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  Subjects -> ENGINEERING (Total: 2265 journals)
    - CHEMICAL ENGINEERING (188 journals)
    - CIVIL ENGINEERING (179 journals)
    - ELECTRICAL ENGINEERING (99 journals)
    - ENGINEERING (1210 journals)
    - ENGINEERING MECHANICS AND MATERIALS (384 journals)
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    - INDUSTRIAL ENGINEERING (60 journals)
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ELECTRICAL ENGINEERING (99 journals)

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3C TIC     Open Access  
Actuators     Open Access   (Followers: 4)
Advances in Electrical Engineering     Open Access   (Followers: 7)
Advances in Microelectronic Engineering     Open Access   (Followers: 8)
Advances in Signal Processing     Open Access   (Followers: 6)
American Journal of Electrical and Electronic Engineering     Open Access   (Followers: 17)
American Journal of Sensor Technology     Open Access  
APSIPA Transactions on Signal and Information Processing     Open Access   (Followers: 9)
Archives of Control Sciences     Open Access   (Followers: 3)
Archives of Electrical Engineering     Open Access   (Followers: 10)
Atom Indonesia     Open Access   (Followers: 1)
Case Studies in Mechanical Systems and Signal Processing     Open Access  
Circuits, Systems, and Signal Processing     Hybrid Journal   (Followers: 9)
Computers & Electrical Engineering     Hybrid Journal   (Followers: 7)
Current Trends in Signal Processing     Full-text available via subscription   (Followers: 4)
Edu Elektrika Journal     Open Access  
Electric Power Components and Systems     Hybrid Journal   (Followers: 5)
Electric Power Systems Research     Partially Free   (Followers: 14)
Electrical and Electronic Engineering     Open Access   (Followers: 16)
Electrical and Power Engineering Frontier     Open Access   (Followers: 18)
Electrical Engineering     Hybrid Journal   (Followers: 18)
Electrical Engineering and Automation     Open Access   (Followers: 5)
Electrical Engineering in Japan     Hybrid Journal   (Followers: 8)
Electrical, Control and Communication Engineering     Open Access   (Followers: 10)
Emerging and Selected Topics in Circuits and Systems     Hybrid Journal   (Followers: 8)
EURASIP Journal on Advances in Signal Processing     Open Access   (Followers: 7)
Ferroelectrics     Hybrid Journal   (Followers: 1)
Ferroelectrics Letters Section     Hybrid Journal   (Followers: 1)
Frequenz     Hybrid Journal   (Followers: 1)
Frontiers of Electrical and Electronic Engineering     Hybrid Journal   (Followers: 8)
IEA Electricity Information     Full-text available via subscription   (Followers: 2)
IEEE Access     Open Access   (Followers: 47)
IEEE Electrical Insulation Magazine     Full-text available via subscription   (Followers: 14)
IEEE Signal Processing Magazine     Full-text available via subscription   (Followers: 55)
IEEE Transactions on Control of Network Systems     Hybrid Journal   (Followers: 9)
IEEE Transactions on Dielectrics and Electrical Insulation     Hybrid Journal   (Followers: 10)
IEEE Transactions on Signal and Information Processing over Networks     Full-text available via subscription   (Followers: 5)
IEEJ Transactions on Electrical and Electronic Engineering     Hybrid Journal   (Followers: 12)
IET Control Theory & Applications     Hybrid Journal   (Followers: 17)
IET Electric Power Applications     Hybrid Journal   (Followers: 16)
IET Electrical Systems in Transportation     Hybrid Journal   (Followers: 9)
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 Advances in Telecommunications, Electrotechnics, Signals and Systems     Open Access   (Followers: 4)
International Journal of Electrical Engineering Education     Full-text available via subscription   (Followers: 5)
International Journal of Electrical Power & Energy Systems     Open Access   (Followers: 18)
International Journal of Emerging Electric Power Systems     Hybrid Journal   (Followers: 4)
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: 12)
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: 7)
International Journal on Signal and Image Processing     Full-text available via subscription   (Followers: 4)
International Transaction of Electrical and Computer Engineers System     Open Access   (Followers: 1)
International Transactions on Electrical Energy Systems     Hybrid Journal   (Followers: 8)
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki : Materials of Electronics Engineering     Full-text available via subscription  
J3eA     Open Access   (Followers: 2)
Journal of Control, Automation and Electrical Systems     Hybrid Journal   (Followers: 6)
Journal of Electrical and Computer Engineering     Open Access   (Followers: 8)
Journal of Electrical and Computer Engineering Innovations     Open Access   (Followers: 3)
Journal of Electrical and Electronics Engineering Research     Open Access   (Followers: 9)
Journal of Electrical Bioimpedance     Full-text available via subscription   (Followers: 2)
Journal of Electrical Engineering     Open Access   (Followers: 17)
Journal of Electrical Engineering & Electronic Technology     Hybrid Journal   (Followers: 5)
Journal of Electrical Systems and Information Technology     Open Access   (Followers: 2)
Journal of Field Robotics     Hybrid Journal   (Followers: 2)
Journal of Micro-Bio Robotics     Hybrid Journal  
Journal of Microwaves, Optoelectronics and Electromagnetic Applications     Open Access   (Followers: 7)
Journal of Power Technologies     Open Access   (Followers: 5)
Journal of the Society for Information Display     Hybrid Journal  
Journal of World's Electrical Engineering and Technology     Open Access   (Followers: 1)
Journal of Zhejiang University SCIENCE C     Hybrid Journal  
Jurnal Elementer     Open Access  
Jurnal Ilmiah Mahasiswa SPEKTRUM     Open Access  
Jurnal Infotel     Open Access  
Jurnal Nasional Teknik Elektro     Open Access   (Followers: 1)
Jurnal Rekayasa Elektrika     Open Access  
Majlesi Journal of Electrical Engineering     Open Access   (Followers: 1)
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: 8)
Photovoltaics, IEEE Journal of     Hybrid Journal   (Followers: 9)
Recent Patents on Electrical & Electronic Engineering     Full-text available via subscription   (Followers: 5)
Recent Patents on Telecommunications     Full-text available via subscription   (Followers: 2)
Research & Reviews : Journal of Embedded System & Applications     Full-text available via subscription   (Followers: 2)
Russian Electrical Engineering     Hybrid Journal   (Followers: 4)
SID Symposium Digest of Technical Papers     Hybrid Journal  
Sustainable Energy, Grids and Networks     Hybrid Journal  
Sustainable Energy, IEEE Transactions on     Hybrid Journal   (Followers: 11)
Synthesis Lectures on Electrical Engineering     Full-text available via subscription   (Followers: 2)
System analysis and applied information science     Open Access  
Telematique     Open Access  
TELKOMNIKA : Indonesian Journal of Electrical Engineering     Open Access   (Followers: 8)
Trends in Electrical Engineering     Full-text available via subscription   (Followers: 3)
Turkish Journal of Electrical Engineering and Computer Science     Open Access   (Followers: 2)
Universal Journal of Electrical and Electronic Engineering     Open Access   (Followers: 4)
Wireless Engineering and Technology     Open Access   (Followers: 3)
Електротехніка і Електромеханіка     Open Access  
Journal Cover Sustainable Energy, IEEE Transactions on
  [SJR: 2.826]   [H-I: 24]   [11 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1949-3029
   Published by IEEE Homepage  [191 journals]
  • Table of Contents
    • Pages: 902
      Abstract: Presents the table of contents for this issue of the publication.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • 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 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • IEEE Industry Applications Society
    • Abstract: Provides a listing of the editors, board members, and current staff for this issue of the publication.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Information for Authors
    • Abstract: These instructions give guidelines for preparing papers for this publication. Presents information for authors publishing in this journal.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • A Two-Stage Model Predictive Control Strategy for Economic
           Diesel-PV-Battery Island Microgrid Operation in Rural Areas
    • Authors: Sachs; J.;Sawodny, O.;
      Pages: 903 - 913
      Abstract: Microgrids consisting of diesel generators, storage devices, and renewable sources present an effective approach for an economic energy supply to rural areas. Advanced control methods are needed to improve the energy dispatch, enable a cost-efficient operation and guarantee an uninterrupted power supply. In particular, sudden variations in load demand or additional power supply from renewable sources are often unpredictable and underline the need for enhanced control. This paper presents an advanced control strategy for the optimal microgrid operation using a two-layer model predictive method. The first optimization layer presents an optimal control problem, based on real-time predictions of future power profiles, for the calculation of the optimal energy dispatch. To improve the robustness of the control strategy toward prediction errors, a boundary value problem is solved to adjust the diesel generator power in the second stage. The model predictive control framework is further used to adapt the weights of the forecast algorithm. Simulation studies are carried out by using real-world data to illustrate the performance and economic benefits of the proposed method. Results show the effectiveness of the control strategy in terms of computational feasibility, accuracy, increased robustness, and reduced cost.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • A Reactive Power Dispatch Strategy With Loss Minimization for a DFIG-Based
           Wind Farm
    • Authors: Zhang; B.;Hou, P.;Hu, W.;Soltani, M.;Chen, C.;Chen, Z.;
      Pages: 914 - 923
      Abstract: An optimal reactive power dispatch strategy is proposed to minimize the total electrical losses of a wind farm (WF), including not only losses in the transmission cables and wind turbine (WT) transformers, but also losses inside wind energy generation systems. The reactive power dispatch inside a WT uses optimal splitting strategy over the stator and the grid side converter (GSC), which aims to minimize the total loss of the wind energy generation system, including the generator, the converters, and the filters. Optimization problems are formulated based on established loss models and WT reactive power limits. A WF is carefully designed and used for case studies. Wake effect is considered when calculating the active power at each WT. The total losses of the WF are calculated by implementing the proposed strategy at different wind speeds and reactive power references. The simulation results show the effectiveness of the proposed strategy.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Dynamic Droop–Based Inertial Control of a Doubly-Fed Induction
           Generator
    • Authors: Hwang; M.;Muljadi, E.;Park, J.-W.;Sorensen, P.;Kang, Y.C.;
      Pages: 924 - 933
      Abstract: If a large disturbance occurs in a power grid, two auxiliary loops for the inertial control of a wind turbine generator have been used: droop loop and rate of change of frequency (ROCOF) loop. Because their gains are fixed, difficulties arise in determining them suitable for all grid and wind conditions. This paper proposes a dynamic droop-based inertial control scheme of a doubly-fed induction generator (DFIG). The scheme aims to improve the frequency nadir (FN) and ensure stable operation of a DFIG. To achieve the first goal, the scheme uses a droop loop, but it dynamically changes its gain based on the ROCOF to release a large amount of kinetic energy during the initial stage of a disturbance. To do this, a shaping function that relates the droop to the ROCOF is used. To achieve the second goal, different shaping functions, which depend on rotor speeds, are used to give a large contribution in high wind conditions and prevent over-deceleration in low wind conditions during inertial control. The performance of the proposed scheme was investigated under various wind conditions using an EMTP-RV simulator. The results indicate that the scheme improves the FN and ensures stable operation of a DFIG.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Optimal Medium-Term Hydropower Scheduling Considering Energy and Reserve
           Capacity Markets
    • Authors: Helseth; A.;Fodstad, M.;Mo, B.;
      Pages: 934 - 942
      Abstract: This paper describes a method for optimal scheduling of hydropower systems for a profit maximizing, price-taking, and risk neutral producer selling energy, and capacity to separate and sequentially cleared markets. The method is based on a combination of stochastic dynamic programming (SDP) and stochastic dual dynamic programming (SDDP), and treats inflow to reservoirs and prices for energy and capacity as stochastic variables. The proposed method is applied in a case study for a Norwegian watercourse, quantifying the expected changes in schedules, and water values when going from an energy-only market to a joint treatment of energy and reserve capacity markets.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Hierarchical Co-Ordinated Wide Area and Local Controls of DFIG Wind
           Turbine and PSS for Robust Power Oscillation Damping
    • Authors: Surinkaew; T.;Ngamroo, I.;
      Pages: 943 - 955
      Abstract: In this paper, the two-level hierarchical scheme, which consists of wide area centralized and local controls of the power oscillation damper (POD) installed with the doubly-fed induction generator (DFIG) wind turbine and the power system stabilizer (PSS) has been proposed for robust power oscillation damping. In the wide area level, the centralized POD and PSS has received the input signals from synchronized phasor measurement units (PMUs). The geometric measures of controllability and observability have been applied to select the suitable DFIG and synchronous generator (SG) for stabilizing the target oscillation modes, the proper input signals of the centralized POD and PSS, and the location of PMUs. In the local level, the suitable DFIG and SG have been equipped with POD and PSS, respectively. In the parameters optimization of POD and PSS, the practical issues such as damping performance, controller structure, communication latency, and robustness against system uncertainties have been considered. The controller efficiency and resiliency of the proposed controller have been evaluated in comparison with other controllers by eigenvalue analysis and nonlinear simulation for a wide range of operating conditions, line outage contingencies, severe faults, and communication failure.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Maximum Power Point Tracking of Variable Speed Wind Turbines With Flexible
           Shaft
    • Authors: Yenduri; K.;Sensarma, P.;
      Pages: 956 - 965
      Abstract: Optimum torque (OT)-based maximum power point tracking (MPPT) is widely used in high power turbines because of its simplicity. Several recent improvements claim better response speeds by augmenting the basic OT algorithm with a suitably scaled inertial torque. However, the underlying dynamic model for all these improved methods is premised on a rigid shaft, which ignores all torsional behavior. This lacuna is addressed in this paper, where a small-signal system description is developed considering a more accurate flexible shaft model. It is shown that the improvements have three possible forms, the third being proposed in this paper. Close-loop stability with each of these is analytically investigated using this accurate small-signal model. It is also proved that one of the reported approaches causes system instability while attempting even moderate improvement over the OT method. The problems in realization of the other two forms are highlighted and a realizable alternative proposed, which requires no additional sensor. Design of the proposed approach is presented in appropriate detail. It is analytically established that the proposed method ensures superior dynamic response. All analytical conclusions are validated by numerical simulations.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Multibody Modelling of Wave Energy Converters Using Pseudo-Spectral
           Methods With Application to a Three-Body Hinge-Barge Device
    • Authors: Paparella; F.;Bacelli, G.;Paulmeno, A.;Mouring, S.E.;Ringwood, J.V.;
      Pages: 966 - 974
      Abstract: Multibody wave energy converters are composed of several bodies interconnected by joints. Two different formulations are adopted to describe the dynamics of multibody systems: the differential and algebraic equations (DAEs) formulation, and the ordinary differential equations (ODEs) formulation. While the number of variables required for the description of the dynamics of a multibody system is greater in the DAE formulation than in the ODE formulation, the ODE formulation involves an extra computational effort in order to describe the dynamics of the system with a smaller number of variables. In this paper, pseudo-spectral (PS) methods are applied in order to solve the dynamics of multibody wave energy converters using both DAE and ODE formulations. Apart from providing a solution to the dynamics of multibody systems, pseudo-spectral methods provide an accurate and efficient formulation for the control of multibody wave energy converters. As an application example, this paper focuses on the dynamic modeling of a three-body hinge-barge device, where wave-tank tests are carried out in order to validate the DAE and ODE models against experimental data. Comparison of the ODE and DAE PS methods against a reference model based on the straightforward (Runge-Kutta) integration of the equations of motion shows that pseudo-spectral methods are computationally more stable and require less computational effort for short time steps.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Optimal Distributed Generation and Reactive Power Allocation in Electrical
           Distribution Systems
    • Authors: Pereira; B.R.;da Costa, G.R.M.;Contreras, J.;Mantovani, J.R.S.;
      Pages: 975 - 984
      Abstract: Optimal and simultaneous siting and sizing of distributed generators and capacitor banks in distribution systems have attracted a lot of attention from distribution companies. The placement and capacity of these devices have direct effects on the system’s performance. This paper presents a model for the simultaneous allocation of capacitor banks and distributed generation, which takes into account the stochastic nature of distributed generation. To solve the model presented, we propose an efficient hybrid method based on Tabu search and genetic algorithms. The hybrid method is applied to a well-known system in literature.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Convex Optimization for DES Planning and Operation in Radial Distribution
           Systems With High Penetration of Photovoltaic Resources
    • Authors: Li; Q.;Ayyanar, R.;Vittal, V.;
      Pages: 985 - 995
      Abstract: In this paper, distributed energy storage (DES) devices, like batteries and ultra-capacitors, are used to alleviate detrimental impacts of high penetration photovoltaic (PV) resources on distribution systems. The impacts are studied at mainly two time resolutions-one minute and one hour. To determine accurately the size of the required DES for the purpose of mitigating the impacts of large-scale distributed PV, sizing procedures based on OpenDSS are proposed. After determining the total size of the required DES, optimization techniques can be used to choose the optimal locations for the DES along the feeder, which is a continuous optimization problem taking into account equality constraints of the AC power flow. The continuity of the problem and the radial network structure make it possible to apply a convex optimization technique called second order cone programming (SOCP) relaxation to obtain the globally optimal solution and avoid the problem of NP-hardness. The exactness of the introduced SOCP relaxation is sensitive to the chosen objective function and additional quadratic equalities. The necessary and sufficient condition of exactness for the SOCP relaxation of the DES optimal allocation and operation in radial distribution systems is studied. The proposed methods are applied to an actual feeder in the southwestern US with high penetration of PV using actual measured data. The simulation results demonstrate the efficacy of the proposed approaches.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Electricity-Natural Gas Operation Planning With Hourly Demand Response for
           Deployment of Flexible Ramp
    • Authors: Zhang; X.;Che, L.;Shahidehpour, M.;Alabdulwahab, A.;Abusorrah, A.;
      Pages: 996 - 1004
      Abstract: This paper proposes an integrated stochastic day-ahead scheduling model to dispatch hourly generation and load resources and deploy flexible ramping for managing the variability of renewable energy system. A comprehensive framework for the natural gas transportation network is considered to address the dispatchability of a fleet of fuel-constrained natural gas-fired units. System uncertainties include the day-ahead load and renewable generation forecast errors. Illustrative examples demonstrate that the real-time natural gas delivery can directly impact the hourly dispatch, flexible ramp deployment, and power system operation cost. Meanwhile, the demand side participation can mitigate the dependency of electricity on natural gas by providing a viable option for flexible ramp when the natural gas system is constrained.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Normal-Based Model for True Power Curves of Wind Turbines
    • Authors: Villanueva; D.;Feijoo, A.;
      Pages: 1005 - 1011
      Abstract: Wind turbine power curves do not consider specific weather conditions, wind shear, turbulence effects of the location where the turbine is going to be installed, or its age. A true power curve is obtained by analyzing data from an installed wind turbine over a year. Here, a model for a true power curve is proposed, considering a normal distribution for each range of wind speed data. Furthermore, a Monte Carlo-based simulation technique is proposed to reproduce data following the normal-based model. The main use of the model is to simulate data to complete lacking real data or to perform long-term assessments. The model was checked with data from two wind turbines at the Sotavento experimental wind farm in the northwest of Spain.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Identification of Wave Energy Device Models From Numerical Wave Tank
           Data—Part 1: Numerical Wave Tank Identification Tests
    • Authors: Davidson; J.;Giorgi, S.;Ringwood, J.V.;
      Pages: 1012 - 1019
      Abstract: In this paper and its companion, the identification of mathematical models describing the behaviour of wave energy devices (WECs) in the ocean is investigated through the use of numerical wave tank (NWT) experiments. This paper deals with the identification tests used to produce the data for the model identification. NWTs, implemented using computational fluid dynamics (CFD), are shown as an effective platform to perform the identification tests. The design of the NWT experiments, to ensure the production of information-rich data for the model identification, is discussed. A case study is presented to illustrate the design and implementation of NWT experiments for the identification of WEC models.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Identification of Wave Energy Device Models From Numerical Wave Tank
           Data—Part 2: Data-Based Model Determination
    • Authors: Giorgi; S.;Davidson, J.;Ringwood, J.V.;
      Pages: 1020 - 1027
      Abstract: In this paper and its companion, the identification of mathematical models describing the behaviour of wave energy devices (WECs) in the ocean is investigated through the use of numerical wave tank experiments. When the wave amplitude and the WEC displacement are not negligible with respect to the WEC dimensions, nonlinear hydrodynamic effects may appear, and the accuracy of linear hydrodynamic models is reduced, leading to the necessity of introducing some nonlinearities in the model structure. This paper proposes, for WEC modelling, the use of discrete-time nonlinear autoregressive with exogenous input (NARX) models, as an alternative to continuous-time models. Techniques of model identification are also explained and applied to a case study.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Frequency Regulation by Distributed Secondary Loads on Islanded
           Wind-Powered Microgrids
    • Authors: Janssen; N.T.;Wies, R.W.;Peterson, R.A.;
      Pages: 1028 - 1035
      Abstract: Frequency regulation is critical to the successful operation of remote wind-diesel electrical grids. When the grid is in `wind-diesel' mode, frequency regulation is (classically) the sole duty of the diesel electric generator (DEG). An alternative approach is proposed whereby responsibility for frequency regulation is shared by the DEG and a network of autonomous distributed secondary loads (DSLs) consisting of electric thermal storage (ETS) devices. This allows surplus wind to be distributed to residential consumers (as space heat) without the need for a centralized communication network. Numerical modeling of system dynamics with active DSLs is conducted using a SIMULINK wind-diesel hybrid test bed model. The effects of controller gain, installed capacity, switching time and unit coordination timing on frequency and voltage regulation is explored. It is shown that the DSLs can improve frequency regulation in wind-diesel mode while providing storable thermal energy to distributed consumers.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Optimal Offering Strategies for Wind Power in Energy and Primary Reserve
           Markets
    • Authors: Soares; T.;Pinson, P.;Jensen, T.V.;Morais, H.;
      Pages: 1036 - 1045
      Abstract: Wind power generation is to play an important role in supplying electric power demand, and will certainly impact the design of future energy and reserve markets. Operators of wind power plants will consequently develop adequate offering strategies, accounting for the market rules and the operational capabilities of the turbines, e.g., to participate in primary reserve markets. We consider two different offering strategies for joint participation of wind power in energy and primary reserve markets, based on the idea of proportional and constant splitting of potentially available power generation from the turbines. These offering strategies aim at maximizing expected revenues from both market floors using probabilistic forecasts for wind power generation, complemented with estimated regulation costs and penalties for failing to provide primary reserve. A set of numerical examples, as well as a case-study based on real-world data, allows illustrating and discussing the properties of these offering strategies. An important conclusion is that, even though technically possible, it may not always make sense for wind power to aim at providing system services in a market environment.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Stochastic Centralized Dispatch Scheme for AC/DC Hybrid Smart Distribution
           Systems
    • Authors: Eajal; A.A.;Shaaban, M.F.;Ponnambalam, K.;El-Saadany, E.F.;
      Pages: 1046 - 1059
      Abstract: This paper presents a two-stage stochastic centralized dispatch scheme for AC/DC hybrid smart grids. The developed dispatch scheme coordinates the operations of a variety of distributed energy resources (DERs), such as distributed generators (DGs) and energy storage systems (ESSs). It also ensures the coordinated charging of electric vehicles (EVs) and models the degradation of their batteries that occurs due to vehicle-to-grid (V2G). The energy coordination problem has been formulated as a two-stage day-ahead resource scheduling problem, with the intermittent supply; the variable demand, which includes EVs; and the fluctuating real-time energy price modeled as random variables. The first stage produces day-ahead dispatch decisions for the dispatchable DG units. For a set of possible scenarios over the next 24 h, the second stage determines appropriate corrective decisions with respect to the import/export schedule, storage charging/discharging cycles, and EV charging/discharging patterns. The objective is to minimize the expected total operating cost while satisfying operational and technical constraints. The new two-stage stochastic centralized dispatch model has been tested on a 38-bus AC/DC hybrid distribution system. The simulation results demonstrate the effectiveness of the developed scheme for optimally coordinating the various components of future AC/DC hybrid smart grids. To demonstrate the necessity for uncertainty modeling, the value of the stochastic solution (VSS) and the expected value of perfect information (EVPI) have been applied for comparing the stochastic solution obtained and the deterministic one.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • A Generation-Interval-Based Mechanism for Managing the Power Generation
           Uncertainties of Variable Generation
    • Authors: Chen; R.;Sun, H.;Guo, Q.;Li, Z.;Zhang, B.;
      Pages: 1060 - 1070
      Abstract: Power generation uncertainty is an important characteristic of variable generation (VG) platforms, such as wind and solar power, which brings additional operational costs to the power systems. To manage this uncertainty, responsibilities should be properly allocated to encourage good behaviors of system participants, especially the VG producers. Currently, the imbalance-cost-based mechanism is most commonly used for uncertainty management. Based on this method, we consider a new mechanism in this paper for capturing the uncertainty, which may achieve a better mechanism performance. The basic idea is to allow producers to purchase generation intervals (GIs) for their potential production output. The analysis presented in this paper indicates that producers can be very responsive to this mechanism. With the proper pricing policies, producers can be encouraged to provide additional information on upcoming uncertainties to the system operators. Additionally, three strategies for pricing GIs are included in this paper. Case studies are used to demonstrate the application of the mechanism as well as its effectiveness.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Gossip Algorithms for Decentralized Congestion Management of Distribution
           Grids
    • Authors: Koukoula; D.I.;Hatziargyriou, N.D.;
      Pages: 1071 - 1080
      Abstract: The paper proposes a gossip algorithm-based architecture for managing power flows on radial distribution grids applying decentralized management of demand. Demand flexibility is associated with a cost-like utility function expressing the inconvenience caused by curtailment. Every node of the distribution grid participates in power flow management by sending locally measured and calculated values to its neighboring nodes following a peer-to-peer architecture. The proposed algorithm is based on the application of gossip algorithms to estimate locally critical physical quantities by reaching a global consensus. More specifically, the solution implements gossip algorithms to achieve consensus in aggregated demand and in minimum cost for curtailment of flexible loads/increase of controllable distributed generators.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Comparison of Airfoil Precomputational Analysis Methods for Optimization
           of Wind Turbine Blades
    • Pages: 1081 - 1088
      Abstract: The objective of this research was to develop and compare various airfoil precomputational parameterization and analysis techniques for aerostructural optimization of wind turbine blades. The airfoils along the blade were added as optimization design variables through precomputational parameterization methods using thickness-to-chord ratios and blended airfoil family factors. The airfoils’ aerodynamic performance was analyzed with three methods of increasing fidelity: a panel method (XFOIL), Navier–Stokes-based computational fluid dynamics (RANS CFD), and wind tunnel data. The optimizations minimized mass over annual energy production ( m/AEP ) and thereby approximated the minimization of cost of energy. The results were compared to the NREL 5-MW reference turbine and a conventional optimization where the airfoils were fixed. Results showed an average m/AEP reduction of 1.7% over conventional optimization methods. The primary benefit in adding the airfoil shape was through an increase in annual energy production (1.6%) with a similar decrease in turbine mass (1.8%). Using the precomputational airfoil parameterization methods provided significant reductions in the cost of energy with relatively minor additional computational cost.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Co-Ordinated Multiloop Switching Control of DFIG for Resilience
           Enhancement of Wind Power Penetrated Power Systems
    • Pages: 1089 - 1099
      Abstract: This paper proposes a co-ordinated four-loop switching controller (SC) for the doubly fed induction generator (DFIG) to improve the transient stability of wind power penetrated power systems. A short-term resilience index is introduced, and it reflects the dynamics of both system frequency and load bus voltage. A four-loop SC is driven by the four outputs of a DFIG, namely, the rotor speed deviation, the reactive power output of stator winding, the reactive power transferred through grid-side converter, and the DC-link voltage, respectively. Referring to a state-dependent switching strategy, the four-loop SC switches between a logic-based bang-bang constant funnel controller (LBCFC) and a vector control theory-based conventional controller (CC) in each control loop. The LBCFC is robust to system nonlinearities, uncertainties, and external disturbances. The control signal of the LBCFC is bang-bang with the upper and lower limits of control variables. Simulation studies are undertaken in a modified IEEE 16-generator 68-bus power system, in which four DFIG-based wind farms are penetrated to provide 9.94% power supply. The performance of the four-loop SC is evaluated in aspects of the integral control of the DFIG and the resilience enhancement of the multimachine power system, respectively.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Co-Ordinated Control Strategy for Hybrid Wind Farms With PMSG and FSIG
           Under Unbalanced Grid Voltage Condition
    • Pages: 1100 - 1110
      Abstract: This paper investigates a control strategy for a wind farm with the direct-driven permanent-magnet synchronous generators (PMSG)-based wind turbines and the fixed speed induction generators (FSIG)-based wind turbines under unbalanced grid voltage condition. By controlling the PMSG-based wind farm to inject negative-sequence current for decreasing voltage unbalance factor (VUF) at point of common coupling (PCC), the double grid frequency oscillations in electromagnetic torque, active, and reactive power output from the FSIG-based wind farm can be suppressed. In this paper, the maximum amplitude of the negative-sequence current provided by the PMSG-based wind farm under different average active power output and different VUF conditions is deduced, and the impacts of its phase angle on the VUF mitigation control effect are further studied. The improved control strategy of injecting negative-sequence current from the PMSG-based wind farm by the modified negative-sequence voltage and current double closed-loop control system is then developed. Finally, the correctness of theoretical analysis and the effectiveness of the proposed control strategy are validated by the experimental results.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Distributed Generation Hosting Capacity Evaluation for Distribution
           Systems Considering the Robust Optimal Operation of OLTC and SVC
    • Pages: 1111 - 1123
      Abstract: With the rapidly increasing penetration of renewable distributed generation (DG), the maximum hosting capacity (MHC) of a distribution system has become a major concern. To effectively evaluate the ability of a distribution system to accommodate DGs, this paper proposes an MHC evaluation method while considering the robust optimal operation of on load tap changers (OLTCs) and static var compensators (SVCs) in the uncertain context of DG power outputs and load consumptions. The proposed method determines the DG hosting capacities corresponding to different conservative levels. Furthermore, this paper discusses how to find out the most critical technical constraint that may limit the MHC by adjusting parameters of the proposed robust formulation. The effectiveness of the proposed method is demonstrated using a modified IEEE 33-bus distribution system.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Resonant Versus Conventional Controllers in Grid-Connected Photovoltaic
           Power Plants Under Unbalanced Grid Voltages
    • Pages: 1124 - 1132
      Abstract: This paper discusses the control of large-scale grid-connected photovoltaic power plant (GCPPP) operating under unbalanced grid voltages. The positive and negative sequences of the grid currents need to be controlled to regulate the power injected into the grid during unbalanced grid voltages. This paper shows that the use of conventional proportional-integral-based controllers compromises stability and dynamic performance of the inverter. The reason is the delays introduced by the filters needed to extract the sequences of the transformed grid currents. Because of such delays, there is a strong restriction on choosing the parameters for the current and voltage controllers, which forces the GCPPP to perform slowly. This can be improved by using resonant controllers instead, which avoid the need for filtering the transformed grid currents. Additionally, a new overcurrent protection is proposed for the GCPPP when it is providing grid voltage support during voltage sags. Simulation and experimental results are presented to evaluate and compare the performance of the GCPPP when operating with the different controllers.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Probabilistic Transient Stability Constrained Optimal Power Flow for Power
           Systems With Multiple Correlated Uncertain Wind Generations
    • Pages: 1133 - 1144
      Abstract: This paper proposes a novel probabilistic transient stability constrained optimal power flow (P-TSCOPF) model to simultaneously consider uncertainties and transient stability for power system preventive control. While detailed wind generator model with rotor flux magnitude and angle control strategy is used to describe the dynamic behaviors of wind generators, uncertain factors with correlations, such as probabilistic load injections, stochastic fault clearing time, and multiple correlated wind generations, are also included to form a representative P-TSCOPF model. A new GSO-PE approach, consisting of an improved group search optimization (GSO) and 2m + 1 point estimated (PE) method with Cholesky decomposition, is then designed to effectively solve this challenging P-TSCOPF problem. The proposed P-TSCOPF model and GSO-PE solution approach have been thoroughly tested on a modified New England 39-bus system with correlated uncertain wind generations. Comparative results with Monte Carlo (MC) simulations have confirmed the validity of the P-TSCOPF model and demonstrated the effectiveness of GSO-PE method.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • A Unified Approach to the Power Flow Analysis of AC/DC Hybrid Microgrids
    • Pages: 1145 - 1158
      Abstract: A promising configuration for future smart grids is an AC/DC hybrid topology that enables the integration of AC/DC energy resources and modern loads, thus permitting the consequent formation of AC/DC hybrid microgrids (HMGs). An understanding of AC/DC HMGs and their operational premise during islanding will certainly pave the way toward the realization of a future smart grid that includes a plug-and-play feature. However, the planning and operation of such isolated and hybrid systems are reliant on a powerful and efficient power flow tool. To this end, this paper proposes a novel unified, generic, and flexible power flow algorithm for isolated AC/DC HMGs. The power flow subproblems related to AC and DC subgrids are described mathematically by a set of linear and nonlinear equations and are solved simultaneously using a Newton trust-region method. The proposed algorithm is generic in the sense that it includes consideration of the unique characteristics of islanded AC/DC HMGs: a variety of possible topologies, droop controllability of the distributed resources (DRs), and bidirectionality of the power flow in the interlinking converters (ICs). The new power flow formulation is flexible and permits the easy incorporation of any changes in DR operating modes and IC control strategies. The developed algorithm was tested and applied for analyzing selected operational and control aspects of isolated AC/DC HMGs, including inaccurate power sharing and interlinking converters characterized by differing control strategies. The proposed load flow program can form the basis of and provide direction for further studies of isolated AC/DC HMGs.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • 2-D Wind Speed Statistical Model for Reliability Assessment of Microgrid
    • Pages: 1159 - 1169
      Abstract: Appropriate wind speed modeling for generating synthetic wind speed data is crucial in microgrid reliability evaluation studies. This paper proposes a 2-D wind speed statistical model based on historical wind speed data. The first dimension of the proposed wind model focuses on the probability distribution on the time duration of different wind speed scales, while the second dimension focuses on the probability distribution of wind speed in each wind speed scale. Unlike traditional wind speed models, the proposed model can simultaneously deal with the probabilistic characteristics of wind speed and wind time duration. This paper also presents a 2-D wind model-based data sampling method, and incorporates it into the microgrid reliability assessment algorithm. Using historical wind speed data in Tianjin, China, it shows that the proposed 2-D wind speed statistical model helps to fully simulate the volatility of wind energy. Furthermore, the proposed wind speed model is applied on the microgrid reliability evaluation study, which shows that the proposed model can be effectively utilized by planners to conduct reliability evaluation for microgrid.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Parzen Window Density Estimator-Based Probabilistic Power Flow With
           Correlated Uncertainties
    • Pages: 1170 - 1181
      Abstract: This paper presents a numerical-based algorithm to solve the probabilistic power flow problem. Parzen window density estimator is used to efficiently estimate probabilistic characteristics of power flow outputs. Correlations between wind generation, load, and plug-in hybrid electric vehicle charging stations are taken into account. The proposed algorithm works properly for random variables with various probability distribution functions and is very useful when limited information is available for each random variable. The algorithm is tested on the IEEE 14-bus and IEEE 118-bus systems considering correlated and uncorrelated conditions. Comparison between the proposed algorithm with 2n, 2n + 1 point estimation methods as well as Monte Carlo simulation and linear diffusion method are provided. In addition, probability density and cumulative distribution functions are determined using the proposed algorithm, diffusion method, and the combined Cumulants and Gram-Charlier for 2n + 1 point estimation method. Error indices are introduced to evaluate all random variables in a single benchmark. Simulation results show the effectiveness of the proposed algorithm to provide complete statistical information for probabilistic power flow outputs.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Probabilistic Analysis of Small Signal Stability for Power Systems With
           High Penetration of Wind Generation
    • Pages: 1182 - 1193
      Abstract: Wind generation is growing fast worldwide. The stochastic variation of large-scale wind generation may impact the power systems in almost every aspect. Probabilistic analysis method is an effective tool to study power systems with random factors. In this paper, a systematic nonlinear analytical probabilistic method is proposed to evaluate the possible effect of random wind power generation on power system small signal stability. A second-order polynomial is proposed to approximate the nonlinear relationship between the wind generation and the damping of a particular dynamic mode, such as the dominant mode. Gaussian mixture model formulates wind uncertainty in a uniform way. Spectral theorem is adopted to reshape the second-order polynomial into a form without cross-product terms. Cholesky decomposition is used to eliminate correlations among outputs of different wind farms. Thereafter the cumulative distribution function (CDF) of the damping ratio with respect to random wind power is consequently constructed. Numerical simulations are carried out in the IEEE standard test system. The proposed method is verified with higher accuracy than the traditional linearized method. Meanwhile, it is much more time-saving in calculation than Monte Carlo simulation.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • An Enhanced Droop Control Method for Accurate Load Sharing and Voltage
           Improvement of Isolated and Interconnected DC Microgrids
    • Pages: 1194 - 1204
      Abstract: In this paper, a distributed local control scheme for dc microgrid is proposed along with the basic droop control. It eliminates the limitations of droop control when the distributed generators are geographically distributed, for which, the line resistances cannot be neglected. Effects of line inductance and constant power loading (CPL) are investigated by analyzing the voltage tracking transfer function for single source system. Stability of two sources single load microgrid with proposed controller is investigated. Simulated responses are presented for two sources single load microgrid (for the sake of simplicity) to depict the proper load sharing and voltage improvement capability of the proposed control method with the consideration of line resistances. However, this can be extended to multiple-source multiple-load configuration connected to the dc bus. A comparison of the result is presented to show the better performance of the proposed control scheme as compared to the conventional droop control and hierarchical secondary control. The interconnected operation of the microgrid is also investigated to show the applicability of the proposed control in the interconnected mode. A centralized controller in each area is used to make the tie-line power flow zero at steady state.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Efficient Single Phase Transformerless Inverter for Grid-Tied PVG System
           With Reactive Power Control
    • Pages: 1205 - 1215
      Abstract: There has been an increasing interest in transformerless inverter for grid-tied photovoltaic (PV) system due to low cost, high efficiency, light weight, etc. Therefore, many transformerless topologies have been proposed and verified with real power injection only. Recently, almost every international regulation has imposed that a definite amount of reactive power should be handled by the grid-tied PV inverter. According to the standard VDE-AR-N 4105, grid-tied PV inverter of power rating below 3.68KVA, should attain power factor (PF) from 0.95 leading to 0.95 lagging. In this paper, a new high efficiency transformerless topology is proposed for grid-tied PV system with reactive power control. The new topology structure and detail operation principle with reactive power flow is described. The high frequency common-mode (CM) model and the control of the proposed topology are analyzed. The inherent circuit structure of the proposed topology does not lead itself to the reverse recovery issues even when inject reactive power which allow utilizing MOSFET switches to boost the overall efficiency. The CM voltage is kept constant at mid-point of dc input voltage, results low leakage current. Finally, to validate the proposed topology, a 1 kW laboratory prototype is built and tested. The experimental results show that the proposed topology can inject reactive power into the utility grid without any additional current distortion and leakage current. The maximum efficiency and European efficiency of the proposed topology are measured and found to be 98.54% and 98.29%, respectively.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Simplified Estimation of the Flicker Level Induced by Wave Energy Farms
    • Pages: 1216 - 1223
      Abstract: Wave energy farms may cause voltage flicker on the local grid to which they will be connected due to the strong fluctuations that their output power may present. IEC standard 61400-21 describes methods for estimating the flicker level for different short-circuit ratios as well as for different numbers of devices composing the farm. This method was initially developed for wind farms but is applicable to wave energy farms as well. However, besides the short-circuit ratio and the number of devices composing the farm, the grid impedance angle has also a strong influence on flicker. Despite this, no method exists in the literature for estimating flicker as a function of this variable. This paper presents the results of a study intended to fill this gap by focusing on developing a simplified method for estimating the flicker level induced by a wave energy farm as a function of the grid impedance angle. The results obtained through this method are compared with those obtained from numerical load flow simulations performed with PowerFactory. These simulations were based on experimental power output time series of a wave energy prototype deployed at sea as part of the European CORES project. The voltage profiles thus generated were then processed by means of a flickermeter compliant with IEC standard 61000-4-15.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • A Constrained Monotonic Charging/Discharging Strategy for Optimal Capacity
           of Battery Energy Storage Supporting Wind Farms
    • Pages: 1224 - 1231
      Abstract: A novel monotonic strategy following a consistent charging/discharging direction for each individual battery connected in parallel to form a large-scale battery energy storage system (BESS) is proposed in this paper. The BESS is coordinated with a large wind farm to smooth out the intermittent nature of the farm's output fed to an electricity grid. The strategy is used to optimize the capacity of each battery reducing the system's capital cost. The strategy also prolongs the battery's lifetime and consequently minimizes the system's operating cost. It is shown that the optimal capacity of the battery decreases as their number increases. Moreover, the optimal capacity of the BESS tends to some positive limit as the number of batteries approaches infinity. A rigorous proof of the mathematical theory underlying the proposed strategy and associated optimization are given in the paper. The effectiveness of the strategy is confirmed with data analysis taken from an actual wind farm. The strategy is generic enough to be applicable to other intermittent generation sources such as solar PV farms.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Multiagent-Based Reactive Power Sharing and Control Model for Islanded
           Microgrids
    • Pages: 1232 - 1244
      Abstract: In islanded microgrids (MGs), the reactive power cannot be shared proportionally among distributed generators (DGs) with conventional droop control, due to the mismatch in feeder impedances. For the purpose of proportional reactive power sharing, a multiagent system (MAS)-based distributed control model for droop-controlled MGs is proposed. The proposed control model consists of two layers, where the bottom layer is the electrical distribution MG, while the top layer is a communication network composed of agents. Moreover, agents on the communication network exchange the information acquired from DGs with neighbors, and calculate set points for DGs they connect to, according to the control laws. Furthermore, a theorem is demonstrated, which yields a systematic method to derive the control laws from a given communication network. Finally, three cases are carried out to test the performance of the control model, in which the uncertainty of intermittent DGs, variations in load demands, as well as impacts of time delays are considered. The simulation results demonstrate the effectiveness of the control model in proportional reactive power sharing, and the plug and play capability of the control model is also verified.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Optimal Offering Strategy for Concentrating Solar Power Plants in Joint
           Energy, Reserve and Regulation Markets
    • Pages: 1245 - 1254
      Abstract: In addition to energy, a concentrating solar power (CSP) plant with thermal energy storage (TES) could also provide ancillary service (AS) in the reserve and regulation markets. On one hand, providing AS contributes to the flexibility of the power systems and increases the revenue of CSP plants. On the other hand, the flexibility of CSP plants to accommodate solar energy, which is of great uncertainty, might be significantly weakened by an inappropriate offering strategy, e.g., offering excessive AS. Insufficient flexibility might cause massive solar energy curtailment and reduce the potential revenue. This paper develops a general model framework on the optimal offering strategy for CSP plants in joint day-ahead energy, reserve and regulation markets, which is robust for solar energy uncertainty and stochastic for market price uncertainty. On this basis, given the optimal day-ahead offering strategy, the offering curves to provide incremental AS capacities in the supplemental AS markets are further derived considering the opportunity cost. A new index, the maximum acceptable curtailment rate, is introduced to formulate the tradeoff of CSP plants between supplying AS to the system and reserving the flexibility for solar energy accommodation. The case study results demonstrate the validity of the proposed model.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Solar Power Prediction Based on Satellite Images and Support Vector
           Machine
    • Pages: 1255 - 1263
      Abstract: Penetration of solar energy into main grid has gradually increased in recent years due to a growing number of large-scale photovoltaic (PV) farms. The power output of these PV farms may fluctuate due to a wide variability of meteorological conditions, and, thus, we need to compensate for this effect in advance. In this paper, we propose a solar power prediction model based on various satellite images and a support vector machine (SVM) learning scheme. The motion vectors of clouds are forecasted by utilizing satellite images of atmospheric motion vectors (AMVs). We analyze 4 years’ historical satellite images and utilize them to configure a large number of input and output data sets for the SVM learning. We compare the performance of the proposed SVM-based model, the conventional time-series model, and an artificial neural network (ANN) model in terms of prediction accuracy.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Optimal Control of Energy Storage in a Microgrid by Minimizing Conditional
           Value-at-Risk
    • Pages: 1264 - 1273
      Abstract: This paper presents two methods for online rolling horizon optimal control of an energy storage unit in a grid-connected microgrid, subject to uncertainty in demand and electricity pricing. The proposed methods are based on the concept of rolling horizon control, where battery charge/discharge activities are determined by repeatedly solving a linear optimization problem over a moving control window. The predicted values of the microgrid net electricity demand and electricity prices over the control horizon are assumed to be uncertain. The first formulation of the control is based on the scenario-based stochastic conditional value at risk (CVaR) optimization, where the cost function includes electricity usage cost, battery operation costs, and grid signal smoothing objectives. Multivariate Gaussian distribution is used to model the variations of electricity prices and net demand power around their predicted nominal values. The second formulation of the control reduces the computations by taking a worst-case CVaR stochastic optimization approach. In this case, the uncertainty in demand is still stochastic but the problem constraints are made robust with respect to price variations in a range. Simulation results under different scenarios are presented to demonstrate the effectiveness of the proposed methods.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Resolving Power Quality Issues Raised by Aerodynamic Aspects of Wind
           Turbine in Isolated Microgrids Using Fuel Cell/Electrolyzer System
    • Pages: 1274 - 1283
      Abstract: This paper shows how the power quality issues can be resolved in wind-diesel microgrids by means of a fuel cell/electrolyzer (FC/ELZ) system. In this regard, an autonomous hybrid power system, including a diesel generator and a fixed-speed wind turbine (FSWT) equipped with a FC/ELZ system, has been investigated. The main aim of employing the FC/ELZ system is to reduce fuel consumption and mitigate the aerodynamic effects of wind turbine (i.e., tower shadow, wind shears, yaw error, and turbulence) on power quality in the microgrid. To conduct a comprehensive study, the detailed models of the devices are used. The aerodynamic and mechanical aspects of WT are simulated using AeroDyn and FAST, and the thermodynamic and electrochemical aspects of FC/ELZ are simulated using models validated by experimental data. Furthermore, control of power electronic interfaces for the FC/ELZ system, including a bidirectional dc/ac voltage source converter (VSC), a dc/dc converter to boost the FC output voltage, and a dc/dc converter to reduce input voltage to the ELZ, is presented. The studied system was implemented in a MATLAB/Simulink software environment. The simulation results demonstrate the efficacy of the FC/ELZ system in reducing the flicker level and suppressing the voltage fluctuations induced by yaw error and turbulence.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Optimal Single Wind Hydro-Pump Storage Bidding in Day-Ahead Markets
           Including Bilateral Contracts
    • Pages: 1284 - 1294
      Abstract: The present evolution of fuel prices together with the reduction of premiums for renewable energies make it of vital importance to improve renewable production management. This paper proposes a model of a single renewable power producer to compete more efficiently against other generators. The single unit is composed of a wind power producer and a hydro-pump storage power producer. The synergies between both renewable producers make relevant the possibility of mitigating wind power uncertainty, and due to this, the imbalances of the wind power producer will be reduced. The reduction of wind imbalances can come from deviating part of the excess of wind generation through a physical connection toward the pumping system or by increasing hydro generation to mitigate the lack of wind generation. To evaluate the problem, stochastic mixed integer linear programming is proposed to address the problem of selling the energy from the single renewable unit through a bilateral contract and in the day-ahead market, as a new contribution to earlier studies. Furthermore, a balancing market is considered to penalize the imbalances. The decision is made to maximize the profit, considering risk-hedging through the Conditional Value at Risk. The model is tested and analyzed for a case study and relevant conclusions are presented.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Compressive Spatio-Temporal Forecasting of Meteorological Quantities and
           Photovoltaic Power
    • Pages: 1295 - 1305
      Abstract: This paper presents a solar power forecasting scheme, which uses spatial and temporal time series data along with a photovoltaic (PV) power conversion model. The PV conversion model uses the forecast of three different variables, namely, irradiance on the tilted plane, ambient temperature, and wind speed, in order to estimate the power produced by a PV plant at the grid connection terminals. The forecast values are obtained using a spatio-temporal method that uses the data recorded from a target meteorological station as well as data of its surrounding stations. The proposed forecasting method exploits the sparsity of correlations between time series data in a collection of stations. The performance of both the PV conversion model and the spatio-temporal algorithm is evaluated using high-resolution real data recorded in various locations in Italy. Comparison with other benchmark methods illustrates that the proposed method significantly improves the solar power forecasts, particularly over short-term horizons.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Autonomous Voltage Security Regions to Prevent Cascading Trip Faults in
           Wind Turbine Generators
    • Pages: 1306 - 1316
      Abstract: Cascading trip faults in large-scale wind power centralized integration areas bring new challenges to the secure operation of power systems. In order to deal with the complexity of voltage security regions and the computation difficulty, this paper proposes an autonomous voltage security region (AVSR) for each wind farm and the point of common coupling (PCC) substation, whose voltage can be controlled in a decoupled way. The computation of the AVSR can be completed using a stepwise search method exchanging voltage and power information between the control center and the wind farms. At each wind farm, an AVSR is determined to guarantee the normal operation of each wind turbine generator (WTG), while in the control center, each region is designed in order to guarantee secure operation both under normal conditions and after an N-1 contingency. A real system in Northern China was used to carry out case studies to verify the effectiveness of the AVSRs proposed, and good performance was demonstrated using the Monte Carlo method.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Optimal Power Scheduling for a Cooperative Network of Smart Residential
           Buildings
    • Pages: 1317 - 1326
      Abstract: This paper attempts to contribute to the development of a new concept focused on a cooperative control scheme for a smart network of residential buildings (SNRB) and to demonstrate advantages of interconnections and coordination among a set of smart residential buildings (SRBs), by taking advantages of fluctuations of stochastic renewable sources and loads, and exploiting the operational flexibilities of thermal loads defined as the required hot water and desired buildings temperature. A comprehensive finite-horizon scheduling optimization problem is formulated to optimally control a SNRB using model predictive control (MPC) method, which integrates both forecasts and newly updated information. The cooperation is reached through a bidirectional communication infrastructure in the SNRB, where the master controller (MC) is available at the network level and in charge of coordinating and managing power in the SNRB. A MPC-based algorithm is used for the future scheduling of power exchanges, charge/discharge state of each energy storage device (ESD), the state of each micro-CHP and the charging state of each plug-in electric vehicle (PEV) available in the network. The MPC strategy is tested through case studies where the influences of both network topology and thermal loads on the operation of each SRB are analyzed via numerical results.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Implementation of Sliding Mode Control System for Generator and Grid Sides
           Control of Wind Energy Conversion System
    • Pages: 1327 - 1335
      Abstract: This paper presents a second order sliding mode control strategy to control the generator and the grid sides of a variable speed experimental wind energy conversion system. At the generator side, the rotational speed is controlled to track a profile generated from the power curve of the wind turbine for maximum power extraction. At the grid side, the dc-link voltage is regulated for a proper transfer of power. The control strategy is based on a disturbed single input-single output error model and a second order sliding mode control algorithm. The proposed second order sliding mode control strategy offers interesting characteristics such as robustness to parametric uncertainties in the turbine and the generator as well as external disturbances. The proposed strategy, for speed and dc-link voltage control in wind energy conversion system, is validated on an emulated wind turbine driven by the OPAL-RT real-time simulator (OP5600). Experimental results show that the proposed control strategy is effective in terms of speed and dc-link voltage control. The sliding mode control approach is robust against unknown disturbances, parametric variations, and uncertainties in the system. Furthermore, it produces no chattering in the generated torque, which reduces the mechanical stress on the wind turbine.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Impacts of Stochastic Wind Power and Storage Participation on Economic
           Dispatch in Distribution Systems
    • Pages: 1336 - 1345
      Abstract: Evaluating the impact related to stochastic wind generation and generic storage on economic dispatch in distribution system operation is an important issue in power systems. This paper presents the analysis of the impacts of high wind power and storage participation on a distribution system over a period of 24 h using grid reconfiguration for electrical distribution system (EDS) radial operation. In order to meet this objective, a stochastic mixed integer linear programming (SMILP) is proposed, where the balance between load and generation has to be satisfied minimizing the expected cost during the operation period. The model also considers distributed generation (DG) represented by wind scenarios and conventional generation, bus loads represented through a typical demand profile, and generic storage. A case study provides results for a weakly meshed distribution network with 70 buses, describing in a comprehensive manner the effects of stochastic wind scenarios and storage location on distribution network parameters, voltage, substation behavior as well as power losses, and the expected cost of the system.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • Introducing the IEEE PES Resource Center
    • Pages: 1346 - 1346
      Abstract: Advertisement, IEEE.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • IEEE Power & Energy Society
    • Pages: 1347 - 1347
      Abstract: Advertisement, IEEE.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
  • IEEE Power of Information
    • Pages: 1348 - 1348
      Abstract: Advertisement, IEEE.
      PubDate: July 2016
      Issue No: Vol. 7, No. 3 (2016)
       
 
 
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