Latest ArticlesIn order to solve the problem of integrated energy coordinated dispatching, the design of virtual power plant based dispatching platform and the application of integrated energy coordinated dispatching model were proposed. The basic grid structure of virtual power plant is analyzed, and the overall architecture of virtual power plant is designed, which is divided into resource layer, platform layer and application layer. A network architecture and data flow architecture are designed. Based on this architecture, a virtual power plant scheduling application model for comprehensive energy coordination is established. The models for photovoltaic, wind power generation, electrolyzers, fuel cells, hydrogen energy storage, and battery energy storage are built, with reliability indicators as the starting point, an objective function with the lowest cost throughout the whole life cycle is proposed, and numerical examples are analyzed to illustrate the advantages of the proposed model in terms of reliability and cost.
With the continuous development of renewable energy, a large number of inverter interfaced distributed generations (IIDG) are connected to the distribution network, which puts forward new requirements for the traditional relay protection technology. In order to improve the power supply reliability of distribution network and adapt to the new power system with large penetration of renewable energy, an adaptive distance protection is proposed for distribution network with Tconnected IIDG. Firstly, the influence of fault at different locations on the protection is analyzed. According to the output characteristics of IIDG in case of system fault, the output current of IIDG is calculated by BP neural network using the local electrical information of the protection, and the action value is set immediately. Because this method does not need to communicate with the remote, the action speed is fast, and the investment of the communication system is reduced. Finally, the 10 kV distribution network model with Tconnected IIDG is established in MATLAB, and compared with the traditional distance protection to verify the superiority of this protection method.
With the rapid penetration of new energy sources such as photovoltaic power generation, the power system has put forward higher requirements for its participation in primary frequency regulation, requiring it to support the power grid in a more flexible way. In order to achieve more comprehensive frequency regulation, the key indicators for evaluating frequency quality are first determined according to the relevant grid specifications. Then, with the help of the motion equation of synchronous generator rotor, the effects of the constant of inertia and damping gain on the frequency quality are analyzed. Based on these research results, a coordinated control strategy of virtual inertia and frequency damping is designed, aiming to achieve the optimal frequency support of photovoltaic system with a certain power reserve. Finally, the performance of the proposed control strategy is verified by simulation, and the advantages and effectiveness of PV system participating in primary frequency regulation are displayed. By coordinating between virtual inertial control and frequency damping control, photovoltaic systems can support the frequency stability of the grid in an efficient manner.
Due to the intermittency and uncertainty of wind power on the time scale and complementarity on the spatial scale, the line capacity is underutilized and the cost of wind power is high in traditional planning. Combined with the output characteristics of largescale wind power, considering the smoothing effect, the construction cost of transmission projects, the cost of wind power curtailment, and the income, the economic evaluation model of offshore wind farm aggregation system is established, and the model is solved by using an improved genetic algorithm. The genetic algorithm is improved based on the minimum spanning tree of dynamic weight variation, and the coding, selection, crossing, and mutation links in the genetic algorithm are improved to promote the efficiency of the algorithm. Taking a wind farm cluster in Jiangsu Province as an example, the topology of wind turbines and the convergence and connection mode of wind farms are optimized, and the results show that the proposed algorithm has good optimization and convergence. And the established topology optimization model of wind farm and internal wind turbines can effectively reduce the engineering investment.
LiN2 battery is a new type of energy storage system with the function of electrochemical nitrogen fixation, and the electrochemical model established in the article used finite element software COMSOL coupled with multiphysics field can reveal the influence of various factors on its discharge performance. The simulation results show that: the discharge current density, temperature, cathode porosity and N2 solubility factor in the electrolyte have an effect on the discharge performance of LiN2 battery; a larger discharge current density will reduce the voltage and capacity of the battery; cathode porosity and N2 solubility factor in the electrolyte are the key factors that affect the voltage and capacity of the battery, and increasing the cathode porosity and N2 solubility factor in the electrolyte can increase the voltage and capacity of the battery; With the temperature rising, the voltage of the discharge platform of the battery increases, but the discharge capacity is almost unaffected by temperature.
Pitch control of large wind turbine is a complex nonlinear control task. How to achieve power regulation and load reduction under system constraints and wind speed disturbance has become a problem. For this problem, a controloriented linear parameter varying (LPV) model is constructed by using mechanism and parameter identification methods. The gap metric theory is introduced to reduce the complexity of the model, which provides a more accurate linear model for control design. Based on the obtained optimal states, an adaptive model prediction pitch controller (MPC)is proposed with the change of realtime wind speed. The coordinated control of powerload for large wind turbine can be realized under the conditions of system constraints. The simulation examples of OpenFAST show the effectiveness of the proposed model and controller.
This study addresses challenges associated with conventional parabolic trough solar power systems, including limited operating temperature and excessive thermal stress caused by uneven energy flux density distribution on the vacuum absorber tube's surface. Rather than altering the parabolic trough collector's structure, we introduce an innovative vacuum absorber tube design. This design involves reducing the diameter of the inner metal tube, shifting it downward, and adding a hyperbolic secondary concentrator above it to enhance solar energy concentration and improve energy flux distribution on the inner metal tube's surface. Simulation results for the new vacuum absorber tube yield promising outcomes. Optically, this novel design increases the concentration ratio from 62 to 71 and improves the uniformity of energy flux distribution by 55.05%. Importantly, these improvements come at the cost of only a 1.88% reduction in optical efficiency compared to traditional vacuum absorber tubes. Consequently, these modifications offer a substantial boost to the overall performance of the parabolic trough collector.