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The purpose of this investigation work was the study of the profile of the electric & magnetic field along live-line workers exposed body. The live line worker is exposed to the Saudi Electricity Company (SEC) 132 KV transmission line. Practical exposure scenarios which represent actual working conditions for live-line workers have been identified...
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Context 1
... real double circuit transmission line is selected by SEC. The selected line spans from substation 8114 (Qortoba Area) to substation 8079 (Alhamra Area-Khorais) in Riyadh region. Its nominal voltage and power ratings are 132 kV and 293 MVA respectively. Detailed line data and tower dimension are presented in Fig.1. and line details is delineated in Table II. The study is being conducted for three different exposure scenarios selected by SEC. The three selected scenarios described in Table III. The computation of the external electric and magnetic fields have been conducted for all three scenarios. These scenarios cover the most probable locations near a transmission line where live line workers are likely to be exposed for activities such as live insulator washing or live visual inspection. These three exposure scenarios are illustrated in Fig. 1. and described in Table III. These scenarios cover the most probable locations of a live line worker near a transmission line conductor. The height of a typical worker (human body) is assumed to be 1.75 m. The computation for both electric and magnetic fields is conducted from 0.5 m to 1.75 m of the human body using a step of 0.25 m. After comp utation of field’s values at these points along the human body, the maximum value of the electric is also ...
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Citations
... The exposure to electromagnetic fields produced by high-voltage facilities was considered in several published papers [5][6][7][8][9][10][11][12], focusing the attention to the electric and magnetic field strength, either by on-site measurements or by simulations. Different transmission lines configurations or exposure scenarios in substation were analyzed. ...
In this paper the authors present the results of a dosimetric analysis related to the exposure of live-line workers to the magnetic fields generated by high voltage overhead lines and substations. The study extends the work published by Dawson et al. in 2002, considering more evolved anatomical models nowadays available, the new reference limits given by the 2013/35/EU Directive, and a new methodology, based on the intercomparison of two alternative solvers and the use of data filtering. Moreover, additional exposure scenarios are here considered with respect to the studies already available in literature. The results show that for the exposure scenario of high voltage live line works with bare hand method, in any analyzed position, the exposure limits for the tissues of the central nervous system, as well as for all other tissues, are never exceeded, despite in some cases the action levels are exceeded. For the exposure of workers in substations near 220 kV and 380 kV line trap coils exposure is compliant with the regulatory limits if the current flowing through the line trap does not exceed the value of 1000 A. Finally, for the exposure of workers in substations near cable connections, electric field values induced in the body are always lower than regulatory limits with a phase current value equal to 1600 A r.m.s.
... As an example, we choose the 132 kV transmission tower that is used to transmit extra-high voltage over a long distance. Figure 1 shows the tower dimensions obtained from [25] and Fig. 2 depicts the tower model and its surface elements. ...
To detect faults on the power transmission and distribution systems, current electric utilities perform a visual inspection by dispatching line crews and helicopters. This practice has disadvantages such as high operation costs and safety concerns. To resolve these issues, power utilities are considering the use of an unmanned aircraft system (UAS). In this paper, we formulate an optimization model to find an efficient flight path for a UAS for visually inspecting a transmission tower. The objective of the model is to maximize a function involving three performance ratios, namely, flight time, image quality, and tower coverage. The optimization model is non-linear, non-differentiable, and multi-modal. We solve the problem by using a particle swarm optimization (PSO) based-algorithm and a simulated annealing (SA) based-algorithm and compare their results. We test the model under three inspection strategies. The experimental results show that the PSO-based algorithm outperforms the SA-based algorithm. They also show that the proposed model can provide a flight path that comprises a good balance over the three performance ratios.
... Increasing the line voltage is reflected in increasing the electric field, and increasing the current flowing through line is mainly reflected in increasing the magnetic field. High value of these fields can cause an adverse impact on the environment [1] and human health [2] occurring near the transmission line. Due to these adverse effects certain recommendations for maximum RMS values of electric Emax and magnetic Bmax fields, summarized in Tab. 1, can be found in ENV 50166 [3] or in ICNIRP guidelines (International Commission on Non-Ionizing Radiation Protection) [4]. ...
This paper describes calculation methods of magnetic and electric field under overhead transmission line (OHL), and a possible way of its reduction. The reduction is obtained by auxiliary shield conductors placed under phase conductors. All aforementioned calculations are derived generally in an analytical form and presented for one example model. The model consists of one tower with one transmission line, and RMS values of magnetic and electric fields are calculated for the control level at a given height above the ground to obtain both the fields profiles under the line. In case the field is too high, auxiliary conductors are placed under the line, and the original field is reduced. Reduction of original field depends on the number and placement of these auxiliary conductors or conductor loops, and a corresponding sensitivity analysis is performed. RMS values of electric and magnetic fields are calculated at control height above the ground and depend directly on the distance from the line. That means RMS values of fields depend directly on the conductors sag which depends on the conductor temperature and hence the current flowing through the line. Thus both the electric and magnetic fields are affected by conductor currents. Aforementioned facts are presented for one example. Sensitivity analysis of the current flowing through the line to magnetic and electric fields is performed, and reduction of fields by addition of auxiliary conductors under the line is calculated.
... Where, ε=8.85*10-12 F/m dielectric constant of air, (yi, yj) heights of conductors i and j above ground; (xi, xj) horizontal coordinates of conductors i and j [26]. ...
... (8) and magnetic field density is given by Eq.9. [26]. ...
In this study, the electric and magnetic fields occurred around the medium voltage power distribution lines (MV-PDL) in the residential area have been analyzed, and different MV and LV power distribution lines (PDL) in Antalya were selected in order to investigate the electromagnetic field exposure according to yearly-based current load on power lines. Knowledge of magnetic field levels determined around power lines is so important for completing acceptable epidemiological studies, and medium voltage power lines established in the residential area close to the apartments have been investigated. There are houses and apartments in a distance of 10m or less which have potential for child leukemia, since magnetic field levels are around 0.4 μT and up.
... Where, ε=8.85*10-12 F/m dielectric constant of air, (yi, yj) heights of conductors i and j above ground; (xi, xj) horizontal coordinates of conductors i and j [26]. ...
... (8) and magnetic field density is given by Eq.9. [26]. ...
In this study, the electric and magnetic fields which are occurred around the medium voltage power distribution lines in the residential areas close to housing are calculated analytically. Study, different MV-LV power transmission lines (PTL) which are settlements in Antalya city center have been selected. The electric and magnetic field values which are occurred around the lines have been examined and the results were evaluated in terms of safety standards and public health.
In this paper, we provide a review of the status and challenges utilizing MTJ based magnetic sensor for Grid applications. We show that with both modeling and experiment measurement, optimized MTJ based magnetic sensor can be utilized to monitor Grid current, particular for each individual line measurement. From sensor perspective, the sensitivity, the signal to noise ratio and the linearity can all meet the needs in the field. Unlike the traditional measurement, this measurement can be based on a contactless or “remote” sensing setup, where the sensor is placed away from the Grid line. One of the challenges is that the complex topology and multiple Grid lines may exists with different current levels. The other challenge is that with an improved sensing capability provided by MTJ sensors, significant more data can be collected, the system bottle neck has been shifted to transfer of data instead of sensing.
