To secure uninterrupted distribution of electricity, effective monitoring and maintenance of power lines are needed This literature review article aims to give a wide overview of the possibilities provided by modern remote sensing sensors in power line corridor surveys and to discuss the potential and limitations of different approaches Monitoring of both power line components and vegetation around them is included Remotely sensed data sources discussed in the review include synthetic aperture radar (SAR) images, optical satellite and aerial images, thermal images, airborne laser scanner (ALS) data, land-based mobile mapping data, and unmanned aerial vehicle (UAV) data The review shows that most previous studies have concentrated on the mapping and analysis of network components In particular, automated extraction of power line conductors has achieved much attention, and promising results have been reported For example, accuracy levels above 90% have been presented for the extraction of conductors from ALS data or aerial images However, in many studies datasets have been small and numerical quality analyses have been omitted Mapping of vegetation near power lines has been a less common research topic than mapping of the components, but several studies have also been carried out in this field, especially using optical aerial and satellite images Based on the review we conclude that in future research more attention should be given to an integrated use of various data sources to benefit from the various techniques in an optimal way Knowledge in related fields, such as vegetation monitoring from ALS, SAR and optical image data should be better exploited to develop useful monitoring approaches Special attention should be given to rapidly developing remote sensing techniques such as UAVs and laser scanning from airborne and land-based platforms To demonstrate and verify the capabilities of automated monitoring approaches, large tests in various environments and practical monitoring conditions are needed These should include careful quality analyses and comparisons between different data sources, methods and individual algorithms

https://cyberleninka.org/article/n/613852.pdf

Remote sensing methods for power line corridor surveys

The purpose of this paper is to present the most important achievements in the field of distribution power line inspection by mobile robots. Stimulated by the need for fast, accurate, safe and low-cost power line inspection, which would increase the quality of power delivery, the field of automated power line inspection has witnessed rapid development over the last decade. This paper addresses automated helicopter inspection, inspection with flying robots and inspection with climbing robots. The first attempts to automate power line inspection were conducted in the field of helicopter inspection. In recent years, however, the research was mostly focused on flying and climbing robots. These two types of robots for automated power line inspection are critically assessed according to four important characteristics: design requirements, inspection quality, autonomy and universality of inspection. Besides, some general not yet identified problems and tasks of inspection robots, which should be addressed in the future, are presented. In conclusion, the two robot types have specific benefits and drawbacks so that none can currently be considered generally advantageous.

A Survey of Mobile Robots for Distribution Power Line Inspection

This paper presents a new method for the boundary protection of series-compensated transmission lines, as well as fault classification. The boundary protection is based on detecting distinct frequency bands contained in the transient fault current wave. Discrete wavelet transform, using db4 as a mother wavelet, is used to capture two bands of frequencies in the transient current signal. The spectral energies of these two bands are obtained and used to determine if the fault is internal or external to the protected zone. Fault classification is done using the discrete wavelet transform. Using Haar as the mother wavelet, the coefficients of a frequency band in the range of 1 kHz-3 kHz are obtained for the three phase and ground currents. The average value of the coefficients of each current wave is then computed and used to classify the faulted phases. The basic principle of the protection scheme is described and its response to the series-compensated transmission lines is studied for a wide range of compensation levels, fault conditions, fault types, and fault locations. The stability of the algorithm under various load switching cases is also tested. Fault simulations are performed using power system computer-aided design/electromagnetic transient and direct current program and the results are then interfaced to MATLAB, where the algorithm is implemented. It is found that the proposed method gives reliable results in the boundary protection and fault classification of series-compensated lines.

Usage of wavelet transform in the protection of series-compensated transmission lines

Power line inspection is of the utmost importance for the reliability and stability of electric power distribution. However, manual inspection is a hazardous, slow, expensive and unreliable task. Therefore, new highly specialized robots are required to improve the overall quality and safety of the power line inspection. The research conducted so far has been mainly focused on the development of climbing and flying robots. This paper first addresses the main achievements in the field of robotic power line inspection. The proposed solutions are critically assessed and the associated problems are outlined. Based on these findings, a new concept for robot-assisted power line inspection, combining both climbing and flying principles, is proposed in the second part of the paper. The proposed concept is critically assessed and related to the other established concepts so as to demonstrate its advantages and feasibility for a routine power line inspection.

New Robot for Power Line Inspection

This paper presents a combined wavelet-support vector machine (SVM) technique for fault zone identification in a series compensated transmission line. The proposed method uses the samples of three line currents for one cycle duration to accomplish this task. Initially, the features of the line currents are extracted by first level decomposition of the current samples using discrete wavelet transform (DWT). Subsequently, the extracted features are applied as inputs to a SVM for determining the fault zone (whether the fault is before or after the series capacitor, as observed from the relay point). The feasibility of the proposed algorithm has been tested on a 300-km, 400-kV series compensated transmission line for all the ten types of faults through detailed digital simulation using PSCAD/EMTDC. Upon testing on more than 25000 fault cases with varying fault resistance, fault inception angle, prefault power transfer level, percentage compensation level, and source impedances, the performance of the developed method has been found to be quite promising.

Combined Wavelet-SVM Technique for Fault Zone Detection in a Series Compensated Transmission Line

An overview of the condition monitoring of overhead lines

A new high-speed protection technique based on fault generated high frequency (HF) voltage signals is developed and applied to the protection of EHV series compensated power transmission lines. It is a nonunit protection technique as it relies totally on locally derived information, but it has the discriminative properties normally associated with unit protection schemes. The protection scheme has been designed using CAD techniques including emulation of analogue interfaces and hardware. It is shown that the new relay scheme is able to overcome many difficult protection problems encountered on such EHV power lines using conventional methods, and discriminates clearly between internal and external faults, producing a fast trip output.

A novel non-unit protection for series compensated EHV transmission lines based on fault generated high frequency voltage signals

In view of increasing demand for reliable and high quality power supply, electrical utilities are interested in avoiding transmission failures by identifying problems at an early stage. However, degradation as a result of ageing and operational service conditions is inevitable. The monitoring and location of incipient failures on overhead lines, known as condition monitoring (CM) is thus imperative. This paper describes the design of a novel CM technique for overhead transmission lines using artificial neural networks (ANNs). The technique is based on utilising the high frequency phenomenon associated with the partial discharge (PD) activity emanating from various line conductor defects.

A new approach to condition monitoring of high voltage overhead lines using neural networks

This paper presents a simulation technique for modelling the partial discharge (PD) phenomena associated with defective conductors on overhead transmission lines. The PD results from the mathematical technique, based on an empirical approach, are compared with actual laboratory tests carried out on a typical 400 kV conductor subjected to defects commonly encountered under service conditions; the results show a close correlation between the two sets of results.

Simulation of the partial discharge phenomena in defective overhead line conductors through an empirical approach

This paper presents the results of an experimental study on the partial discharge (PD) characteristics of a single EHV overhead line conductor under AC voltage conditions in a metal cage. The conductor was subjected to various defects commonly encountered in line conductors under service conditions; these included the influence of rain on the PD characteristics. The results presented show the potential for the detection and subsequent emulation of PD caused by broken strands or damaged surface in overhead lines.

http://ieeexplore.ieee.org/iel4/5629/15083/00694816.pdf

J.A.S.B. Jayasinghe

Papers

An overview of the condition monitoring of overhead lines

A novel non-unit protection for series compensated EHV transmission lines based on fault generated high frequency voltage signals

A new approach to condition monitoring of high voltage overhead lines using neural networks

Simulation of the partial discharge phenomena in defective overhead line conductors through an empirical approach

An experimental investigation into the partial discharge phenomenon in defective high-voltage conductors