Types Of Power Sources Research Articles

Small-scale Bio Gas Combined Heat and Power Plant with Biochar Catalyst

Alternative energy sources allows to replace traditional fossil fuels and firewood. However the most widely used wind and solar power plants can not provide constant power generation due to multiple factors that makes necessary to develop new types of power sources and to to improve efficiency of already existing ones. One of such energy sources are bio gas-fueled power plants which allow to combine the power generation and organic waste disposal functions. Efficiency and quality of bio gas production in such facilities can be significantly increased by using different catalysts such as biochar. A brief analysis of biochar production usage perspectives was held which showed that it can be used in different applications and can significantly increase efficiency of different technological processes. The influence of biochar on the biogas production processes was studied. The structure of bio gas-fueled heat and power plant with local bio gas generation was proposed.

Coordinated planning of thermal power, wind power, and photovoltaic generator units considering capacity electricity price

AbstractWith the implementation of China's carbon reduction policies, the role of thermal power units will transition to a regulating power source. Hence, the electricity market fails to accurately reflect the capacity value of thermal power units, resulting in potential future losses for these units. Therefore, it is imperative to establish a rational capacity compensation mechanism that guarantees the revenue of thermal power units and offers effective investment and construction signals. Therefore, this paper proposes a capacity compensation mechanism for thermal power units based on effective capacity. To achieve this, a two‐layer power source planning model is established. At the upper level of the model, the installed capacity and capacity price of various types of power sources are optimized, while minimizing the operating costs of the planning horizon year under constraints such as annual net profit of units. The lower level focuses on the operation of typical days, optimizing the output of various types of units. Through case analysis, it can be concluded that the proposed model can achieve coordinated planning of capacity and capacity prices for various types of units, effectively ensuring the economic efficiency of the system while safeguarding the revenue of each unit.

Distributed Optimization of Islanded Microgrids Integrating Multi-Type VSG Frequency Regulation and Integrated Economic Dispatch

The question of how to simultaneously perform frequency regulation and integrated economic scheduling for microgrids with low-inertia islanding operation under communication constraints is a difficult problem that needs to be solved for many current applications. To this end, this paper establishes a microgrid scheduling control model containing a virtual synchronous generator (VSG) with multiple types of power sources and proposes a distributed optimization algorithm that integrates frequency regulation and comprehensive economic scheduling to simultaneously realize frequency regulation and economic scheduling in a microgrid. Firstly, a distributed economic dispatch problem is proposed based on a comprehensive consideration of the costs and benefits of various types of power VSGs, as well as the overall inertia and standby capacity requirements of the microgrid, which minimizes the integrated costs incurred by the participation of each type of VSG in the frequency regulation and improves the stable operation of the microgrid in terms of frequency under perturbation. Then, the optimal scheduling problem is solved by reconstructing the optimization problem based on considering the dynamic characteristics of microgrid inverters and using event-triggered communication to sense and compensate for the supply-demand imbalance online. The proposed method can avoid inter-layer coordination across time scales, improve the inertia, frequency regulation capability, and economy of the system, and enhance its robustness to short-term communication failures. Finally, simulation results are used to verify the effectiveness of the method.

Research on joint dispatch of wind, solar, hydro, and thermal power based on pumped storage power stations

In the context of energy conservation and emission reduction, the integration and consumption of large-scale wind and solar resources is an inevitable trend in future energy development. However, with the increase of wind and solar grid-connected capacity, the power system also requires more flexible resources to ensure safe operation. To enhance the economic efficiency of the complementary operation of wind, solar, hydro, and thermal sources, considering the peak regulation characteristics of different types of power sources, the study of the joint dispatch model of complementary utilization of various generation methods like wind, solar, hydro, thermal, and storage is of great significance for the economic dispatch of the power system. Existing studies mainly focus on traditional thermal power units or hydropower units, with few studies investigating the impact of pumped-storage power stations on the absorption of renewable energy. Firstly, this paper introduces the composition and function of each unit under the research framework and establishes a joint dispatch model for wind, solar, hydro, and thermal power. Secondly, the paper elaborates on the objective function within the model, mainly covering the operating costs of thermal power units, hydropower units, pumped storage, wind and solar units, the cost of discarding new energy, and the cost of load shedding. Subsequently, the paper presents the constraints of the system model, mainly the feasible boundaries for the operation of each unit within the system. Finally, The results of the calculations show that the proposed model reduces the total operating cost by 12% and the power abandonment rate by 82% compared to the conventional model. It is shown that the proposed model can not only significantly improve the economic efficiency of the system operation but also reduce the level of energy waste and load shedding, effectively enhancing the degree of energy utilization within the system.

Environmental and economic dispatching strategy for power system with the complementary combination of wind-solar-hydro-thermal-storage multiple sources

The linkage, coordination, and complementary cooperation of energy supply can improve the efficiency of transportation and utilization. At present, the level of new energy consumption needs to be improved, the coordination of the source network load storage link is insufficient, and the insufficient complementarity of various types of power sources in the power system. This article fully explores the differences and complementarities of various types of wind-solar-hydro-thermal-storage power sources, a hierarchical environmental and economic dispatch model for the power system has been established. Among them, the upper level model takes the flexible consumption of new energy as the optimization goal, the middle level model uses a combination of hydropower station and energy storage to minimizes the fluctuation variance and peak-to-valley difference of the net load curve, the lower level model aims to achieve optimal environmental and economic benefits of the power system, comprehensively considers the coal consumption cost, startup and shutdown cost, energy storage operation cost, and pollutant emissions of thermal power units, determines the startup and shutdown mode and output power of thermal power units. Finally, an improved IEEE 6-machine 30-node system is used as an example for simulation analysis, the results show that after applying the proposed hierarchical environmental and economic dispatch strategy of the power system, the fluctuation variance and the peak-to-valley difference of the net load curve have been reduced by 46.3% and 31.5%, respectively, and the environmental and economic benefits of the system is improved by 5.1% compared with the traditional economic dispatch strategy. It can meet the requirements of energy system cleaning and decarbonization while improving the operation economy, which verifies the effectiveness of the proposed environmental economic dispatch model.

Two-Stage Optimal Scheduling Based on the Meteorological Prediction of a Wind–Solar-Energy Storage System with Demand Response

With large-scale wind and solar power connected to the power grid, the randomness and volatility of its output have an increasingly serious adverse impact on power grid dispatching. Aiming at the system peak shaving problem caused by regional large-scale wind power photovoltaic grid connection, a new two-stage optimal scheduling model of wind solar energy storage system considering demand response is proposed. There is a need to comprehensively consider the power generation cost of various types of power sources, day-ahead load forecasting information, and other factors and plan the day-ahead output plan of the energy storage system with the minimum system operation cost as the optimization objective of day-ahead dispatching. The demand response strategy is introduced into the time-ahead optimal scheduling, and the optimization of the output value of the energy storage system in each period is studied with the goal of minimizing the system adjustment cost. The particle swarm optimization algorithm is used to solve the model, and the IEEE33 node system is used for an example simulation. The results show that using the demand response and the collaborative effect of the energy storage system can suppress the uncertainty of wind power and photovoltaic power, improve the utilization rate of the system, reduce the power generation cost of the system, and achieve significant comprehensive benefits.

State-of-the-art review on energy management systems, challenges and top trends of renewable energy based microgrids

Due to the increasing demand for electrical energy worldwide and environmental concerns, modern power systems are looking for a fundamental change. These changes include reducing dependence on the primary electricity grid and using renewable energy sources on a large scale. The emergence of microgrids in electrical energy systems will improve the level of these systems due to technical, economic, and environmental benefits. In this research work, the authors have conducted extensive studies on control methods, types of power sources, and the size of microgrids and analyzed them in tabular form. In addition, the review of communication technologies and standards in microgrids, as well as the review of microgrid energy management systems to optimize the efficiency of microgrids, is one of the main goals of the authors in this article. Also, in this article, the top 10 trends of microgrids in 2023 have been examined to increase the flexibility of network infrastructure, which helps readers to improve their strategic decisions by providing an overview of emerging technologies in the energy industry.

Generation Coordination and Planning of New Power System Considering Industry Hydrogen Load

Considering the impact of industrial hydrogen load on the consumptive capacity of new energy, it is necessary to research the generation coordination and planning of new power systems considering industry hydrogen load. Firstly, considering the energy consumption in the hydrogen production and storage process, as well as the energy storage for hydrogen addition/use, hydrogen load transfer, and interruptible flexibility, an equivalent electrical load conversion model for multiple forms of hydrogen loads is established. Secondly, considering the impact of industrial hydrogen load on the absorption capacity of new energy, the investment decision-making problem of power supply, hydrogen production, and storage equipment is unified with the operation simulation problem of the system at the planning level, to minimize the annual cost of the system. To reduce the complexity of the model, the proposed model plan to the expansion capacity of various types of power sources from the perspective of power types. Finally, by using actual data from a power grid in a certain province as an example, the results verified the rationality and effectiveness of the model compared with the power grid planning without hydrogen load.

Design and analysis of robot and fixture pedestal for OTC FD-V8 MAG welding robot

The use of automation in the welding process is favoured due to its capacity to enhance the welding quality and expedite the completion of the task. Welding is a commonly automated process in assembly lines, with many companies relying on robotic welding due to its efficient nature. The key advantages of an automated welding process include higher-quality welds, increased productivity, reduced waste production, and lower labour costs. Gas Metal Arc Welding (GMAW) is of two types: namely, Metal Inert Gas (MIG) welding or Metal Active Gas (MAG) welding. GMAW is a welding process that involves a welding gun through which a wire electrode and a shielding gas are fed continuously. This process is commonly performed using a direct current power source with constant voltage, but other types of power sources can also be used. GMAW offers four primary methods of metal transfer, namely globular, short-circuiting, spray, and pulsed-spray, each of which has its unique properties and benefits as well as limitations. In this study, the OTC FD-V8 model robot is used for welding. The pedestal for the robot is designed using SOLIDWORKS and the static analysis of the robot pedestal is done. The fixture is used to hold the work piece for welding. The quality of the weld bead is determined by parameters like voltage, welding current, wire diameter, and composition of the shielding gas.

A Resilience Evaluation Method Considering Power Source Ability and Network Topology of Power Systems

Power system resilience refers to the ability of power grid to withstand extreme events and to recover quickly from disturbances. Recently, most resilience evaluation methods are based on the topological structure of grid, while the impacts of power sources on resilience were not taken into consideration. By analogy power system resilience to the change progress of operating state under external force in mechanics, this article proposes a power system resilience evaluation method based on the power support ability of power sources and network topology. Taking high-voltage direct-current and battery energy storage as a typical power electronic-based power source, its capacity, regulation ability, and stability are, respectively, given as the characteristics of power source and are considered in the resilience evaluation process. The effectiveness of the proposed method is verified via the IEEE 39-bus system, the IEEE 14-bus system, as well as an actual power system in a province of China. The results prove that the proposed resilience evaluation method is more applicable for power system with multiple types of power sources. In addition, compared with other methods, the proposed method has higher accuracy for the impact of changes in topology and power distribution on system resilience.

Power Source Importance Assessment Based on Load Importance and New Energy Uncertainty

With the increasing penetration of new energy sources, the volatility and uncertainty of new energy output can lead to interruptions or fluctuations in the supply of electricity. Power cuts to critical loads can have a significant impact on public safety, social stability, and the economy. Dealing with the effects of uncertainty from new energy sources means we need to find and strengthen the important loads and power sources when designing and operating the power system. Therefore, the assessment of the importance of loads, conventional power sources, and new energy sources is crucial. This paper proposes a power source importance evaluation method based on load importance and new energy uncertainty. The method constructs a load importance evaluation system considering structural characteristics, outage loss, regulation capability, and other factors. To determine the importance of each load, the method uses the ideal solution method and ranks them accordingly. Next, the method calculates the power supply coefficient, which represents the power supply capability of the power source to the critical loads. This calculation involves using the three-point estimation method, which combines the characteristics of the new energy output and the importance of each load. Following that, the evaluation of load importance and the power supply capacity to critical loads is accomplished based on the ideal solution method, taking into account the diversity of power supply characteristics. This comprehensive evaluation allows us to assess the significance of each load and the power supply capability to meet the needs of critical loads, considering the unique characteristics of each power source. Finally, an example analysis is carried out on the IEEE39 to calculate the importance of various types of power sources, which can accurately reflect the power supply capacity of power sources to important loads and verify the validity of the evaluation method. This method provides subsidies for future power system grid planning and operation.

Analysis of the spatiotemporal distribution pattern and driving factors of renewable energy power generation in China

Existing studies have primarily focused on the resources and technologies related to renewable energy. However, it is essential to investigate the influence of economic, social, and governmental actions on the spatiotemporal changes in renewable energy. This paper utilizes spatial autocorrelation analysis, fixed effects modeling, and Geographical and Time Weighted Regression (GTWR) to analyze the phased characteristics and spatial differences of renewable energy electricity, based on time series and spatial layout data of renewable energy power by province and power source type in China. Additionally, it incorporates relevant economic, demographic, and investment data to identify the driving factors behind the spatiotemporal transformations of photovoltaic (PV) and wind power, as well as the main forces promoting sustainable growth. The study reveals the presence of spatial agglomeration in China’s renewable energy power generation. Moreover, a positive correlation is observed between investments in environmental protection (EPI), state-owned electric power (SPI), scientific and technological advancements (STI), and renewable energy electricity. Technological progress has reduced the dependence of renewable energy on the natural environment, facilitating its promotion and widespread adoption. These findings provide empirical support and policy guidance for the sustainable and rapid growth of China’s renewable energy industry.

A real-time operational management strategy for vehicular hybrid propulsion system based on GRNN-AECMS

The driving characteristics of a hybrid propulsion system (HPS) depend on operational management strategies. However, the differences in output and response of various types of power sources make real-time management of operating conditions complex. In this study, an operational management strategy, which combines adaptive equivalent consumption minimization strategy (AECMS) and general regression neural network (GRNN), is proposed for optimizing power controls within hybrid power sources. Under this strategy, the optimal function of the AECMS is adaptively calculated by the load profile changes based on GRNN’s prediction results, and it is more suitable for the HPS. Furthermore, the proposed GRNN-AECMS method can minimize fuel consumption and meet requirements for power tracking. From simulation results, fuel consumption under GRNN-AECMS method can be reduced by 2.715 kg, or 31.8%.

Multi‐type power generation planning method for power systems based on complex adaptive system theory

AbstractAiming at the problem of multi‐point power source layout planning for power systems, the output characteristics of a power system composed of wind power, photovoltaic power, hydropower, traditional thermal power, concentrated solar power and electrochemical energy storage are comprehensively analyzed. A power source multi‐point layout planning model for a power system based on complex adaptive system theory is proposed with a focus on the complementarity among these different energies and the combination of power optimization planning and complex adaptive system theory. With the minimum construction unit of various types of power sources as the ‘agent’, considering the interactions among agents and the accumulation of experiences, the behaviour rules of the model are constantly changed, the grid‐connected positions of various types of power sources are adjusted, and the optimal layout schemes for all kinds of power capacities for each node are obtained. In addition, an agent modelling method based on complex phenomena emergence with simple rules is proposed, which reveals the core idea of the complex adaptive system theory: adaptability creates complexity. Taking the new energy construction base in Northwest China as an example, the proposed method is verified to have a significant effect on improving energy consumption in the new system. Based on the current power capacity layout and the future grid structure in this area, the future power optimization scheme is determined, and it provides guiding significance for actual engineering construction.

Adaptive additional current-based line differential protection in the presence of converter- interfaced sources with four quadrant operation capability

As typical representatives of converter-interfaced sources with four quadrant operation capability, battery energy storage station (BESS) and VSC-HVDC station behave differently with synchronous generator. This leads to the high risk of incorrect operation of current differential protection (CDP), seriously threatening the security of transmission network. Motivated by this issue, this paper presents adaptive additional current-based differential protection (AAC-DP). Adaptive additional current is introduced to modify the criterion of current differential protection. Ulteriorly, the unified expression of adaptive additional current for internal and external faults is designed. Adaptive additional current can increase the sensitivity during internal fault, whereas it improves the security during external fault. The sensitivity and dependability of AAC-DP was widely evaluated by changing operation mode, fault condition, and type of power source using PSCAD and RTDS-based experimental platform. Also, the adverse factors, such as saturation and error of current transformer(CT), and noise, were taken into account; thereof, the excellent security of AAC-DP was confirmed. The results confirm that AAC-DP exhibits excellent performance in operating speed, sensitivity, the adaptation to fault behaviors of BESS and VSC-HVDC, and robustness against saturation and error of CT, and noise.

Effect of EN ratio on bead profile and mechanical properties of MC 600 steel in submerged arc welding

ABSTRACT In the present work, the effect of electrode negative (EN) ratio on bead cross-section, mechanical properties and microstructure was analysed. The welding was performed on MC-600 steel of 12.5 mm thickness by two passes in butt configuration at three different EN ratios varying from 0.25 to 0.75. Out of different types of power sources, alternating current (AC) with the square wave was selected here for the experiment. Penetration depth and bead width decreased with an increase in EN ratio, but reinforcement height increased with an increase in EN ratio. There is no notable effect on yield strength but ultimate tensile strength increased slightly due to an increase in the EN ratio. Vickers hardness of weld at lowest and highest EN ratios is almost similar and slightly higher than that of the middle one. The impact toughness of all three locations improved with an increase in the EN ratio.

Fault phase selection method for high voltage transmission line of high proportion renewable energy system

In the high-proportion renewable energy source grid (HP-RES grid), the nonlinear controlled characteristics of renewable energy sources, make the fault characteristics of power grid more complex, which deteriorates the performance of traditional phase selection components of high-voltage transmission lines. Based on the engineering practice of typical HP-RES grid, this paper analyzes the adaptability of traditional phase selection methods under different operation modes of the system. On this basis, a fault phase selection method adapted for high voltage transmission line of HP-RES grid is proposed. The method combines the voltage amplitude and variation comparison to identify single-phase fault and multi-phase fault based on the instantaneous value integral algorithm. The single-phase fault identification and faulty phase selection are carried out by using the proportional relationship between the intermediate value and the minimum value of the measurement phase voltage, and the multi-phase fault phase identification and faulty phase selection is carried out by using the amplitude of the measurement line voltage. Considering the large short-circuit current in large operation mode as the factor, the fault phase voltage value will be increased to a great extent in the case of fault resistance. In order to prevent the phase selection error, the single-phase fault selection is carried out by using the phase type and proportional relationship between the maximum value of phase compensation voltage variation and the minimum value of phase-phase compensation voltage variation when the above single-phase selection criterion fails. The simulation results show that the proposed fault phase selection method is not affected by the power source type, suitable for weak power source side and can correctly select faulty phase under different operation modes of HP-RES grid, which has high reliability and sensitivity.

Research on power-load matching dispatching of Hydro-Wind-PV hybrid system in cascade

With the goal of “double carbon,” wind power and PV are connected to the grid on a large scale, which poses a great challenge to the safe operation of the grid. The synergistic optimization of “hydro-wind-PV hybrid systems” can bring into play the ability of coordination and mutual assistance between different types of power sources, which is one of the important measures to increase the safe operation of the power grid and reduce abandoned wind and photovoltaic power. Based on the analysis of the characteristics of hydro-wind-PV power, the “hydro-wind-PV” integrated network-source cooperative optimization scheduling model is constructed to maximize the source-load matching and the consumption of clean energy. Finally, the results of a case study of a hydropower-wind power-photovoltaic cluster project in southwest China are used to verify the rationality and feasibility of the model.

A closed-loop data-driven optimization framework for the unit commitment problem: A [formula omitted]-learning approach under real-time operation

Real-time operation of electric power systems under high penetration of renewable energy generation has to incorporate strategies for managing the uncertainty associated with this type of power sources. In the case of the unit commitment problem, models based on robust optimization have been widely used for the day-ahead computation of power dispatch and reserves schedule. Typical approaches use uncertainty sets with fixed levels of conservativeness, without considering the real-time performance of the solutions. This paper proposes a solution scheme for the adaptive robust unit commitment problem using online adjusted data-driven uncertainty sets. Conservativeness parameters of the uncertainty sets are dynamically calculated as a function of previous operating results and incoming data via reinforcement learning, resulting in an online learning-optimization framework. The paper also develops an experimental framework to simulate real-time operation under the proposed methodology. Out-of-sample experiments illustrate the effectiveness of the proposed scheme against well-known benchmarks with fixed robustness levels. Results show improvements in power generation costs, voltage violations, and use of reserves. Two systems of different sizes are analyzed, illustrating the scalability of the proposed approach.

Structure and electrochromic properties of WO3 thin films by direct current, pulsed direct current, and radio frequency magnetron sputtering from metallic and ceramic targets

The structure, morphology, and electrochromic properties of sputtered-WO3 thin films from ceramic and metallic targets were investigated. The films were produced using different types of power sources, namely, direct current (DC), pulsed DC, and radio frequency (RF) generators. Highly transparent as-deposited WO3 thin films grown at room temperature using each target changed to dark blue upon introduction of an electric field in electrolyte regardless of types of sputtering power. WO3 films obtained by sputtering the ceramic target using a pulsed DC power exhibited a large transmittance difference of 97.5% and high coloration efficiency of 55.2 cm2/C compared to the films using DC and RF powers, these films had higher response speeds and stable transmittance modulation after long-term cycle tests. WO3 thin films produced by sputtering a metallic tungsten target showed enhanced electrochromic performance when grown under DC power and a coloration efficiency of 69.1 cm2/C due to their porous microstructure. This article presents methods for the fabrication of low-cost and large-scale oxide electronic devices for various applications, such as electrochromic displays, that can be applied for mass production.