Output Line Research Articles

Capacity Value Assessment for a Combined Power Plant System of New Energy and Energy Storage Based on Robust Scheduling Rules

With the rapid increase in new energy penetration, the uncertainty of the power system increases sharply. We can smooth out fluctuations and promote the more grid-friendly integration of new energy by combining it with energy storage. This paper proposes an evaluation method for assessing the value of a combined power plant system of new energy and energy storage using robust scheduling rules. Firstly, the k-means clustering algorithm is improved by using the elbow method in order to generate typical scenarios that can be used for the operation optimization of the combined power plant system of new energy and energy storage. Then, a two-stage robust optimization model of the combined power plant system of new energy and energy storage with a min–max–min structure is constructed according to the uncertainty of new energy. In this model, the operation constraints and coordinated control of wind–solar–thermal–storage units are considered. By constructing the uncertainty set of the new energy output, the overall operating cost of the system is minimized and uncertainty adjustment parameters are introduced to flexibly adjust the conservatism of the scheduling rules. Furthermore, based on the column and constraint generation algorithm and strong duality theory, the original problem can be decomposed into a master problem and subproblems with mixed integer linear characteristics for an alternating solution, so as to obtain the optimal solution of the original problem, and finally obtain the robust scheduling rule with the lowest operating cost under the worst scenario. Finally, based on the wind and solar power output curves and the output of each unit under the robust scheduling rules, combined with the value estimation method of the combined power plant system of new energy and energy storage, the value of the combined power plant system of new energy and energy storage is evaluated. Through the establishment of models and example analysis, it is proven that raising the quantity of the grid-connected power generated with new energy will cause an increase in the volatility of the power system; it will also bring considerable benefits to new energy plants, and the energy storage can improve the stability of the system. The above can provide references for the subsequent energy storage configuration in the planning of a combined power plant system of new energy and energy storage.

Flowmeter-free chemical dosing control system: A new volume measurement-based design offers cost-effective and reliable operations

This study discusses a new volume measurement-based chemical dosing control system design and performance analysis. In conventional dosing systems, chemical dosing control is carried out by an analogue or digital flowmeter with different operating principles placed on the pump outlet line. In these systems, the amount of dosing chemicals is controlled based on the feedback received via the flowmeter. To obtain a steady measurement with flowmeters, the pulsations from the dosing pumps must be dampened and the line pressure must be kept constant with pressure regulators. In the proposed dosing system, the measurement of the dosing chemical is performed via the pump suction line, making it independent of the pump output character and line pressure. The amount of dosing chemicals is measured instantaneously by placing a volume-level measurement tube on the pump suction line. The system is designed to handle the metering of viscous fluids at an operating pressure of (0–400) bar and a flow rate of 10 L/h. The proposed and the conventional systems have been experimentally tested and performance data have been obtained at various operating pressure and flow rates. Experimental results confirmed that a simple and flowmeter-free flow control system is achieved, thanks to the low component count. Furthermore, a cost saving of 40 % has been achieved compared to conventional systems.

Risk-based optimization for facilitating the leasing services of shared energy storage among renewable energy stations

Due to the inherent power output correlation and uncertainty, renewable energy stations normally incur the deviation penalty in the day-ahead and real-time electricity market. Meanwhile, shared energy storage operators have been appearing to provide energy storage leasing services for neighboring renewable energy stations. In this context, this paper presents a novel optimization strategy to provide leasing services for renewable energy station clusters while improving the utilization rate and revenue of shared energy storage simultaneously. Especially, the proposed strategy utilizes a two-stage optimization model to incorporate the overselling risk. In the first stage, a matching index is defined to select a cluster of wind and solar power stations in the geographically-close region, when a set of highly complementary stations are selected by matching the typical output curve of the shared energy storage. In the second stage, an optimization strategy is determined to explore the benefit and risk of overselling for shared energy storage with the goal of maximizing the total revenue, when the correlation of wind and solar power output is realized in the scenario generation and sampling process. The results of numerical experiments have demonstrated that employing a moderate overselling method can provide an economical and efficient operational solution to improving the utilization of shared energy storage.

Investigation on the coordinated operation control technology of distributed new energy grid connection using artificial intelligence algorithms

New energy power generation has strong randomness and volatility. Especially in the case of a high proportion of NE (network security) power generation, its sudden random power generation in a short period of time will seriously affect the stable operation of the power grid. Therefore, this paper proposes BP neural network algorithm to study the distributed NE grid-connected cooperative operation control technology. First of all, this paper studies the artificial intelligence algorithm in detail and applies it to the coordinated operation control of distributed NE grid-connected; then, based on the status quo of renewable energy PG (power generation), this paper establishes a suitable wind speed time series model, and thus proposes an optimization model based on a rolling scheduling optimization algorithm. The experimental results show that the average running time of the rolling scheduling optimization algorithm is maintained at about 0.2 s, which can effectively realize online operation. In addition, through rolling adjustment, the error between the total output curve of the unit and the actual total output curve of the unit can be significantly reduced. The research shows that the rolling scheduling optimization algorithm has a good optimization effect, can promote the coordinated development of wind farms and power systems, and increase the capacity of power systems.

The Discussion on the Impact of the COVID-19 Epidemic on the Macro-economy and the Establishment of the Work and Production Resumption Model

In order to explore the impact of the COVID-19 epidemic on the macro-economy, this paper established the IS-LM model and the AD-AS model, made corresponding adjustments and calculations to the models, analyzed the impact of the epidemic on aggregate demand and aggregate supply respectively, and put forward policy suggestions according to the actual situation by using the models. And in order to help the government better decide the best timing to return to work and production in different industries, this article utilized the total cost model in epidemic control to build a work resumption coefficient evaluation model of different industries, getting the coefficients of the high-density population industry, the industry whose work resumption can be carried out online, the industry of fewer average interactions, highly mechanized industry and special industries, respectively. And we formulated the standard of work resumption based on the work resumption coefficient under the condition of controlling the total cost to be minimized. After getting the work resumption coefficients of different industries and corresponding resumption standard, the government will be easier to balance the cost of the shutdown and the risk of resuming work and production under the epidemic.

Deep hierarchical distillation proxy-oil modeling for heterogeneous carbonate reservoirs

This paper presents a novel few-shot proxy modeling approach for the oil and gas industry to reduce reliance on numerical simulators for reservoir analysis. The strategy introduces a regression framework leveraging deep hierarchical self-distillation to construct a meta-model based on ensemble learning. The proposed method employs a cascade training scheme, which uses predictions derived from a superior hierarchical level to distill knowledge into the next predictor. The pivotal idea of self-distillation is to generate “soft targets” rather than hard ones. Soft targets represent probability distributions over potential output curves rather than a correct answer. This smoothing information provides additional guidance to the model during training, helping it generalize better. This architecture utilizes three-dimensional (3D) maps in proxy modeling to forecast cumulative fluid production and generate risk curves indispensable for effective field decisions. The study employed data acquired from a complex oil field characterized by a substantial degree of uncertainty. The hierarchical self-distillation technique outperforms alternative methods, achieving a symmetric mean absolute percentage error (SMAPE) below 2%. It reduces computational overhead by 84% for a probabilistic model with 900 simulations and 62% for a model with 200 simulations. The developed proxy model delivers valuable insights for decision-making in oil field management, offering the potential to decrease expenses and enhance efficiency in field exploration endeavors.

An efficient power extraction technique for improved performance and reliability of solar PV arrays during partial shading

Partial shading in the arrays reduces the power output, creates hotspots and damages the modules affecting the performance of the system. The modules bypass diodes create non-convexity in the power curves causing additional power losses. Hence, this work proposes a black widow reconfiguration (BWR) with reduced switch counts for mitigating the effects of partial shading in the arrays. The methodology effectively reduces the current difference between rows of the PV array within a short period with a faster calculation rate and electrically reconnects the modules. The reconnection ensures reduced mismatch among modules, higher power output and smoother power curves during partial shading. To show the effectiveness of the BWR in arbitrary-sized arrays, three arrays of 2 × 4, 5 × 5, and 9 × 9 sizes are considered and tested under static and dynamic partial shadings. The results are then compared with three conventional, six static, and three dynamic techniques using power curves and various parameters. Besides validation in the MATLAB environment, the experimental setup and OPAL-RT platform are considered to show the application in real-time environment. From the investigation, an average power improvement of 25.49%, 15.47%, and 9.29% in BWR compared to the existing conventional, static, and dynamic techniques with 99.60% efficiency have been observed.

Research on Park Energy System Based on Grid Connection of Renewable Energy Power Generation

With the maximum consumption of renewable energy, the minimum emission of pollutants and the minimum comprehensive investment cost as the optimization objectives, the operation model of the park’s energy system considering the thermal power balance constraint, natural gas balance constraint and power grid power constraint was proposed, and the scenic power generation and electricity equipment of the park were studied. By comparing different operation scenarios, the influence of adding different equipment on the operation optimization of the whole park under the thermoelectric coupling is comprehensively analyzed. The balance curve of equipment output and related energy use is analyzed on a yearly cycle, indicating that the power supply grid of the park based on the thermoelectric coupling has great reliability and effectiveness in the consumption of renewable energy, and its economy is also significantly improved.

Circulating Current Control in Interleaved and Parallel Connected Power Converters

This article analyzes circulating current control in single-phase power electronic converters, focusing on two different topologies: interleaved and parallel configurations. The study involves a bridgeless interleaving topology with two boost converters for increased efficiency. A parallel connection is also examined for monitoring line current, circulating currents, and power factor control. The article widely explains all current loops, including Common Mode Circulating Currents (CMCC) in the bridgeless interleaved topology and Differential Mode Circulating Currents (DMCC) in parallel-connected interleaved power converters. The proposed control scheme employs voltage and current control loops for output voltage and line current control and introduces CMCC and DMCC compensators to eliminate all types of circulating currents. An efficient Power Factor Correction (PFC) and output voltage control method is presented in this article. The effectiveness of the proposed schemes is validated through comparisons with modern control systems. The results are verified using Simulink/MATLAB and experimental setups with TI Instruments Piccolo prototypes and C2000 (TMS320F28035 microcontroller MCU) microcontrollers in parallel configurations.

Self-Attention Generative Adversarial Network Enhanced Learning Method for Resilient Defense of Networked Microgrids Against Sequential Events

The resilient responses of networked microgrids (MGs) can greatly improve the survival of critical loads during extreme events. In order to efficiently handle the scarce data issue as well as improve the adaptability of deep reinforcement learning (DRL) methods for complex sequential extreme events (SEEs) such as hurricanes and tornadoes, a new learning-based method is proposed for the survival of critical loads in MGs during SEEs. A generative adversarial network (GAN) is applied to generate a sufficient extreme event-related database in a model-free way. Specifically, a self-attention GAN (SA-GAN) is developed to capture sequential features of the SEE process. Then, the SA-GAN is integrated into a DRL framework, and the corresponding Markov decision process (MDP) and the environment are designed to realize adaptive networked MG reconfiguration for the survival of critical loads. Faced with uncertain distributed generator (DG) output and sequential line damage, the SA-GAN-DRL method provides an adaptive model-free solution to continuously supply critical loads during SEEs. The effectiveness of the proposed method is validated using a 7-bus test system and the IEEE 123-bus system, and the results demonstrate both a strong learning ability with limited practice data, and robustness and adaptability for highly changeable SEE processes.

Wind Power-Photovoltaic-Hydropower Optimization in Watershed Based on Wind Power-Photovoltaic Cluster Convergence

With the construction of wind power-photovoltaic-hydropower (WVH-system) clean energy base in the river basin, the complex geographical distribution characteristics of WVH-system along the river basin and the randomness and fluctuation of their output bring challenges to the basin on a large scale. How to consider the complementary characteristics of wind-photovoltaic (WV-power) output and cluster effect to smooth the WV-power output curve is an important way to solve this challenge. For this reason, a WVH-system bundling optimization method based on WV-power cluster convergence is proposed in this paper. Considering the complementary coupling characteristic of wind power and photovoltaic output, the output characteristic index of the WV-power cluster is constructed to evaluate the output complementarity, output stationarity and load tracking characteristics of the WV-power cluster. Based on the characteristic index, the clustering method of the WV-power cluster is constructed to divide the WV-power power cluster along the river basin. A basin WVH-system bundling optimization model is developed based on the division of clusters and efficient utilization of pumped storage units’ regulation capacity. Finally, the WVH-system data of a river basin in southwest China are taken as an example to verify the effectiveness of the proposed method.

Output Curves Based Hierarchical Clustering Screening Method With Static/Dynamic Current Balancing for Paralleled SiC MOSFETs

Output Curves Based Hierarchical Clustering Screening Method With Static/Dynamic Current Balancing for Paralleled SiC MOSFETs

Emergence and highly directed output of long-lived resonances in photonic step ladder structure

A bound state eigenfunction is defined here to be strictly localized within a subspace of a system and has no decreasing behavior. Its eigenvalue can be within state continua. Bound states in the continuum (BICs) and long-lived resonances have become a unique way to produce the extreme localization of light waves. In this communication, we present a theoretical and numerical demonstration of infinite bound states in the continuum (IBIC) and long-lived resonances in photonic ladder-like structures with four semi-infinite leads, together with their existence conditions. IBIC states are localized in an infinite subspace domain. Some of these states are inactive in the scattering and induce output zeros. Other are scattering active and induce output ones in the middle of long-lived resonances. Several continua of IBIC states remain hidden. They are bound in one of two infinite guides and some of them also in the closed loop. These discoveries are reported here for the first time to our knowledge. The ladder reference structure is composed of connected open loops of lengths L1 and L2 and four semi-infinite leads. The obtained results take due account of the state number conservation between the final system and the reference one. This conservation rule enables to find all the states of the final system and among them the bound in the continuum ones. In addition, we show the existence of long-lived resonances in each of two parallel output lines and long-lived anti-resonances in each of the two other output lines, when one uses two identical parallel simultaneous inputs. The analytical results are obtained by means of the Green’s function technique. The structures and the long-lived resonances presented in this work may have potential applications, in particular in sensing, filtering and communications.

Three-way maximized net power output from alkaline membrane fuel cell stacks

This work uses an experimentally validated mathematical model to maximize alkaline membrane fuel cell (AMFC) stacks net power output. Temperature distribution, efficiency, polarization, and power output curves are obtained. Fundamental optimization opportunities exist for the internal and external structure, which led to a two-way optimized AMFC stack for maximized net power. After system optimization, a parametric analysis was carried out for electrolyte KOH mass fraction, stoichiometric ratios and total fuel cell stack size (volume). KOH content was shown to lead to a third optimum, i.e., 40 wt %. The three-way optimized AMFC stack (ξs=1.37×10−3, y = 40 wt% KOH)opt was shown to be independent of the stoichiometric ratio and stack size variation, but (ξy/ξx=ξz/ξx)opt was affected by total stack volume (or size). In fact, it was found that the three-way maximized dimensionless AMFC stack net power output rises as the stack volume rises in a path that is well correlated by W˜net,mmm×10−3=36.266V˜T0.74, which is similar to the allometric law of nature that correlates basal metabolic rate (BMR, W) and body mass (mb,kg) for living beings, i.e., BMR∼mb0.74, that could be understood as an indication that inanimate and animate systems follow the same evolution laws.

Phosphorus concentration by sorbents based on polyacrylonitrile fiber modi ed with iron(III) hydroxide

The resu lts of phosphorus recovery by sorbents of our production on the base of polyacrylonitrile ber modi ed with iron(III) hydroxide from solutions with di erent pH were presented. The phos phorus degree of recovery, the dynamic exchange capacity, and the total dynamic exchange capacity of sorbents for phosphorus have been established. The output curves of phosphorus sorption were constructed, and the results of a study of the sorption physicochemical regularities (isotherm and kinetics) were presented. The sorption e ciency of 32P and 33P from rainfall samples using sorbents based on polyacrylonitrile ber modi ed with iron(III) hydroxide was evaluated. Monitoring of 32P, 33P in atmospheric fallout of the Sevastopol region was carried out.

A comprehensive investigation of a solar array with wire length under partial shading conditions

ABSTRACT Partial shading condition (PSC) leads to mismatch losses and multiple peaks on the output curves. Several static-based reconfigurations like total cross-tied (TCT), skyscraper reconfiguration (SSR), and odd-even reconfiguration (OER) were reported to address these issues. But, less shade dispersion and more wiring losses occur in these arrays. This work focuses on both power improvement and wire length reduction of solar arrays under PSC. Based on the reduced wire length to more than 50% for SSR over OER, a novel enhanced skyscraper reconfiguration (ESR) is proposed in this work. ESR is cheaper by 169.13 INR and 1699.07 INR as compared to SSR and OER respectively. Further, the performance of the novel ESR is compared by obtaining several parameters like fill factor (FF), efficiency (Ƞ), global power (GP), execution ratio (ER), current loss (IL), and mismatch loss (ML) with the existing SSR and OER. It is observed that the Ƞ is improved by 4% and 13.05% and GP is maximized by 3.74W and 4.48W for the novel-proposed ESR over SSR and OER, which is experimentally verified under regional and corner shadings respectively. Overall, the novel-proposed ESR confirms its supremacy over other considered models in this study.

Quantum-dot cellular automata-based design for three-level nanoscale full-subtractor

• A new approach to full-subtractor circuit design is proposed in this research. • The new design is built with XOR and majority gates, making it both efficient on the gate level and abstract. • This structure is created with a significant reduction in the number of cells and the amount of space used. • The QCADesigner-E tool is used for circuit design and verification, as well as for power analysis. Future digital devices and circuits can be frequently designed using quantum-dot cellular automata (QCA). High density and speed are good matches for QCA. As a result, a full subtractor is well suited for this technology. QCA can be utilized to create the full-subtractor at the nanoscale since it is a specific sort of circuit employed in important applications. A subtractor circuit can be created similarly to an adder circuit in electronics. When utilizing the traditional two's complement notation, subtractors are commonly implemented within a binary adder for a low cost by supplying an addition/subtraction selector to the carry-in and inverting the second operand. In this research, we present a new full-subtractor circuit construction. The XOR and majority gates, which work on the Columbic interaction of cells, are utilized for this purpose. QCADesigner-E is used to model and test the proposed structure's functionality. The full-subtractor architecture provides a platform for easier access to the input and output lines. This design is made using the multi-layer crossover approach and 22 QCA-based cells. The number of cells in the suggested structure has been improved by 31 percent, while the occupied area has been improved by 30 percent.

A novel reconfiguration of the solar array to enhance peak power and efficiency under partial shading conditions: experimental validation

Abstract Non-homogeneous irradiation patterns and temperature levels immensely affect the performance of solar photovoltaic arrays. Partial shading conditions on solar arrays reduce the peak power and efficiency. This paper provides a new remedy called a novel Ramanujan reconfiguration (NRR) to eliminate this physical shading problem in solar photovoltaic systems. NRR is a static-based reconfigured technique that is built using a three-diode model with the help of the MATLAB®/Simulink® tool. The special feature of the proposed NRR technique is that when shade occurs on the solar modules, it gets realigned in a particular row, column, diagonal, corner, centre and middle peripheral cages. This helps over a wide range of shade dispersion on the solar array. The novel topology is tested against the conventional total cross-tied (TCT) model and recently introduced advanced reconfigured models, namely odd–even topology (OET) and Kendoku topology (KDT). The results are tested under certain shading conditions. The proposed NRR technique increases the peak power by 4.45, 2.15 and 2.17 W under the first shading condition regarding TCT, OET and KDT. Its efficiency is improved by 0.51–2.18% under the third shading condition compared with other considered models in this study. In addition, NRR leads to smooth output curves under the second, third and fourth shading conditions, effectively mitigating the local power peaks. The experimental results show the proposed enhanced performance of the novel model against the other models.

Comparative performance of modular with cascaded H-bridge three level inverters

<span lang="EN-US">The conventional two-level inverter becomes no longer has the ability to cope with the high-power requirement, so this paper discusses two very common topologies of multilevel inverter like modular multi-level converter (MMC) and cascaded H-bridge (CHB) multi-level inverter for induction motor drive applications. This work attempts to investigate the comparison between MMC and CHB. The comparison is done in aspects of the configuration, concept of operation, advantages and disadvantages, the comparison is also consider output voltage (line to line) waveform, total harmonic distortion (THD) of the output line voltage waveform and the current drawn by both inverters. The performance of the inverters under carrier-based pulse width modulation (PWM) technique and mainly in-phase disposition (IPD), level shifted pulse width modulation is viewed. The paper discusses the comparison between the two multilevel inverters (MLIs) with motor drive applications especially induction motor. The operation of the motor is studied under certain value of load torque. The simulation results for the induction motor with the two inverters (modular multi-level and Cascaded H-bride) for three numbers of levels using MATLAB/Simulink are provided). The obtained results are encouraging and promising especially in the improvement of the THD% results.</span>

The IS-LM model and monetary policy (podcast)

Explicación macroeconómica del Modelo IS – LM en inglés adaptado las disfunciones visuales del alumnado. Dentro de las tecnologías multimedia, el uso de audios (como material de enseñanza) ha atraído la atención de los docentes debido a sus beneficios para el aprendizaje, tanto en términos de atención como de motivación de los estudiantes (Almobarraz, 2018; Brecht, 2012; Orús et al., 2016; entre otros). Entre los beneficios del aprendizaje, la literatura existente resalta los siguientes: 1) permite un proceso de aprendizaje más flexible temporal y espacial; 2) representa un ahorro en costes y tiempo tanto para los estudiantes como para las instituciones educativas; 3) mejora la autonomía del estudiante en el proceso de aprendizaje; y 4) promueve el aprendizaje colaborativo y bajo demanda. Actualmente se está realizando un testeo con el alumnado con disfunciones visuales de la Asignatura de Economía II del Grado de Turismo que culminará con una comparativa de las notas en el curso anterior a la puesta a disposición del mismo del material preparado. Se espera que las calificaciones sean superiores con el uso de esta locución.