Wireless sensor networks (WSNs) are widely used in industrial applications. However, many of them have limited lifetimes, which has been a considerable constraint on their widespread use. As a typical application of WSNs, distributed measurement of the electric field under high-voltage direct-current (HVDC) transmission lines also suffers from this issue. This paper first introduces the composition of the electric-field measurement system (EFMS) and its working principle. Considering the actual power supply of the system, this paper mainly introduces the composition of the wireless sensor node (WSND) and analyzes the power consumption and potential working state transformation of the WSND, together with a comprehensive study on parameters affecting the power consumption of the wireless communication unit. Moreover, an energy-efficient scheduling approach is proposed after specially designing a working sequence and the study on system parameters. The proposed approach is verified by experiments on not only the experimental line of the national HVDC test base, but also a commercial operation HVDC transmission line with the challenge of long endurance, which is considered in this paper with a new strategy. The results show that the proposed method can greatly extend the lifetime of the WSND.

The electric field is an essential electromagnetic environmental parameter in designing and constructing high-voltage direct-current (HVDC) transmission lines. In this paper, a differential structure is proposed to improve the performance of the field mill sensor. Two groups of vanes with the same characteristics generate induced currents with opposite phases, and the difference operation calculates the ground electric field. We calculated the charges and induced currents and optimized the number of vanes of the sensing electrode using the simulation model. Then we designed the I/V circuit and amplifier based on the differential structure and conducted circuit simulation and sensor calibration experiments. Compared with the single input electric field sensor, the noise of the sensor with the differential structure is significantly reduced, and the sensitivity reaches 0.085 V/(kV/m). The results indicate that the field mill sensor with improved differential structure enhances the anti-interference ability and sensitivity.

With the increase of space activities, the safety detection of equipment in supercold environment becomes more and more important. However, the safety detection of equipment in liquid hydrogen environment is an unsolved worldwide problem. In this article, we present a new method to detect acoustic emission (AE) signals in liquid hydrogen environment, which can be used to confirm the safety and reliability of the equipment working in liquid hydrogen. First, the principle of mandrel-based fiber-optic ring (MBFOR) AE sensor and the corresponding demodulation method are introduced. Second, the effects of physical parameters, such as the length of the sensing fiber, the diameter and material of the mandrel, and the number of fiber winding layers on the sensor's sensitivity, are studied by experiment. Finally, the AE source localization accuracy test of the FOR AE detection system at low temperatures and the adaptability test of the proposed method in −252.8 °C liquid hydrogen are carried out. The results show that the proposed MBFOR sensor and the multichannel AE detection system can complete the defects detection of aerospace pressure vessel in liquid hydrogen. Certainly, it can be used for safety detection for other spacecraft equipment in harsh environments.

High voltage direct current (HVDC) transmission lines have been widely used in China, and the electromagnetic effects of the synthetic electric field generated by them on the surrounding environment have attracted more and more attention. Especially when there are residential buildings around the transmission lines, the distortion of the electric field makes the research and development of synthetic electric field sensors with three-dimensional (3D) measurement capability an urgent technical demand. Based on the basic principle of the field mill electric field sensor, this paper presents a three-dimensional field mill structure to obtain the three-dimensional component of the electric field vector by using unidirectional motion. With the signal processing circuit, we realize the reading of three-dimensional electric field data. The feasibility of the proposed structure is verified by theoretical deduction analysis, numerical simulation, and prototype tests. The proposed structure provides a new scheme to solve the problems of three-dimensional synthetic electric field measurement and can enrich the existing methods.

Much attention has been paid to audible noise in the design of ultra-high voltage (UHV) direct current (DC) transmission lines because of its negative impact on residents' lives. In order to analyze audible noise, shorten the research period, and reduce experimental costs, firstly, a digital twin model for audible noise of UHV DC transmission lines is proposed. Then, the model’s structure and related principles are explained in detail. Finally, an application, as a research paradigm, uses digital twin to study the source distribution on transmission lines and influencing factors of audible noise. The A-weighted sound level of audible noise on the ground is calculated and compared with the data obtained by the BPA empirical formula. The results show that the position of the sound source tends to have uniform distribution and the intensity tends to have Gaussian distribution, while temperature and relative humidity exert obvious effects on audible noise, illustrating the great value of digital twin technology in the study of audible noise. This paper not only provides a new method for audible noise research, but also provides a reference for the design of UHV DC transmission lines.

Audible noise is crucial in designing and constructing high-voltage transmission lines. However, when measuring the audible noise of power lines, it is susceptible to interference from other noise sources in the external environment, posing significant challenges to data analysis and processing. To address the issue, we propose a method for measuring audible noise using a microphone array based on beamforming. We design filters using the FIR wideband beamforming algorithm and apply them to a single-direction incidence model. Filters designed using the phase iteration method are applied to a multi-direction incidence model. Factors affecting beamformer accuracy and solutions have also been discussed. Simulation results demonstrate that both filters effectively suppress interference signals from other directions while preserving the desired direction signal. Experiments in a corona cage show that the beamforming filters can suppress external interference noise by more than 10.2 dB, validating the proposed algorithms and providing guidance to design high-voltage transmission lines in the future.