•Proposing a multiple-radius OPF model for the power systems under the penetration of off-shore WFs.•Introducing a weighted IGDT technique which considers the geographical location of ...WFs.•Considering VSC-HVDC to connect off-shore WFs to the grid.
Increasing the penetration of renewable energies creates various operational and even security challenges for power systems, due to the variability of their output power and inability to provide system inertia. These issues are even more inevitable in power systems which are connected to off-shore wind farms (WFs) in different locations, creating more complexity in decision making process. This paper, proposes a decision making model to increase the robustness of optimal power flow in presence of off-shore WFs. Information gap decision theory (IGDT) is used as a decision making tool for dealing with the uncertainty radius of multiple WFs, by definition of weighting factors for the uncertainty of each WF. Voltage source converter (VSC)-based high voltage DC (HVDC) transmission links are considered to connect the off-shore WFs to the main AC grid. The proposed optimization model, which includes both AC transmission and HVDC systems constraints, is implemented on the IEEE 118-bus standard test system and solved by general algebraic modeling system (GAMS) optimization software. The simulation results show the economic effect of location factor in definition of uncertainty for WFs.
Dynamic economic dispatch (DED) aims to schedule the committed generating units' output active power economically over a certain period of time, satisfying operating constraints and load demand in ...each interval. Valve-point effect, the ramp rate limits, prohibited operation zones (POZs), and transmission losses make the DED a complicated, non-linear constrained problem. Hence, in this paper, imperialist competitive algorithm (ICA) is proposed to solve such complicated problem. The feasibility of the proposed method is validated on five and ten units test system for a 24 h time interval. The results obtained by the ICA are compared with other techniques of the literature. These results substantiate the applicability of the proposed method for solving the constrained DED with non-smooth cost functions. Besides, to examine the applicability of the proposed ICA on large power systems, a test case with 54 units is studied. The results confirm the suitability of the ICA for large-scale DED problem.
► Dynamic economic dispatch of committed generating units'. ► Economic Energy supply for customers. ► Reducing energy losses. ► Proposing Artificial intelligence and heuristic search optimization method. ► Imperialist competition algorithm (ICA) for solving a nonlinear non-smooth problem.
•A local fuzzy based damping controller is proposed for TCSC.•The aim is to improve transient stability of power systems.•The detailed model of TCSC is adopted.•The parameters of controller are tuned ...through chaotic optimization algorithm.
This paper proposes a local fuzzy based damping controller (LFDC) for thyristor controlled series capacitor (TCSC) to improve transient stability of power systems. In order to implement the proposed scheme, detailed model of TCSC, based on actual behavior of thyristor valves, is adopted. The LFDC uses the frequency at the TCSC bus as a local feedback signal, to control the firing angle. The parameters of fuzzy controller are tuned using an off-line method through chaotic optimization algorithm (COA). To verify the proposed LFDC, numerical simulations are carried out in Matlab/Simpower toolbox for the following case studies: two-area two-machine (TATM), WSCC three-machine nine-bus and Kundur’s two-area four-machine (TAFM) systems under various faults types. In this regard, to more evaluate the effectiveness of the proposed method, the simulation results are compared with the wide-area fuzzy based damping controller (WFDC). Moreover, the transient behavior of the detailed and phasor models of the TCSC is discussed in the TATM power system. The simulation results confirm that the proposed LFDC is an efficient tool for transient stability improvement since it utilizes only local signals, which are easily available.
► New approach to solve power systems dynamic economic dispatch. ► Considering Valve-point effect, prohibited operation zones. ► Proposing TVAC-IPSO algorithm.
The objective of the dynamic economic ...dispatch (DED) problem is to schedule power generation for the online units for a given time horizon economically, satisfying various operational constraints. Due to the effect of valve-point effects and prohibited operating zones (POZs) in the generating units cost functions, DED problem is a highly non-linear and non-convex optimization problem. The DED problem even may be more complicated if transmission losses and ramp-rate constraints are taken into account. This paper presents a novel and heuristic algorithm to solve DED problem of generating units, by employing time varying acceleration coefficients iteration particle swarm optimization (TVAC-IPSO) method. The effectiveness of the proposed method is examined and validated by carrying out extensive tests on different test systems, i.e. 5-unit and 10-unit test systems. Valve-point effects, POZs and ramp-rate constraints along with transmission losses are considered. To examine the efficiency of the proposed TVAC-IPSO algorithm, comprehensive studies are carried out, which compare convergence properties of the proposed TVAC-IPSO approach with conventional PSO algorithm, in addition to the other recently reported approaches. Numerical results show that the TVAC-IPSO method has good convergence properties and the generation costs resulted from the proposed method are lower than other algorithms reported in recent literature.
Seaports are responsible for consuming a large amount of energy and producing a sizeable amount of environmental emissions. However, optimal coordination and cooperation present an opportunity to ...transform this challenge into an opportunity by enabling flexibility in their generation and load units. This paper introduces a coordination framework for exploiting flexibility across multiple ports. The proposed method fosters cooperation between ports in achieving lower environmental emissions while leveraging flexibility to increase their revenue. This platform allows ports to participate in providing flexibility for the energy grid through the introduction of a green port-to-grid concept while optimising their cooperation. Furthermore, the proximity to offshore wind farms is considered an opportunity for the ports to investigate their role in harnessing green hydrogen. The proposed method explores the hydrogen storage capability of ports as an opportunity for increasing the techno-economic benefits, particularly through coupling them with offshore wind farms. Compared to existing literature, the proposed method enjoys a comprehensive logistics-electric model for the ports, a novel coordination framework for multi-port flexibility, and the potentials of hydrogen storage for the ports. These unique features position this paper a valuable reference for research and industry by demonstrating realistic cooperation among ports in the energy network. The simulation results confirm the effectiveness of the proposed port flexibility coordination from both environmental and economic perspectives.
•A comprehensive logistics-electric model for optimising port operation.•A multi-port coordination framework for investigating port cooperation.•Integrating multi-port flexibility into the whole energy system.•Highlighting the potentials of harnessing hydrogen.•Introducing the green port to grid concept.
► New approach to solve power systems economic dispatch. ► Considering valve-point effect, prohibited operation zones, multi-fuel options. ► The quick group search optimizer (QGSO) algorithm is ...modified for solving continuous optimization problems. ► Proposed CQGSO is applied on different benchmark functions and economic dispatch test systems.
In this paper a new optimization algorithm is applied for solution of non-convex and large scale economic dispatch (ED) problems. A continuous version of quick group search optimizer (QGSO) algorithm is proposed. A more realistic ED formulation with considering valve-points effect, prohibited operating zones, transmission losses and ramp-rate limits is utilized. The performance of the proposed method is verified by implementation on five test systems. Case studies and numerical examples show that the proposed continuous QGSO algorithm has better solution quality comparing with the most of the latest reported algorithms in the literature.
Integrated electricity and gas systems (IEGS) with power-to-gas (PtG) units, as novel sector coupling components between electricity and gas systems, have been considered a promising solution for the ...reliable and economic operation of the integrated energy systems which can effectively reduce the challenges associated with the high penetration of renewable energy sources (RES). To confirm the economic viability and technical feasibility of the IEGS, its coordinated planning will play a crucial role. The more comprehensive the modeling and evaluation of IEGS planning studies are, the more precise and practical the results obtained will be. In this paper, an in-depth and up-to-date assessment of the available literature on the IEGS planning is presented by addressing critical concerns and challenges, which need further studies. A vast variety of related topics in the IEGS planning, including the impact of costs, constraints, uncertainties, contingencies, reliability, sector coupling components, etc., are also reviewed and discussed. In addition, the role of PtGs and their impacts on the coordinated IEGS planning are reviewed in detail due to their crucial role in increasing the penetration of RES in future energy systems as well as limiting greenhouse gas emissions. The literature review completed by this paper can support planners and policymakers to better realize the bottlenecks in the IEGS development, so that they can concentrate on the remaining unsolved topics as well as the improvement of existing designs and procedures.
Gas Network's Impact on Power System Voltage Security Rabiee, Abbas; Kamwa, Innocent; Keane, Andrew ...
IEEE transactions on power systems,
2021-Nov., 2021-11-00, 20211101, Letnik:
36, Številka:
6
Journal Article
Recenzirano
Due to the energy linkage between electricity and gas networks, assessing the voltage security of the electricity system without considering the practical constraints of both systems, may lead to ...unrealistic values of loading margins (LM). This work proposes a model for investigating the impact of gas networks on the voltage security of electric transmission networks. The overall objective is to maximize the LM of the electricity network while satisfying all relevant constraints in both gas and electricity networks such as hourly line pack of gas pipelines, reactive power capability limits of generators, and complementarity constraints representing the generators active/reactive power limits based on the capability curves, power flow equations at both current operation, and security limit points. Three (small, medium, and large) case studies are presented as the applications of the proposed model for LM maximization in power systems that are highly coupled with gas networks. The obtained results corroborate the impact of both gas and electrical networks operation constraints such as voltage and reactive power limits, nodal gas pressure limits, gas network loading as well as the line pack phenomenon of gas pipelines on the LM of power systems.
Distribution transformers (DTs) are deemed fundamental and high-priced equipment for power grids, and their failure influences grid reliability. The continuity of DT operation highly depends on its ...insulation conditions and following that to the hotspot temperature (HST). In this article, a novel formula is proposed for HST prediction of DTs by considering the effective electrical and mechanical parameters on heat dissipation capacity. Additionally, complete and accurate 3D modeling based on computational fluid dynamics (CFD) is presented to validate the proposed novel formula for HST prediction. In this modeling, the conservator, which plays a key role in the HST value, is accurately modeled. Optical fiber sensors are utilized in the studied 500-kVA DT to verify the accuracy of the proposed HST prediction formula during the experimental temperature rise test. Experimental results show that the proposed formula is highly accurate and has an acceptable correlation with the empirical values. The root-mean-square error, mean error, and average error percentage (AEP) of the proposed formula are 0.3 °C, 0.3 °C, and 0.37%, respectively, in HST transient values, and 0.3 °C, 0.3 °C, and 0.29% in HST steady-state values, which substantiate the precision and proficiency of the proposed HST prediction formula rather than IEC and IEEE equations. Finally, a thermal camera is employed to verify the results of CFD-based 3D modeling in top-oil temperature, bottom-oil temperature, and conservator oil temperature during the experimental tests. According to the measurement results, temperatures of CFD-based 3D simulation and thermal camera in the aforementioned three points are in good agreement with each other and AEP is less than 1.4%, which indicates the accuracy and efficiency of the proposed 3-D modeling.
The objective of dynamic economic dispatch (DED) problem is to determine the generation schedule of the committed generation units, which minimizes the total operating cost over a dispatch period, ...while satisfying a set of constraints. The effect of valve points and prohibited operating zones (POZs) in the generating units' cost functions makes the DED a highly nonlinear and nonconvex optimization problem with multiple local minima. Considering the ramp-rate limits and transmission losses makes the DED problem even more complicated. Hence, proposing an effective solution method for this optimization problem is of great interest. This paper presents a novel heuristic algorithm to solve DED problem of generating units by employing a hybrid immune-genetic algorithm. To illustrate the effectiveness of the proposed approach, four test systems that consist of different numbers of generating units are studied. The valve-point effects, POZs, and ramp-rate constraints along with transmission losses are also considered in simulation cases. The results obtained through the proposed method are compared with those reported in the literature. These results substantiate the applicability of the proposed method for solving the constrained DED problem with nonsmooth cost functions.
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