Features of Transient Research in Three-Phase High-Voltage Power Transmission Cable Lines (original) (raw)

Electromagnetic Transients in Multiconductor Transmission Lines

Journal of Microwaves, Optoelectronics and Electromagnetic Applications

The theory of multiconductor transmission lines is based on the principle of superposition. According to this principle, any electric or magnetic field can be represented as the sum of individual electric or magnetic fields. This theory is used to analyze and design electrical systems involving multiple conductors. In this work, the procedures for analyzing electromagnetic transients in 3-conductor transmission lines are presented, which is the last step for generalization in the case of lines to "n" conductors. The paper presents elementary cases and a more general one to illustrate such an approach.

Analysis of the transients on the multi-circuit overhead transmission line

Journal of Electrical Engineering, 2017

In this paper a method for a transient analysis on the multi-circuit overhead transmission line with different voltage levels (EHV and HV) is presented. The influence of inductive and capacitive couplings between the parallel circuits placed on the same tower is studied. The transmission line model consists of mutual coupled two-port cascades which can be described by a system of ordinary differential equations (ODE). This system has been solved numerically in MATLAB, the obtained results provide the time distribution of currents and voltages in all conductors along the transmission line. The presented algorithm allows solving various types of transients which can occur during switching off- and on-operations, shortcircuits etc.

Electromagnetic Transients in Multi-Voltage Transmission Lines during Non-Simultaneous Faults

Energies

It is vitally important that a transmission network provides a continuity of electricity to end users and that the transmission system operator prioritizes its safety and reliability. This article presents the possibilities of using multi-track overhead lines with varying levels of rated voltage, run on a common support structure. This solution would ensure safe operation of the system, reduce the area used for the construction of new overhead lines, and, at the same time increase the transmission network capacity. This article focuses on the method of modeling overhead lines for the analysis of electromagnetic transient states that occur during non-simultaneous disturbance phenomena. This article presents the idea of multi-circuit, multi-voltage lines and their validity of use in power systems. An analysis of electromagnetic transient states for non-simultaneous disturbances in multi-path, multi-voltage lines is presented. This analysis has been made on the basis of a network model...

A New Approach for Closed-Form Transient Analysis of Multiconductor Transmission Lines

IEEE Transactions on Electromagnetic Compatibility, 2004

A novel closed-form model for multiconductor transmission lines is presented. The proposed model is derived from the analytical characterization of half-T ladder networks, which using closed-form polynomials (named DFF and DFFz), allow one to exactly extract poles and residues of the two-port representation of multiconductor transmission lines, thus, generating a time domain macromodel that can be incorporated in a circuit simulator. Since the model is derived from a stable and passive equivalent network, its stability and passivity are strictly preserved. Simulation results for one, two, and three-conductor transmission lines with linear and nonlinear terminations are presented, confirming the validity of the proposed model.

Efficient procedure to evaluate electromagnetic transients on three-phase transmission lines

IET Generation, Transmission & Distribution, 2010

This paper presents a hybrid way mixing time and frequency domain for transmission lines modelling. The proposed methodology handles steady fundamental signal mixed with fast and slow transients, including impulsive and oscillatory behaviour. A transmission line model is developed based on lumped elements representation and state-space techniques. The proposed methodology represents an easy and practical procedure to model a three-phase transmission line directly in time domain, without the explicit use of inverse transforms. The proposed methodology takes into account the frequency-dependent parameters of the line, considering the soil and skin effects. In order to include this effect in the state matrices, a fitting method is applied. Furthermore the accuracy of proposed the developed model is verified, in frequency domain, by a simple methodology based on line distributed parameters and transfer function related to the input/output signals of the lumped parameters representation. In addition, this article proposes the use of a fast and robust analytic integration procedure to solve the state equations, enabling transient and steady-state simulations. The results are compared with those obtained by the commercial software Microtran (EMTP), taking into account a three-phase transmission line, typical in the Brazilian transmission system.

Equivalent for Electromagnetic Transient Calculation in Power System with Multiple Transmission Line

Energy and Power Engineering, 2013

The results of searching of equivalent for electromagnetic transient calculation in power system with the big number of transmission lines are shown. Brief information on the proper transmission line model is given. Comparison of results of simulation in real and reduced system is presented taking into consideration three methods of identification. Some example are examined for different number of transmission lines in reduced system and consequently the recommendation are given for searching of equivalents of systems with many lines.

Some Renovations in Transient Analysis of Transmission Lines by State-Space Techniques

Mathematical and Computational Applications, 1(1), 181-190, 1996

A method for transient analysis of single phase transmission lines based on state-space technique is presented. Transmission lines are considered as the interconnection of many lumped parameter sections. By this approach state equations are formulated for the system by choosing the capacitor voltages and inductor currents as the state variables. These equations are solved by state space techniques to compute steady-state and transient responses of transmission lines for various source and load connections. A computer program called LPTLAP (Lumped Parameter Transmission Line Transient Analysis Program) has been prepared for both formulation and solution steps. Transmission faults and switching operations in power systems cause sudden changes in voltage and current. Transient overvoltages must be known to indicate system isolation level in the planning stage, to protect system equipment and for the design of protective devices. Voltage and current at any point on the line can be represented by both space and time dependent partial differential equations. Analytic solutions of these equations are available for a few cases. For this reason, in the past Transient Network Analyzer (TNA) was used for the prediction of overvoltages and many applications are referred [1]. Later, by the use of digital computers numerical methods have got importance and several methods have been developed. These methods may generally be classified as time domain and frequency domain methods.

Computation of electromagnetic transients on transmission lines with nonlinear components

IEE proceedings, 2003

The paper presents the calculation of electromagnetic transients (EMT) on three-phase transmission lines with frequency dependent parameters and corona, the latter represented by the model of Ref. [1]. The transmission line is divided into segments, each with a small travel delay, a longitudinal block for the modelling of frequency dependence, and a transversal model of the nonlinear effect of corona. Longitudinal 'shaping' is obtained by parallel R,L elements corresponding to a series of such blocks obtained by fitting the modal line impedances over a wide range of frequencies. The computations are performed in the modal domain for longitudinal phenomena and in the phase domain for the transversal branches which include corona in each phase. The travel delay effectively decouples the nodes and the calculations for the corona branches. Thus it permits the representation of the line by Norton equivalents at its ends, so that the model can be included in a general purpose ElectroMagnetic Transients Program (EMTP). The computational results presented in the paper show wave shapes similar to those observed in measurements [13] and clearly demonstrate the significance of modelling both frequency dependence and corona.

Enhancing the frequency-domain calculation of transients in multiconductor power transmission lines

Electric Power Systems Research, 2015

In this paper numerical improvements are proposed to enhance the accuracy and efficiency of frequencydomain transient transmission line modeling. The adopted procedure is based on a robust eigenvector tracking algorithm and an accurate shape-preserving interpolation routine, formulating the highly resonant nodal admittance matrix from a minimal number of frequency data. The proposed method is integrated with the numerical Laplace transform and its performance is demonstrated in a configuration, consisting of an underground cable and an overhead line. Results are validated with the corresponding obtained from a frequency-domain model with regular sampling, revealing the high accuracy of the proposed formulation. The computational efficiency of the proposed numerical improvements is highlighted by comparisons of the execution times in cases of high sampling rates.

Transient voltage and current distributions on transmission lines

IEE Proceedings - Generation, Transmission and Distribution, 2002

Transient conditions such as switching operations and faults cause the generation of travelling waves on power transmission lines. Spatial current and voltage distributions on the transmission line are computed in the time domain using the state-space technique. The state-space representations of the transmission lines for short-and open-circuit faults and for various types of terminations are given. The results obtained by the method are compared with the solutions obtained in the frequency domain.