The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this article, it is represented by state variables phase a transmission line which parameters are considered frequency independently and frequency dependent. It is analyzed what is the reasonable number of π circuits and the number of blocks composed by parallel resistor and inductor in parallel for reduction of numerical oscillations. It is simulated the numerical routine with and without the...
The objective of this paper is to show a methodology to estimate the longitudinal parameters of transmission lines. The method is based on the modal analysis theory and developed from the currents and voltages measured at the sending and receiving ends of the line. Another proposal is to estimate the line impedance in function of the real-time load apparent power and power factor. The procedure is...
The phases of a transmission line are tightly coupled due to mutual impedances and admittances of the line. One way to accomplish the calculations of currents and voltages in multi-phase lines consists in representing them in modal domain, where its n coupled phases are represented by their n propagation modes. The separation line in their modes of propagation is through the use of a modal transformation...
The correction procedure for Clarke's matrix, considering three-phase transmission line analyzes, is analyzed step by step in this paper, searching to improve the application of this procedure. Changing the eigenvectors as modal transformation matrices, Clarke's matrix has been applied to analyses for transposed and untransposed three-phase transmission line cases. It is based on the fact that Clarke's...
This paper presents a mathematical model to simulate and analyze electromagnetic transients in transmission lines using a mono-phase representation of these lines comparing results models with and without frequency influence in longitudinal parameters. For this, π circuits and state variables are used for composing a linear system that is solved through iterative numeric routines. This routine is...
The objective of this paper is to show an alternative representation in time domain of a non-transposed three-phase transmission line decomposed in its exact modes by using two transformation matrices. The first matrix is Clarke's matrix that is real, frequency independent, easily represented in computational transient programs (EMTP) and separates the line into quasi-modes a, b and zero. After that,...
Single real transformation matrices can change the Z and Y matrices into diagonal ones for transposed three-phase lines. Considering non-transposed non-symmetrical three-phase lines, the errors between the Clarkepsilas matrix application results (called quasi-modes) and the eigenvectors are negligible. In this text, some other analyses are performed for two line designs. So, the arithmetic media among...
The application of modal transformation models for transmission lines have been analyzed extensively because in mode domain there are facilities in representation of frequency dependent line parameters. Because the determination of exact modal transformation matrices for general cases is not a simple task, simplifications about these applications can be considered. Using non-transposed three-phase...
Clarkepsilas matrix has been applied as a phase-mode transformation matrix to three-phase transmission lines substituting the eigenvector matrices. Considering symmetrical untransposed three-phase lines and the frequency range into 10 kHz, some transient simulations have been made with the application of this single real matrix. An actual symmetrical three-phase line on untransposed conditions is...
Clarke's matrix has been used as an eigenvector matrix for transposed three-phase transmission lines and it can be applied as a phase-mode transformation matrix for transposed cases. Considering untransposed three-phase transmission lines, Clarke's matrix is not an exact eigenvector matrix. In this case, the errors related to the diagonal elements of the Z and Y matrices can be considered negligible,...
The objective of this paper is to show an alternative representation in time domain of a non-transposed three-phase transmission line decomposed in its exact modes by using two transformation matrices. The first matrix is darkens matrix that is real, frequency independent, easily represented in computational transient programs (EMTP) and separates the line into quasi-modes alpha, beta and zero. After...
The paper shows an alternative methodology to calculate transmission line parameters per unit length and to apply it in a three-phase line with a vertical symmetry plane. This procedure is derived from a general procedure where the modal transformation matrix of the line is required. In this paper, the unknown modal transformation matrix requested by general procedure is substituted by Clarke's matrix...
Clarke's matrix is an eigenvector matrix for transposed three-phase transmission lines and its application as a phase-mode transformation matrix for untransposed three-phase transmission lines has been studied using error and frequency scan analyses. Considering untransposed asymmetrical three-phase transmission lines, a correction procedure is applied searching for better results from the Clarke's...
The objective of this paper is to show an alternative representation in time domain of a non-transposed three-phase transmission line decomposed in its exact modes by using two transformation matrices. The first matrix is Clarke's matrix that is real, frequency independent, easily represented in computational transient programs (EMTP) and separates the line into quasi-modes alpha, beta and zero. After...
For typical symmetrical systems with three-phase double-circuit transmission lines or two parallel three-phase double-circuit transmission lines, single real transformation matrix is applied. The objective is to determine Z (impedance) and Y (admittance) diagonal matrices in the mode domain. The proposed analyses are based on eigenvector and eigenvalue studies, using linear combinations of Clarke...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.