Conventional Power Network Research Articles

Fuzzy assisted optimal tilt control approach for LFC of renewable dominated micro-grid: A step towards grid decarbonization

Grid decarbonization is very crucial for the energy transition. The massive penetration of renewables in conventional power networks is the essential step for decarbonization but at the cost of complex control architecture. Due to the stochastic behaviour of renewables, load frequency control (LFC) is a very tedious task. This paper addresses the LFC issue in a standalone micro-grid (S-μG) via wild horse optimizer (WHO) assisted intelligent fuzzy tilt integral derivative with filter – one plus integral (FTIDF-(1 + I)) controller. The proposed S-μG consists of a solar photovoltaic (PV), wind turbine (WT) generator (WTG), and diesel engine generator (DEG) as power generating units and a flywheel as the energy storage unit (ESU). A nonlinear WTG model is used to extract the power from varying wind speeds, and a variable step size incremental conductance (V-InC) maximum power point (MPP) tracking (MPPT) technique is considered to harvest the optimal power from PV. To replicate the practical scenarios, nonlinearities of the governor, turbine, and flywheel are also considered in this work. The proposed intelligent WHO-FTIDF-(1 + I) controller can handle huge uncertainties and nonlinearities of the considered μG. FTIDF-(1 + I) controller prominence has been established over TIDF and FTIDF controllers. The effectiveness of WHO has been demonstrated over particle swarm optimization (PSO) and grey wolf optimization (GWO). From the obtained results, it is perceived that the reduction in maximum frequency deviation Δf with the proposed controller as compared to WHO-TIDF, WHO-FTIDF, PSO-FTIDF-(1 + I), and GWO-FTIDF-(1 + I) are 99.75%, 97.71%, 94.87% and 33.34% respectively. Finally, detailed robustness analysis, stability evaluation and real-power system validation via the IEEE 39 bus system of the proposed controller are also performed.

Continuous estimation of power system inertia using convolutional neural networks

Inertia is a measure of a power system’s capability to counteract frequency disturbances: in conventional power networks, inertia is approximately constant over time, which contributes to network stability. However, as the share of renewable energy sources increases, the inertia associated to synchronous generators declines, which may pose a threat to the overall stability. Reliably estimating the inertia of power systems dominated by inverted-connected sources has therefore become of paramount importance. We develop a framework for the continuous estimation of the inertia in an electric power system, exploiting state-of-the-art artificial intelligence techniques. We perform an in-depth investigation based on power spectra analysis and input-output correlations to explain how the artificial neural network operates in this specific realm, thus shedding light on the input features necessary for proper neural-network training. We validate our approach on a heterogeneous power network comprising synchronous generators, static compensators and converter-interfaced generation: our results highlight how different devices are characterized by distinct spectral footprints - a feature that must be taken into account by transmission system operators when performing online network stability analyses.

A Super-Efficient GSM Triplexer for 5G-Enabled IoT in Sustainable Smart Grid Edge Computing and the Metaverse.

Global concerns regarding environmental preservation and energy sustainability have emerged due to the various impacts of constantly increasing energy demands and climate changes. With advancements in smart grid, edge computing, and Metaverse-based technologies, it has become apparent that conventional private power networks are insufficient to meet the demanding requirements of industrial applications. The unique capabilities of 5G, such as numerous connections, high reliability, low latency, and large bandwidth, make it an excellent choice for smart grid services. The 5G network industry will heavily rely on the Internet of Things (IoT) to progress, which will act as a catalyst for the development of the future smart grid. This comprehensive platform will not only include communication infrastructure for smart grid edge computing, but also Metaverse platforms. Therefore, optimizing the IoT is crucial to achieve a sustainable edge computing network. This paper presents the design, fabrication, and evaluation of a super-efficient GSM triplexer for 5G-enabled IoT in sustainable smart grid edge computing and the Metaverse. This component is intended to operate at 0.815/1.58/2.65 GHz for 5G applications. The physical layout of our triplexer is new, and it is presented for the first time in this work. The overall size of our triplexer is only 0.007 λg2, which is the smallest compared to the previous works. The proposed triplexer has very low insertion losses of 0.12 dB, 0.09 dB, and 0.42 dB at the first, second, and third channels, respectively. We achieved the minimum insertion losses compared to previous triplexers. Additionally, the common port return losses (RLs) were better than 26 dB at all channels.

Establishing and Operating Experiential Benchmark Setups of dc Microgrids: A Guideline

Increased attention is given to microgrids for their numerous advantages over conventional power networks. However, there are still a limited number of real microgrid networks that are currently in service, and this raises shortages in expertise on microgrids testing and evaluation before actual deployment. Low-cost, rapid, realistic, and flexible testing are the key challenges that face the microgrids’ validation. This article focuses on the importance of experiential validations to reduce the risks and ensure the desired microgrids performances. It highlights the major challenges for establishing and operating realistic and accurate experimental microgrid testbeds. It also provides guidelines and recommendations for the validation of microgrid studies. An experimental dc microgrid setup showcase is demonstrated, and helpful tips and remarks are suggested. Different case studies on the developed dc microgrid’s setup are presented, and the authors’ experiences and analyses are shared. The experimental results show the accuracy of microgrid testbeds and their expansion capabilities as well as their effectiveness in testing various microgrid conditions.

A review ofSTATCOMcontrol for stability enhancement of power systems with wind/PVpenetration: Existing research and future scope

In recent years, the development of renewable energy sources (RESs) and their integration with the conventional power network have increased significantly. Due to the power grid transformation brought about by the large penetration of power electronics converter-based RESs such as wind and solar photovoltaic (PV), the operation and control of the interconnected power system has become a challenging task with respect to sustaining its stability and reliability. Power systems are confronted by several new stability issues because the dynamic behavior of converter-interfaced renewable sources differs from conventional generation. In this respect, static synchronous compensator (STATCOM), a shunt connected flexible AC transmission system (FACTS), is recognized as a fundamental solution for maintaining power system stability. This paper presents a thorough and state-of-the-art review of STATCOM control in wind- and/or PV-interfaced power systems for enhancing system performance by addressing key stability issues related to rotor angle stability, voltage stability, and resonance stability. A comprehensive analysis of various control techniques of STATCOM based on conventional, adaptive, nonlinear, predictive, robust, and coordinated control and soft computing techniques is provided. Furthermore, the function of the grid-side converter of the wind/PV plant as a STATCOM is also evaluated. Finally, the shortcomings of existing research are highlighted, current control challenges are presented, and several topics for future research are suggested. This paper provides researchers the opportunity to consider the current state of research and develop new control schemes for STATCOM to further improve the stability of modern power grids.

Optimal frequency response of VPP-based power systems considering participation coefficient

The remarkable presence of renewable resources and the consequent development of virtual power plants (VPPs) in interconnected networks can reduce inertia and spinning reserve in power systems. This issue has created a challenge for power system engineers and analysts to maintain frequency stability in VPPs. Based on the system frequency response (SFR) model and the principal equations of VPPs, this paper presents a new model for the frequency response of a VPP-based interconnected power system. By presenting a method, the optimal reserve amount of generation units of VPP is determined in order to obtain the best frequency response in the frequency recovery for deal with system disturbances. Finally, to analyze the frequency response of the system, various scenarios of the presence or absences of each new resource and its combination with the conventional power networks are simulated. The simulation results indicated the need for the participation of energy storage systems (ESS) and renewable generation resources to safeguard the network frequency stability.

Fault Management in DC Microgrids: A Review of Challenges, Countermeasures, and Future Research Trends

The significant benefits of DC microgrids have instigated extensive efforts to be an alternative network as compared to conventional AC power networks. Although their deployment is ever-growing, multiple challenges still occurred for the protection of DC microgrids to efficiently design, control, and operate the system for the islanded mode and grid-tied mode. Therefore, there are extensive research activities underway to tackle these issues. The challenge arises from the sudden exponential increase in DC fault current, which must be extinguished in the absence of the naturally occurring zero crossings, potentially leading to sustained arcs. This paper presents cut-age and state-of-the-art issues concerning the fault management of DC microgrids. It provides an account of research in areas related to fault management of DC microgrids, including fault detection, location, identification, isolation, and reconfiguration. In each area, a comprehensive review has been carried out to identify the fault management of DC microgrids. Finally, future trends and challenges regarding fault management in DC-microgrids are also discussed.

Intelligent Control Algorithm of Impulse Current for Two Stage Wide Input Marine Switching Power Supply

Wang, G. and Hu, Y., 2020. Intelligent control algorithm of impulse current for two stage wide input marine switching power supply. In: Yang, Y.; Mi, C.; Zhao, L., and Lam, S. (eds.), Global Topics and New Trends in Coastal Research: Port, Coastal and Ocean Engineering. Journal of Coastal Research, Special Issue No. 103, pp. 956–960. Coconut Creek (Florida), ISSN 0749-0208.In order to solve the problem of large ripple caused by high current pulse load in the operation of conventional ship power network, an intelligent control algorithm for shock current of two-stage wide input switching power supply for ships is proposed. Based on the variation law of disturbance period, the influence of frequency disturbance is analyzed, a steady-state large signal model is established, the small signal disturbance of switch frequency is calculated, the parallel current sharing technology is used to realize the parallel current sharing control of switch power supply, and the intelligent control algorithm of shock current of two-stage wide input ship switch power supply is completed. The experimental results show that, after using the proposed control algorithm, the secondary current and the primary current have a high degree of agreement, which indicates that it can effectively prevent the occurrence of excessive ripple caused by current pulse load.

Enhancing electricity supply mix in Oman with energy storage systems: a case study

ABSTRACT Over the past decade, population growth and industry expansion in Oman have led to an increase in electricity demand of more than 240%. The main challenges of utilising renewable energy resources in Oman include high capital costs and their intermittent nature. Enhancing the integration of renewable energy sources from wind and solar into the conventional power network requires the mitigation of vulnerabilities posed to the network owing to the intermittent nature of these sources. One possible solution for such a problem is to utilise large-scale energy storage such as pumped-hydroelectric, compressed air, or Hydrogen storage. This paper aims to review energy storage options for the Main Interconnected System (MIS) in Oman. In addition, it presents a techno-economic case study on utilising pumped hydro energy storage (PHES) facilities to supply peak demand. Abbreviations: CAES: Compressed Air Energy Storage; CAPEX: Capital Expenditure or Construction Cost; CCGT: Combined Cycle Gas Turbine; CCS: Carbon Capture and Storage; CF: Capacity Factor; CO2: Carbon Dioxide; COE: Costs of Energy; CRT: Cost-Reflective Tariff; DPS Dhofar Power System; GHG: Greenhouse Gas; IRR: Internal Rate Of Return; MIS: The Main Interconnected System; OCGT: Open Cycle Gas Turbine; OETC: Oman Electricity Transmission Company; OPEX: Operation Expenditure or Running Cost; OPWP: Oman Power and Water Procurement Company; PHES: Pumped Hydro Energy Storage; PPA: Power Purchase Agreement; RAEC: Rural Areas Electricity Company; SMES: Superconducting Magnetic Energy Storage

Power Delivery Exploration Methodology Based on Constrained Optimization

The conventional power network design process requires iterative modifications to the existing power network to eliminate hot spots and to converge to target impedance parameters. At later stages in the IC design process, this procedure may require significant time and human resources due to the limited flexibility to accommodate necessary changes. Power delivery exploration during early stages of the design process may bring considerable savings to the system development effort. The number of iterations may be greatly reduced by choosing the initial parameters sufficiently close to the optimum. This paper presents a power delivery exploration framework based on constrained global optimization. The power network parameters are estimated at early stages of the development process, while considering both electrical and nonelectrical factors, such as area and cost. A Laplace transform-based circuit simulator is described that is well suited for optimization purposes due to the high computational efficiency when a large number of iterations is required. The proposed framework has been applied to the distribution of voltage domains in a large scale complex integrated system, while minimizing the cost of the decoupling capacitor placement. The optimal number of voltage rails are determined, demonstrating an approximately 40% lower on-chip area than alternative solutions.

Comprehensive Review of Islanding Detection Methods for Distributed Generation Systems

The increased penetration of distributed generation (DG), renewable energy utilization, and the introduction of the microgrid concept have changed the shape of conventional electric power networks. Most of the new power system networks are transforming into the DG model integrated with renewable and non-renewable energy resources by forming a microgrid. Islanding detection in DG systems is a challenging issue that causes several protection and safety problems. A microgrid operates in the grid-connected or stand-alone mode. In the grid-connected mode, the main utility network is responsible for a smooth operation in coordination with the protection and control units, while in the stand-alone mode, the microgrid operates as an independent power island that is electrically separated from the main utility network. Fast islanding detection is, therefore, necessary for efficient and reliable microgrid operations. Many islanding detection methods (IdMs) are proposed in the literature, and each of them claims better reliability and high accuracy. This study describes a comprehensive review of various IdMs in terms of their merits, viability, effectiveness, and feasibility. The IdMs are extensively analysed by providing a fair comparison from different aspects. Moreover, a fair analysis of a feasible and economical solution in view of the recent research trend is presented.

Dynamic Economic Dispatch Incorporating Photovoltaic and Wind Generation using Hybrid FPA with SQP

ABSTRACTThis paper presents a hybrid approach to explore the effect of wind and photovoltaic energy on conventional power network using dynamic economic dispatch. This model deals with stochastic and unpredictable character of wind and solar power output while considering the gaps between the real and predicted output power. A hybrid flower pollination algorithm with sequential quadratic programming is applied to reduce the overall operating costs of generators, while allocating generation to the committed units. The proposed technique is applied on power system having 13 solar units and a wind plant connected with 3, 5, and 10 generating units, respectively. The results of algorithm simulations performed in MATLAB 2014b confirm the competence of the suggested method.

Biologically inspired modelling of smart grid for dynamic power-flow control under power failure

Smart grid is an electric power network that enables an effective use of electric power in a highly parallel-distributed manner. We have first formulated the basic equations for the smart grid by inspiring from the mechanisms in biological organism, and controlled the power-flow dynamically in the smart grid by monitoring an objective function, which reflects the power-flow and the constraint imposing on the power nodes. To validate the operation of the smart grid, we performed several simulation experiments, which include the operations of a conventional power network, a microgrid (comprises eight power nodes), and a smart grid (comprises three microgrids integrated into the conventional power network) both in synchronous and asynchronous manners for the operation of power nodes. Furthermore, even for several cases of power failure such as outage, a thunderbolt shock on the power plant and disconnection of power cables, power recovery can be automatically achieved through bypass connections similar to synaptic interconnections in a dynamic function of brain. Thus, the proposed control method guarantees a dynamically stable operation even in several cases of power failure by monitoring the objective function, while always reflecting an optimal state in smart grid as a whole system.

Biologically inspired modelling of smart grid for dynamic power-flow control under power failure

Smart grid is an electric power network that enables an effective use of electric power in a highly parallel-distributed manner. We have first formulated the basic equations for the smart grid by inspiring from the mechanisms in biological organism, and controlled the power-flow dynamically in the smart grid by monitoring an objective function, which reflects the power-flow and the constraint imposing on the power nodes. To validate the operation of the smart grid, we performed several simulation experiments, which include the operations of a conventional power network, a microgrid (comprises eight power nodes), and a smart grid (comprises three microgrids integrated into the conventional power network) both in synchronous and asynchronous manners for the operation of power nodes. Furthermore, even for several cases of power failure such as outage, a thunderbolt shock on the power plant and disconnection of power cables, power recovery can be automatically achieved through bypass connections similar to synaptic interconnections in a dynamic function of brain. Thus, the proposed control method guarantees a dynamically stable operation even in several cases of power failure by monitoring the objective function, while always reflecting an optimal state in smart grid as a whole system.

Analyzing the effects of converter and DC line outages due to Distributed Voltage Control in AC-MTDC Distribution Network

Technological advancements in power electronics devices in recent years and the increase in the integration of distributed energy resources (DER) due to green energy awareness has transformed the conventional power network into a sophisticated and smart network. With the large-scale integration of sensitive DC load along with AC, and availability of DER with AC and DC type outputs results in an inevitable shift to develop an efficient and reliable layout for a distribution network known as AC-MTDC distribution network. In this paper, an AC-MTDC distribution network is realized to perform the load flow analysis, employing voltage source converter (VSC). A distributed DC voltage control technique is also implemented on VSC based AC-MTDC distribution network, and its effects are analyzed considering the converter and DC line outages for various network scenarious. A modified IEEE 33-bus AC-MTDC distribution network with VSC is considered for this study, and results are analyzed according to power sharing requirement and operational efficiency using MATPOWER, an open source power flow package.

Maximum Likelihood Output Curve and Modal Bounds for Active Pitch-Regulated Wind Turbine

A scatter of operating points is commonly observed over time whenever a pitch angle controlled (PAC) wind energy conversion system (WECS) operates in source wind susceptible to short duration variations caused by turbulence and gusts. A suitable interpretation of the distributed operating points can be useful in the context of real-time performance of WECS, and its evaluation once integrated within a conventional power network. This paper provides conceptual background culminating in an algorithm that allows estimation of most probable ( maximum likelihood ) operating points for a pitch angle-controlled WECS. It further allows establishment of modal bounds , within which short duration operating points are expected to occur given a modal cumulative probability . The concepts and algorithm are illustrated for a popular make of WECS assumed to operate in source wind conditions according to IEC61400-1 standards. Following from the concepts proposed, indications are provided for possible refinement of WECS output power curves thereby aiming to achieve better short duration unit performance.

Converting an Old Machines Lab Into a Functioning Power Network With a Microgrid for Education

As colleges prepare or revise their power engineering courses to include discussions on the smart grid, the microgrid, distributed energy sources and renewable energy resources, the need for new material suitable for inclusion in a typical 4-year undergraduate engineering course has never been more obvious. Toward this effort, an old machines lab was remodelled and converted into a small power network that can be operated in both grid-connected and grid-islanded microgrid modes. The intent of this paper is to devise laboratory experiments to supplement a course in conventional power systems analysis at the undergraduate level. During the remodeling process, two of six synchronous machines in the lab were converted to represent distributed generating units within a laboratory-based microgrid. The use of electromechanical distributed generators (EDG) with a low start-up time allows the system to operate as a conventional power network with provisions for frequency and voltage variations. Students can experiment with voltage control and power sharing between the EDGs in islanded mode. A Laboratory Grid Central Controller (LGCC) was developed in LabVIEW® to coordinate the operation of the EDGs, the utility grid and the loads. Its functions are similar to those of a central dispatch office, albeit on a much smaller scale. A one credit hour lab course held on this laboratory was offered for the first time during the Fall semester of 2012 at Missouri S&T.

Chaos detection and control in a typical power system

In this paper, a new chaotic system is introduced. The proposed system is a conventional power network that demonstrates a chaotic behavior under special operating conditions. Some features such as Lyapunov exponents and a strange attractor show the chaotic behavior of the system, which decreases the system performance. Two different controllers are proposed to control the chaotic system. The first one is a nonlinear conventional controller that is simple and easy to construct, but the second one is developed based on the finite time control theory and optimized for faster control. A MATLAB-based simulation verifies the results.

Impacts of Superconducting Fault Current Limiters on the Recloser Operation in Distribution Electric Power Systems

Superconducting fault current limiter (SFCL) is a promising novel electric equipment to reduce excessive fault current in electric power systems effectively. However, in practical application of this novel device into electric networks, SFCL could cause some unfavorable impacts on the electric power system. Especially, coordination between the SFCL and the recloser which has a conventional protection scheme is a major concern because it could cause severe reliability and stability problems in power systems. Several important characteristics of SFCL, which affects on a recloser operation scheme, are quenching phenomena, recovery from the quenching state, limiting impedance and its triggering time. Therefore, careful assessment of coordination issues with a recloser should be investigated to evaluate reliabilities of electric power system by installing SFCL into conventional power networks. This paper presents the impacts of SFCL on the recloser operation by considering various aspects of newly developed hybrid resistive SFCL into distribution systems in Korea. Consequently, it was deduced that conventional recloser scheme might be altered in order to meet the performance and requirements of hybrid SFCL into distribution electric power systems.

Investigation of real field application issues for resistive type SFCLs for distribution electric power networks

Conventional electric power networks were designed and operated not considering fault current limiting devices. Therefore, the performance and characteristics of resistive superconducting fault current limiter (SFCL) should be reviewed considering the coordination with other electric circuit protecting devices. In this paper, real field application issues of resistive SFCL were investigated considering utilities’ demands and coordination with other protection devices. Pure resistive SFCL and hybrid resistive SFCL were compared in order to determine suitable solutions for electric power systems. SFCLs were modeled and analyzed using electro-magnetic transients program (EMTP) and their performances were compared to identify the adaptability to the conventional power networks. Consequently, Simulation results showed that hybrid resistive SFCL have more advantages than pure resistive SFCL considering the requirements and specification for the distribution networks.