The current methods for predicting the state of health of lithium batteries often suffer from low accuracy. This paper introduces a method for state of health prediction using a seagull optimization algorithm optimized deep extreme learning machine. Key health feature parameters, such as constant voltage charging and discharging times during battery cycles, are selected and their correlation with the battery state of health is analyzed using Pearson correlation. The proposed model predicts subsequent state of health values by learning from samples. Experiments conducted with battery data compare the proposed method with single extreme learning machine, single deep extreme learning machine, and other literature. Evaluation metrics, including maximum absolute error and root mean square error, demonstrate that the seagull optimization algorithm optimized deep extreme learning machine model achieves higher accuracy and faster prediction times, with errors below 1.1%, indicating superior prediction accuracy and applicability.

This paper introduces the analysis process of a 500 kV substation DC system inter-pole short circuit fault. In order to deeply explore this special kind of DC insulation fault, based on the balance bridge principle of the DC insulation monitor, a circuit model of the DC inter-pole short circuit is established, and the process of obtaining the short circuit resistance of mutual short circuit is given. By calculating and analyzing the relationship between the control bus voltage and the short circuit resistance during DC inter-pole short circuit, the characteristics of DC inter-pole short circuit are summarized to provide reference for handling similar DC system faults.

In this paper, the high-voltage and high-power electrical connection methods of more- electric engines are reviewed. Firstly, the technical challenges of electrical connection faced by more-electric engines due to high-power motor components, high-voltage systems, and new control modes are analyzed. Secondly, the key technology analysis is carried out from the aspects of high-current connectors, transmission cables, laminated busbars, partial discharge, and electromagnetic compatibility. The design measures such as contact clearance, creepage distance, interface sealing, contact sealing and interlocking function of joining and separating are proposed for high-voltage and high-current connectors. The electrical transmission capacity of three transmission cables, such as copper power cables, lightweight power cables and superconducting cables, is analyzed. The busbar connection technology with high voltage and high working temperature is studied. The mechanism and solution measures of high-altitude partial discharge are analyzed. A combination of simulation and test solution is proposed for electromagnetic interference. Finally, it is pointed out that multi-dimensional optimization design should be carried out in the design process of more-electric engine to achieve the optimal electrical connection. The work of this paper can provide reference for the current design of lightweight electrical system of more-electric engine.

Considering that the network utilization cost in peer-to-peer (P2P) integrated energy transactions often accounts for more than 25% of the transaction costs, which significantly impacts the transaction benefits for prosumers, a P2P transaction strategy for the integrated electricity-heat energy system, which accounts for the network utilization cost, is proposed. Electrical distances in transaction path for electrical energy, and thermal resistances and lengths of pipelines in transaction path for thermal energy, are modeled to calculate the network utilization cost for both electricity and heat networks. By using the reputation index to assess the willingness of both parties participating in transactions, the optimization problem of P2P energy transaction strategy is constructed. Furthermore, a distributed solution method based on alternating direction method of multipliers (ADMM) is proposed. A P2P integrated energy simulation system comprising a 15-node electrical grid and an 8-node thermal network is established and further extended to a 33-node electrical grid and a 23-node thermal network system to verify the effectiveness of the proposed method and its scalability in P2P energy trading. Simulation results show that electricity-heat integrated energy P2P transactions with considering the network utilization cost are helpful to reducing energy transaction costs, promoting local energy consumptions, and increasing social welfares.

For a 220kV substation with 35kV capacitive voltage transformer secondary voltage abnormal drop fault, this paper introduces the structure of capacitive voltage transformer and its working principle. Then, combined with fault phenomenon, diagnostic test data, equipment disintegration inspection, the cause of the fault as ferromagnetic resonance overvoltage causing insulation breakdown of the differential and angular coils is analyzed and determined. Finally, some suggestions are put forward for the infrared temperature measurement and secondary voltage monitoring in the daily operation and maintenance inspection to improve the reliability of capacitive voltage transformer operation.

This study aims to effectively identify abnormal or non-compliant electricity consumption behaviors in electric vehicle charging stations, thereby enhancing the efficiency and accuracy of electricity management for these stations. Initially, the study analyzes the electricity consumption behavior characteristics of low-voltage charging stations, determining the differences in load characteristic curves between normal and abnormal electricity consumption states. Based on this, a clustering analysis algorithm is employed to extract load curve characteristics from operational charging stations and compare them with standard load curves to assess the presence of abnormal electricity consumption behaviors. Additionally, considering potential misjudgments arising from the “fast charging” and “slow charging” phases during the charging process, the concept of sliding difference linear fitting is introduced. This involves calculating the slope between each pair of 96-point load data points and using the number of slope changes to assist in the judgment of clustering analysis results. Through the aforementioned methods, users exhibiting abnormal electricity consumption behaviors have been successfully identified, providing technical support for the management of electricity consumption in charging stations.

The microgrid is an important part of the new power system. The energy coordination and interaction between microgrids is conducive to the consumption of new energy and improving the economy of the group. An energy collaborative optimization method considering demand response and carbon trading is proposed for multi-microgrid systems. Firstly, the framework of multi-microgrid energy collaborative optimization is constructed. Then, the internal resources of the microgrid are modeled, and demand response and carbon trading mechanisms are added on the original basis. Then, the objective function of energy coordination between single microgrid and multi-microgrid is constructed, and the improved beluga whale optimization is used to solve it. Finally, based on the simulation, it is verified that the algorithm can effectively improve the economy of multi-microgrid system energy cooperative optimization, and provide certain reference for the actual coordinated optimization operation of multi-microgrid.

Both sides of the high and low voltages of the auxiliary transformer, which is in the standby state for long time in the nuclear power plant, is still balanced after the single phase open on the high voltage side, posing a threat to the safe operation of nuclear power units. In order to detect the open-phase timely, the optical current transformer is selected to measure the current of the high voltage side accurately according to other electrical characteristics of the auxiliary transformer after phase open, and the corresponding identifying logic is developed according to different working conditions to determine the open-phase monitoring scheme. The setting method, resolution and measuring range of the optical current transformer are studied to understand its technical characteristics. The open-phase monitoring system is introduced from the aspects of hardware, software and logic. At last, maintenance strategy of regular inspection for optical current transformer is given.

Due to the input capacitive load characteristics of unmanned aerial vehicle (UAV) onboard electronic equipment, a high inrush current is easily induced during DC power-on transients, leading to reduced stability of the power system and potential system-level electromagnetic compatibility (EMC) issues. To address the demand for suppressing transient inrush currents, this study proposes an innovative pre-charge circuit suppression method based on a systematic analysis of traditional surge suppression schemes. By constructing a controllable pre-charge circuit and optimizing the RC time constant design, precise matching between the charging current and time constant is achieved, significantly reducing implementation costs while ensuring system reliability. Engineering validation demonstrates that this method effectively suppresses the peak inrush current within the rated operational current range and maintains stable power bus voltage. The research provides an engineering-practical solution for ensuring power quality in onboard electronic systems, particularly suitable for UAV platforms with stringent requirements for power supply integrity and electromagnetic compatibility.

In actual production and daily life, non-linear loads such as LED lights and LED screens are widely used. Such devices generate 3n harmonics, resulting in an excessively large current in the N line. The N line curent can be managed by configuring neural line safety protector (SNP) at the terminal. When there are a large number of SNP devices, the inspection personnel need to check them one by one, resulting in relatively low operation and maintenance efficiency. When there is an overcurrent in the N-line or other faults, timely feedback cannot be obtained, and ultimately, the SNP is damaged, causing economic losses. This paper proposes a method for N-line overcurrent protection and detection based on neutral line safety protector, which is realized through the internal hardware circuit. When the current value of the N-line exceeds the set value, the internal relay sends a dry contact signal to control the shutdown and alarm of the SNP. At the same time, users can monitor data and control the operation through the WiFi module and the network communication circuit. Finally, the practicality and safety of this method are verified through experiments. It has the advantages of providing timely feedback of information, protecting the safety of equipment, and facilitating operation and maintenance.