Single-circuit Transmission Line Research Articles

Shunt faults detection and classification in electrical power transmission line systems based on artificial neural networks

PurposeThis study aims to focus on an adaptive method for fault detection and classification of fault types that trigger in three-phase transmission lines using artificial neural networks (ANNs). The proposed scheme can detect and classify several types of faults, including line-to-ground, line-to-line, double-line-to-ground, triple-line and triple-line-to-ground faults.Design/methodology/approachThe fundamental components of three-phase current and voltage were used as inputs in the ANNs. An analysis of the impact of variations in the fault resistance, fault type and fault inception time was conducted to evaluate the ANNs performance. The survey compares the performance of the multi-layer perceptron neural network (MLPNN) and Elman recurrent neural network trained with the backpropagation learning technique to improve each of the three phases of the fault detection and classification process. A detailed analysis validates the choice of the ANNs architecture based on the variation in the number of hidden neurons in each step.FindingsThe mean square error, root mean square error, mean absolute error and linear regression are measured to improve the efficiency of the ANN models for both fault detection and classification. The results indicate that the MLPNN can detect and classify faults with a satisfactory performance.Originality/valueThe smart adaptive scheme is fast and accurate for fault detection and classification in a single circuit transmission line when faced with different conditions and can be useful for transmission line protection schemes.

Image processing based fault classification in power systems with classical and intelligent techniques

This paper is devoted to develop interest of power system engineers in learning basic concepts of image processing and consequently using deep networks to solve problems of complex power system networks. To this end, we study fault classification in a power system through automation of equal area (EAC) criterion. By considering EAC graphs as images and using classical image processing techniques, we successfully distinguish between different transient conditions including sudden change of input power as well as short circuit at the sending end and middle points of a single and double circuit transmission lines. In addition to classification, some parameters are also determined from EAC images such as initial rotor angle, clearing angle, and maximum rotor angle. Further, the use of deep networks is introduced to perform the same task of fault classification and a comparison is drawn with multilayer perceptron neural networks. Developed algorithms are tested in MATLAB as well as Pytorch environments.

Analysis of Electromagnetic Environment in 1200 kV Single Circuit UHVAC Transmission Line by using FACE Software and Semi-empirical Formulae

In order to ensure efficient, bulk-power transmission over a long distance, need of increasing transmission-level voltage is being thought for the past many years. As a result, Ultra High Voltage AC (UHVAC) Transmission has appeared as a feasible solution. Many countries like Italy, Japan, USA, USSR, Brazil, China, India are developing technology for UHVAC transmission systems. Operating at 1000 kV (and above voltage level) demands careful design of transmission structure, switchgear, and equipment design. This paper presents a review of several studies carried out to analyze the electro-magnetic environment in UHVAC lines. The electromagnetic environment (Field, Audible Noise, Corona Loss, Radio Interference) of 1200 kV, Wardha-Aurangabad single-circuit transmission line, India is also evaluated using FACE (Field and Corona Effect) software. The results of the study of static AC field and magnetic field of the line are found to be within prescribed limits suggested by International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines.

Measurement of Electric and Magnetic Field Strengths under 765 kV UHVAC Single Circuit Transmission Line

Transmission line corridors of developing countries are increasingly dense and expensive with construction of new ultrahigh voltage (UHV) transmission lines. Right of way of transmission line in the corridor, construction cost of transmission lines including towers, is directly influenced by electric and magnetic field strength emission (EMF) of that line. In UHV range, emission of electric and magnetic field strength in the vicinity of lines is of great public concern, as are likely to have hazardous effects to human being when their exposure level exceeds specified limits. Higher the transmission voltage and stronger the electric field. Though the results on effect of EMF on human being is inconclusive, to create awareness to common public and working professional, it is mandatory to measure the emission level of EMF in lateral and longitudinal profile. This paper reports experiences of EMF emission measurement of 765 kV UHVAC quadruple ACSR bundled conductor single circuit transmission line in India. Measurement results of EMF with vegetation is reported.

Overhead Transmission Lines Sag and Voltage Monitoring Method Based on Electrostatic Inverse Calculation

Transmission line sag and voltage are key information to reflect the real-time operation state of power grid. Contactless measurement method has great advantages of no electrical contact, flexibility and mobility, but it is also vulnerable to environmental changes. In this article, a novel overhead transmission line contactless sag and voltage monitoring method is proposed, which only needs a simple potential measurement array and can apply to dynamic conductor measurement. The electrostatic coupling model between the transmission lines and the measuring points is established. The sag and voltage inversion calculation model is proposed and the ill-posed problem is solved. The measurement array and the data acquisition method are designed. The equivalent measurement area (EMA) is determined considering the difference between 3-D model and 2-D model of overhead line. Finally, the effectiveness of the proposed method is verified by single-circuit transmission line simulation and scale-down experiment.

Transmission line protection algorithm based on voltage sequence component under high penetration of inverter-based resources

• Protection challenges under high penetration of inverter-based resources • A novel protection algorithm is proposed which uses voltage sequence components to identify faulty events occurrence in transmission line network. • The proposed protection algorithm reliability has been investigated under different network's impacts. • The proposed protection algorithm sensitivity is tested on a big transmission network under different contingency scenarios. A new protection algorithm based on sequence voltage components is proposed in this paper. The new algorithm helps overcome the sensitivity and maloperation issues of the traditional protection schemes in the transmission line network, especially with a high penetration level of inverter-based resources. In this algorithm, the differential fault sequence components are used to identify faulty events in the transmission network. The fault voltage component across the protected line is compared to a setting value of multiple parameters-based voltage makes the final decision of tripping for internal faults only. The proposed algorithm has been tested on a 400kV, 50 Hz single circuit transmission line network supplied with a mix of 90% wind turbines and 10% synchronous generators. The new algorithm simulation testing showed high accuracy when it comes to rapid trip activation with high discrimination reliability between internal and external events. High impedance with different fault locations has been tested to improve the proposed algorithm reliability. The study also performed on the IEEE 9-bus system to validate the proposed algorithm under various faults when strong and weak infeed performed into a bigger transmission network.

Influence of the current front time representation on the assessment of backflashover occurrence of transmission lines by deterministic and probabilistic calculation approaches

This work addresses the impact on the backflashover occurrence in transmission lines of two different assumptions for representing the front time of return-stroke currents, namely a constant parameter, set as the median Td30 front time, and a varying parameter, determined from expressions correlating the front time and the peak current. To support the analysis, computational simulations assuming the HEM-DE deterministic approach and the ATP-DE-MC probabilistic approach based on the application of Monte Carlo method were developed, taking typical configurations of 138- and 230-kV single circuit transmission lines as case studies. The results show that the two methods of representing the current front time lead to similar critical currents and, therefore, percentages of backflashover. The observed difference in the results demonstrated to be larger only for those cases in which the percentage of backflashover is extremely low (of the order of 1% or lower), and, therefore, do not contribute to modify the calculated outage rate of the transmission line, in most cases.

Research on Type Selection of Diving Tower in 110kV Single and Double Circuit Transmission Line

With the continuous development of EHV (UHV) transmission lines，new lines often need to drill through the built lines，so it is urgent to study the type of diving towers. Based on typical weather conditions and commonly used ground wire models, the basic type and tower type selection of 110kV single and double circuit overpass towers in high altitude areas are studied, and two single and double circuit overpass tower schemes are planned and arranged. And according to the pole tower structure design and optimization theory, the 110kV single-circuit diving tower and the 110kV dual-circuit diving tower are optimized from the structural optimization layout and the pole tower structure node optimization design. The research results show that the single-circuit diving tower adopts the wine glass tower, and the wires are arranged horizontally, and the double-circuit diving tower effectively reduces the height of the tower. The dish-shaped tower is used, and the single-circuit wires are arranged in a triangle pattern, which provides a certain practical guiding significance for the 110kV diving-across technology application.

ПРОДОЛЬНОЕ СОПРОТИВЛЕНИЕ ОДНОЦЕПНОЙ ЛЭП С ДВУМЯ ГРОЗОЗАЩИТНЫМИ ТРОСАМИ В ЗАДАЧЕ ДИСТАНЦИОННОГО ОМП

One of the most important tasks in remote fault location in a 110 kV+ network is modeling the power lines taking into account the electromagnetic and electrostatic interaction of their conductive elements. A common approach is to use the mathematical models recommended by the guidelines for calculating short-circuit currents for relay protection. However, these models of power transmission lines take into account the geometric mean distance between the wires and the lightning protection cables, which means they average the values of the mutual induction impedances. In cases where wires and cables are located asymmetrically relative to each other, this leads to an overestimation of the zero-sequence impedance of power lines and, as a consequence, to an underestimation of the single-phase short-circuit current. This situation can affect the results of remote fault location. To eliminate this drawback, the article proposes a combined equivalent circuit for a single-circuit power transmission line with two lightning protection cables, based on a combination of methods of phase coordinates and symmetric components. The given equivalent circuit of power transmission lines allows calcula¬ting the mode parameters using the method of symmetric components and, at the same time, simulating those of interest for calculating power lines using phase coordinates.

A new protection scheme for transmission lines utilizing positive sequence fault components

In this paper, a novel integrated approach of protective relaying methodology has been adopted for detecting faults and its location estimation in long transmission line. First, the detection algorithm has been formulated using positive sequence admittance. Subsequently, fault location algorithm has been developed using positive sequence voltage and current phasors. The proposed algorithms have been implemented on a 50 Hz, 400 kV single-circuit transmission line in MATLAB environment. A wide range of diversified and challenging cases have been simulated to test the reliability of this scheme. The results confirm the preciseness of the algorithm, as it can produce accurate results under stressed conditions, viz. high impedance fault (HIF), current transformer (CT) saturation/ capacitive voltage transformer (CVT) transient, close-in faults, swing condition, source strength variation, etc. Moreover, this scheme has also been successfully tested in series-compensated and double-circuit transmission line, which brings out the superiority of this scheme. The comparative analysis with recent protective relaying techniques institutes the potentiality and robustness of the scheme.

Capacitive Power Tapping From Insulated Shield Wire of Overhead High Voltage Transmission Lines With Tuning

Due to a lack of high and stable power supplies for large-scale online monitoring devices, the intelligent development of high voltage transmission lines has always been restricted. This paper presents a method for capacitive power tapping from an insulated shield wire of overhead high voltage transmission lines with tuning. A general equivalent model, which considers the influence of line sag and landform on the equivalent circuit parameters, is established. The calculated equivalent circuit parameters show good agreement with the field measured data obtained by a 220 kV single-circuit transmission line. In order to maximize the tap-off power, a nonlinear tuning method is proposed since linear tuning can cause an overvoltage problem, and a tuned reactor is developed. Based on the measured equivalent circuit parameters, an experiment platform is built in the laboratory to measure the tap-off power under different resistive loads. The experimental results indicate that the maximum power is about 900 W, which represents an improvement of 80% compared with the maximum power without tuning. Additionally, the tuned reactor shows good robustness to the perturbation of equivalent circuit parameters, which validates the effectiveness of the proposed power tapping method.

Optimal selection and positioning of conductors in multi-circuit overhead transmission lines using evolutionary computing

This paper presents a new approach for designing transmission lines to transmit more power in a narrower space. Multi-circuits lines are a good alternative to attain this objective. However, the optimum solution is not obtained by just positioning several regular single-circuit transmission lines in a single tower structure. Although double-circuit and multi-circuit transmission lines have been used over the last years, there are not many studies about non-conventional multi-circuit transmission lines. Thus, in this research a mathematical model to represent the problem related to increasing the surge impedance loading level of each circuit, and reducing the costs, the ROW and the height of the towers by optimizing their bundle geometry and conductor type by applying genetic algorithms is proposed. The overall transmission lines presented as examples have an improvement between 52% and 149% in the objective function.

Transient Stability Improvement on Jos – Gombe 330kV Line Using Static Var Compensator

In this paper, the result of a study carried out to determine the impact of static VAr compensator on voltage profiles and reactive power flow in the Nigerian 330kV transmission grid network is presented. The research seeks to mitigate the challenge of high reactive power on Jos – Gombe 330kV single circuit transmission line. The high reactive power is produced in that axis as a result of low industrial demand in the North-Eastern region of Nigeria which results in low-inductive loading of the long transmission line that spans from Jos to Gombe and its extension to Yola, Damaturu and Maiduguri. The study also performed optimal placement of the static VAr compensator in the area where it can influence the voltage at the static VAr compensator device connection point by controlling the reactive power flow through the grid. This was accomplished by modeling the existing 330kV Nigerian network in DIgSILENT PowerFactory. The result is an improved power stability on the line between Jos and Gombe. The voltage tolerance with the approved Nigerian Grid Code and compliance was ensured. Also, the static VAr compensator was proposed over reactors due to the fact that it is dynamically switched.

Outliers Analysis of RI Long-Term Data in Fair Weather From 1000 kV UHV AC Power Lines

Radio interference (RI) measurement data had been recorded by establishing long-term measurement stations close to the Chinese first 1000 kV UHV ac double-circuit and single-circuit transmission line. Due to the randomness and variation of RI data in fair weather, it is necessary to detect the outliers from measurement data. Two methods have been tried for analyzing the outliers by using two samples from both 1000 kV UHV AC double-circuit and single-circuit line in this letter. With nonparametric method, the outlier detection algorithm based on β ( g, h ) distribution has been proved to be more reasonable than normality assumption method.

DWT approach based differential relaying scheme for single circuit and double circuit transmission line protection including STATCOM

Abstract This paper describes fault detection and classification in a double–circuit transmission line with presence of STATCOM (Static Synchronous compensator) in one circuit. DWT (Discrete Wavelet Transform) approach based differential relaying scheme is used to detect and classify the fault pattern in the above transmission line. The scheme starts with current signals extracted from both end of the transmission line synchronously and processed through DWT to obtain Spectral Energy (SE). The Differential Spectral Energy (DSE) is computed by subtracting SE obtained from both sending end and receiving end of the line which is the key indicator for fault detection and classification. The proposed scheme is extensively tested on faulted conditions with wide variation in operating parameters and the test result indicate that it can reliably detect and classify fault both in single and double circuit line in presence of STATCOM with a relay response time of less than one cycle.

Improved electro‐geometric model for shielding failure analysis of transmission lines

An improved electro-geometric model (EGM) based on upward corona leader system consideration is introduced. The proposed method is a modified version of EGM and its high accurate results are independent of the height, voltage level, and circuit type of structure. The equations of the proposed method are modified by means of genetic algorithm based on the leader progression models (LPM) results which are consistent with the experimental results. To evaluate the performance of the proposed method, the shielding failure rates (SFR) of a single-circuit transmission line with different protection angles are calculated and compared to those of LPM and a revised EGM. The comparisons show that the results of the improved method roughly agree with the results of LPM. To ensure about the performance of the proposed method, it is applied on ten different practical structures with different characteristics. The results of IEGM are compared to the field data and the results of the revised EGM. The comparisons demonstrate that the proposed IEGM is an appropriate method for SFR calculation irregardless of the height, voltage level, and circuit type. In other words, the proposed IEGM is as simple as conventional EGM and as accurate as LPM.

A DWT Based Differential Relaying STATCOM Integrated Wind Fed Transmission Line

This paper presents the differential scheme of relaying protection of transmission line in a Static Synchronous Compensator (STATCOM) integrated wind fed single circuit line. The Discrete Wavelet Transform (DWT) and Discrete Fourier Transform (DFT) technique are applied for classification and detection of fault in STATCOM including wind farm. The STATCOM is positioned at central point of the transmission line and wind farm is connected at receiving end of the transmission line. The reactive power injection or absorption (i.e, shifting phase voltage with respect to bus voltage) depends upon the apparent impedance during the fault. The individual fault current signal (i.e, A, B and C) of three phase is extracted at both end of sending and receiving side of single circuit transmission line synchronously. It starts processing with the DWT and DFT to find the spectral energy content of each phase current signals at both end of transmission line. The Differential Spectral Energy(DSE) of current signals (i.e spectral energy of current measured at sending end minus spectral energy of current measured at receiving end) of each phase of transmission lines is used to register the fault pattern. This scheme is very accurate, effective and simple for fault classification and detection of transmission line.

A Time-Frequency Transform Based Fault Detectionand Classificationof STATCOM Integrated Single Circuit Transmission Line

<p align="center"> </p><p align="center"> </p><table width="593" border="1" cellspacing="0" cellpadding="0"><tbody><tr><td valign="top" width="387"><p>This paper discusses the time-frequency transform based fault detection and classification of STATCOM (Static synchronous compensator) integrated single circuit transmission line. Here, fast-discrete S-Transform (FDST) based time-frequency transformation is proposed for evaluation of fault detection and classification including STATCOM in transmission line. The STATCOM is placed at mid-point of transmission line. The system starts processing by extracting the current signals from both end of current transformer (CT) connected in transmission line. The current signals from CT’s are fed to FDST to compute the spectral energy (SE) of phase current at both end of the line. The differential spectral energy (DSE) is evaluated by subtracting the SE obtained from sending end and SE obtained from receiving end of the line. The DSE is the key indicator for deciding the fault pattern detection and classification of transmission line. This proposed scheme is simulated using MATLAB simulink R2010a version and successfully tested under various parameter condition such as fault resistance (Rf),source impedance (SI), fault inception angle (FIA) and reverse flow of current. The proposed approach is simple, reliable and efficient as the processing speed is very fast to detect the fault within a cycle period of FDT (fault detection time).</p></td></tr></tbody></table>

Methodology for optimizing the capacity and costs of overhead transmission lines by modifying their bundle geometry

The electrical power systems demand is continuously growing, in such a way that it is necessary to pursue methods to increase the overhead transmission line power capacity for single circuit lines. In this paper, it is proposed a methodology to increase the line energy transport capacity at lower costs. The enhancement is done by modifying the bundle geometry by using a heuristic optimization process divided into two steps. Firstly, a fixed bundle geometry is generated. Secondly, this form is modified seeking the optimization of line energy transmission capacities. During all process, electrical, mechanical and economical analyses are performed. As result, single circuit line geometries with almost 26% higher surge impedance loading than the original, significant costs reduction (50%), moderate bundles size (smaller than 2.5m), similar electric fields within the conductors of the bundle, smaller right of way, and similar transient response were obtained. Thus, compared with regular single circuit transmission lines, these new transmission lines have a lower overall cost and environmental impact. Finally, a transient analysis of the proposed transmission line is presented.

DT‐based relaying scheme for fault classification in transmission lines using MODP

In this study, a novel intelligent relaying scheme is proposed for fault classification and faulted phase selection using magnitude of differential power (MODP). The DP is the multiplication of difference between the magnitude of the real and estimated voltage and current phasors. The MODP for each phase is used as an input data to the data mining model known as decision tree (DT). The DT is used to generate thresholds to detect and classify the faults, since determination of robust thresholds is an important challenge in protective relay engineering. The proposed method has been tested for different operating modes of single-circuit transmission line in Simulink/MATLAB software. Simulation results indicate that the proposed method is able to detect and classify the faults with acceptable accuracy, in less than half cycle.