Marius Valerian Paulet, Alexandru Salceanu, Catalin Lazarescu, Ovidiu Bejenaru, B. D. Alistar
The paper presents a study on the relevance of the relative position of the human trunk to the plane of the supporting pylons of various Overhead High Voltage Power Lines (OhHVPL), from the perspective of currents induced by the generated magnetic field. A homogenous model of the human body that considers the trunk as a cylindrical ellipsoid has been developed in CST Studio software. After necessary theoretical brevity, the results obtained by simulation for the loop currents along the perimeter associated with the large axis of the transversal section of the trunk and that associated with...
Ovidiu Bejenaru, Catalin Lazarescu, Marius Valerian Paulet, Alexandru Salceanu
It is well known that the biological and health effects of electromagnetic fields (EMF) are an up to date theme and the associated impact should be taken into consideration. Aiming to estimate these biological effects, an essential item is the accurate estimation of the human exposure to different types of non-ionizing electromagnetic sources. The evaluation of human exposure is performed by determining the currents distributions inside the biological organs or tissues, modeling the different acting mechanisms and understanding the effects developed in living beings by various exposure...
Honghui Li,Wenhui Cao, Zengmin Wang, Jinjin Li, Qing He
Previously a differential programmable Josephson voltage standard (DPJVS) has been developed for precision ultra low-voltage measurement of microvolt (µV) level at NIM. In this paper we present an updated technology for microvolt Josephson voltage standard (MJVS) which uses a dual-channel Josephson array chip with NbSi barrier developed at NIM. It is a new type device to build two symmetric paths of microwave irradiation for differential frequencies applying to a pair of channels of Josephson junction array. This new approach can efficiently simplify the complicated DPJVS system, which has...
Guan Ze-xin, Li Wen-qiang, Zhao Yan, Ma Xue-feng, Sun Xiao-yan, Wang Da-long, Yan Hongrui
Frequency counter is an instrument for measuring frequency signal. According to whether the internal crystal oscillator is output or not, it can be divided into the oscillator output frequency counter and no oscillator output frequency counter. For the detection of non crystal oscillator output frequency counter, manual verification method is time-consuming and laborious. In order to realize automatic operation and improving the quality and the efficiency of verification, a research on design of the automatic system is carried out. On the basis of verification regulation, a automatic test...
Nejc Klevišar, Dušan Agrež
In this paper, the method for detecting cracks on graphite commutator with resistance measurement is described. Resistance is measured with four-point resistance measurement method when commutator is rotated. Result of measurement is surface resistance profile of graphite from which a cracks can be recognized. Information of the crack on the commutator graphite surface is hidden in the amplitude behaviour of a strongly distorted signal. Since the period of the amplitude changing is not constant the interpolation DFT algorithm is used first to estimate the current period along the turn of the...
Daniel Belega, Dario Petri, Dominique Dallet
This paper investigates the contribution to the sine-wave frequency estimator returned by the interpolated discrete Fourier transform (IpDFT) algorithm of a small amplitude interharmonic component located at least one bin apart the unknown frequency. An analytical expression for the frequency estimation error is derived assuming that a maximum sidelobe decay (MSD) window is employed and its accuracy is verified through computer simulations. Based on the derived expression some useful remarks are finally drawn.
A. Mariscotti, D. Giordano
Electric arcs are an unavoidable by-product of current collection by sliding contact in electrified transportation systems. Electric arcs are transient phenomena with implications for PQ measurements and wearing estimation and prevention of the sliding contact and catenary. Besides being heavily influenced by mechanical characteristics and material properties, their electrical characterization encompasses spectral properties and the influence of train and traction line circuits and relative position of infrastructure elements. This paper identifies the influence of such electrical and system...
Andrea Mariscotti
PQ metrics for DC distribution systems are considered and reviewed with the objective of covering typical PQ phenomena, of finding similarity with the more proven indexes for AC systems, identifying the most promising approaches. Both time and frequency domain methods are considered, with emphasis on compact implementation and immediacy of output quantities. Behaviour and performance are verified against a first set of data representing the line voltage of a DC 3 kV railway system.
Xuefeng Ma, Wenqiang Li, Mei Yang, Xinyan Wang, Jianbo Liu, Shang Wang, Zhixiong Chen
In this paper, the transfer characteristics of current measuring network for wet contact are determined, the current measuring network is calibrated with the method of high frequency voltage source. It has been verified that the measurement results consist with the requirements of IEC 61010-1.
Diego Cavaliere, Alessandro Mingotti, Gaetano Pasini, Lorenzo Peretto, Roberto Tinarelli
This paper presents a pole-mounted measurement system to detect the leakage current of surge arresters. Such a current is a paramount index to determine the aging of the surge arrester. Moreover, all the measurements acquired by the developed pole-mounted system are collected using drones. This way, in every drone flight a huge amount of data can be gathered from the grid. Hence, improving and fastening the power network monitoring and maintenance.