HV Transmission 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%.

Identification of broken conductor faults in interconnected transmission systems based on discrete wavelet transform.

Interconnected transmission systems are increasingly spreading out in HV networks to enhance system efficiency, decrease reserve capacity, and improve service reliability. However, the protection of multi-terminal lines against Broken Conductor Fault (BCF) imposes significant difficulties in such networks as the conventional distance relays cannot detect BCF, as the BCF is not associated with a significant increase in current or reduction in voltage Traditionally, the earth fault relays in transmission lines may detect such fault; Nonetheless, it suffers from a long delay time. Moreover, many of the nearby earth fault relays detect the BCF causing unnecessary trips and badly affecting the system stability. In this article, a novel single-end scheme based on extracting transient features from current signals by discrete wavelet transform (DWT) is proposed for detecting BCFs in interconnected HV transmission systems. The suggested scheme unit (SSU) is capable of accurately detecting all types of BCFs and shunt high impedance faults (SHIFs). It also adaptively calculates the applied threshold values. The accurate selectivity in multi-terminal lines is achieved based on a fault directional element by analyzing transient power polarity. The SSU discriminates between internal/external faults effectively utilizing the time difference observed between the first spikes of aerial and ground modes in the current signals. Different fault scenarios have been simulated on the IEEE 9-Bus, 230 kV interconnected system. The achieved results confirm the effectiveness, robustness, and reliability of SSU in detecting correctly BCFs as well as the SHIFs within only 24.5 ms. The SSU has confirmed its capability to be implemented in interconnected systems without any requirement for communication or synchronization between the SSU installed in multi-terminal lines.

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.

Study of the Current Harmonics Generated by Two-Phase Loads on HV Transmission Power Grid: a Case Study of a Substation Supplying the High-Speed Rail

Study of the Current Harmonics Generated by Two-Phase Loads on HV Transmission Power Grid: a Case Study of a Substation Supplying the High-Speed Rail

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.

SECURITY OF OPERATION AND IDENTIFICATION OF POSSIBLE BOTTLENECKS IN SOUTHEAST EUROPE TRANSMISSION NETWORK UNDER MARKET CONDITIONS

Based on the results of calculations of power flows and on the analysis of the operation of the HV transmission network in Southeast Europe, with the market focus on generation facilities, the basic characteristics of the network are described, and possible bottlenecks identified. The calculations were done within the EC-funded REBIS project (Regional Balkans Infrastructure Study) and the Generation Investment Study (GIS) of new power generation capacities in the region. The market offering of generation facilities in Southeast Europe at forecast system peak loads in 2010 and 2015, for different hydrological conditions, was determined by the WASP (IAEA) and GTMax (Argonne NL) software. Calculations of power flows were carried out by using the PSS/E software (Siemens PTI). The article particularly discuses simulated power plant output and the operation of the transmission network in the Republic of Croatia.

Lessons Learnt from Modelling and Simulating the Bottom-Up Power System Restoration Processes

This paper aims to present the gained experience in modeling and simulating bottom-up power system restoration processes. In a system with low inertia, such as a restoration path, the Common Information Models for the regulation systems appear to no longer be suitable for the estimation of the frequency behavior, and thus a detailed model must be considered. On the other hand, due to the predominantly inductive behavior of the HV transmission network, the assumption of decoupling the power-frequency behavior to study the restoration stability seems to be licit. All these issues are discussed and justified in the paper by means of the use of different software packages and of the comparison with on-field recordings.

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

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

Analysis, Sources and Study of the Biological Consequences of Electromagnetic Pollution

The actions and health effects of electromagnetic fields in the radio frequency (RF) domains, referred to as radio frequencies and HV transmission networks have been studied for several decades. Following the appearance of questions and debates within the population, the actions and potential effects of radiofrequency and HV transport networks on health, in connection with the development of new wireless technologies, are generating a certain revival of interest. Thus, the increasing exposure to electromagnetic fields and the concerns of the public have led health organizations to undertake large-scale research programs to respond to the concerns expressed. These research programs have contributed to significantly increasing the number of studies on the actions and effects of electromagnetic pollution as well as their consequences on living beings. The objective of our research is focused on the analysis, sources, and study of the biological consequences of electromagnetic pollution. To do this, we have used physical laws and theorems, in particular Maxwell-Ampère, Maxwell-Gauss, Maxwell-Faraday, and Ohm’s law, to model the interactions between electromagnetic fields and living matter. In this article we have chosen the approach based on the electrical model of human biological tissue, taking into account on the one hand the physical phenomena of the propagation of an electromagnetic microwave plane wave in the range from 0 to 300GHz and on the other hand, the experimental values to simulate the relaxations α, β and γ and the impedance of the biological tissue faced with the variation of the frequency of propagation of the electromagnetic waves to identify the biological consequences relating thereto. The results obtained in the literature show the linear dependence of bio-impedance on frequency, these observations suggest that the tissue can be physiologically stressed at high frequencies. This can cause biological consequences for humans. The 2D simulation based on the proposed model has been developed as well as the verification of the consistency of the different mathematical models, by comparing the fractal dimensions of the results of the program with those of the figures obtained experimentally.

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.

Application of FACTS devices for flexibility control of transmission networks

Maintenance of power balance at each time moment in every node and in the electric power system as a whole is a mandatory condition for supplying the electric power of required quality (frequency, voltage levels). Property of the system to be considered as its ability to control power balance is referred to as flexibility. Technologies for operating conditions control or systems services are an efficient means of regulating the flexibility of HV transmission networks in the cycle of on-line and anti-emergency control. Present-day FACTS of the second generation based on power electronics whose control systems ensure high efficiency of control and stabilization are the most perspective means of flexibility regulating and control. The paper considers potentials of using those devices for regulating the flexibility of 500/200 kV network that is a section of a real EPS. Calculations were performed in the simulation experiment and were based on real telemetry measurements using the State Estimation Software. The results of the studies have showed that substitution of the first-generation FACTS devices by the controlled second-generation FACTS devices and installation of new present-day FACTS allows notable enhancement of HV electric networks controllability and ensures the required level of networks flexibility.