Single Power Line Research Articles

Simulation and Analysis of Arc-drop Deformation of High-voltage Cables with Three-dimensional Laser Scanning Point Cloud

In order to investigate the influence of environmental factors on the deformation problems occurring in high voltage cables, this paper proposes a method for analyzing the deformation of high voltage cables based on 3D laser scanning. Firstly high voltage cable point cloud data is acquired. Secondly, a single power line is segmented using a density-based clustering method, and a mathematical model of the high-voltage cable is established using the least squares method. Then the high-voltage cable is downscaled from three-dimensional points to two-dimensional points to do the fitting of parabola on the plane. Finally compare the horizontal displacement and vertical displacement of the lowest overhanging point of the high-voltage cable with the weather to affect its deformation causes. The experimental results show that: the parabolic approximate fitting equation of the high voltage cable can accurately express the shape of the cable, and the R value of the equation is around 0.999. The vertical displacement of the high-voltage cable in the high-temperature and high humidity environment changes significantly, up to 0.556 m. Horizontal displacement is significantly affected by the wind, the wind in the 7mph horizontal displacement change is the largest, the average displacement change of 0.197m.

Electrocution of Eagles in Mongolia

Steppe Eagles (Aquila nipalensis) and Golden Eagles (Aquila chrysaetos) are species of conservation and cultural importance in Mongolia. Electrocution at electricity distribution lines is a threat faced by both species across Central Asia. We present the results of power line surveys conducted in the Mongolian steppe region to elucidate temporal patterns of electrocution and specific danger points on power poles for eagles. There was spatial and temporal variation in electrocution rates for Steppe Eagles and Golden Eagles. Autumn surveys across Mongolia recorded the electrocuted carcasses of 18 Steppe Eagles and 9 Golden Eagles. The distribution of electrocutions revealed that Steppe Eagles are mainly killed at power lines in the central steppe zone; in contrast, only Golden Eagles were found at power lines in the southern ‘gobi’ desert zone. Daily surveys conducted for a year at a single power line in the eastern steppe detected 8 Golden Eagles and 6 Steppe Eagles. All Steppe Eagle electrocutions occurred between April and September as they are predominantly summer visitors in Mongolia, whereas six of the eight Golden Eagle electrocutions occurred in winter indicating that Golden Eagles can range over predominantly flat, open steppe landscapes at this time. Significantly more electrocutions occurred at poles with no crossarm mitigation compared to poles with deflectors, deterrents or covers, indicating that mitigation on the crossarm can reduce eagle electrocution rates. Furthermore, the absence of eagle carcasses at poles with crossarm mitigation suggests that crossarms are the main site of electrocution for eagles in Mongolia. Country-scale retrofitting of insulation to crossarms and pole tops significantly reduced eagle electrocution events.

Investigating the impacts of high voltage powerlines on ground current fields

Stray currents are a typical problem of areas crossed by electric railways. This well-known phenomenon can cause significant damage to all underground metallic installations, especially in case of DC stray currents. In areas close to the railway, the presence of stray currents is expected, and protective measures are applied to all sensitive installations like pipelines. However, field measurements have shown that the presence of high voltage power lines can significantly affect the ground current field due to the well-grounded ground wire representing an excellent alternative path for ground currents. This way, stray currents can appear in areas where the presence of ground current field from DC traction is normally not expected. Preliminary simulations have confirmed that high voltage power lines are a significant element affecting the spreading of ground current and the presence of high voltage power lines must be considered when investigating the ground current field of an area. However, these simulations were performed only for a limited area with a very simplified geometry of railway truck and a single power line. This paper presents results of a more complex simulation involving a large area crossed by a DC railway traction system and a complex high voltage network. The simulation is based on real topology representing an area around the town of Zilina, an industrial area with a complex high voltage network and an important railway hub.

Multifold Insights for Power System Dynamics From Data Assimilation: Meeting Current Challenges

The world’s electric power grids have evolved over the last 120 years from a single power line to today’s large networks. The evolution will continue at an accelerated rate with extensive smart grid development worldwide. For example, the U.S. government has set a goal of reaching 100% carbon pollution-free electricity by 2035, while the U.S. Department of Energy shared a goal to deploy 30 and 110 GW of offshore wind by 2030 and 2050, respectively. To meet such ambitious goals, a significant percentage of electricity will come from intermittent renewable sources and be supplied to a vast number of loads that will actively respond to grid conditions and incentive signals. This development is largely driven by environmental and economic factors, such as reducing carbon emissions and reducing electricity costs for consumers. These energy resources and responsive loads lead to new uncertain behaviors and dynamics that the grid has never seen and that were not considered in its design. Operating such a dynamic grid with sufficient reliability and efficiency is a monumental challenge. <xref ref-type="fig" rid="fig1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Figure 1</xref> presents three challenges faced by software tools used in power systems planning and operation along with solutions.

Mathematical Model of Single Overhead power Line in Symmetrical operation Mode of Higher Harmonic Switching

Mathematical Model of Single Overhead power Line in Symmetrical operation Mode of Higher Harmonic Switching

Research on Dual-Mode Communication Technology Based on Power Line Carrier and Micro Power Wireless

At present, the power meter reading system mainly uses the single power line carrier meter reading mode or the single micro power wireless meter reading mode. Due to the disadvantages of the two modes, the single meter reading mode can not meet the meter reading under different environmental conditions. In order to improve the success rate of communication, this paper puts forward the dual-mode communication technology of power line carrier and micro power wireless integration, which is based on the power line carrier It overcomes the defects of single meter reading mode and improves the real-time performance, reliability and success rate of meter reading.

Smart Grid Communication Using Open Smart Grid Protocol

The smart grid transfers electricity from power utilities to the customers’ end using full-duplex digital communication technology and helps us to control the home appliances and factory machines to save electricity while reducing costs and increasing reliability and transparency. So, in order to ensure the grid reliability, we need to monitor and control the smart me-ters by means of data transfer and command signals on the single power line without using any other communication media to improve the cost-effectiveness of the proposed study. This paper proposes a hardware implementation of a Power Line Communication (PLC) protocol named Open Smart Grid Protocol (OSGP). This protocol is based on the Open System Interconnection (OSI) model. The proposed system comprises monitoring and controlling server (Lap-top/Desktop), power line communication modem, two PIC18f4520 microcontrollers, one energy meter and power line as transmission media. This protocol is first implemented on a server in C-sharp by using the OSI model approach, and then on micro-controllers in order to control the energy meter. The power line communication modem is used to send and receive the data between the server and the energy meter. Finally, results are presented to validate the hardware implementation of the protocol.

Variation in Electrocution Rate and Demographic Composition of Saker Falcons Electrocuted at Power Lines in Mongolia

We examined variation in the number and demographic composition of electrocuted Saker Falcons (Falco cherrug) in Mongolia. We found 1721 electrocuted Saker Falcons during our surveys of multiple power lines in 2013–2015 and 2018. At a single power line surveyed over a 16-mo period in 2013–2014, the lowest electrocution rates occurred from December to March, with a rise in April coinciding with the return of migrant juveniles from their wintering areas. Electrocution rates rose sharply during juvenile post-fledging dispersal, and then declined in October as migrants departed. Monthly changes in electrocution rate and age profile reflected predicted variation in abundance and age structure of the local Saker Falcon population. We found that 88% of electrocuted Saker Falcons were juveniles, mostly killed during their first calendar year. The sex ratio of electrocuted juveniles fledged in the 2013 cohort (hatch-year birds) was significantly female-biased, in contrast to the equal sex ratio of the 2012 juvenile cohort (second calendar-year birds) killed in the same year (2013). Sex ratio of the 2013 juvenile cohort did not differ significantly from parity at other power lines across Mongolia, indicating that sex ratio of electrocuted juveniles can vary in time and space. The sex of electrocuted adults, predominantly males, and an age profile of breeding Saker Falcons that includes younger females suggests a possible male-biased sex ratio among adult Saker Falcons in Mongolia. Given that large numbers of endangered Saker Falcons are electrocuted annually in Mongolia, our study suggests electrocution may be an important driver of demographic trends that can potentially result in population declines.

Research on High Voltage Power Line extraction based on Transmission Line Point Cloud characteristics and Model fitting

High-voltage power line digitization is one of the key contents of intelligent inspection of transmission line. Airborne LiDAR has obvious advantages in three-dimensional digital reconstruction of high-voltage power line. In this paper, a power line extraction algorithm for transmission line corridor based on LiDAR point cloud data is proposed. According to the distribution characteristics of point clouds in transmission line corridors, rough extraction of power lines is carried out. Noise points are eliminated by improved Hough and RANSAC parabola fitting method. Then the power lines are segmented horizontally and vertically. According to the vertical parabola model of a single power line and the straight line model of water surface, the complete power lines are extracted by model growth algorithm. Line point. The experimental results show that the accuracy of the proposed algorithm is 99.6%.

Short-Term Electromagnetic Interference on a Buried Gas Pipeline Caused by Critical Fault Events of a Wind Park: A Realistic Case Study

Short-term electromagnetic interference (EMI) pertains to the total result produced by the occurrence of intermittent, inductive, and conductive couplings on a buried pipeline system. For example, this type of EMI takes place when considering the fault conditions of a single ac power line, acting in the nearby vicinity of a pipeline system. In the context of this article, the effect of the short-term EMI is unfolded through a real case study. This case study involves a 20.7-MW wind park (WP) with extended underground power cable connections, which are laid nearby a high-pressure gas pipeline system. In particular, the impact of critical fault events, associated with the WP's power cables, on the pipeline system is comprehensively assessed. The assessment is achieved by the concurrent use of two powerful software tools that are respectively eligible for the accurate short-circuit analysis of the electrical circuit of the WP and for EMI evaluation on the pipeline. To this extent, the simulation results are thoroughly discussed and an effective mitigation solution is evidently presented.

A surface wave exciter adapting to different‐diameter lines and its application to single power line communications

A surface wave exciter adapting to different-diameter lines for single power line communications is proposed in this article. A side-feeding structure is designed which enables surface wave communication on existing power lines without any damage. The proposed surface wave exciter is mainly composed of a horn, two symmetrical feeding structures, a separable feeding ring, and a separable short-circuit metal ring. In order to avoid high order modes caused by insufficient excitation of side-feeding structure, two-port feeding structure is proposed. Meanwhile, the impedance matching of the exciter is improved. The exciter is designed to adapt to several lines with different diameters by using the separable feeding ring and short-circuit metal ring. Two prototypes for the proposed design are fabricated and tested. The measured results indicated that the input reflection coefficients ( S11) are less than −10 dB and the efficiencies are better than 30% in the Sub-6 GHz wireless communications. Moreover, a single power line communication system, which uses surface wave to transmit signal, is set up and tested. The transmission loss and the throughput are investigated to further prove the reliability of single power line surface wave communications.

A Novel Method for High-Voltage Bundle Conductor Reconstruction from Airborne LiDAR Data

The security of high-voltage power transmission corridors is significantly vital to the national economy and daily life. With its rapid development, LiDAR (Light Detection and Ranging) technology has been widely applied in the inspection of transmission lines. As the basis of potential hazard detection, a robust and precise power line model is a necessary requirement for rapid and correct clearance. Thus, this paper proposes a novel method for high-voltage bundle conductor reconstruction, which can precisely reconstruct each sub-conductor. First, points in high-voltage power transmission corridors are detected and classified into four categories; second, for classified power lines, single power line spans are extracted, and bundle conductors are identified by analyzing the single spans’ fitting residuals; and then, each sub-conductor of bundle conductors is extracted by a projected dichotomy method on the XOY and XOZ planes, respectively; finally, a double-RANSAC (random sample consensus)-based algorithm was introduced to reconstruct each power line. The proposed method makes use of the distribution of bundle conductors in high-voltage transmission lines, and our experiments showed that it could preferably reconstruct the real structure of bundle conductors robustly with a high precision better than 0.2 m.

Detecting Inspection Objects of Power Line from Cable Inspection Robot LiDAR Data.

Power lines are extending to complex environments (e.g., lakes and forests), and the distribution of power lines in a tower is becoming complicated (e.g., multi-loop and multi-bundle). Additionally, power line inspection is becoming heavier and more difficult. Advanced LiDAR technology is increasingly being used to solve these difficulties. Based on precise cable inspection robot (CIR) LiDAR data and the distinctive position and orientation system (POS) data, we propose a novel methodology to detect inspection objects surrounding power lines. The proposed method mainly includes four steps: firstly, the original point cloud is divided into single-span data as a processing unit; secondly, the optimal elevation threshold is constructed to remove ground points without the existing filtering algorithm, improving data processing efficiency and extraction accuracy; thirdly, a single power line and its surrounding data can be respectively extracted by a structured partition based on a POS data (SPPD) algorithm from “layer” to “block” according to power line distribution; finally, a partition recognition method is proposed based on the distribution characteristics of inspection objects, highlighting the feature information and improving the recognition effect. The local neighborhood statistics and the 3D region growing method are used to recognize different inspection objects surrounding power lines in a partition. Three datasets were collected by two CIR LIDAR systems in our study. The experimental results demonstrate that an average 90.6% accuracy and average 98.2% precision at the point cloud level can be achieved. The successful extraction indicates that the proposed method is feasible and promising. Our study can be used to obtain precise dimensions of fittings for modeling, as well as automatic detection and location of security risks, so as to improve the intelligence level of power line inspection.

Phases-controlled coordinated charging method for electric vehicles

When private electric vehicles (EVs), which will be the main part of the EVs' cluster in the future, are plugged in power system by single phase power line, can result to three-phase unbalance problem of distribution network. In this work, a phased-controlled coordinated charging method was put forward to solve this problem. Firstly, the impacts of charging load to distribution network was analyzed based on the equivalent circuit; and then an architecture of the control method and its corresponding optimal control model were introduced. The optimal model is a multi-objective optimization model, which includes minimizing load variance of each phase and minimizing the power asymmetrical degree of three-phase load; lastly, three scenarios considering balance and unbalance cases were envisioned to verify the reasonableness of this control method based on IEEE-37 distribution network. Results show that the phased-controlled coordinated charging method can minimize the load variance as well as the negative sequence current.

Evaluation of the correctness of operation of adaptive under-impedance criterion for HV single and double-circuit overhead power line with increased capacity

Evaluation of the correctness of operation of adaptive under-impedance criterion for HV single and double-circuit overhead power line with increased capacity

Analysis of power and energy losses in power systems of electric bus battery charging stations

Two variants of electricity transmission from the Transfer-Switching Station (TSS) to the battery charging station were analysed in the paper. The first variant under analysis referred to the transmission of electricity via a three phase a.c. line with rated voltage of 15 kV. In the second variant of electricity transmission, the d.c. line with the working voltage of 1500 V was used. For both variants, lines and other equipment such as transformers, rectifier system and voltage stabilisation system in the battery charging station were modelled. For both solutions, analysis of energy per annum was conducted depending on the distance of the charging station from the TSS. On top of this, the simultaneous operation of several chargers was taken into account, which would correspond to the case of charging many buses at the same time from a single power line. The paper demonstrates that in the case of the analysed electricity transmission systems in the electric bus battery charging systems it is possible to use a more advantageous solution, which is characterised by reduced power and energy losses.

Cost effective disaggregation mechanism for the NIALM system

Non-intrusive appliance load monitoring (NIALM) technology enables to detect the amount of power usage of each home appliance with single point sensing. In order to improve the performance (i.e., disaggregation/classification accuracy), features such as real power and harmonic components of electrical current of appliances are considered. However, taking more features into an account for better performance also increases the total cost of NIALM-related system. In this paper, a cost effective approach for NIALM is presented. With measured real power data sampled at low speed (about 1~2 Hz) from a single power line, classification of home appliances with high accuracy (about 80%) is achievable based on the proposed NIALM mechanism. The proposed mechanism is based on the real power time window pattern during a transient state and the real power level in a steady state after transition. The performance of the proposed mechanism is evaluated through simulation; classification accuracy is improved by 28% compared to the conventional NIALM approach based on real power delta scheme and 17% compared to the time window pattern.

Prototype AEGIS: A Pixel-Array Readout Circuit for Gamma-Ray Imaging.

Semiconductor detector arrays made of CdTe/CdZnTe are expected to be the main components of future high-performance, clinical nuclear medicine imaging systems. Such systems will require small pixel-pitch and much larger numbers of pixels than are available in current semiconductor-detector cameras. We describe the motivation for developing a new readout integrated circuit, AEGIS, for use in hybrid semiconductor detector arrays, that may help spur the development of future cameras. A basic design for AEGIS is presented together with results of an HSPICE™ simulation of the performance of its unit cell. AEGIS will have a shaper-amplifier unit cell and neighbor pixel readout. Other features include the use of a single input power line with other biases generated on-board, a control register that allows digital control of all thresholds and chip configurations and an output approach that is compatible with list-mode data acquisition. An 8×8 prototype version of AEGIS is currently under development; the full AEGIS will be a 64×64 array with 300 μm pitch.

Reactive Power Compensation in Single Phase Power Line Using FIR Filter

In order to compensate for the reactive power and to eliminate harmonic components of the current in single phase power lines, an active power filter with an FIR (finite impulse response) digital filter technique is worked out. The validity of the proposed method is studied by computer simulations and model experiments. In the experiments, the active power filter which consists of a single-phase full-bridge power MOS-FET inverter is used. The inverter is controlled by a DSP (digital signal processor). The active power filter is connected in parallel between the voltage source and the full-bridge diode rectifier as a load. Digital filtering operation done by the DSP provides the load current of the fundamental frequency. The voltage-in-phase load current of the fundamental frequency is computed with the phase signal of the line voltage. Subtracting the voltage-in-phase load current from the total load current, the reference of the compensation current is obtained. Comparing the reference and measured compensation currents, the voltage pulse width pattern of the inverter is generated.The digital filter used in this study was designed as a band-pass filter of 50Hz. Its filter length and the sampling frequency are 200 and 10kHz, respectively. Therefore, the time length of the sampling data of the measured load current required for the digital filtering operation is 20ms, i.e. one period for 50Hz. In other words, the transient response time for the reactive power compensation including harmonic current elimination is 20ms.With the active power filter, both of the third and fifth harmonics of the source current were reduced by 1/7.

On the Wave Impedance for Power Lines

Expressions for the wave impedance of traveling wave current on a single wire power line for frequencies in the 100 Hz-l MHz range are derived. The wave impedance (Z <L xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</L> ) is defined as the ratio of the vertical electric and the horizontal magnetic fields. A simple expression for Z <L xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</L> is given which is accurate to within 10%. A favorable comparison is made with experimental results. It is shown that Z <L xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</L> is usually significantly larger than the free space wave impedance (120π). However, for measurements in the AM broadcast band, 10-20 meters from the wire, 120πis a fair approximation to the wave impedance.