scholarly journals Computation of Lightning Voltage Surges on Tall and Conventional Transmission Towers

2020 ◽  
Author(s):  
Anderson R. J. de Araújo ◽  
Claudiner M. de Seixas ◽  
Bamdad Salarieh ◽  
Sérgio Kurokawa ◽  
Behzad Kordi
Keyword(s):  
Power Systems ◽  
Forest Canopy ◽  
Electric Circuit ◽  
Voltage Response ◽  
Transmission Tower ◽  
Lightning Strikes ◽  
Grounding System ◽  
Vector Fitting ◽  
Transmission Towers ◽  
The Time Domain

Transmission tower modelling is very important to assess the electromagnetic transient caused by lightning strikes in power systems. In this context, conventional tower models are very well studied in the literature. However, there are few studies on tall transmission towers which have been receiving great attention recently due to their own characteristics. Tall transmission towers are built on river crossings and/or over dense forest canopy to reduce environmental impact in these areas. In this paper, the voltage surge caused by an incidentlightning at the top of the conventional and tall towers are determined. For both structures, a lumped electric circuit approximated by Vector Fitting technique is proposed which takes into account the tower-footing grounding system buried in different homogeneous soils. The results show a clear difference in the time domain voltage response for the conventional and tall transmission towers which is more pronounced as the soil resistivity increases and/or the tower becomes taller.

Transient Voltages on Grounding Grids buried in Stratified Soils

2020 ◽  
Author(s):  
Anderson Anderson R. J. de Araújo ◽  
Walter L. M. de Azevedo ◽  
José Pissolato Filho ◽  
Jaimis S. L. Colqui ◽  
Sérgio Kurokawa
Keyword(s):  
Power Systems ◽  
Electric Circuit ◽  
Lightning Strikes ◽  
Vector Fitting ◽  
Full Wave ◽  
Vertical Electrode ◽  
Radiation Theory ◽  
Lightning Discharges ◽  
Grounding Grids ◽  
Transient Voltages

Grounding grids (GG) play a fundamental role in the protection of personnel and prevention of damages in equipment during surge transients on substations caused by lightning discharges on power systems. In this context, a precise GG modeling must consider several factors such as the arrangement and the soil compacted in stratified layers. This paper proposes a lumped approach for GG buried in several stratified soils to compute the transient node voltages when subjected to lightning strikes. The vertical and horizontal electrodes are modelled separately by lumped circuit approach. The vertical electrode impedances buried in a stratified soil are computed by the numerical Method of Moments (MoM) in the full-wave electromagnetic software FEKOR , directly in frequency domain, and then, an electric circuit is obtained by the Vector Fitting technique. The horizontal electrodes are modelled based on the electromagnetic radiation theory, where each segment of the electrode can be regarded as a lamental currentcarrying conductor. Lightning currents of fast and slow-front waveforms, are employed in the simulations. Results show that when stratified soils are considered, the differences of the transient voltage peaks, in comparison with the ones calculated for the homogeneous soil is more pronounced as the thickness of soil decreases.

scholarly journals An Electromagnetic Model for the Calculation of Tower Surge Impedance Based on Thin Wire Approximation

2020 ◽  
Author(s):  
Bamdad Salarieh ◽  
H. M. Jeewantha De Silva ◽  
Aniruddha M. Gole ◽  
Akihiro Ametani ◽  
behzad kordi
Keyword(s):  
Electromagnetic Waves ◽  
Direct Method ◽  
Field Measurements ◽  
Theoretical Models ◽  
Thin Wire ◽  
Transmission Tower ◽  
Lightning Strikes ◽  
Grounding System ◽  
Electromagnetic Transient ◽  
Electromagnetic Model

When a lightning strikes the top of a transmission line tower or shield wires, electromagnetic waves propagate through the tower back and forth, increasing the voltage across insulator strings. is can eventually lead to a back-fl ashover (BF), which may cause damage to equipment or costly power outages. To calculate the over-voltages and predict the probability of a BF, an accurate model of the tower and its grounding system is needed in electromagnetic transient (EMT) type simulators. There are a number of theoretical models for the equivalent circuit of a transmission tower. However, they either are not accurate enough or they are derived for a certain type of transmission tower, which limits their applicability. Numerical electromagnetic analyses have less simplifications compared to the theoretical solutions and are by far less expensive than field measurements. They also have the flexibility to analyze any type of tower. In this paper, the direct method for the measurement of tower impedance is implemented by NEC4 and applied to a 400-kV double circuit tower with all its details. Th e process of obtaining the wire network of the tower used in this paper is completely automated and it can be applied to any other type of transmission tower. Th e results of the numerical simulations are compared to those obtained with existing tower models. Th e developed model in this paper is capable of considering all the details of the tower and including the finite resistance of the ground and grounding electrodes.

scholarly journals Grounding System Modeling and Evaluation Using Integrated Circuit Based Fast Relaxed Vector Fitting Approach, Considering Soil Ionization

2020 ◽  
Vol 10 (16) ◽  
pp. 5632
Author(s):  
Maziyar Fakhraei ◽  
Mehrdad Mahmoudian ◽  
Eduardo Manuel Godinho Rodrigues
Keyword(s):  
Integrated Circuit ◽  
System Modeling ◽  
Model Verification ◽  
Lightning Strikes ◽  
Grounding System ◽  
Vector Fitting ◽  
Grounding Grids ◽  
Electro Magnetic ◽  
Soil Ionization ◽  
System Frequency

Since high voltage transmission line towers or wind turbines structures are installed in high-altitude areas, it is essential to achieve a high overvoltage protection system against direct and indirect lightning strikes collisions. The lightning current must be discharged quickly into the protective earth, to prevent the dangerous over-voltages formation and define a reference voltage node. This paper presents a novel model to assess the behavior of the grounding system, based on Pocklington integral equations under lightning magnetic fields and variations in soil ionization, in which an explicit circuit-based vector fitting RLC admittance branches are proposed. The frequency-dependent behavior of grounding system frequency response and soil ionization effect is modeled in time domain, straightly to implement into the electro-magnetic transient program (EMTP). The model verification contains horizontal, vertical, and their combinations of grounding grids to represent the complete investigations under lightning strikes. The harmonic impedance mathematical formulations and principles are derived based on a rational function, that could be applicable on ground potential rise (GPR) investigation.

Overvoltage Analysis Considering Transmission Tower Models Based on Impedances and Inductances

2015 ◽  
Vol 775 ◽  
pp. 373-377
Author(s):  
John Morales ◽  
Julio Montesdeoca ◽  
Guillermo Guidi
Keyword(s):  
Power Systems ◽  
Comparative Study ◽  
Electric Power ◽  
Transmission Lines ◽  
Short Circuit ◽  
Electric Power Systems ◽  
Transmission Tower ◽  
Impedance Model ◽  
Distributed Parameters ◽  
Transmission Towers

It is clear that lightning strokes produce overvoltages on Transmission Lines (TLs), which can be higher that the Basic Insulator Level (BIL), generating a fault or short circuit. Thus, in order to adequately analyze when a lightning hits on a TL, it is necessary to simulate different elements corresponding to Electric Power Systems (EPSs) as real as possible. In this context, transmission towers are considered crucial parameters in lightning studies, which must be correctly selected and simulated in order to consider reflected voltage waveforms from cross arms. Based on the above said, this paper presents a comparative study corresponding to the transmission tower simulation using two models. The first uses inductances, and the second uses distributed parameters impedances characterized by their impedance and travel time. This paper presents voltage variations that exist in each phase, using different lightning features. Alternative Transients Program (ATP) is used to simulate the TL model considering different lightning currents and the two tower models. Results show that the impedance model analyze reflected waveforms, while that the inductance model does not analyze this issue.

scholarly journals An Electromagnetic Model for the Calculation of Tower Surge Impedance Based on Thin Wire Approximation

2020 ◽  
Author(s):  
Bamdad Salarieh ◽  
H. M. Jeewantha De Silva ◽  
Aniruddha M. Gole ◽  
Akihiro Ametani ◽  
behzad kordi
Keyword(s):  
Electromagnetic Waves ◽  
Direct Method ◽  
Field Measurements ◽  
Theoretical Models ◽  
Thin Wire ◽  
Transmission Tower ◽  
Lightning Strikes ◽  
Grounding System ◽  
Electromagnetic Transient ◽  
Electromagnetic Model

<div>"© 20xx IEEE.Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works."</div><div><br>DOI: <a href="https://doi.org/10.1109/TPWRD.2020.3003250" target="_blank">10.1109/TPWRD.2020.3003250</a></div><div><br></div><div>Abstract:<br></div><div>When a lightning strikes the top of a transmission line tower or shield wires, electromagnetic waves propagate through the tower back and forth, increasing the voltage across insulator strings. is can eventually lead to a back-fl ashover (BF), which may cause damage to equipment or costly power outages. To calculate the over-voltages and predict the probability of a BF, an accurate model of the tower and its grounding system is needed in electromagnetic transient (EMT) type simulators. There are a number of theoretical models for the equivalent circuit of a transmission tower. However, they either are not accurate enough or they are derived for a certain type of transmission tower, which limits their applicability. Numerical electromagnetic analyses have less simplifications compared to the theoretical solutions and are by far less expensive than field measurements. They also have the flexibility to analyze any type of tower. In this paper, the direct method for the measurement of tower impedance is implemented by NEC4 and applied to a 400-kV double circuit tower with all its details. Th e process of obtaining the wire network of the tower used in this paper is completely automated and it can be applied to any other type of transmission tower. Th e results of the numerical simulations are compared to those obtained with existing tower models. Th e developed model in this paper is capable of considering all the details of the tower and including the finite resistance of the ground and grounding electrodes.</div>

scholarly journals An Electromagnetic Model for the Calculation of Tower Surge Impedance Based on Thin Wire Approximation

2020 ◽  
Author(s):  
Bamdad Salarieh ◽  
H. M. Jeewantha De Silva ◽  
Aniruddha M. Gole ◽  
Akihiro Ametani ◽  
behzad kordi
Keyword(s):  
Electromagnetic Waves ◽  
Direct Method ◽  
Field Measurements ◽  
Theoretical Models ◽  
Thin Wire ◽  
Transmission Tower ◽  
Lightning Strikes ◽  
Grounding System ◽  
Electromagnetic Transient ◽  
Electromagnetic Model

<div>"© 20xx IEEE.Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works."</div><div><br>DOI: <a href="https://doi.org/10.1109/TPWRD.2020.3003250" target="_blank">10.1109/TPWRD.2020.3003250</a></div><div><br></div><div>Abstract:<br></div><div>When a lightning strikes the top of a transmission line tower or shield wires, electromagnetic waves propagate through the tower back and forth, increasing the voltage across insulator strings. is can eventually lead to a back-fl ashover (BF), which may cause damage to equipment or costly power outages. To calculate the over-voltages and predict the probability of a BF, an accurate model of the tower and its grounding system is needed in electromagnetic transient (EMT) type simulators. There are a number of theoretical models for the equivalent circuit of a transmission tower. However, they either are not accurate enough or they are derived for a certain type of transmission tower, which limits their applicability. Numerical electromagnetic analyses have less simplifications compared to the theoretical solutions and are by far less expensive than field measurements. They also have the flexibility to analyze any type of tower. In this paper, the direct method for the measurement of tower impedance is implemented by NEC4 and applied to a 400-kV double circuit tower with all its details. Th e process of obtaining the wire network of the tower used in this paper is completely automated and it can be applied to any other type of transmission tower. Th e results of the numerical simulations are compared to those obtained with existing tower models. Th e developed model in this paper is capable of considering all the details of the tower and including the finite resistance of the ground and grounding electrodes.</div>

Ultrasonic unilateral double-position excitation lamb wave defect detection and quantification method for ground electrode of transmission tower

2021 ◽  
pp. 1-15
Author(s):  
Kuan Ye ◽  
Kai Zhou ◽  
Ren Zhigang ◽  
Ruizhe Zhang ◽  
Chunsheng Li ◽  
...  
Keyword(s):  
Guided Waves ◽  
Power Transmission ◽  
Geometric Model ◽  
Guided Wave ◽  
Quantization Error ◽  
Dispersion Function ◽  
Stable Operation ◽  
Transmission Tower ◽  
Ultrasonic Guided Wave ◽  
Transmission Towers

The power transmission tower’s ground electrode defect will affect its normal current dispersion function and threaten the power system’s safe and stable operation and even personal safety. Aiming at the problem that the buried grounding grid is difficult to be detected, this paper proposes a method for identifying the ground electrode defects of transmission towers based on single-side multi-point excited ultrasonic guided waves. The geometric model, ultrasonic excitation model, and physical model are established, and the feasibility of ultrasonic guided wave detection is verified through the simulation and experiment. In actual inspection, it is equally important to determine the specific location of the defect. Therefore, a multi-point excitation method is proposed to determine the defect’s actual position by combining the ultrasonic guided wave signals at different excitation positions. Besides, the precise quantification of flat steel grounding electrode defects is achieved through the feature extraction-neural network method. Field test results show that, compared with the commercial double-sided excitation transducer, the single-sided excitation transducer proposed in this paper has a lower defect quantization error in defect quantification. The average quantization error is reduced by approximately 76%.

scholarly journals Application of Multi-Branch Cauer Circuits in the Analysis of Electromagnetic Transducers Used in Wireless Transfer Power Systems

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 2052
Author(s):  
Milena Kurzawa ◽  
Cezary Jędryczka ◽  
Rafał M. Wojciechowski
Keyword(s):  
Power Systems ◽  
Field Model ◽  
Wireless Power Transfer ◽  
Equivalent Model ◽  
Power Transfer ◽  
Wireless Power ◽  
The Finite Element Method ◽  
Harmonic Field ◽  
Time Harmonic ◽  
The Time Domain

In this paper, the feasibility of applying a multi-branch equivalent model employing first- and second-order Cauer circuits for the analysis of electromagnetic transducers used in systems of wireless power transfer is discussed. A method of formulating an equivalent model (EqM) is presented, and an example is shown for a wireless power transfer system (WPTS) consisting of an air transformer with field concentrators. A method is proposed to synthesize the EqM of the considered transducer based on the time-harmonic field model, an optimization algorithm employing the evolution strategy (ES) and the equivalent Cauer circuits. A comparative analysis of the performance of the considered WPTS under high-frequency voltage supply calculated using the proposed EqM and a 3D field model in the time domain using the finite element method (FEM) was carried out. The selected results of the conducted analysis are presented and discussed.

scholarly journals Earth-termination system for onshore wind Turbines.

2020 ◽  
Vol 11 (7-2020) ◽  
pp. 66-72
Author(s):  
Liubov A. Belova ◽  
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Lightning Strike ◽  
Lightning Protection ◽  
Protection Measures ◽  
Lightning Strikes ◽  
Grounding System ◽  
Initial Stage ◽  
Wind Turbine Towers ◽  
Surge Protection

The earth-termination system for towers of ground-based wind turbines in addition to protective and functional grounding provides lightning protection grounding, which is especially important since the wind turbine is susceptible to lightning strikes. If insufficient protective measures are taken, the risk of damage to a wind turbine due to a lightning strike increases. Therefore, a well-thought-out built-in grounding system for wind turbine towers is needed, which would function as necessary and guarantee long-term mechanical strength and corrosion resistance. The configuration of grounding systems for wind turbines is discussed in IEC 61400-24, which deals with the topic of lightning protection for wind turbines, including detailed information on the choice of lightning protection measures and surge protection. It is advisable to create a lightning protection concept at the initial stage of planning a wind turbine in order to avoid later costly repairs and retrofitting.

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