Now showing 1 - 10 of 59
  • Publication
    Multi-objective planning model for integration of distributed generations in deregulated power systems
    (Shiraz University, 2010-01) ;
    This paper presents a long-term dynamic multi-objective model for distributed generation investment. The proposed model optimizes three objectives, namely active losses, costs and environmental emissions and determines the optimal schemes of sizing, sitting of DG units and specially the dynamics of investment over the planning period. The Pareto optimal solutions of the problem are found using a GA algorithm and finally a fuzzy satisfying method is applied to select the optimal solution considering the desires of the planner. The solutions of Pareto optimal front are analyzed to extract general useful information for planners about the appropriate DG technologies and placement schemes. The effectiveness of the proposed model is demonstrated by applying it on a test distribution system and the results are presented, discussed and compared to other methods.
  • Publication
    Possibilistic evaluation of distributed generations impacts on distribution networks
    (Institute of Electrical and Electronic Engineers (IEEE), 2011-03-17) ; ; ;
    In deregulated power systems, the distribution network operator (DNO) is not responsible for investment in distributed generation (DG) units, and they are just concerned about the best architecture ensuring a good service quality to their customers. The investment and operating decisions related to DG units are then taken by entities other than DNO which are exposed to uncertainty. The DNO should be able to evaluate the technical effects of these uncertain decisions. This paper proposes a fuzzy evaluation tool for analyzing the effect of investment and operation of DG units on active losses and the ability of distribution network in load supply at presence of uncertainties. The considered uncertainties are related to load values, installed capacity, and operating schedule of DG units. The proposed model is applied on a test system and also a real French urban network in order to demonstrate its functionality in evaluating the distribution expansion options.
      744Scopus© Citations 119
  • Publication
    Taxonomy of Uncertainty Modeling Techniques in Renewable Energy System Studies
    (Springer, 2014-01-28)
    With the introduction of new concepts in operation and planning of power systems, decision making is becoming more critical than ever before. These concepts include restructuring, smart grids, and the importance of environmental concerns. The art of decision making is defined as choosing the best action among available choices considering the constraints and input data of the problem. Decision making is usually a complex task which becomes more sophisticated when the input data of the problem are subject to uncertainty. This chapter presents a critical review of the state-of-the-art uncertainty in handling tools for renewable energy studies. Different uncertainty modeling tools are first introduced and then the appropriate ones for renewable energies are identified. Then, each method is implemented on a simple two-bus case study.
      176Scopus© Citations 18
  • Publication
    Use of Power Flow Controllers to Enhance Transmission Network Utilisation on the Irish Transmission Network
    The Ireland and Northern Ireland power system is in a period of rapid transition from conventional generation to renewable generation and has seen a rapid increase in large demand sites requiring connection into the backbone transmission system. The role of EirGrid and SONI as Transmission System Operator in Ireland and Northern Ireland is to operate, maintain and develop the electricity transmission network. EirGrid ensure that new transmission projects are developed in a way that balances technical, economic, community and other stakeholder considerations. This has resulted in much more detailed evaluation of planning options to maximize utilisation of the existing network which may include but are not limited to uprating the capacity of the existing transmission system mainly through the thermal or voltage uprate of existing circuits. Another method to increase network utilisation is to strategically deploy Power Flow Control devices to relieve system overloads and maximise network transfer capacities. EirGrid has developed a new grid development strategy which places particular emphasis on identifying technologies to help resolve network issues. This paper presents the study findings for application of power flow controller (PFC) to relieve system issues.
  • Publication
    Restoration in a Self-healing Distribution Network with DER and Flexible Loads
    This paper develops an algorithm for energy management of a distribution network considering a restorative plan for most possible devastating contingencies in the network. The distribution network is selfhealing and consists of smart meters and remotely controlled automated switches. Distributed energy resources and flexible loads provide the redundant capacity for restoration. Under normal operating conditions, the objective of the energy management system is to minimize the generation cost, while under emergency conditions, the objective is to minimize the amount of shed load, giving priority to critical loads. The energy management problem forms a non-linear programming problem. Simulation results verify the effectiveness of the proposed algorithm in energy management and restoration of a distribution network.
      367Scopus© Citations 7
  • Publication
    Use of fitted polynomials for the decentralised estimation of network variables in unbalanced radial LV feeders
    (Institution of Engineering and Technology (IET), 2020-06-19) ; ;
    The lack of comprehensive monitoring equipment in low voltage (LV) residential feeders, impedes a near-term deployment of centralised schemes for the integration of domestic-scale distributed generation (DG). In this context, this study introduces a technique that generates a set of fitted polynomials, derived from offline simulations and regression analysis, that characterise the magnitude of representative network variables (i.e. key for network operation) as a direct analytical expression of the controllable local conditions of any DG unit (i.e. active and reactive power injections). Crucially, the coefficients of these polynomials can be estimated, autonomously at the location of each DG unit, without the need for remote monitoring (i.e. using only locally available measurements). During online implementation, the method only consists of direct calculations (i.e. non-iterative), facilitating real-time operation. The accuracy of the polynomials to estimate the magnitude of the network variables is assessed under multiple scenarios on a representative radial LV feeder. Furthermore, the robustness of the method is demonstrated under the presence of new generation and electric vehicles.
      88Scopus© Citations 1
  • Publication
  • Publication
    Resiliency Assessment of Electric Power Distribution Systems
    (Nova Science Publishers, Inc., 2017-05-15) ; ; ;
    This chapter discusses the resiliency aspect of electric power distribution systems considering the role of distributed generation. A restoration tool is developed that can emulate the recovery path of the distribution system after a contingency situation, then engineering resiliency assessment framework is applied to (semi)-quantitatively measure the dimensions of resiliency. The proposed procedure is implemented on a test system to demonstrate the key factors affecting the resiliency of a distribution system, including distributed generation.
  • Publication
    Decision making under uncertainty in energy systems: State of the art
    (Elsevier, 2013-12) ;
    The energy system studies include a wide range of issues from short term (e.g. real-time, hourly, daily and weekly operating decisions) to long term horizons (e.g. planning or policy making). The decision making chain is fed by input parameters which are usually subject to uncertainties. The art of dealing with uncertainties has been developed in various directions and has recently become a focal point of interest. In this paper, a new standard classification of uncertainty modeling techniques for decision making process is proposed. These methods are introduced and compared along with demonstrating their strengths and weaknesses. The promising lines of future researches are explored in the shadow of a comprehensive overview of the past and present applications. The possibility of using the novel concept of Z-numbers is introduced for the first time.
      2096Scopus© Citations 351
  • Publication
    Possibilistic-scenario Model for DG Impact Assessment on Distribution Networks in an Uncertain Environment
    (Institute of Electrical and Electronics Engineers, 2012-08)
    The distribution network operators (DNOs) are responsible for securing a diverse and viable energy supply for their customers so the technical and economical impacts of distributed generation (DG) units are of great concerns. Traditionally, the DNOs try to maximize the technical performance of the distribution network, but it is evident that the first step in optimizing a quantity is being able to calculate it. The DG investment/operation which is performed by distributed generation operators/owners (DGOs) (under unbundling rules) has made this task more complicated. This is mainly because the DNO is faced with the uncertainties related to the decisions of DG investors/operators where some of them can be probabilistically modeled while the others are possibilistically treated. This paper proposes a hybrid possibilistic-probabilistic DG impact assessment tool which takes into account the uncertainties associated with investment and operation of renewable and conventional DG units on distribution networks. This tool would be useful for DNOs to deal with the uncertainties which some of them can be modeled probabilistically and some of them are described possibilistically. The proposed method has been tested on a test system and a large-scale real distribution network to demonstrate its strength and flexibility.
      623Scopus© Citations 132