HV Transmission Lines Research Articles

220KV HV Transmission Line from Deir Ammar to Deir Nbouh in Northern Lebanon

220KV HV Transmission Line from Deir Ammar to Deir Nbouh in Northern Lebanon

Research Status and Development Trend of Obstacle Crossing Mechanism of HV Transmission Line Inspection Robot

With the rapid development of the power grid industry, the traditional manual inspection method is gradually being replaced by intelligent robot technology, which has been widely concerned around the world. The research of inspection robots aims to improve the efficiency and safety of transmission line inspection, while reducing labor costs and quickly identifying potential risks. The obstacle crossing mechanism of inspection robot is the core part of normal inspection of robot. This paper analyzes the obstacle crossing mechanism of inspection robot developed at home and abroad, summarizes the types and characteristics of the obstacle crossing mechanism, and finally puts forward the development trend of the obstacle crossing mechanism of inspection robot

Thermal analysis for multi-conductor bundle in high voltage overhead transmission lines under the effect of strong wind

Bundle conductors are widely used in HV transmission lines to suppress the corona discharge and reduce the line reactance. To determine its current ampacity of multi-conductor bundle, the thermal analysis is indispensable. A three-dimensional flow-thermal coupling model of multi-conductor bundle considering the effect of strong wind is developed in our study. Using the finite element method, both the temperature field and the fluid field are computed; the characteristics for the multi-physics fields are discussed; the interaction between the fields as well as the mutual influence between subconductors are elucidated. Moreover, a set of sensitivity analysis have been performed, and the effects of load current, conductor spacing, wind speed on temperature field and fluid field are investigated. Based on the pitch-diameter ratio, a novel method to improve the thermal performance of multi-conductor bundle is proposed. Finally, the optimized structure is obtained, and the current ampacity is expected to be greatly enhanced.

Experimental investigation of electromagnetic interference impact on phase change material coated solar photovoltaic panel

ABSTRACT High Voltage Transmission Line Electromagnetic Field’s (HVTL-EMF) impact on solar PV performance is analyzed in the proposed work. Depending on HV-EMF, the electrical characteristics and conversion process of PhotoVoltaic (PV) panels are analyzed. Electromagnetic (EM) field from HV lines has a partially positive and somewhat negative impact on solar PV. When absorption probability is low, one photon and one phonon are required. Phonons are vibrational energy units. A solar PV cell made of Silicon (Si) semiconductor material requires phonons to have high conversion efficiency and electric field from HV transmission line induces phonon. In addition, electric field from HV line increases the solar cell temperature (10 to 15°C) to the ambient temperature. Because of high solar PV cell temperature and high EM field, solar PV power generation is affected by increasing panel temperature. The proposed system uses unnatural Phase Change Material (PCM-Glauber salt (Na2SO4.10 H2O)) coated to the backside of solar PV to normalize the temperature. The impact of electromagnetic fields produced by HV lines on solar cells coated with PCM is validated with experimental testing results. The experiment considers a HVTL of 230kV and solar PV rating of 20 W. The experimental results are measured at various distance ranging from 12 to 22 meters between solar PV and HV transmission lines. Conversion efficiency of solar PV with PCM coating under the impact of HVTL- EMF has increased by 3%.

Прогнозирование влияния электромагнитного поля контактной сети модернизированного участка Октябрьской железной дороги на ВЛ высокого напряжения

The article is devoted to the issue of changing the intensity of the electromagnetic influence of the AC overhead contact system on the disconnected HV transmission line as a result of the modernization of the railway section. Calculation models of AC traction network and power transmission line are built in the ATP-EMTP program. The comparison of the results of calculations of the induced voltage on the disconnected transmission line caused by the influence of the AC overhead contact system of a single- and double-track sections of an АС current railway is carried out.

Mathematical Models of the Phase Voltages of High-, Medium- and Low-Voltage Busbars in a Substation during a Phase-to-Ground Fault on High-Voltage Busbars

The electrical energy supply of industrial equipment is provided by electrical power stations with high- (HT), medium- (MV) and low-voltage (LV) busbars. Consumers are connected to either MV or LV busbars. In this paper, a real power station was considered, through which the gasoline extraction from the well gas installation is powered. Electric consumers (electric motors) supplied by a MV busbar have active power of 13.54 MW, and those fed by a LV busbar have active power of 6.4 MW. Since electrical consumers operate in explosive environments, the design and operating conditions are more severe than in the case of electrical installations operating in non-explosive environments. The case of a single phase-to-ground fault occurring on the HV transmission lines feeding the power station has been analysed. First, the mathematical models for the calculation of the phase voltages, the dissymmetry and asymmetry coefficients, the reduction coefficient of the plus sequence component, and the effective values of the phase voltages were established. The influence of the source impedance (the equivalent impedance of the HV transmission lines) and of the neutral point configuration of the HV/MV medium-voltage transformer on the calculated quantities was analysed. Then, the results obtained using the established mathematical models were compared with those obtained experimentally by provoking a single-phase-to-ground fault near the HV busbars of the real power station. This study has shown that the de-symmetrisation of the phase voltages of the MV and LV busbars is lower when using the Y/Δ connection for the HV/MV transformer. As a result, it is recommended the Y/Δ connection be used for this transformer, instead of the Y0/Δ connection.

Application of Transmission Line Tower Foundation Protection in Power Engineering

The area of mountains, hills and plateaus in China accounts for about 69% of the total land area of the country. It is inevitable that the UHV and HV transmission lines under construction will be built in areas with complex geomorphic characteristics. This paper mainly describes the application of transmission line towers in practical projects, from geological survey, tower stability to foundation reinforcement solutions.

A Novel Algorithm Design for Locating Fault Distances on HV Transmission Lines

A Novel Algorithm Design for Locating Fault Distances on HV Transmission Lines

Mitigating the effects of magnetic coupling between HV transmission line and metallic pipeline using slime mould algorithm

An aerial metallic pipeline experiences induced voltage if drawn in close vicinity of a high voltage power transmission line as suggested by Faraday's law of electromagnetic induction. Such voltages, if not appropriately mitigated, may prove fatal. This paper initially focuses on the evaluation of the induced voltage under the normal operating condition of power transmission lines followed by methods of passive mitigation of the induced voltages. The research also formulates the strategies to enhance mitigation efficiency by optimizing certain features of passive loop techniques using a new optimization algorithm called Slime Mould Algorithm (SMA). A 400 kV single circuit horizontal configuration line with an aboveground pipeline serves as a comprehensive test case to study the efficacy of the proposed algorithm. Results show that the induced voltage levels can be reduced up to 60% using the optimal location of loop conductors and the number of loops, in addition to using shielding material with high permeability. Comparing the obtained results with those obtained using Carson's formula and with genetic algorithm indicates the superior performance of the proposed technique.

A novel wavelet packet transform based fault identification procedures in HV transmission line based on current signals

A novel wavelet packet transform based fault identification procedures in HV transmission line based on current signals

Tests of selected distance protection functions of modern protective relay used for HV and EHV transmission lines protection

Tests of selected distance protection functions of modern protective relay used for HV and EHV transmission lines protection

On the impact of geomagnetically induced currents in driving series capacitor compensated power systems to ferroresonance

Solar storms cause disturbances in the Earth's magnetic field, which results in quasi-DC geomagnetically induced currents (GICs) flow in the grounded sections of the system. The flow of GICs in the power system may drive the power transformers to the saturation region. Moreover, HV transmission lines are often compensated by series capacitor units for enhancing the capability of power transmission lines. The proximity of power transformers and series capacitor compensation units during GICs may enhance the chance of the ferroresonance phenomenon in power transformers. The occurrence of ferroresonance produces extensively high voltages/currents in system apparatus, including transformers which can consequently result in severe damages. This paper puts forward the analysis of the power transformer ferroresonance phenomenon due to GICs in series capacitor compensated networks. This issue has been addressed through mathematical analysis and verified by an experimental test setup, in order to demonstrate the effect of GIC on ferroresonance. Through the employment of an example test system in EMTP-RV environment, impacts of different involving parameters such as system loading, compensation level, and substations' grounding resistances are evaluated on the occurrence of ferroresonance due to GICs. The results indicate that for series capacitor compensated power grids, GICs can profoundly enhance the vulnerability of power transformers to the occurrence of ferroresonance phenomena.

Improving tower grounding vs. insulation level to obtain the desired back-flashover rate for HV transmission lines

This paper aims to present a novel proposed formula, along with technical viewpoints, to solve the problem of transmission lines outage rate due to back-flashover phenomena in terms of soil resistivity, the number of disc insulator units in the string, and tower grounding system structure. Improving the tower grounding system (reducing the impedance) and developing the insulation level are appropriate solutions to prevent the occurrence of the back-flashover, dependent on many factors. To the best of our knowledge, the trade-offs between these two parameters, in respect of soil resistivity, to obtain the desired back-flashover rate (BFR) has not been presented via a compact formula yet. In this paper, it will be shown that in a specific soil resistivity and grounding structure, there is a minimum required insulator unit number and grounding conductor length to achieve the desired BFR, which could be calculated by the proposed formula, straightforwardly. Also, the economic selection between increasing the insulator unit number and developing the tower grounding system in terms of soil resistivity and BFR is investigated. The simulation procedure is coded with Matlab and linked to EMTP/ATP program to analysis the BFR. This method is done for a typical 150 kV overhead transmission line, however, it can be applied to any voltage level of transmission line and significantly facilitate the cost effective design of them.

Adaptive single-end transient-based scheme for detection and location of open conductor faults in HV transmission lines

Detection and location of open conductor in transmission systems using single-end data is a challenging task. This paper proposes a novel integrated scheme to detect and locate different types of open conductor faults (OCFs) in HV transmission systems. The proposed scheme unit (PSU) applies Discrete Wavelet Transform (DWT) with single-level decomposition on local current signals to detect OCFs correctly using adaptively estimated threshold values. PSU is also capable of dealing correctly with various normal transient conditions such as load/capacitor switching. To ensure quick repair of OCFs, PSU captures the transient voltage surges and applies a fault location scheme using DWT and Clark Transformation to accurately estimate the location of different OCFs types. Extensive ATP simulations are employed to check the PSU performance under various OCFs conditions on a 345kV, 100km transmission line. The achieved results confirm the effectiveness, robustness, and reliability of PSU in detecting correctly OCFs as well as the low-impedance faults within only 1.25 cycles. Moreover, the percentage error in estimating OCFs location is less than 1%. PSU has also confirmed its capability to be applied in cascaded lines without any communication or synchronization between PSUs.

A novel wavelet packet transform based fault identification procedures in HV transmission line based on current signals

<p>This paper presents an adaptive fault identification algorithm bases on wavelet packet transform (WPT) for two-terminal power transmission lines. The proposed scheme performs four functions which are the fault detection, fault classification, distinguishing among the temporary and the permanent faults, and detection of the arc extinguish instant. The presented algorithm only uses the measured current at one terminal reducing the required cost. Also, it can mitigate the error resulting from the load variations via updating the presetting value. Consequently, it does not need retesting under changing the transmission system configurations. The proposed scheme is deduced in the spectral domain and depended on the application of the WPT. The db6 wavelet packet is used for decomposing the faulty phase current waveform (level 7) to get the energy coefficients. The presented algorithm is assessed under various fault conditions such as fault distances, inception angles, and faults nature via simulating different secondary arc models via using ATP/EMTP. The obtained results are investigated and evaluated.</p>

Fault Location in High Voltage Transmission Lines Using Resistance, Reactance and Impedance

This paper presents two methods for on-line computation of dynamic fault location in HV transmission lines using three means; resistance, reactance and impedance. These methods can be used for dynamic distance protection of the transmission line. The Gilchrist method and McInnes method are presented. The proposed methods use digital set of short circuit current and voltage measurements for estimating fault location. A practical case study is presented in this work to evaluate the proposed methods. A study is done to evaluate the best mean to locate the fault. A comparison of these two methods is presented. MATLAB-Simulink software was used to do all the tests. Results are reported and conclusions are drawn. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Accelerated aging studies of silicon-rubber based polymeric insulators used for HV transmission lines

Accelerated aging experimental investigations are performed on polymeric insulators which are used for extra high voltage (EHV) and ultra high voltage (UHV) transmission. A newly developed rotating wheel and dip test facility as per std. IEC 62217 is used for the study. The experimental study is conducted with AC stress for 15000 cycles. The specimen insulators used are of 725 mm creepage and treated under different environmental stresses close to the real service life. The present study focuses on the effect of acidic environment during acid rain encountered by the polymeric insulators. The contaminants used for the study are as per standard and practically observed acid rain information. A comparative study is carried out for normal and acidic environmental conditions, some interesting results are observed. Leakage current monitoring and visual observation were conducted at regular intervals. Results show acid treatment is found to be comparatively more severe than the normal treatment. Further Physico-chemical investigation are carried out using Fourier Transform Infrared (FTIR) Spectroscopy and Scanning Electron Microscopy (SEM), Energy dispersive X-ray Analysis (EDAX) and Thermo-Gravimetric Analysis (TGA) which confirm the severity of material degradation of polymeric insulators and corrosion over metal end fittings under acidic environmental condition.

Back-flashover Investigation of HV Transmission Lines Using Transient Modeling of the Grounding Systems

Back-flashover Investigation of HV Transmission Lines Using Transient Modeling of the Grounding Systems

Local opposition against high-voltage grids: public responses to agency-caused science–policy trolls

ABSTRACTHigh-voltage (hV) transmission grids are projects of societal importance that potentially have controversial social and environmental impacts. Former research shows that public opposition is sparked by the perception of negative local impacts and unjust concessionary processes. In this paper, we complement these perspectives by assessing the institutional practices of the regulatory agencies in dealing with scientific uncertainties. The regulatory agencies’ ‘ways of doing things’ are often designed to serve policy and management needs. A critical point is that the demarcation between scientifically based facts, values and assessments is often blurred in the decision-making process. This paper draws on two Norwegian case studies to investigate how the regulatory agencies dealt with (1) electromagnetic fields and health risks and (2) overhead lines versus sea cables. We argue that ambiguities and uncertainties that arise in the hV transmission line processes create ‘trolls’, and we explore how the local inhabitants and affected stakeholders in the two cases responded to these and how it triggered further opposition. By investigating how and why trolls appear and are handled, we conclude by discussing how public opposition related to hV transmission grids may be reduced – and how some ‘trolls’ may crack.

Critical aspects on wavelet transforms based fault identification procedures in HV transmission line

The fault identification process in transmission systems involves three functions: discrimination, classification and phase selection. The current study classifies the methods that applied for each function. Moreover, this study introduces criticism and assessment study that helps the power system protection engineer to choose the best fault identification scheme at responsible indices. Investigated solutions for the drawbacks appeared with the previous methods are suggested. This study also proposes sensitive and automated fault identification scheme to solve the existing challenges such as high-impedance faults (HIFs), non-linear modelling of arcing etc. Several simulation studies are employed using alternative transients program/electromagnetic transient program (ATP/EMTP) package on a sample 500 kV test system to ensure the performances of the proposed scheme compared with the previous methods. Simulation results concluded that: the proposed identification scheme has the ability to discriminate correctly between HIF and low-impedance faults using current signal captured from one end only. Moreover, the proposed scheme alleviates perfectly the problems associated with load variations by adaptive threshold settings and reduces the impacts on the environmental and external phenomena.