The role of gas storage in regulating natural gas peaks is crucial. Improper allocation of gas injection schemes during the injection process not only results in excessive energy consumption by compressors, but also leads to excessive pressure changes in certain individual wells and convergence of salt karst cavities, thereby affecting the long-term stable operation of gas storage. By combining the simulated annealing algorithm with actual field conditions, a multi-objective optimization function was established considering both compressor energy consumption and dispersion degree of wellhead pressures across all gas storage wells within the same block. The variable for this optimization was set as the gas injection volume during the task period for each gas storage well, while variables such as maximum design pressure of pipelines, minimum operating pressure, and maximum operating pressure of gas storage wells were taken into account. Additionally, constraints were imposed based on the maximum design flow rate measured by target flowmeters for multi-objective optimization purposes. Results indicate that compressor power consumption can be reduced by over 40% and formation pressure differences can be decreased by more than 90%. It is evident that this scheme provides assurance for ensuring long-term stable operation of gas storage through effective guidance on actual production operations.

In order to better protect the safety of bridge piers and ships, a step-by-step progressive high energy consumption anti-collision magnetorheological damper for bridge piers was designed for the problems of passive energy dissipation, poor dynamic response and anti-collision energy dissipation, and limited adaptability of the device. The structural parameters of the damper were established through the establishment of a mechanical model. The structural strength and magnetic circuit were analyzed using finite elements. The results show that the strength of the structural components meets the requirements, the magnetic induction strength at the gap under 2 A current can reach about 1.2 T, three pistons are set up in the cylinder barrel, which can work together under different crash depth displacements to divide the energy dissipation of the damper into three stages, the minimum damping force under no current is 15 kN, the maximum damping force is 496 kN, and the damping force improves with displacement by 481 kN. The damping force under 2.5 A current increases with displacement from 78 kN to 1 204 kN, which is an improvement of about 15 times. It effectively improve the force of the damper and achieve the excellent effect of graded progressive impact energy dissipation. The application in the bridge pier collision avoidance device can achieve semi-active collision avoidance energy dissipation. The theoretical and finite element simulation results basically coincide with each other, proving the rationality of the damper design.

In order to solve the problems of excessively long droplet break time and excessively large droplet length to diameter ratio in the production of high-temperature and high-viscosity temporary plugging agent, the minimum velocity of droplet forming of temporary plugging agent was obtained by theoretical calculation, and the formula for calculating the optimal disturbance period was derived. The numerical simulation method was used to analyze the droplet forming process of temporary plugging agent, and the changes of the flow field of the droplet forming under the action of no disturbance and external square wave disturbance were explored. The simulation results show that without disturbance, the jet is difficult to break into droplets within 300 mm, the jet temperature is basically unchanged within 0.5 s, and the jet velocity increases to 2.13 times of the initial velocity. When square wave disturbance is added to the outside, too short disturbance period is not conducive to uniform droplet forming, and too long disturbance period will lead to excessive elongation of liquid column before fracture. When the disturbance period is about 0.11 s, the droplet forming efficiency is the highest, the fracture frequency is stable at 0.11 s, and the final droplet length-diameter ratio is stable at about 2. The research results provide a basis for the selection of process parameters for droplet forming of high viscosity temporary plugging agent.

Aiming at the problem of redundancy in the phase space reconstruction of sample entropy algorithm, the phase space reconstruction process of sample entropy algorithm was replaced by a symbolic variable matrix, and an improved sample entropy algorithm was established. The analysis of white noise and powder noise simulation signals shows that the improved sample entropy algorithm can extract signal features effectively and has high computational efficiency. In the past, bearing clearance faults of complex compressors were studied, and the improved sample entropy algorithm was applied to extract features and compared with sample entropy. The feature extraction results of the method are highly consistent with the sample entropy algorithm, and the computational efficiency of the algorithm is much higher than that of the sample entropy algorithm.

In order to explore the application of carbon fiber composite in portable weapons, the technical research on the structural properties of the launcher and the method of composite laminating was carried out. The working pressure of a certain type of launcher was obtained through experiments, and different carbon fiber composite layering models were established by using finite element numerical simulation method. Then the mechanical properties of the launcher under working load were studied. The results show that the layering method of carbon fiber has a great influence on the stiffness and damage failure of the launcher. Under the condition of the same working pressure, the same number of layers and the total thickness, the maximum deformation of the launcher structure is 2.41 mm in the layering mode Ⅰ. The maximun deformation of mode Ⅱ is 7.66 mm, and the latter is more than 3 times of the former. According to the Hashin failure criterion, there is no damage in the carbon fiber cylinder of the mode Ⅰ, except for the 6th to 12th fiber layers in the middle of the cylinder according to the mode Ⅱ, a large range of initial damage points are found in other layers. The research results can provide reference for the stucture design of the launcher and the carbon fiber composite layering scheme.

To enhance the grid connection stability of virtual synchronous machines, a global optimization design method for virtual synchronous machine control parameters was proposed. Firstly, a small-signal model of the virtual synchronous generator with virtual exciter and governor was established, and the system eigenvalues were obtained by solving the state matrix. Secondly, the sensitivity of the controller parameters to the position of eigenvalues was studied, and a wide range of parameter optimization was conducted using genetic algorithms based on the main eigenvalue positions. Finally, analytical solutions of the model and MATLAB/Simulink simulation data were compared. The results show that significant improvements in frequency stability can be achieved by optimizing a wide range of virtual synchronous machine parameters. After optimization, the system response transient stability time is 0.25 s, only 5% of the transient stability time with general parameters, and the frequency stability improves noticeably with load changes.

A novel multi-objective optimization design method for permanent magnet roller based on improved particle swarm optimization algorithm and RMxprt co-simulation was developed to address the issue of low optimization efficiency when relying solely on expert experience. Firstly, an improved particle swarm optimization algorithm was proposed to enhance the convergence speed of the optimization process. Secondly, based on the analysis of the relationship between the structural and performance parameters of the permanent magnet roller, the variable parameters, constraint parameters, and optimization parameters for the improved particle swarm optimization algorithm were determined. Lastly, a MATLAB program for the improved particle swarm optimization algorithm was developed to achieve closed-loop iteration and comparative optimization of the input and output parameters in RMxprt, thereby improving the efficiency and effectiveness of the optimization design for the permanent magnet roller.

With the acceleration of the transition to new energy systems, it is urgent to carry out in-depth research on the complex energy characteristics of multi-load users. A technology of constructing user energy characteristic label library and a user portrait method were proposed, which comprehensively considered the coupling characteristics of electric, cold and thermal multiple loads. Firstly, the high redundancy and low correlation features were eliminated by the fast correlation filtering algorithm, and the features with strong distinguishing ability were selected by the random forest and recursive feature elimination algorithm. In the clustering stage, the improved three-way adaptive density peak clustering (3W-ADPC) algorithm improved the load clustering effect by combining the adaptive neighbor search and the three-branch clustering algorithm. The empirical results show that the proposed method has dual advantages in computational efficiency and clustering accuracy, and can accurately reveal the comprehensive energy use characteristics and deep information of multi-load users, which confirms the practical value of the proposed method in the study of multi-load users’ behavior.

Aiming at the problems of anti-noise, anti-high resistance and complex threshold setting of traditional pole selection methods, a fault selection method of flexible DC distribution line based on Res-BiLSTM network was proposed. Firstly, the original fault signal was subjected to complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN), and then the reconstructed signal was obtained by using the correlation coefficient and Shannon entropy for reconstruction. Secondly, the Res-BiLSTM network model was constructed for the pole selection. In order to improve the network accuracy and the convergence speed, the channel attention module was introduced into the split-attention network. The reconstructed signal features were extracted using the convolutional bidirectional long short-term memory and the improved split-attention network at the same time. The extracted features were fused using the attention feature fusion module, and the fused features are classified. Finally, PSCAD/EMTDC was employed to construct the model and to verify the proposed methodology. The simulation results show that the proposed pole selection method is highly accurate, anti-interference, and independent of fault distance.

Under the dual carbon background, a multi-domain communication architecture was constructed to address issues such as a single communication mode and poor adaptability between business and communication technology in the new power load management system. The key supporting technologies of this architecture were comprehensively analyzed. Additionally, an adaptability evaluation system for business and communication technology was developed based on varying business types and their specific communication requirements. A communication technology adaptation method was proposed, employing the fuzzy analytic hierarchy process (FAHP), the CRITIC method, and grey relational analysis-technique for order preference by similarity to an ideal solution (GRA-TOPSIS). The proposed method facilitates the analysis of adaptability between differentiated business requirements and multi-domain communication technologies. The analysis of case studies indicates that the proposed architecture and the adaptation method offer an effective theoretical basis and solution for selecting multi-domain communication technology for the new power load management system business.