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The increasing demand for the high-capacity power transmission in areas with limited construction spaces has led to the inevitable application of multi-circuit high voltage underground cable systems. However, this solution can result in the occurrence of elevated sheath voltages together with increased power losses and it may potentially compromise the operational safety and efficiency of the systems. This study presents a detailed analysis using EMTP-RV software to compute the steady-state induced voltage on metal sheaths of multi-circuit underground cable systems. In addition, the sheath induced voltage influencing parameters such as the arrangement of cables and the configuration of sheath bounding strategies are verified through typical computation results. Moreover, a performance evaluation of sheath induced voltage mitigations is then carried out for a practical high voltage double circuit power cable system. The evaluation results show that the phase arrangement solution can be the suitable one to reduce the sheath induced voltage effectively without any additional cost while the power loss in the system is restrained at a reasonable level.

This paper presents on FBG Code Supervision into Single Core Underground Cable Power Line for Health Condition. Fiber Bragg Grating (FBG) is a novel technique for network health monitoring, offering numerous advantages such as high precision, multiplexing capabilities, resistance to electromagnetic interference, and excellent repeatability. The FBG sensor integrated into the network has been employed in numerous applications to monitor system and environmental conditions. Any interruption on the system or environment can be sensed and monitored through the status of network health. A consistent Fiber Bragg Grating (FBG) array situated before and after the splitter will be utilized to reflect the optical signal that has been transferred along the fiber. As the network’s FBGs use different wavelengths to represent each line connection, FBG codes will serve as an indicator between one connection to another. In this paper, a new technique is shown to monitor network health for single core underground cable by developing fault branch identification FBG configuration designs (FBG codes) up to 36 branches while maintaining quality of power transmission. Its capabilities are confirmed by simulations using real model data and it shows the potential to solve the various problems presently we have.

Mountainous regions, such as the Alps, Appalachians, Andes, and Qingzang Plateau, offer vast renewable energy potential, but geographical and ecological challenges limit conventional overhead transmission lines. Underground alternatives, including gas-insulated lines and cables, provide viable solutions but require comprehensive techno-economic evaluation for sustainable deployment. This study integrates multi-physics analysis, combining electromagnetic, thermal, and fluid dynamics, with lifecycle cost assessment per unit transmission task to compare overhead and underground tunnel transmission systems. Optimized conductor designs and ventilation strategies enhance cable capacity and improve economic performance, particularly in regions with high external costs. Here, we show that underground tunnel based power transmission systems, especially gas-insulated lines, deliver cost-effective, high-capacity transmission solutions for mountainous renewable energy concentrated regions, outperform overhead power transmission infrastructure when external costs, including ecological, landscape, and infrastructure constraints, are significant, thus advancing the goals of sustainable renewable energy integration and net-zero. The study evaluates underground tunnel transmission for renewable energy in mountains, using multi-physics analysis and lifecycle cost evaluation. It finds gas-insulated lines are cost-effective in areas with high environmental impact costs, optimizing conductor layout and ventilation for increased capacity.

Due to the unique challenges of underground environments, such as complex terrain, limited lighting, and safety hazards like collapses, water accumulation, and hazardous gases, the safety and health of personnel are at significant risk. Therefore, accurately detecting the physiological state of workers, particularly the recognition of eye states, becomes crucial. To meet the demands of detecting the eye states of workers in deep excavation operations under lower hardware conditions and in complex environments, this paper proposes an improved TOOD algorithm. The algorithm enables real-time detection in continuous frame sequences and extracts features using a well-designed lightweight ResNet50-NBt1D. Additionally, the use of a compact Feature Pyramid Network (FPN) to process data extracted by the backbone network further reduces computational complexity. By integrating an anchor-based training strategy, the model effectively selects multi-scale features and performs upsampling to achieve accurate classification and localization tasks, ensuring final detection precision while reducing unnecessary target information and parameter calculations. This provides a cost-effective solution for safety risk detection in deep excavation operations of underground power transmission lines. Finally, the proposed TOOD method was evaluated on a self-constructed dataset. Results show that the method achieved an average recall rate of 96.25% and an average precision of 97.16% in detection tasks, with a reduction in model parameters by approximately 71.62%. This demonstrates that the improved method offers an efficient and feasible solution for safety risk detection in deep excavation operations of underground power transmission lines.

This paper investigates the problem of wireless power transmission in underground pipeline detection systems. In response to the fact that during the study of the underground pipeline detection system, the coil inductance value changes due to environmental and anthropogenic factors, making the system detuned and unable to effectively acquire the underground microtag ID signal. Therefore, we raised a novel capacity compensation method to solve the problem mentioned above. Firstly, the hardware structure of the system is modelled, derived and analysed with the system in a resonant state. The topology applied to the system is then subjected to capacitive compensation operations to obtain the power transfer efficiency of the system in the resonant state with the best topology model. Finally, it is demonstrated through functional tests that the capacitive compensation of the optimal topology model achieves a good power transfer performance and acquires an effective ID signal.

Detailed and location-aware distribution grid information is a prerequisite for various power system applications such as renewable energy integration, wildfire risk assessment, and infrastructure planning. However, a generalizable and scalable approach to obtain such information is still lacking. In this work, we develop a machine-learning-based framework to map both overhead and underground distribution grids using widely-available multi-modal data including street view images, road networks, and building maps. Benchmarked against the utility-owned distribution grid map in California, our framework achieves > 80% precision and recall on average in the geospatial mapping of grids. The framework developed with the California data can be transferred to Sub-Saharan Africa and maintain the same level of precision without fine-tuning, demonstrating its generalizability. Furthermore, our framework achieves a R 2 of 0.63 in measuring the fraction of underground power lines at the aggregate level for estimating grid exposure to wildfires. We offer the framework as an open tool for mapping and analyzing distribution grids solely based on publicly-accessible data to support the construction and maintenance of reliable and clean energy systems around the world. Granular geospatial information of distribution grids is needed for various power system applications. Here the authors develop a machine-learning-based model which can accurately map distribution grids in both the U.S. and Sub-Saharan Africa.

Buried cables are located in harsh environments with high corrosion, uneven soil acidity and alkalinity, and groundwater immersion, resulting in complex structures. Especially for long-distance 10 kV transmission cables, the path planning is relatively long and cannot be connected at once, requiring a connection at the middle end of the cable. The production of cable joints is generally carried out in the foundation pit or well, with complex processes and manual production throughout the entire process, which cannot avoid manual technical deviations. Therefore, cable line faults mostly occur in the intermediate joints. Due to the uneven distribution of the temperature field caused by the accumulation of the electric field, the heat is transferred outward from the peeling chamfer point, resulting in uneven heating. In addition to the skin effect and proximity effect of current, the accumulation of electric field at the chamfer process point of the main insulation and outer semiconducting layer is intensified, and then the insulation is gradually broken down, causing a short circuit or ground fault. This article first studies the temperature and electric field distribution at the cable joint, and considers installing a small temperature sensor at the middle joint of the cable. The sensor is powered by a small electromagnetic energy coil, which can monitor abnormal temperature and electric field changes at the joint in real-time.

Electromagnetic interference from transmission lines to adjacent pipelines can adversely affect the safe functioning of these pipelines. In this paper, a simulation model that the transmission line crosses the buried pipeline is established in CDEGS software. The influence of current amplitude, soil resistivity, and cross angle on the electromagnetic interferences are analyzed under different operation conditions of transmission line, including normal operation, short circuit fault and lightning fault. The analysis results are as follows: the soil resistivity has a great influence on the coating withstand voltage under the short circuit fault and lightning fault condition; with the increase of the current amplitude and the cross angle, the coating withstands voltage increases and decreases, respectively. These results indicate that, during construction, it is advisable to avoid parallel layouts of transmission lines and pipelines. Pipelines ought to be built in regions characterized by lower soil resistivity.

The urgent need for power transmission is the reason for leading research on the safer operation of high‐voltage cables. These high‐voltage cables are emerging as an efficient technology for underground power transmission. However, the electrochemical corrosion of aluminium (Al) metal sheaths in these cables is a common and challenging degradation process. Herein, the corrosion mechanisms and electrochemical analysis are investigated by using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS) and laboratory‐designed electrochemical characterisation techniques. In the corrosion experiments, the authors evaluated the corrosion rate by measuring the release rate of hydrogen gas and explored the different roles of sodium polyacrylate (NaPA) during the corrosion process. It is found that the complexation reactions between NaPA and Al inhibited corrosion while increased the resistance of the buffer layer. The proposed mechanisms of corrosion in this study can improve the lifespan and sustainability of high‐voltage power transmission.