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At present, the method of obtaining the voltage of transmission lines by using the inverse problem of the electric field is generally faced with the difficulties of solving data equations. Aiming at the above problems, the method that solves transmission wire voltage through spatial electric field integration based on D-dot sensor is proposed. In this paper, with the ground as the reference potential and the vertical line of the transmission line to the ground as the integral path, D-dot electric field sensor is applied to measure the instant electric field values of several nodes on the integral path and the transmission wire voltage is directly solved combined with Gauss–Legendre numerical integration algorithm. The Gauss–Legendre algorithm is verified by the electric field distribution data on the integration path obtained by simulation. Furthermore, the improvement of the Gauss–Legendre algorithm is realized through optimizing the integral interval so that the location of integral nodes is more reasonable. Finally, the measurement system based on LabVIEW is designed and the experiment platform of the analog transmission line is constructed. Experiment results show that the measurement method of transmission wire voltage through the improved Gauss–Legendre algorithm based on D-dot sensor owns high accuracy with an error of less than 1%. [ABSTRACT FROM AUTHOR]

In urban and industrial areas, a relevant presence of buried metallic objects (e.g., gas and water pipes, etc.) can be detected. Usually, these elements are imagined as widespread meshed metallic grids in a good contact with the soil. In the last years, an arising interest on their role in the identification of a global earthing system has been expressed by the scientific community. Unfortunately, the geometrical and electrical properties of this kind of buried metallic parts cannot be provided by any documentations. This is mostly due to the fact that no trustworthy schemes are provided, as the management of these metallic parts is responsibility of different companies, which have installed them during several years. In order to characterize the buried metallic elements with reference to the electrical safety issue, the main quantity of interest is their resistance to earth. With this aim, a field measurement campaign was organized and the resistance to earth of more than 800 metallic objects has been evaluated through a simplified measurement protocol. In this paper, the measurement protocol, the setup, the results, and their analysis are reported. [ABSTRACT FROM PUBLISHER]

Based on the similarity theory, a reduced-scale model is proposed to study the voltage distribution characteristics in ultrahighvoltage direct current converter transformer windings under the impulse voltage. Through comparing the distribution characteristics of electric field intensity and magnetic flux intensity of the scale model with that of the original model, the effectiveness of the reduced-scale method is verified. Furthermore, the actual production design is also considered in the model. The matrices of the inductance, capacitance, and resistance parameters for the reduced-scale model are obtained by finite element method. Then, the multi-conductor transmission line model is set up to study the propagation process of impulse voltage along the windings of the converter transformer. The voltage distribution curve is obtained under a standard lighting impulse voltage and the turn-to-turn fault is taken into consideration as well. The simulation results are the basis for the following experimental study. [ABSTRACT FROM AUTHOR]