from the measurement data that wind ramps often occur with specific patterns. Specifically, using the historical data of the wind turbine power outputs recorded at an actual wind farm, data analytics-based finite-state Markov models are first developed to model the normal fluctuations of wind generation, while taking into account the diurnal nonstationarity and the seasonality of wind generation. Next, the forecast by the SVM is integrated cohesively into the finite-state Markov models. Based on the SVM-enhanced Markov model, both short-term distributional forecasts and point forecasts are then derived. Numerical test results, using real wind generation data traces, demonstrate the significantly improved accuracy of the proposed forecast approach.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Flexibility Envelopes for Power System Operational Planning
    • Authors: Nosair; H.;Bouffard, F.;
      Pages: 800 - 809
      Abstract: Modern power systems are undergoing a transitional phase, increasingly incorporating renewable energy sources (RES) to harness their economic and environmental benefits. The main challenge with this transitional phase is the management of the increased variability and uncertainty in the power balance. Legacy operation and planning practices are gradually seen as becoming inadequate or ill-adapted in addressing this challenge. One particular gap in the state of the art, which is of great importance, is estimating the operational flexibility potential of individual power system assets and their aggregation at the system level. System operators need to evaluate and plan ahead flexibility adequacy for their power systems in order to ensure feasible and economical operation under high RES penetration. Likewise, asset owners need to integrate the notion of asset flexibility as part of their investment and operations decisions. To this end, we propose the concept of the flexibility envelope to describe the flexibility potential dynamics of a power system and its individual resources in the operational planning time-frame. We demonstrate that the resulting envelope dynamics can be a starting point for flexibility adequacy planning in systems with highly variable generation.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • A Fuzzy-Multiagent Service Restoration Scheme for Distribution System With
           Distributed Generation
    • Authors: Elmitwally; A.;Elsaid, M.;Elgamal, M.;Chen, Z.;
      Pages: 810 - 821
      Abstract: This paper proposes a new multiagent control system (MACS) for service restoration in distribution systems with integrated distributed generation (DG) units. First, the MACS detects and locates faults, then decides the optimal reconfiguration of the network for restoring de-energized loads, and finally regulates the nodes voltages. Unintentional islanding operation of DG units is avoided and different postfault response modes of DG unit are addressed in the MACS design. The MACS has a hybrid centralizeddecentralized structure where agents are arranged in two layers with different responsibilities and communication capabilities. Agents at load buses in the first layer can only communicate directly with its next neighbor load agents on the same feeder and to its feeder agent, whereas the higher level agents in the second layer can communicate directly with each other. This MACS structure reduces the possibilities of control system failures for a moderate communication network infrastructure. Full dynamic simulation model for evaluating the MACS is implemented.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Stochastic Reconfiguration and Optimal Coordination of V2G Plug-in
           Electric Vehicles Considering Correlated Wind Power Generation
    • Authors: Kavousi-Fard; A.;Niknam, T.;Fotuhi-Firuzabad, M.;
      Pages: 822 - 830
      Abstract: This paper investigates the optimal operation of distribution feeder reconfiguration (DFR) strategy in the smart grids with high penetration of plug-in electric vehicles (PEVs) and correlated wind power generation. The increased utilization of PEVs in the system with stochastic volatile behavior along with the high penetration of renewable power sources such as wind turbines (WTs) can create new challenges in the system that will affect the DFR strategy greatly. In order to reach the most efficiency from the PEVs, the idea of vehicle-to-grid (V2G) is employed in this paper to make a bidirectional power flow (either charging/discharging or idle mode) strategy when providing the main charging needs of PEVs. In this regard, we suggest a new stochastic framework based on unscented transformation (UT) to model the uncertainties of the PEVs behaviors when considering the correlated power generation of WTs. The feasibility and satisfying performance of the proposed framework are examined on the IEEE 69-bus test system.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Distributed Model Predictive Control of a Wind Farm for Optimal Active
           Power ControlPart I: Clustering-Based Wind Turbine Model Linearization
    • Authors: Haoran Zhao;Qiuwei Wu;Qinglai Guo;Hongbin Sun;Yusheng Xue;
      Pages: 831 - 839
      Abstract: This paper presents a dynamic discrete-time piece-wise affine (PWA) model of a wind turbine for the optimal active power control of a wind farm. The control objectives include both the power reference tracking from the system operator and the wind turbine mechanical load minimization. Instead of partial linearization of the wind turbine model at selected operating points, the nonlinearities of the wind turbine model are represented by a piece-wise static function based on the wind turbine system inputs and state variables. The nonlinearity identification is based on the clustering-based algorithm, which combines the clustering, linear identification, and pattern recognition techniques. The developed model, consisting of 47 affine dynamics, is verified by the comparison with a widely used nonlinear wind turbine model. It can be used as a predictive model for the model predictive control (MPC) or other advanced optimal control applications of a wind farm.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Distributed Model Predictive Control of a Wind Farm for Optimal Active
           Power ControlPart II: Implementation With Clustering-Based Piece-Wise
           Affine Wind Turbine Model
    • Authors: Haoran Zhao;Qiuwei Wu;Qinglai Guo;Hongbin Sun;Yusheng Xue;
      Pages: 840 - 849
      Abstract: This paper presents distributed model predictive control (D-MPC) of a wind farm for optimal active power control using the fast gradient method via dual decomposition. The objectives of the D-MPC control of the wind farm are power reference tracking from the system operator and wind turbine mechanical load minimization. The optimization of the active power control of the wind farm is distributed to the local wind turbine controllers. The D-MPC developed was implemented using the clustering-based piece-wise affine wind turbine model. With the fast gradient method, the convergence rate of the D-MPC has been significantly improved, which reduces the iteration numbers. Accordingly, the communication burden is reduced. A wind farm with ten wind turbines was used as the test system. Case studies were conducted and analyzed, which include the operation of the wind farm with the D-MPC under low and high wind conditions, and the dynamic performance with a wind turbine out of service. The robustness of the D-MPC to errors and uncertainties was tested by case studies with consideration of the errors of system parameters.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Simulation and Hardware Implementation of New Maximum Power Point Tracking
           Technique for Partially Shaded PV System Using Hybrid DEPSO Method
    • Authors: Seyedmahmoudian; M.;Rahmani, R.;Mekhilef, S.;Maung Than Oo, A.;Stojcevski, A.;Tey Kok Soon;Ghandhari, A.S.;
      Pages: 850 - 862
      Abstract: In photovoltaic (PV) power generation, partial shading is an unavoidable complication that significantly reduces the efficiency of the overall system. Under this condition, the PV system produces a multiple-peak function in its output power characteristic. Thus, a reliable technique is required to track the global maximum power point (GMPP) within an appropriate time. This study aims to employ a hybrid evolutionary algorithm called the DEPSO technique, a combination of the differential evolutionary (DE) algorithm and particle swarm optimization (PSO), to detect the maximum power point under partial shading conditions. The paper starts with a brief description about the behavior of PV systems under partial shading conditions. Then, the DEPSO technique along with its implementation in maximum power point tracking (MPPT) is explained in detail. Finally, Simulation and experimental results are presented to verify the performance of the proposed technique under different partial shading conditions. Results prove the advantages of the proposed method, such as its reliability, system-independence, and accuracy in tracking the GMPP under partial shading conditions.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • A Two-Echelon Wind Farm Layout Planning Model
    • Authors: Huan Long;Zijun Zhang;
      Pages: 863 - 871
      Abstract: In this paper, a two-echelon layout planning model is proposed to determine the optimal wind farm layout to maximize its expected power output. In the first echelon, a grid composed of cells with equal size is utilized to model the wind farm, whereas the center of each cell is the potential slot for locating a wind turbine. Optimization models are developed to determine the optimal size of grid cells and the optimal cells for locating wind turbines. In the second echelon, the selected grid cells are then translated to sets of Cartesian coordinates. The model for determining the optimal coordinate rather than the center in a grid cell for locating each wind turbine is formulated. Due to the model complexity in both echelons, the random key genetic algorithm (RKGA) and particle swarm optimization (PSO) algorithm are applied to obtain the optimal solutions in the first and second echelon separately. The comparative analysis between the proposed two-echelon planning model and the traditional grid/coordinate-based planning models is conducted.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Modeling and Design Optimization of an Autonomous Multisource System Under
           a Permanent Power-Supply Constraint
    • Authors: Layadi; T.M.;Champenois, G.;Mostefai, M.;
      Pages: 872 - 880
      Abstract: In this paper, we aim to optimize the sizing of an autonomous multisource system in order to minimize the cost of the installation and to improve the dynamic behavior of the whole system. The multisource system comprises a solar generator, a wind generator (WG), a diesel generator (DG), and a lead-acid battery bank. The modeling of such a system is done by using the power model to describe the behavior of each subsystem. The cost of the multisource system is estimated by implementing the embodied energy (EE) concept. A dynamic simulator (DS) has been developed. Due to the complexity of the multisource system in terms of input variables and meteorological data, the simulation becomes difficult, requiring high-performance computing and moreover, the determination of the optimal configuration is not assured. Therefore, we propose to simplify the model by introducing the design of experiment (DOE) approach. The obtained model has been validated and used to perform a single-objective optimization. This model allows us to ensure the simulation of the multisource system efficiently and faster. An optimal configuration has been determined.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Cost Savings From Relaxation of Operational Constraints on a Power System
           With High Wind Penetration
    • Authors: McGarrigle; E.V.;Leahy, P.G.;
      Pages: 881 - 888
      Abstract: Wind energy is predominantly a nonsynchronous generation source. Large-scale integration of wind generation with existing electricity systems, therefore, presents challenges in maintaining system frequency stability and local voltage stability. Transmission system operators have implemented system operational constraints (SOCs) in order to maintain stability with high wind generation, but imposition of these constraints results in higher operating costs. A mixed integer programming tool was used to simulate generator dispatch in order to assess the impact of various SOCs on generation costs. Interleaved day-ahead scheduling and real-time dispatch models were developed to allow accurate representation of forced outages and wind forecast errors, and were applied to the proposed Irish power system of 2020 with a wind penetration of 32%. Savings of at least 7.8% in generation costs and reductions in wind curtailment of 50% were identified when the most influential SOCs were relaxed. The results also illustrate the need to relax local SOCs together with the system-wide nonsynchronous penetration limit SOC, as savings from increasing the nonsynchronous limit beyond 70% were restricted without relaxation of local SOCs. The methodology and results allow for quantification of the costs of SOCs, allowing the optimal upgrade path for generation and transmission infrastructure to be determined.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Alleviation of Neutral-to-Ground Potential Rise Under Unbalanced
           Allocation of Rooftop PV Using Distributed Energy Storage
    • Authors: Alam; M.J.E.;Muttaqi, K.M.;Sutanto, D.;
      Pages: 889 - 898
      Abstract: A high penetration of one-phase rooftop solar photovoltaic (PV) units with unbalanced allocation can create considerable neutral current and neutral potential rise in low voltage (LV) four-wire multigrounded distribution networks, even with balanced loads. Because of the limitations of traditional strategies to mitigate the combined effect of load and PV unbalance, this paper proposes the use of distributed energy storage to reduce the neutral current and neutral potential under a high penetration of unbalanced rooftop solar PV allocation. A power-balancing algorithm based on charge/discharge control is developed to continuously adjust the power exchange with the grid to mitigate the neutral current and neutral potential rise, while minimizing power drawn from the energy storage. A dynamic model of the integrated PV-storage system is developed to investigate the dynamic performance of the proposed strategy. An Australian LV distribution system is used to verify its performance and the results are presented.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Impact of Electric Vehicles and Solar PV on Future Generation Portfolio
           Investment
    • Authors: Vithayasrichareon; P.;Mills, G.;MacGill, I.F.;
      Pages: 899 - 908
      Abstract: This study assesses the impact of electric vehicle (EV) uptake and large-scale photovoltaic (PV) investment on the economics of future electricity-generation portfolios. A Monte-Carlo-based portfolio modeling tool was used to assess the expected overall industry cost, associated cost uncertainty, and CO2 emissions of future generation portfolios, where both EVs and PV generation have achieved major deployment. The Australian National Electricity Market (NEM) was used as a case study under uncertain future fuel and carbon prices, electricity demand, and plant capital costs. Two EV charging scenarios were considered: 1)unmanaged charging which commences immediately as the EVs arrive at suitable charging infrastructure and 2)managed charging where EV charging loads are managed so that they better align with PV output. Results show that there are potentially valuable synergies between PV generation and EV charging demand in minimizing future electricity industry costs, cost uncertainties, and emissions, particularly when EV charging loads can be managed. The value of PV generation and managed EV charging is greater for higher EV fleet size and moderate carbon prices.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Accuracy Improvement of the Ideal PV Model
    • Authors: Mahmoud; Y.;El-Saadany, E.;
      Pages: 909 - 911
      Abstract: The only photovoltaic (PV) model in the literature featuring low computational effort is the ideal PV circuit model because it uniquely relies on a simple nontranscendental equation. Unfortunately, it suffers from a deteriorated accuracy at low irradiance levels. This letter enhances the accuracy of the ideal PV model at low irradiance levels without affecting its simplicity. The proposed approach modifies the equation of the saturation current such that it takes the irradiance variations into consideration. The effect of the proposed modification on the complexity of the model is shown to be negligible. The accuracy improvement is also demonstrated by comparing the proposed and existing ideal models to the measurements provided by the manufacturing datasheet of a monocrystalline PV module.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Table of Contents
    • Pages: 913 - 914
      Abstract: Presents the table of contents for this issue of the publication.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Guest Editorial: Special Section on Large-Scale Grid Integration and
           Regulatory Issues of Variable Power Generation
    • Authors: Islam; S.;
      Pages: 915 - 915
      Abstract: The twenty-nine papers in this special section focus on the topic of large scale power grid integration and the regulatory issues involved. These include information on stochastic models of solar and wind power generation dispatch including case studies; transmission flexibility in accommodating more wind power; robust and optimal inertial control for frequency support; challenges associated with assessment, testing, and development inverter technologies for LVRT; inter-area oscillation of interconnected wind power plants; artificial intelligent applications in complex scenarios associated with futuristic plug-in hybrid vehicles; distributed energy storage for approaches for frequency support; and high penetration of variable power generation systems.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Wind and Photovoltaic Large-Scale Regional Models for Hourly Production
           Evaluation
    • Authors: Marinelli; M.;Maule, P.;Hahmann, A.N.;Gehrke, O.;Norgard, P.B.;Cutululis, N.A.;
      Pages: 916 - 923
      Abstract: This work presents two large-scale regional models used for the evaluation of normalized power output from wind turbines and photovoltaic power plants on a European regional scale. The models give an estimate of renewable production on a regional scale with 1h resolution, starting from a mesoscale meteorological data input and taking in account the characteristics of different plants technologies and spatial distribution. An evaluation of the hourly forecasted energy production on a regional scale would be very valuable for the transmission system operators when making the long-term planning of the transmission system, especially regarding the cross-border power flows. The tuning of these regional models is done using historical meteorological data acquired on a per-country basis and using publicly available data of installed capacity.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Recent Trends in Variable Generation Forecasting and Its Value to the
           Power System
    • Authors: Orwig; K.D.;Ahlstrom, M.L.;Banunarayanan, V.;Sharp, J.;Wilczak, J.M.;Freedman, J.;Haupt, S.E.;Cline, J.;Bartholomy, O.;Hamann, H.F.;Hodge, B.-M.;Finley, C.;Nakafuji, D.;Peterson, J.;Maggio, D.;Marquis, M.;
      Pages: 924 - 933
      Abstract: The rapid deployment of wind and solar energy generation systems has resulted in a need to better understand, predict, and manage variable generation. The uncertainty around wind and solar power forecasts is still viewed by the power industry as being quite high, and many barriers to forecast adoption by power system operators still remain. In response, the U.S. Department of Energy has sponsored, in partnership with the National Oceanic and Atmospheric Administration, public, private, and academic organizations, two projects to advance wind and solar power forecasts. Additionally, several utilities and grid operators have recognized the value of adopting variable generation forecasting and have taken great strides to enhance their usage of forecasting. In parallel, power system markets and operations are evolving to integrate greater amounts of variable generation. This paper will discuss the recent trends in wind and solar power forecasting technologies in the U.S., the role of forecasting in an evolving power system framework, and the benefits to intended forecast users.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Impact of Weather Regimes on the Wind Power Ramp Forecast in Portugal
    • Authors: Couto; A.;Costa, P.;Rodrigues, L.;Lopes, V.V.;Estanqueiro, A.;
      Pages: 934 - 942
      Abstract: Short-term forecasting and diagnostic tools for severe changes of wind power production (power ramps) may provide reliable information for a secure power system operation at a small cost. Understanding the underlying role of the synoptic weather regimes (WRs) in triggering the wind power ramp events can be an added value to improve and complement the current forecast techniques. This work identifies and classifies the WRs over mainland Portugal associated with the occurrence of severe wind power ramps. The most representative WRs are identified on compressed surface level atmospheric data using principal component analysis by applying K-means clustering. The results show a strong association between some synoptic circulation patterns and step variations of the wind power production indicating the possibility to identify certain WRs that are prone to trigger severe wind power ramps, thus opening the possibility for future development of diagnostic warning systems for system operators use.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Predictive Direct Power Control of Doubly Fed Induction Generators Under
           Unbalanced Grid Voltage Conditions for Power Quality Improvement
    • Authors: Jiefeng Hu;Jianguo Zhu;Dorrell; D.G.;
      Pages: 943 - 950
      Abstract: This paper proposes a new control strategy of doubly fed induction generators (DFIGs) under unbalanced grid voltage conditions. The proposed controller includes a model predictive direct power control (MPDPC) method and a power compensation scheme. In MPDPC, the appropriate voltage vector is selected according to an optimization cost function, hence the instantaneous active and reactive powers are regulated directly in the stator stationary reference frame without the requirement of coordinate transformation, PI regulators, switching table, or PWM modulators. In addition, the behavior of the DFIG under unbalanced grid voltage is investigated. Next, a power compensation scheme without the need of extracting negative stator current sequence is developed. By combining the proposed MPDPC strategy and the power compensation scheme, distorted currents injected into the power grid by the DFIGs can be eliminated effectively.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Frequency Regulation and Oscillation Damping Contributions of
           Variable-Speed Wind Generators in the U.S. Eastern Interconnection (EI)
    • Authors: Yong Liu;Gracia; J.R.;King, T.J.;Yilu Liu;
      Pages: 951 - 958
      Abstract: The U.S. Eastern Interconnection (EI) is one of the largest electric power grids in the world and is expected to have difficulties in dealing with frequency regulation and oscillation damping issues caused by the increasing wind power. On the other side, variable-speed wind generators can actively engage in frequency regulation or oscillation damping with supplementary control loops. This paper creates a 5% wind power penetration simulation scenario based on the 16 000-bus EI system dynamic model and developed the user-defined wind electrical control model in PSSE that incorporates additional frequency regulation and oscillation damping control loops. The potential contributions of variable-speed wind generations to the EI system frequency regulation and oscillation damping are evaluated and simulation results demonstrate that current and future penetrations of wind power are promising in the EI system frequency regulation and oscillation damping.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • The Joint Adequacy of AGC and Primary Frequency Response in Single
           Balancing Authority Systems
    • Authors: Chavez; H.;Baldick, R.;Matevosyan, J.;
      Pages: 959 - 966
      Abstract: This paper generalizes previous work on automatic generation control (AGC) gain in a single balancing authority system. In previous work, a control performance standard 1 (CPS1)-compliant AGC gain for a single balancing authority interconnection was proposed, assuming that frequency response can be decoupled from AGC dynamics by widening governor dead bands. However, current practices suggest that widening dead bands may not be a wise course to take as it may deteriorate primary frequency response. This paper formulates sufficient conditions for the adequacy of the joint operation of AGC control and primary frequency response to be consistent with frequency response adequacy. Historical data and a simulation of ERCOT are presented to show numerical results.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Interarea Oscillation Damping Controls for Wind Power Plants
    • Authors: Singh; M.;Allen, A.J.;Muljadi, E.;Gevorgian, V.;Yingchen Zhang;Santoso, S.;
      Pages: 967 - 975
      Abstract: This paper investigates the potential for wind power plants (WPPs) to damp interarea modes. Interarea modes may be the result of a single or a group of generators oscillating against another group of generators across a weak transmission link. If poorly damped, these power system oscillations can cause system instability and potentially lead to blackouts. Power conversion devices, particularly, megawatt-scale converters that connect wind turbines and photovoltaic power plants to the grid, could be used to damp these oscillations by injecting power into the system out of phase with the potentially unstable mode. In our model, this power may be provided by a WPP. Over time, the net energy injection is near zero; therefore, providing this static damping capability is not expected to affect the energy production of a WPP. This is a measurement-based investigation that employs simulated measurement data. It is not a traditional small-signal stability analysis based on Eigenvalues and knowledge of the power system network and its components. Kundurs well-known two-area, four-generator system and a doubly fed induction generator (DFIG)-based WPP are modeled in PSCAD/EMTDC. The WPP model is based on the Western Electricity Coordination Council (WECC) standard model. A controller to damp interarea oscillations is added to the WECC DFIG model, and its effects are studied. Analysis is performed on the data generated by the simulations. The sampling frequency is set to resemble the sampling frequency at which data are available from phasor measurement units in the real world. The YuleWalker algorithm is used to estimate the power spectral density of these signals.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • CPS1-Compliant Regulation Using a PSD Analysis of Wind Expansion in a
           Single Balancing Authority
    • Authors: Chavez; H.;Duehee Lee;Baldick, R.;
      Pages: 976 - 983
      Abstract: The integration of wind power has imposed new requirements for regulation reserves. For ensuring adequate regulation reserves, wind power variability and uncertainty must be estimated, and system frequency must comply with frequency performance standards. This work determines regulation capacity and ramping capability requirements as a function of wind-installed capacity to comply with CPS1, the North American Electric Reliability Corporation (NERC) Control Performance Standard 1 for the case of a single balancing authority. A simulation of the Electric Reliability Council of Texas (ERCOT) will be presented to examine the performance of the formulation.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Wind Power Plant Model Validation Using Synchrophasor Measurements at the
           Point of Interconnection
    • Authors: Yingchen Zhang;Muljadi; E.;Kosterev, D.;Singh, M.;
      Pages: 984 - 992
      Abstract: A wind power plant (WPP) is different from a conventional power plant in the sense that a WPP may consist of hundreds of small (e.g., 1.5-MW) wind turbine generators (WTGs), whereas a conventional power plant may consist of one or several large generators. Common practice in power system planning to simulate a WPP is to use a single-turbine representation. However, it is important to realize that the response of a single-turbine representation is not the response of an individual turbine; instead, it represents the collective behavior of a WPP. In this paper, we present our experience in validating WPP from available measured data. We investigate the discrepancies between the simulation results and the actual measurement, and we examine the probable causes of these discrepancies. Finally, we offer methods to validate WPP dynamic model to better match the simulation result to the measured data. Understanding the nature of a WPP and the meaning of WPP equivalency is very important to determine the representation of a WPP.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • An Optimal Model-Based Control Technique to Improve Wind Farm
           Participation to Frequency Regulation
    • Authors: Baccino; F.;Conte, F.;Grillo, S.;Massucco, S.;Silvestro, F.;
      Pages: 993 - 1003
      Abstract: This paper presents a model-based control technique to provide the contribution of wind power generators to primary frequency regulation in electric power systems. Models of individual wind power generators and wind farm (WF) as a whole are presented and the proposed control strategy is detailed. It consists of a central controller, a central Kalman filter (KF), and some local KFs, one for each wind turbine. The central controller is disabled in normal operation conditions and its task is to set the power reference for each wind turbine, overwriting the local reference, when a disturbance occurs. Central KF is in charge of estimating the external load variation, while each local KF estimates wind speed and the wind turbines dynamical state. The key feature of this approach is that each wind turbine can react to grid disturbances in a different way, which depends on wind speed as seen by the wind turbine itself and by its dynamical conditions. Real wind data and a large WF connected to the grid in a dedicated simulation environment have been used to test the effectiveness of the proposed control strategy.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Investigating the Impacts of Wind Generation Participation in
           Interconnection Frequency Response
    • Authors: Gevorgian; V.;Yingchen Zhang;Ela, E.;
      Pages: 1004 - 1012
      Abstract: The electrical frequency of an interconnection must be maintained very close to its nominal level at all times. Excessive frequency deviations can lead to load shedding, instability, machine damage, and even blackouts. There is rising concern in the power industry in recent years about the declining amount of inertia and primary frequency response (PFR) in many interconnections. This decline may continue due to increasing penetrations of inverter-coupled generation and the planned retirements of conventional thermal plants. Inverter-coupled variable wind generation is capable of contributing to PFR and inertia; however, wind generation PFR and inertia responses differ from those of conventional generators, and it is not entirely understood how this will affect the system at different wind power penetration levels. The simulation work presented in this paper evaluates the impact of the wind generation provision of these active power control strategies on a large, synchronous interconnection. All simulations were conducted on the U.S. Western Interconnection with different levels of wind power penetration levels. The ability of wind power plants to provide PFRand a combination of synthetic inertial response and PFRsignificantly improved the frequency response performance of the system. The simulation results provide insight to designing and operating wind generation active power controls to facilitate adequate frequency response performance of an interconnection.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Optimal Generation Dispatch With High Penetration of Photovoltaic
           Generation
    • Authors: Eftekharnejad; S.;Heydt, G.T.;Vittal, V.;
      Pages: 1013 - 1020
      Abstract: Power system operation practices are changing with the addition of renewable energy resources such as photovoltaic (PV) sources. The diverse and intermittent nature of these resources demands new operation strategies to ensure system reliability. As more PV units are added to power systems, the power generated by conventional generation resources should be reduced to accommodate these new resources. The reduction in fossil-fired generation allows realization of benefits in the sustainability of the generation mix. While some of the conventional generating units are retired, some should be retained for system reliability. This paper investigates the impact of generation redispatch or generation displacement in systems with high PV penetration. Comparing various study scenarios, a method based on regression techniques and Chebyshevs inequality is introduced in this paper. This method is used to calculate the dispatch or displacement ratio of the conventional generators for optimal steady state and transient response of the system. Recommendations are formulated based on an actual large-scale power system in the western United States.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Assessing the Economic Benefits of Compressed Air Energy Storage for
           Mitigating Wind Curtailment
    • Authors: Cleary; B.;Duffy, A.;O'Connor, A.;Conlon, M.;Fthenakis, V.;
      Pages: 1021 - 1028
      Abstract: Renewable energy generation in the All-Island of Ireland (AII) is set to increase by 2020 due to binding renewable energy targets. To achieve these targets, there will be periods of time when 75% of electricity will be generated mainly from onshore wind. Currently, the AII system can accommodate a 50% maximum permissible instantaneous level of wind generation. The system operators must make system-wide wind curtailment decisions to ensure that this level is not breached. Subsequently, the ability to limit wind curtailment using large-scale energy storage such as pumped hydroelectric energy storage and compressed air energy storage (CAES) is increasingly being scrutinized as a viable option. Thus, the aims of this paper are to estimate the level of wind curtailment on the 2020 AII system for various scenarios including with and without CAES, and assess and quantify the revenue loss due to wind curtailment using power systems simulation software PLEXOS.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Reserves in Stochastic Unit Commitment: An Irish System Case Study
    • Authors: Lowery; C.;O'Malley, M.;
      Pages: 1029 - 1038
      Abstract: As the level of variable renewable sources integrated into the power system increases, their nature forces a re-evaluation of traditional methodologies for managing uncertainty in power generation. This paper quantifies the interaction among the implicit reserve carried by a rolling planning stochastic unit commitment, deterministic reserve criteria, and the quality of information around wind forecast error, for a fully isolated 2020 Irish system. To perform this, three case studies were run. The first demonstrates that the implicit reserve carried by the stochastic model causes the implicit value of lost load set by the inclusion of explicit reserve requirements to be disproportionately high compared to the deterministic model. The second demonstrates that the relative value of the reserve rules does not have consistent impact between the models. In the final case, it is shown that the forecast error information utilized changes the security behavior of stochastic models. This is of importance, given the frequency at which normal distributions are used to model wind forecast error. Together, these results indicate a need for a holistic solution to reserve provision which considers the implicit nature of stochastic models, and forecast error assumptions when deciding reserve criteria.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Grid Inertial Response-Based Probabilistic Determination of Energy Storage
           System Capacity Under High Solar Penetration
    • Authors: Meng Yue;Xiaoyu Wang;
      Pages: 1039 - 1049
      Abstract: It is well known that responsive battery energy storage systems (BESSs) are effective means to improve the grid inertial response to various disturbances including the variability of the renewable generation. One of the major issues associated with its implementation is the difficulty in determining the required BESS capacity mainly due to the large amount of inherent uncertainties that cannot be accounted for deterministically. In this study, a probabilistic approach is proposed to properly size the BESS from the perspective of the system inertial response, as an application of probabilistic risk assessment (PRA). The proposed approach enables a risk-informed decision-making process regarding 1)the acceptable level of solar penetration in a given system and 2)the desired BESS capacity (and minimum cost) to achieve an acceptable grid inertial response with a certain confidence level.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • The Effect of Welfare Distribution and Cost Allocation on Offshore Grid
           Design
    • Authors: Hadush; S.Y.;De Jonghe, C.;Belmans, R.;
      Pages: 1050 - 1058
      Abstract: Innovative offshore grid designs such as integrating offshore wind farms (OWFs) with interconnectors are gaining popularity. Adequate investment in these designs requires aligning the interest of stakeholders through an appropriate cost allocation method. The aim of this paper is twofold. First, it shows how welfare distribution can influence a stakeholders offshore grid design choice. Second, it evaluates the effect of various cost allocation schemes in aligning diverse stakeholder interests toward efficient grid design. The results confirm that an investment in an efficient offshore grid design may not be guaranteed as long as the chosen cost allocation method ignores the welfare distribution effect. Most methods fail in this regard. Even when they provide cost incentives, they do not always ensure cooperation. Cognizant of this limitation, this study proposes a method that allocates costs in proportion to the incremental net benefit (PINB) of each stakeholder. This method reflects both the distribution of welfare and cost savings.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Blending HVDC-Link Energy Storage and Offshore Wind Turbine Inertia for
           Fast Frequency Response
    • Authors: Junyent-Ferre; A.;Pipelzadeh, Y.;Green, T.C.;
      Pages: 1059 - 1066
      Abstract: This paper explores the benefits of combining the dc-link energy storage of a voltage source converter-based high-voltage dc (VSC-HVDC) link and the kinetic energy storage from wind turbines to facilitate in fast primary frequency control and system inertia to an ac network. Alongside physical and analytical justifications, a method is proposed which blends the energy stored in the HVDC link with the power control capabilities of the wind turbines to provide frequency response that is fast while not requiring excessive volume of capacitance nor demanding performance requirements on the wind turbines.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Robust Control for Power Sharing in Microgrids With Low-Inertia Wind and
           PV Generators
    • Authors: Hossain; M.J.;Pota, H.R.;Mahmud, M.A.;Aldeen, M.;
      Pages: 1067 - 1077
      Abstract: This paper presents a robust control design scheme for a multidistributed energy resource (DER) microgrid for power sharing in both interconnected and islanded modes. The scheme is proposed for micgrogrids consisting of photovoltaic (PV) units and wind turbine driven doubly fed induction generators (DFIGs). A battery is integrated with each of the wind and solar DER units. The control scheme has two levels: 1)one centralized multi-inputmulti-output robust controller for regulating the set reference active and reactive powers and 2)local real and reactive power droop controllers, one on each DER unit. The robust control scheme utilizes multivariable H∞ control to design controllers that are robust to the changes in the network and system nonlinearities. The effectiveness of the proposed controller is demonstrated through large-disturbance simulations, with complete nonlinear models, on a test microgrid. It is found that the power sharing controllers provide excellent performance against large disturbances and load variations during islanding transients and interconnected operation.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Doubly Fed Induction Generator Controller Design for the Stable Operation
           in Weak Grids
    • Authors: Li-Jun Cai;Erlich; I.;
      Pages: 1078 - 1084
      Abstract: With the increasing integration of doubly fed induction generator (DFIG)-based large wind power plants, their impacts on power system static and dynamic behavior must be analyzed. Especially, large wind power plants are always connected to grids with relatively long transmission lines or cables (weak grids). Therefore, the wind power plants stable operation in these weak grids must be considered. This paper provides a method for designing an adaptive DFIG line side converter (LSC) control for enhancing the controller stability and reinforcing the power system stability. SENVION wind turbine and its wind power plant voltage control strategy are applied as an example of the LSC control strategy. Simulation results show the efficiency of the proposed approach.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Design and Strategy for the Deployment of Energy Storage Systems in a
           Distribution Feeder With Penetration of Renewable Resources
    • Authors: Nagarajan; A.;Ayyanar, R.;
      Pages: 1085 - 1092
      Abstract: Integration of distributed energy resources has the potential to impact the operation of the distribution systems by affecting the equipment reliability and customer power quality. The stochastic nature of the distributed energy resources have been accommodated using the energy storage systems along with providing economical benefits to the distribution systems. This paper provides a generalized framework for strategic deployment of a lithium-ion-based energy storage system to increase the benefits in a distribution feeder. Convex optimization is specifically developed to exploit the energy price arbitrage along the optimization time horizon. A significant amount of work has been performed in this paper for detailed characterization of the life cycle costs of the battery energy storage system (BESS). A novel approach for effective utilization of the energy storage system to mitigate the intermittent nature of the photovoltaic (PV) generation has been presented in this paper. The objectives include reduction of the substation transformer losses, reduction of the life cycle cost of the battery storage system, and accommodate PV variability. A convex optimization with a quadratic objective has been formulated to calculate the charge/discharge schedule of the energy storage system. A field validated model of the distribution feeder in OpenDSS has been used to determine the impact of optimal scheduling of the BESS on the substation transformer losses and the feeder head voltage.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • An Effective Power Dispatch Control Strategy to Improve Generation
           Schedulability and Supply Reliability of a Wind Farm Using a Battery
           Energy Storage System
    • Authors: Abu Abdullah; M.;Muttaqi, K.M.;Sutanto, D.;Agalgaonkar, A.P.;
      Pages: 1093 - 1102
      Abstract: The uncertainty in the availability of wind generation and the lack of coincidence between wind generation and system peak demand make wind farms (WFs) to be nondispatchable energy resources and impose limits on the potential penetration of wind generation in the generation mix. Battery energy storage systems (BESSs) integrated with WFs can reduce the variability of wind generation output allowing them to be dispatched for the network support, especially under peak load conditions. This paper proposes an effective power dispatch control strategy of WFs with the aid of BESSs to improve the supply reliability taking into account the uncertainties in wind generation output and load demand. A stochastic programming model is formulated considering uncertainty in wind generation and energy price to schedule WF dispatch. A novel rank-based BESS dispatch control algorithm is developed to achieve the assured WF power output levels for dispatch. Also, the application of the power dispatch control strategy is presented with the simulation study. Simulation results suggest that the implementation of the proposed strategy will improve supply reliability and revenue stream of the WFs.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Economic Assessment of Energy Storage in Systems With High Levels of
           Renewable Resources
    • Authors: Nan Li;Hedman; K.W.;
      Pages: 1103 - 1111
      Abstract: High penetration levels of renewable resources impose increasing uncertainty and variability on power system operations. Traditionally, power systems rely on conventional generators (CGs) to balance the uncertainty in renewable generation. However, as renewable penetration levels increase, CGs may suffer from higher operating costs while receiving lower profits. In contrast, since bulk energy storage can store and shift clean energy and have fast ramping capability, they may become more competitive under high renewable penetration levels. In this paper, a stochastic unit commitment model with energy storage will be presented to evaluate the short-term profitability of CGs and energy storage under different levels of renewable penetrations. The short-term profitability of CGs and energy storage units will be compared to identify the impact of increasing renewable penetration on the attractiveness of bulk energy storage in comparison to CGs.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Fuzzy Approach for Online Coordination of Plug-In Electric Vehicle
           Charging in Smart Grid
    • Authors: Masoum; A.S.;Deilami, S.;Abu-Siada, A.;Masoum, M.A.S.;
      Pages: 1112 - 1121
      Abstract: This paper proposes an online fuzzy coordination algorithm (OL-FCA) for charging plug-in electric vehicles (PEVs) in smart grid networks that will reduce the total cost of energy generation and the associated grid losses while maintaining network operation criteria such as maximum demand and node voltage profiles within their permissible limits. A recently implemented PEV coordination algorithm based on maximum sensitivity selection (MSS) optimization is improved using fuzzy reasoning. The proposed OL-FCA considers random plug-in of vehicles, time-varying market energy prices, and PEV owner preferred charging time zones based on priority selection. Impacts of uncoordinated, MSS, and fuzzy coordinated charging on total cost, gird losses, and voltage profiles are investigated by simulating different PEV penetration levels on a 449-node network with three wind distributed generation (WDG) systems. The main advantage of OL-FCA compared with the MSS PEV coordination is the reduction in the total cost it introduces within the 24h.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Increasing Transmission Grid Flexibility by TSO Coordination to Integrate
           More Wind Energy Sources While Maintaining System Security
    • Authors: Guha Thakurta; P.;Maeght, J.;Belmans, R.;Van Hertem, D.;
      Pages: 1122 - 1130
      Abstract: The transmission grid in Europe is interconnected to guarantee the security of supply and to facilitate the competition among different market players, thereby making the system highly meshed. It is a challenging task for the transmission system operators (TSOs) to manage the power flows in their system, especially in the light of integration of renewable energy generation sources into the transmission system. The intermittent nature of such generation sources creates variable power flows and loop flows, in turn, questing for installation of controllable devices to manage these flows. The TSOs are currently installing such devices to cope with the situation. A proper coordination is needed for the operation of these devices, since they can lead to adverse effects on power flows in a meshed system. Coordination among TSOs in Central Western Europe (CWE) is performed, however, not towards a full system-wide objective, since there is no regulatory framework that exists for such coordination. This paper focuses on the potential of coordination among TSOs with respect to operation of the controllable devices. Two aspects are investigated: management of constraints in the system in the day-ahead scheduling process and wind in-feed optimization. Both approaches are implemented at the Regional Security Center and tested on a high-stress situation in the CWE region. Furthermore, a case study at the coordination center is performed using actual data for the month of January 2013 to assess the usefulness on a longer time period.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • A Voltage Detection Method for the Voltage Ride-Through Operation of
           Renewable Energy Generation Systems Under Grid Voltage Distortion
           Conditions
    • Authors: Cong Ma;Feng Gao;Guoqing He;Guanghui Li;
      Pages: 1131 - 1139
      Abstract: This paper proposes a new voltage detection method to assist the low-voltage ride-through operation of grid-tied converters. In particular, it consists of one synchronous reference frame phase-locked-loop (SRF-PLL) and two voltage detection modules. The fast voltage detection module tracks maximum points or zero points of three-phase grid voltage waveforms to calculate the phase voltage amplitude. The accurate voltage detection module operated in parallel assumes an additional cascaded delayed signal cancellation block to filter out the possible low-order voltage harmonics and then employs the same operational principle as the fast voltage detection module to precisely derive the phase voltage amplitude. Coupling with the SRF-PLL, where the grid voltage amplitude before voltage sag or surge can be precisely calculated, the voltage variation ratios can then be derived in sequence. A progressive logic algorithm is designed to determine the converter control commands by fully considering the different voltage variation ratios derived at different time points. Doing so, the proposed method can assist the grid-tied converter to satisfy the grid voltage ride-through operation requirements under various grid voltage distortion conditions. Finally, validity and accuracy of the proposed method were verified by simulation and experimental results.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Novel LVRT Testing Method for Wind Turbines Using Flexible VSC Technology
    • Authors: Espinoza; N.;Bongiorno, M.;Carlson, O.;
      Pages: 1140 - 1149
      Abstract: Wind energy is one of the fastest growing renewable energy sources. For this reason, several countries have included requirements in their grid codes to guarantee proper operation of wind turbines under stable operations of the power systems as well as under grid disturbances. This paper presents a novel methodology for grid code testing of wind turbines based on voltage source converter (VSC) technology. In particular, this paper focuses on a low voltage ride through (LVRT) test of a full size converter-based wind turbine. The investigated testing setup consists of a 4-MW wind turbine and an 8-MW back-to-back VSC system, operated as test equipment. The control algorithm of the testing device is derived in detail and validated through time-domain simulations. The risk of poorly damped resonances and possible interaction between the testing equipment and the tested object is investigated through small signal analysis. The obtained results demonstrate the flexibility of the proposed approach in controlling the voltage at the wind turbine terminals, including the ability in emulating the short-circuit impedance of the grid at the connection point.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Single- and Two-Stage Inverter-Based Grid-Connected Photovoltaic Power
           Plants With Ride-Through Capability Under Grid Faults
    • Authors: Mirhosseini; M.;Pou, J.;Agelidis, V.G.;
      Pages: 1150 - 1159
      Abstract: Grid-connected distributed generation sources interfaced with voltage source inverters (VSIs) need to be disconnected from the grid under: 1)excessive dc-link voltage; 2)excessive ac currents; and 3)loss of grid-voltage synchronization. In this paper, the control of single- and two-stage grid-connected VSIs in photovoltaic (PV) power plants is developed to address the issue of inverter disconnecting under various grid faults. Inverter control incorporates reactive power support in the case of voltage sags based on the grid codes (GCs) requirements to ride-through the faults and support the grid voltages. A case study of a 1-MW system simulated in MATLAB/Simulink software is used to illustrate the proposed control. Problems that may occur during grid faults along with associated remedies are discussed. The results presented illustrate the capability of the system to ride-through different types of grid faults.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Challenges Associated With Assessment and Testing of Fault Ride-Through
           Compliance of Variable Power Generation in Australian National Electricity
           Market
    • Authors: Badrzadeh; B.;Halley, A.;
      Pages: 1160 - 1168
      Abstract: This paper presents challenges associated with the assessment and testing of fault ride-through (FRT) compliance for intermittent power generation, in particular wind and solar generation in the Australian National Electricity Market. Examples discussed in this paper focus on wind farm applications. The same principles, however, hold true for other intermittent generation technologies such as solar generation. Two aspects of compliance are discussed, namely, adherence to technical performance requirements and accuracy of model data subsequently used for undertaking power system simulations. Analytical assessment of compliance through simulation studies and the impact of positive-sequence and detailed electromagnetic transient (EMT) models are discussed. On-site demonstration of FRT compliance through long-term monitoring and staged fault testing are presented. Results obtained from each method are compared against simulation studies and differences between measurements and simulations are discussed.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Impact of the Combined Integration of Wind Generation and Small Hydropower
           Plants on the System Reliability
    • Authors: Lopes; V.S.;Borges, C.L.T.;
      Pages: 1169 - 1177
      Abstract: The purpose of this paper is to assess the impact of the integration of wind generation, together with small hydropower plants (SHPs), in the reliability of the power system. In order to preserve the characteristics of the time series of the variable energy sources (wind and river inflows) and the variable load, the analyses are based on the sequential Monte Carlo simulation. By calculating the reliability indices, we intend to evaluate how the uncertainty of wind energy production impacts on system planning, especially with the reduction of capacity of reservoirs associated with SHPs. We also intend to evaluate the existence of complementarity between wind and hydro-generation, or even between different wind generation and/or the load. Finally, we intend to analyze how the correlation between these energy sources can benefit the supply of the future foreseen demand.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • IEEE PES Resource Center
    • Pages: 1178 - 1178
      Abstract: Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • The power of information
    • Pages: 1179 - 1179
      Abstract: Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
  • Scholarship Plus Initiative
    • Pages: 1180 - 1180
      Abstract: Advertisement, IEEE.
      PubDate: July 2015
      Issue No: Vol. 6, No. 3 (2015)
       
 
 
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