Situation Of Power Generation Research Articles

Vibration control on coupled unit-plant structure of pumped storage power station during sudden load-up process

The versatile regulatory capacity of pumped storage power station (PSPS) stems from the reversible pumped turbine unit switching between multiple operating conditions. Nevertheless, the unit and plant structure experience heightened vibrations owing to the intricate interplay of hydraulic, electrical, and mechanical excitations during transition processes, and the vibration responses fluctuate as operating conditions shift, posing a significant challenge to the safety and high quality operation of power station. To tackle the practical engineering issue, this paper delves into the sudden load-up scenario in power generation situation of pumped turbine, leveraging a finite element model encompassing the coupled hydraulic-mechanical-electrical-structural system (HMES) of PSPS and a mathematical model of unit shaft system, the impacts of dynamic loads induced by various vibration source on the unit and plant structure during transient condition, are meticulously analyzed and discussed through numerical simulations. Additionally, the magnetorheological damper (MRD), is incorporated into the PSPS to explore the effectiveness of MRD in controlling transient vibration in the interconnected unit-plant structure. The results indicate that the system parameters and associated load excitations undergo rapid fluctuations during the load-up process, bringing about noticeable oscillations in vibration amplitudes of rotor and turbine. The floors and fan hood of plant are the most vulnerable areas in terms of structural strength, with associated displacement amplitudes being most noticeable. The incorporation of MRD proves to be highly effective in mitigating the unsteady vibrations in both the unit and the plant structure during load-up course, as well as optimizing the motion patterns of rotor and turbine, promoting a notable reduction in frequency amplitudes of spectrum. Moreover, the maximal transient displacement amplitude of unit is significantly diminished, with the rotor experiencing a decrease of approximately 79%, while the amplitude of turbine declines by 16%. The displacement fluctuation ranges of the plant structure are observably diminished, and the complex frequency components of vibration signal are efficiently controlled. The transient vibration characteristics of the coupled unit-plant structure and the damping behavior of MRD during the transition process are unveiled by the research findings in this paper, which can offer valuable insights for the stability assessment and the research on vibration management of HMES for PSPS under the unsteady operation conditions.

Research on Optimal Control Method of Load Side Virtual Power Plant Based on Cloud Edge Collaboration

With the advancement of new power system construction, the large-scale layout of new energy power generation has gradually become a new format, and the overall new energy presents the characteristics of “rapid development of installed capacity, an increased proportion of low-voltage grid connection, and ultra-high penetration rate in some areas”. Under the new situation of power generation, power transmission, power distribution, and power consumption, to solve the problem of efficient and friendly interaction of “source, network, load and storage” in the power system and the consumption of renewable energy, “virtual power plant” came into being. However, there are limitations in aggregating resources in virtual power plants. To improve the effective participation of users, such as medium and low loads in power grid interaction, this article designs and implements a load-side virtual power plant control software system based on cloud-side collaboration. We use the virtual power plant operation control system to realize resource bidding and flexible participation in the response. The system can flexibly aggregate multiple types of resources through deployment verification, effectively realize precise tracking of instructions, and guarantee effective grid interaction.

Life cycle carbon footprint of electric vehicles in different countries: A review

Facing with upward pressure on carbon emissions from the transportation sector, governments actively promote the automation and electrification of the transportation industry, and intelligent electric vehicles (EVs) are ushering in their golden age. However, the debate over whether EVs are lower carbon than traditional internal combustion engine vehicles (ICEVs) has never stopped. To objectively evaluate the role of EVs in mitigating climate change and carbon emissions, this study provides an extensive review of the literature on the life cycle carbon footprint of various EVs, and compares the carbon emissions of EVs and ICEVs. Considering that the carbon emissions of EVs vary significantly geographically due to differences in the power mix, ambient temperature, and driving conditions, this review further compares the carbon emission reduction effects of deploying EVs in different countries. The results show that the life cycle carbon footprint of EVs is lower than that of ICEVs, despite the higher carbon emissions from battery production. According to the power generation situation of each country, countries dominated by renewable energy power generation are more suitable for adopting EVs, while in countries with a predominantly coal-fired power generation, the popularization of EVs should be accompanied by a focus on decarbonization of the electricity sector and infrastructure improvements. Overall, improving the production technology of EVs and increasing the proportion of clean energy generation will be helpful to achieve the decarbonization goal in the transportation sector.

Modeling and Simulation Analysis of Solar Thermal Electric Plants Based on Petri Net

At present, solar thermal power generation is in the demonstration stage, and the large-scale production is affected by many factors. In view of the characteristics of different operating modes of photothermal power generation, it is analyzed that the turbine needs to be started and stopped frequently due to different operating modes, which will lead to the instability of the output energy and the reduction of power generation efficiency. In this paper, the dynamic equation of energy conversion process is established by using the law of conservation of energy and conservation of mass. Combined with the logic switching criterion of the system, the system model was established by using the extended differential Petri net, and the validity and accuracy of the model were verified. Through the Petri net model of the system, the system’s working mode switching and power generation situation are analyzed due to the difference of direct normal irradiation intensity (DNI). Finally, the accuracy of the model is proved by comparing it with experimental data of the photovoltaic and thermal demonstration projects that have been connected to the grid.

Power system analysis and integration of the proposed Nigerian 750-kV power line to the grid reliability

The present situation of power generation in Nigeria obviously represents a challenge to our ability for rethinking the delivery of energy at maximum efficiency. Previous research on the existing Nigerian 330-kV network grid, recommended that the network be transformed from radial to ring because of high losses inherent in it and the voltage insecurity. In this study, the existing 330-kV network was reconfigured based on the identified regions mapped out for upgrade to form a ringed 750-kV super grid. The bus voltages of some of the buses in the existing 330-kV were upgraded to 750-kV and new transmission lines added to create an integrated super grid with a ring structure as compared to the radial nature of the existing 330-kV grid. These proposed buses have been selected for upgrade based on the fact that they are positioned in critical areas within the topology of the grid that transforms the existing radial structure to a ring one. The method is also cheaper than making the entire network a 750-kV system. Load-flow analysis was carried out on the existing 330-kV Nigerian Grid and the proposed Nigerian 750-kV integrated into the existing grid using Newton–Raphson algorithm. The results analysis of the new network revealed a significant reduction of 30.2% power loss. This was validated using the code-based MATLAB and Power World Simulation model-based software. Contingency analysis was also carried out on both grids using the Power World Simulator. The study revealed that the 750-kV super grid was able to mitigate the losses experienced on the existing grid significantly with better voltage profiles in all the buses. It also revealed that the new network (330-kV and 750-kV integrated) performed better to the single line contingency analysis with less violations occurring and no unsolvable cases.

Research on fault-tolerant operation strategy of rectifier of square wave motor in wind power system

In wind power system, the randomness of wind energy increases the probability of components fault. once the switch fault of the PWM rectifier is detected, it will lead to the distortion of the motor voltage and current waveform, the increase of torque ripple, the fluctuation of filter capacitor voltage, and the increase of harmonic content, which will affect the control performance and operation safety of the system. A common fault in a three-phase PWM rectifier is the open-circuit fault of the switch. This paper analyzes the current waveform distortion of the square wave motor when the rectifier switch fault, and proposes different fault-tolerant control strategies for different situations of switch fault, include single, double and triple switches fault. This method is based on several special driving modes under power generation situation of square wave motor. The strategy is easy to implement and does not need to change the circuit topology. It can realize fault-tolerant control of switch faults in the same side half bridge or the same bridge arm of the three-phase PWM rectifier. The effectiveness of the proposed fault-tolerant strategy is verified by simulation and experiment at the end of the article.

Hydrogen production technology by electrolysis of water and its application in renewable energy consumption

In order to deal with the energy crisis and environmental pollution, renewable energy power generation in the world has been rapid development. At present, the most widely used is solar energy and wind energy, but also caused a serious problem of abandoning light and wind. Hydrogen energy has become an ideal carrier of electric energy storage due to its high efficiency, clean and renewable characteristics. Electrolytic water hydrogen production technology with renewable energy as power source is one of the most promising energy conversion methods. This paper briefly analyzes the current situation of power generation and consumption of renewable energy in China in recent years, and then expounds the characteristics, principles, development status and improvement methods of alkaline, proton exchange membrane and high temperature solid oxide electrolytic water hydrogen production technology, and demonstrates its application prospect in the field of renewable energy power generation and energy storage with examples.

Resilient distributed economic dispatch of a cyber-power system under DoS attack

The economic dispatch problem of a smart grid under vicious denial of service (DoS) is the main focus of this paper. Taking the actual situation of power generation as a starting point, a new distributed optimization model is established which takes the environmental pollution penalty into account. For saving the limited bandwidth, a novel distributed event-triggered scheme is proposed to keep the resilience and economy of a class of cyber-power systems when the communication network is subject to malicious DoS attack. Then an improved multi-agent consensus protocol based on the gradient descent idea is designed to solve the minimization problem, and the prerequisites to minimize the system power generation cost are analyzed from the aspects of optimality and stability. Finally, the theoretical results are verified through a single-area 10-generator unit simulation.

Effect of Fouling on the Corrosion Properties of Solar Photovoltaic

With the gradual development of applications on solar photovoltaic, the PV power plant construction stage has transited to the PV power plant operation stage in China. In the most process of the solar photovoltaic, it is frequent that the decrease of the photovoltaic system efficiency and economic benefits always occurs, which are caused by the fouling on the surface area of the photovoltaic modules. And it has attracted the attention of the experts and scholars in this area. In this paper, through investigating the application status in photovoltaic station and the research status in fouling problems, the power generation situation of the practical projects on the clean and fouling monolithic solar panels is comparatively analyzed. So as to quantitatively analyze the influence extent of the fouling on photovoltaic power generation efficiency. And a kind of mechanized, automated cleaning device is developed, and the improving method of this problem is put forward.

De-carbonization of Electricity Generation in an Oil and Gas Producing Country: A Sensitivity Analysis over the Power Sector in Egypt

Fossil fuels are used in power generation in oil and gas producing countries due to the resource availability. However, the growing electricity demand, the potential exports revenues associated to hydrocarbons as well as the environmental policies have to be taken into account for the definition of the electricity generation mix. Thus, the development of the power generation capacities according to the resource availability and the economic factors (demand and costs) is investigated through a modeling approach. Over the past ten years, Egypt has become an important gas producer and a strategic gas supplier for Europe. Moreover, natural gas represents around eighty percent of the Egyptian power sector mix. However, this extensive share of natural gas in power generation mix could not be sustainable in long-term due to the limited hydrocarbons’ resources of Egypt. In this study, the current and future power generation situation of the country is analyzed through a dynamic linear programming model. Finally, a power generation strategy based on a gradual integration of nuclear and renewable is suggested.

Electricity generation analyses in an oil-exporting country: Transition to non-fossil fuel based power units in Saudi Arabia

In Saudi Arabia, fossil-fuel is the main source of power generation. Due to the huge economic and demographic growth, the electricity consumption in Saudi Arabia has increased and should continue to increase at a very fast rate. At the moment, more than half a million barrels of oil per day is used directly for power generation. Herein, we assess the power generation situation of the country and its future conditions through a modelling approach. For this purpose, we present the current situation by detailing the existing generation mix of electricity. Then we develop an optimization model of the power sector which aims to define the best production and investment pattern to reach the expected demand. Subsequently, we will carry out a sensitivity analysis so as to evaluate the robustness of the model's by taking into account the integration variability of the other alternative (non-fossil fuel based) resources. The results point out that the choices of investment in the power sector strongly affect the potential oil's exports of Saudi Arabia. For instance, by decarbonizing half of its generation mix, Saudi Arabia can release around 0.5 Mb/d barrels of oil equivalent per day from 2020. Moreover, total power generation cost reduction can reach up to around 28% per year from 2030 if Saudi Arabia manages to attain the most optimal generation mix structure introduced in the model (50% of power from renewables and nuclear power plants and 50% from the fossil power plants).