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Fault diagnosis of insulators in aerial images is an essential task of power line inspection to maintain the reliability, safety, and sustainability of power transmission. This paper develops a novel method for intelligent diagnosis of electrical insulators based on deep learning, termed Box-Point Detector, which consists of a deep convolutional neural network followed by two parallel branches of convolutional heads. These two branches are utilized to locate the fault region and estimate insulator endpoints, which presents a new representation for insulator faults. Endpoints of the faulty insulator string can provide detailed and correlative information for enhancing the diagnosis capability of component-dependent faults that occur on component bodies. The proposed Box-Point Detector implements all predictions including region and endpoint into one network thus forms an efficient end-to-end structure, and adopts a smaller downsampling ratio to generate high resolution feature-maps in order to preserve more original information for small size faults. Experimental results indicate that Box-Point Detector can accurately diagnose high-voltage insulator faults in real-time under various conditions. Compared with some previous works using Faster R-CNN, SSD, and cascading network, our Box-Point Detector shows more competitively capabilities with high accuracy and robustness. [ABSTRACT FROM AUTHOR]

Vegetation encroaching on overhead power lines can cause short circuit faults and pose a major threat to the security and stability of power grids. Therefore, establishing an effective visual detection algorithm to oversee potential circuit failures of the power lines is critical to the ongoing inspection of vegetation encroachment. This paper establishes a deep learning-based detection framework that utilizes the images obtained from vision sensors mounted on power transmission towers. The proposed detection framework includes three cascaded modules: (1) detection of vegetation regions based on the Faster Region Convolution Neural Network (Faster R-CNN), (2) detection of power lines based on the Hough transform, and (3) detection of vegetation encroachment based on an advanced stereovision (SV) algorithm. In particular, the proposed SV algorithm converts the detected two-dimensional (2D) image data of the vegetation and power lines to three-dimensional (3D) height and location results in order to obtain precise geographical locations. Case studies using field captured images provided by a Transmission System Operator (TSO) demonstrate the effectiveness of the proposed framework in detecting vegetation failures, thus improving overall reliability and reducing economic loss. [ABSTRACT FROM AUTHOR]

This paper presents a new adaptive fault protection scheme for transmission lines using synchronized phasor measurements. The work includes fault detection, direction discrimination, classification, and location. Both fault-detection and fault-location indices are derived by using two-terminal synchronized measurements incorporated with distributed line model and modal transformation theory. The fault-detection index is composed of two complex phasors and the angle difference between the two phasors determines whether the fault is internal or external to the protected zone. The fault types can be classified by the modal fault-detection index. The proposed scheme also combines online parameter estimation to ensure protection scheme performance and achieve adaptive protection. Extensive simulation studies show that the proposed scheme provides a fast relay response and high accuracy in fault location under various system and fault conditions. The proposed method responds very well with regards to dependability, security, and sensitivity (high-resistance fault coverage). Index Terms--Computer relaying, digital protection, global positioning system (GPS), phasor measurement unit (PMU), transmission-line protection.

Coupling phenomena between two parallel multiconductor transmission lines is usually dealt with using modal analysis techniques. However, when the interaction length is small compared to the wavelength, a simpler quasistationary approach can and should be employed. Using the latter approach, the general problem of the determination of capacitive and inductive differential voltages between conductors of the victim transmission-line circuit is addressed, resorting to the formalism of the per-unit-length series impedance and shunt admittance matrices. An application example concerning the interaction between an overhead power line and a two-conductor railway is presented. Results obtained are interpreted and validated using electromagnetic-field calculations. The dependence of the differential voltages on the frequency, on the interaction length, and on the lateral distance between interacting transmission lines is analyzed and discussed. [ABSTRACT FROM AUTHOR]

Insulator contamination remains an important technical problem because contamination-caused insulator flashovers may jeopardize the security of high voltage power systems. This paper updates an insulator selection guide with respect to contamination first published 25 years ago. As in that guide, this update relates primarily to contamination conditions in North America. Results of research that have led to a better understanding of contamination-caused flashovers, particularly for some types of nonceramic insulators are summarized. Assessment techniques for site severity are discussed. Even though they have improved significantly, no leading method has emerged. Artificial contamination test methods have been standardized. Mitigation techniques are discussed for extreme contamination-caused dangers, including important new knowledge regarding ice and snow flashover voltage reduction. caused. [ABSTRACT FROM AUTHOR]

Abstract-This paper studies the effect of the conducting hoods used to protect workers from the exposure to high-voltage power frequency and high-frequency communication electromagnetic fields. The finite-difference time-domain technique is employed to solve for the electric-field strength inside a human head model filled with biological material representing the human brain. By evaluating the field at several points and comparing the results with and without the hood, it is shown that at some spots in the head, the field is higher by a significant factor when the hood is present. It is also shown that with the presence of a see-through screen, the field intensity inside the head can be drastically. reduced by eliminating the resonance effects. Following our analysis, a general safety guideline can be prescribed and used by the workers when exposed to a broad frequency range spanning from extremely low frequencies to the radio frequencies. The method also enables investigations on how to design a hood that is most suitable for a given frequency spectrum. [ABSTRACT FROM AUTHOR]

An accurate method for the evaluation of 50-Hz magnetic fields produced by overhead power lines is presented. The method, which is based on the matrix formalism of multiconductor transmission lines (MTL), allows for a correct evaluation of all the currents flowing in the MTL structure, including the currents in the subconductors of each phase bundle, the currents in the ground wires, the currents in the mitigation loop (if present), and also the earth return currents. Furthermore, the analysis also incorporates the nonuniform character of the structure arising from conductor sagging between towers. Frequency domain magnetic field calculations are performed by vectorial sum of the magnetic effects originated by all the existing currents. For exemplification purposes the case of an actual 400-kV-1.4-GVA single-circuit three-phase line is examined. Results presented include a discussion on the effects of mitigation loops with or without capacitor compensation. [ABSTRACT FROM AUTHOR]

This paper presents a new methodology for automated route selection for the construction of new power lines, based on geographic information systems (GIS). It uses a dynamic programming model for route optimization. Environmental restrictions are taken into account together with all of the operating, maintenance, and equipment installation costs, including a new approach to the costs associated with the slope of the terrain crossed by the power lines. The computing and visual representation capacities of GIS are exploited for the selection of economic corridors, keeping the total costs under a threshold imposed by the user. Intensive simulation examples illustrate the power and flexibility of the proposed methodology. [ABSTRACT FROM PUBLISHER]

Tokyo Electric Power Company, Inc. began operation of the Nishi-Gunma UHV trunk line, the first 1000 kV-designed power line in Japan, in April, 1992. This line is expected to be the key line in a major trunk-line system that is being developed. It traverses high-altitude mountainous areas subject to severe environmental and meteorological conditions for a long distance. A system using Composite Fiber-optic Overhead Ground Wire (OPGW) is constructed to obtain precise information on this line for maintenance purposes. This system comprises three major functions; (1) meteorological and facility's monitoring for gathering meteorological data on such elements as winds, and icing and snow accretion, and for evaluating the corresponding reaction of the components such as conductor tension, and strain in the tower structure, (2) Industrial TV (ITV) monitoring for visual observation of weather, surrounding conditions and site facilities, and (3) fault section location for pinpointing faults quickly and determining the maintenance office that should respond to the faults. This is done by estimating the fault section accurately around the boundaries of the maintenance jurisdictions. This paper describes the development of these functions and results obtained from practical operation. Keywords: Power Transmission Line; Composite Fiber-optic Overhead Ground Wire (OPGW); Maintenance Information System; Fault Location

The electric field generated by power lines is usually evaluated by a simple 2-D model. Due to the presence of buildings or other objects near the power line, measurements are often in disagreement with the model. In this letter, the adaptive integral method (AIM) is used to analyze a power line in a real environment. The presence of a conducting ground plane, as well as a planar dielectric interface, is also efficiently built into the algorithm. [ABSTRACT FROM AUTHOR]