Transmission Line Parameters Research Articles

A method for estimating line industrial frequency parameters based on wideband information

Accurate acquisition of transmission line parameters is the basis for grid condition monitoring and data analysis, which is of great significance for the safe and economic operation of the grid. With the widespread use of phasor measurement unit (PMU) technology, the wideband information in the grid can be exploited, which broadens the new direction for line parameter identification. In this paper, a method is proposed to identify line frequency parameters based on wideband information. A mathematical model for line parameter identification with wideband information is established, and the identification of line frequency parameters is achieved by iterative solution through least squares. The results show that the accuracy of the parameter identification is improved by adding wideband information, and the identification of industrial frequency parameters for lightly loaded lines can be achieved. Finally, the feasibility and correctness of the method is verified by simulation.

Power System Voltage Stability Margin Estimation Using Adaptive Neuro-Fuzzy Inference System Enhanced with Particle Swarm Optimization

In the current era of e-mobility and for the planning of sustainable grid infrastructures, developing new efficient tools for real-time grid performance monitoring is essential. Thus, this paper presents the prediction of the voltage stability margin (VSM) of power systems by the critical boundary index (CBI) approach using the machine learning technique. Prediction models are based on an adaptive neuro-fuzzy inference system (ANFIS) and its enhanced model with particle swarm optimization (PSO). Standalone ANFIS and PSO-ANFIS models are implemented using the fuzzy ‘c-means’ clustering method (FCM) to predict the expected values of CBI as a veritable tool for measuring the VSM of power systems under different loading conditions. Six vital power system parameters, including the transmission line and bus parameters, the power injection, and the system voltage derived from load flow analysis, are used as the ANFIS model implementation input. The performances of the two ANFIS models on the standard IEEE 30-bus and the Nigerian 28-bus systems are evaluated using error and regression analysis metrics. The performance metrics are the root mean square error (RMSE), mean absolute percentage error (MAPE), and Pearson correlation coefficient (R) analyses. For the IEEE 30-bus system, RMSE is estimated to be 0.5833 for standalone ANFIS and 0.1795 for PSO-ANFIS; MAPE is estimated to be 13.6002% for ANFIS and 5.5876% for PSO-ANFIS; and R is estimated to be 0.9518 and 0.9829 for ANFIS and PSO-ANFIS, respectively. For the NIGERIAN 28-bus system, the RMSE values for ANFIS and PSO-ANFIS are 5.5024 and 2.3247, respectively; MAPE is 19.9504% and 8.1705% for both ANFIS and PSO-ANFIS variants, respectively, and the R is estimated to be 0.9277 for ANFIS and 0.9519 for ANFIS-PSO, respectively. Thus, the PSO-ANFIS model shows a superior performance for both test cases, as indicated by the percentage reduction in prediction error, although at the cost of a higher simulation time.

Estimation of the electrical parameters of overhead transmission lines using Kalman Filtering with particle swarm optimization

The parameter estimation for transmission systems is important to power flow analysis, planning the expansion of electric power systems, stability, dispatch and economic analysis. This type of task is developed through systems identification methods, being the least squares method and its variations the most common techniques to obtain the transmission line parameters. However, these techniques have some disadvantages, such as non-recursive parameter estimation or the availability of an ideally transposed line, in order to address a problem with symmetric matrices, which simplifies the estimation process. In this paper, a non-linear method (Extended Kalman Filter) is presented to obtain the states of the transmission line terminals jointly with the vectorized matrix of parameters; such approach is strongly affected by the initial conditions; these conditions are usually obtained manually, which requires a lot of time and effort. Therefore, an optimization method (Particle Swarm Optimization) is applied in order to improve the convergence of the EKF, which reduces the time for adjusting the hyper-parameters and improves the estimated results. The proposed method showed accurate results for non-transposed systems, and also in comparison with results obtained from the same EKF-based method without the proposed optimization technique.

Transmission Line Sag Measurement and Simulation Research Based on Non-Contact Electric Field Sensing.

Sag is an important indicator of the operational health of a transmission line, and its timely measurement is of great significance to maintain the stability and reliability of power systems. However, traditional contact measurements may be affected by the electromagnetic interference of conductors. In contrast, measurement methods without direct electrical contact with the subject provide greater portability and flexibility. This paper presents a study of a transmission line sag measurement and simulation based on non-contact electric field sensing. The finite element method was used to analyze the conductor distribution, establish the coupling relationships among the electric field, transmission line, and measurement point, propose a sag inverse calculation model, and assess the impact of the transmission line parameter on the curved drooping measurement. Simultaneously, sag measurement schemes for single-round and dual-circuit lines were designed for multi-conductive lines, and measurement array studies were conducted. The vertical component of the electric field in space measured by the array was obtained, which could be used to perform conductor sag measurement simply and efficiently. The proposed method will facilitate the monitoring of the overhead transmission line status, which is conducive to the effective operation of the entire system.

Power System State Estimation Approach Considering Transmission Line Temperature

The transmission line parameters vary with the change of temperature, which has a significant impact on power system state estimation (SE). Based on the theory of electro-thermal coordination (ETC), this paper proposes two ETC-SE approaches with the consideration of transmission line temperature. The heat balance equation (HBE) is combined with the conventional weighted least square SE for establishing an ETC-SE model. Moreover, an augmented Jacobian ETC-SE approach is developed by integrating the HBE into pseudo measurements and the line temperature into state vectors. The Jacobian matrix is augmented correspondingly and the partial differential coefficients of measurements to line temperature are provided, which enables to calculate line temperature and voltage phasors simultaneously. Furthermore, in order to accelerate the solving process, an improved two-step ETC-SE algorithm is proposed, in which the SE and temperature estimation are decoupled and solved via alternate iteration. The effectiveness of the proposed ETC-SE approaches is verified by the IEEE 14-, 39-, and 118-bus systems. The results show that the proposed ETC-SE approach is effective to reduce the calculation errors and possesses good convergence performance with varying environmental circumstances and ill-conditioned branches.

The Optimization Study for Electromagnetic Radiation With Ultrahigh Voltage Transmission Lines

Several factors affect the electromagnetic environment changes generated underneath high-voltage transmission lines. This article carries out a study on the impact of the electromagnetic environment on high-voltage transmission lines based on different tower structures, voltage levels, conductor layouts, conductor parameters, and other full range of engineering factors. First, the model of wire three-phase phase sequence, ground height, horizontal phase spacing, wire splitting number, split spacing, and model values are built. By continuously adjusting and optimizing the parameters, the electromagnetic environment distribution curve at 1.8 m above the horizontal plane is obtained. Then, according to the characteristic analysis of the distribution law after optimization, the simulation results under some typical factors are compared with the standard limits. Simultaneously, the effect of this optimization is verified by comparison with relevant literature. Finally, some suggestions on the optimization of the pole tower structure, transmission line parameters, and the influence of electromagnetic radiation in transmission line corridors are proposed in high-voltage transmission line projects, which may potentially have constructive contributions and value.

State and Parameter Estimation of Non-Uniform Transmission Line Using Kronecker Product Based Modeling

The distributed parameters of a non-uniform transmission line (NTL) are assumed to depend on a finite set of unknown parameters, for example, their spatial Fourier series coefficients. The line equations are set up taking random voltage and current line loading into account with the random loading being assumed to be white Gaussian noise in the time and spatial variables. Bypassing over to the spatial Fourier series domain, these line stochastic differential equations (SDEs) are expressed as a truncated sequence of coupled stochastic differential equations for the spatial Fourier series components of the line voltage and current. The coefficients that appear in these stochastic differential equations are the spatial Fourier series coefficients of the distributed line parameters and these coefficients in turn are linear functions of the unknown parameters. By separating these complex stochastic differential equations into their real and imaginary part, the line equations become a finite set of SDEs for the extended state defined to be the real and imaginary components of the line voltage and current as well as the parameters on which the distributed parameters depend. The measurement model is assumed to be white Gaussian noise corrupted versions of the line voltage and current sampled at a discrete set of spatial points on the line and this measurement model can be expressed as a linear transformation of the state variables, i.e, of the spatial Fourier series components of the line voltage and current plus a white measurement noise vector. This work uses sparse matrix factorization using Kronecker product to implement the Fourier unitary transform. This work implements perturbation theory for non-uniform transmission line. The extended Kalman filter (EKF) equations are derived for this state and measurement model and our real timeline voltage and current and distributed parameter estimates show excellent agreement with the true values based on MATLAB simulations. The use of sparse matrix factorization using Kronecker product ease the mathematical complexity and provides compact representation.

Electromagnetic Shielding Analysis of Planar Materials Using ASTM D4935 Standard Fixture

In this article, analytic models are proposed for electromagnetic shielding analysis of planar materials using the ASTM D4935 standard fixture typically employed to measure far-field shielding effectiveness (SE). The fixture with an inserted planar material is divided into two coaxial line sections and one material section that are modeled as lossless and lossy transmission lines (TLs), respectively. Using the ABCD parameters of TLs, the far-field SEs of planar materials are analytically derived and calculated. In order to analyze the case where the conductive materials are coated on insulating substrates, contact impedances are considered at the inner and outer conductors of the flanged coaxial fixture. The proposed high-frequency model can accurately predict the absorption loss especially in the high-frequency where the skin depth of the material becomes smaller than its thickness. Low-frequency and lumped models are also derived by approximation of the high-frequency model. In addition, correction factors are introduced to remove the SE error in the low-frequency range due to the attached insulating substrates of the conducting materials. For verification, the proposed models are compared with the theoretical plane-wave SE and the measurement results presented in other literatures. They show a good agreement with each other. Lastly, an influence of the errors in the thicknesses and electrical parameters of actual materials on the analytic SE models is analyzed.

Faults identification in high voltage direct current transmission lines using adaptive neuro-fuzzy inference system

ABSTRACT This paper presents an innovative approach in line commutated converter-based high-voltage direct-current (LCC-HVDC) transmission line for recognizing the section of the faults. In this work, three adaptive neuro-fuzzy inference system (ANFIS) modules have been suggested to investigate the safety responsibilities in the LCC-HVDC line. The ANFIS-1 aims to ascertain the faults in both sections; ANFIS-2 is to distinguish the section of the fault; and ANFIS-3 is to recognize the characteristics of the fault. To ascertain the effectiveness of the ANFIS approach, it has been compared with the differential protection (DP), wavelet transform (WT), fuzzy and artificial neural network (ANN). Furthermore, the proposed methods have been tested by varying the fault resistance (up to 500 Ω), power angle (from 5 to 15 degrees), near and end faults, and changing the transmission line parameters (±15 %). The simulation outcomes are disclosed that the proposed ANFIS technique yields better performance than other studied methods in terms of percentage of accuracy, time of fault section recognition, and reach setting.

Effects of Conditional Changes on High-Voltage Direct Current Transmission Line Characteristic

The high-voltage direct current (HVDC) transmission system, which links the Gurun Substation of the National Electric Authority of Malaysia (Tenaga Nasional Berhad, TNB) with the Khlong Ngae Station of the Electricity Generating Authority of Thailand (EGAT), has been extensively researched to achieve the highest quality because it is the largest of its kind in Thailand, and there is a plant to expand its transmission power. However, the impact on the whole system is under-researched. To study and develop this system, the HVDC transmission line is modelled with the MATLAB/Simulink program and a laboratory setup to investigate the effect of transmission line distance, load power, and voltage on power loss, voltage drop, and waveform. The HVDC transmission line parameters are calculated from the actual transmission line parameters and converted to the simulation model parameters using the per-unit method. The model is verified and tested by the simulation program before creating the experimental setup. The simulation and experimental results demonstrate the effects of changing system conditions via the three aspects. All the three conditions directly affect the HVDC transmission line; nevertheless, they affect each aspect differently.

Investigations on 3D printed primary recycled ABS for one-way programming

ABSTRACTIn the past two decades, number of studies have been reported on one-way programming (OWP) of virgin acrylonitrile butadiene styrene (ABS)-based substrate for sensing applications inform of dielectric constant (εr) and loss tangent/dissipation factor (tanδ). But hitherto little has been reported on the OWP of primary (1°) recycled ABS (by dielectric tuning of a 3D-printed substrate and mechanical bending to ensure conformal designs). This study reports the OWP of 3D-printed 1° recycled ABS as a sensor (for acetone detection in a distillery, patients with diabetic ketoacidosis as an internet of things (IoT)-based solution). For sensor fabrication, a ring resonator was initially designed using a commercial software package (CST studio suite) and fabricated by 3D printing of 1°recycled ABS for the resonant frequency of 2.45 GHz. Transmission line parameters (S21) were observed using a vector network analyser (VNA). Further, morphological, radio frequency (RF), current-voltage (I–V), and Fourier transformed infrared (FTIR) characterisation were performed to understand the effect of two stimuli (acetone and temperature) on ABS substrate for OWP of εr and tanδ. Also, the mechanical bending analysis of a one-way programmable substrate was observed for its suitability in sensors miniaturisation.

An Identification Algorithm of Relay Protection Parameter for Flexible High-Voltage Direct Current Transmission Lines Under Synchronous Sampling

Relay protection device is a protection device when the flexible DC transmission line is long and leads to line failure. Therefore, in order to ensure the reliable identification of relay protection parameters, an identification algorithm of relay protection parameter for flexible DC transmission line under synchronous sampling is proposed. By calculating the relay protection parameters based on synchronous sampling, the algorithm obtains the positive sequence parameters and zero sequence parameters of flexible DC transmission line’s relay protection, and uses the matrix beam algorithm to identify the positive sequence parameters and zero sequence parameters, so as to obtain the subsynchronous oscillation modal parameters. In order to improve the identification effect, the extended particle swarm optimization algorithm is used to optimize the identification results. The test results show that the algorithm has the feasibility of relay protection parameter identification and the calculation function of positive sequence parameters and zero sequence parameters of relay protection device. It can reliably identify the current change and the change results of positive sequence parameters and zero sequence parameters with minimal identification error.

A modified implementation of the Folded Line Equivalent transmission line model in the Alternative Transient Program

This paper proposes a modified implementation of the Folded Line Equivalent transmission line model to represent three-phase transmission lines. The Folded line equivalent decomposes a line into its open circuit and short circuit contributions. We propose an alternative orthogonal matrix to transform single-phase transmission line parameters, voltages, and currents to the Folded Line Equivalent domain. Because the proposed matrix is orthogonal, it can directly represent bidirectional transformations using circuit components in simulation software, such as the ATP-EMTP. First, the circuit implementation of Clarke’s matrix decouples a three-phase transmission line into its modes. Then, the circuit implementation of the proposed matrix decouples each mode into its open circuit and short circuit contributions. This paper proves that the proposed approach outputs similar results as those obtained by the Universal Line Model and the JMarti model in the simulation of transmission lines under open-circuit, energization, and fault conditions. However, because the proposed model does not derive from the method of characteristics, it can run with simulation times greater than the propagation delay of the transmission line. It is shown that the proposed approach outputs accurate results for time steps that are 10%, 100%, 200%, and 400% of the propagation delay of the transmission line. Thus, one major advantage of the proposed approach is that it can be used to reduce runtimes in the representation of short transmission lines in large complex networks by increasing time steps without compromising accuracy.

Electrical distribution grid of Kirkuk City: A case study of load flow and short circuit valuation using ETAP

The load flow study and short circuit analysis can be considered as the backbone of the electrical power network. This study based on real data collected from 12 substations, each substation contains many feeders provide the electricity network of Kirkuk city (a city in Iraq located at the north of Baghdad). The methodology of this article depended on using the Electrical Transient Analyzer Program (ETAP) software in assessing the performance of Iraqi electrical distribution network (Kirkuk city as a model) by starting modeling and simulation in order to assess the reliability through testing the load flow, and short circuit test. A complete study of load flow assessment of an actual Kirkuk city power distribution network with actual load values is presented (data have been taken from the Directorate of Electricity Distribution of Kirkuk city). The results of modeling the whole city and the detailed reports of this study can give us a comprehensive assessment with the presence of actual loads values, including total demand, PF, transmission line parameters, and the weakness points of the electrical grid.

Investigations Of Transmission Losses And Efficiency

This study presents Evaluation of transmission losses and efficiency, aim at to determine the losses associated with power transmission line and provide solution to improve power transmission line. This study was carried out at Benin regional power transmission station on 330KV/132KV power network, Sapele Road, Benin City. The Data collected were hourly reading recorded by various system operators on duty on a twenty-four hour basis, for duration of one year, from July 2009 to June 2010. Data collected were transmission parameters such has the sending voltage, Current and Power from Delta 330KV power station to Benin 330 KV received power station with voltage, current and power. In addition, 132KV transmission line parameters were also considered. The average voltage loss per month from 132KV transmission line from Benin to Irrua is 2.67KV, while the current is 16.25 Amp. The average voltage loss per month on 330KV transmission line from delta to Benin power regional centre is 4.725KV. While the current obtained is 22.5Amp. It observed that the higher power transmitted the higher the losses associated with the power system. In addition, size of cable and the distance covered are major factor that lead to loss on the power transmission line.

Electronic Controller Automatic Test System Based on Intelligent Control Algorithm

In order to improve the automatic test effect of the electronic controller, this paper combines the intelligent control algorithm to construct the automatic test system of the electronic controller. Moreover, the paper makes a detailed theoretical analysis of several basic problems relating to signal integrity and gives a general method to solve the main SI problems. In addition, this paper analyzes the principle of the microstrip transmission line parameter model and its relationship with the signal integrity and constructs an automated test system for an intelligent electronic controller. The simulation test results show that the electronic controller automated test system based on the intelligent control algorithm proposed in this paper can play an important role in the electronic controller automated test.

Synchrophasor Data Analytics: Transmission Line Parameters Online Estimation for Energy Management

Transmission line parameters are fundamental parameters of power system models that influence the safety, stability, and economy of power utility grids. Transmission line parameter estimation is a basic and necessary function and module of a power grid energy management system. However, traditional offline parameter estimation methods cannot cope well with parameter uncertainties caused by transmission line aging, environmental factors, and modern power grid developments. The widespread deployment of phasor measurement units (PMUs) in power networks has paved the way for accurate real-time-measurement-based transmission line parameter tracking. This article proposes PMU-based parameter estimation models considering series and shunt compensators. An online parameter estimation method is developed based on recursive least squares with a variable forgetting factor, which can adapt to various parameter mutations and has strong robustness to outlier measurements. This article also analyzes the sensitivity of parameters with respect to synchrophasor data. The simulation results under different scenarios verify the effectiveness, robustness, and adaptivity of the proposed method, which exhibits significant advantages over other existing parameter estimation methods.

Specifics of Power Losses in Power Lines Including Parallel Lines

Abstract Reducing power losses is invested in the trend of combating climate warming. It is necessary to know what parameters of power transmission lines affect the losses in them. In short and medium lines with accounted lumped parameters, the role and influence of the line parameters on losses are visible. In the lines with distributed parameters, at least with one series parameter and one parallel parameter, the role played by them, computing losses in ordinary way as difference between power at line sending and receiving end, is hidden. This is pronounced when considering parallel lines. In two parallel lines the losses can be greater than in a single line. This may occur when the current at the end of the lines is less than the boundary value: the value when two parallel lines and a single line have the same losses. The longer the line and the higher the rated voltage, the stronger the effect. In view of this aspect, it is necessary to know the boundary current. This current can be determined in ordinary way by a series of calculations changing the load value. In some cases, boundary current is affected not only by modulus of the current at the end of the line but also by its angle. It is better to calculate the boundary current by a formula, while studying the role of each parameter.

Printed electronics for extreme high temperature environments

There is a rapidly growing interest in the development of electronic microsystems that can maintain functionality in high temperature environments, particularly in power generation and aircraft engines where the operating temperatures can exceed 500 °C. The current work presents a major advancement toward development of additively printed electronics made for high temperature applications. Here, the electronic system is represented by gold-based electrical structures that have been printed on 3D printed ceramic substrates. The substrate is alumina-based with a purity level of 99.8% and was fabricated through photopolymerization digital light processing (DLP). An aerosol jet printing technique that can deposit an ink stream down to 10 µm was utilized to fabricate gold-based electronic structures. The gold ink printability and its adhesion to the ceramic substrate were assessed. Furthermore, the microwave dielectric constant and loss tangent of the alumina substrate were extracted through measurements of the scattering parameters of transmission lines up to 750 °C. A 3D printed conformal broadband antenna was successfully fabricated and tested at temperatures up to 850 °C. The printed gold structures showed excellent stability and adhesion after aging at temperatures up to 750 °C. The substrate dielectric constant slightly increased for temperatures up to 450 °C and significantly increased for temperatures between 450 °C and 750 °C. It was found that the dielectric loss increased as the temperature increased. This work presents an entirely additive manufacturing-based approach to fabricate electronic components including substrates, interconnects, and RF elements for high temperature applications.

INSTRUMENTAL ERRORS OF TRANSMISSION LINE PARAMETERS METER

The article is devoted to the construction of the instrumental errors dependences of the transmission line parameters meter on the parameters of the physical or structural hardware components of the meter. For this, when constructing a mathematical model, only the main functional connections between the structural links of the measuring device were selected, neglecting the influence of external factors on the stability of the structural elements parameters. As is know, each measuring instrument must have a certain set of metrological characteristics. According to these characteristics, measuring instruments are selected for use in certain technological processes, and it is they that determine the reliability of the data obtained as a result of measurements. These characteristics include a list of physical quantities that can be measured, the conditions under which the measurement process can be carried out, metrological (informational) reliability, accuracy class or permissible errors of the measuring instrument itself. The conditions under which the measuring instruments can be used depend on the constructive and technological implementation of the device, since the measurement technique and its implementation in the electrical circuit are not accompanied by special requirements for the operation of the device. This means that such a meter can be produced with a focus on laboratory use, for use in a mobile version and in the field, for use in complex electronic systems as an element of built-in control, etc. All this follows from the given measurement technique and analysis of the synthesized meter circuit. The exact characteristics of a measuring instrument include two important components: method errors and instrumental errors. To build such dependencies on the parameters of physical or structural hardware components and the values of the measured quantities, it is necessary to build a mathematical model of the measuring equipment. It is advisable to restrict ourselves to the construction of a mathematical model, which will take into account the dominant factors of the accuracy characteristics that cause first-order errors. Such a model, depending on the needs that arise during the operation of the measuring instrument, can be supplemented by certain sources of influences, certain causal actions that will cause the appearance of errors of the second and even third order. These are errors caused by changes in temperature, humidity, atmospheric pressure, mechanical vibrations, electromagnetic and acoustic fields, etc.