Showing 4 results for Transmission Lines
M. Farshad, J. Sadeh,
Volume 9, Issue 3 (9-2013)
Abstract
In this paper, an approach is proposed for accurate locating of single phase faults in transmission lines using voltage signals measured at one-end. In this method, harmonic components of the voltage signals are extracted through Discrete Fourier Transform (DFT) and are normalized by a transformation. The proposed fault locator, which is designed based on Random Forests (RF) algorithm, is trained based on these normalized harmonic components. RF algorithm has the capability of learning patterns with a large number of features. The proposed approach only requires voltage signals measured at one-end hence, there are not problems of transmitting and synchronization of two-end data. In addition, current measurement is not required and the proposed approach is sheltered against current transformer errors and its saturation. No need for very high sampling frequency is another advantage of the proposed approach. Numerous tests carried out on a sample system indicate that accuracy of the proposed fault locator is secure against changing fault location, fault inception angle, fault resistance, and magnitude and direction of pre-fault load current. An average of 0.11% is obtained for the fault locating test errors.
M. Khalaj Amirhosseini,
Volume 9, Issue 3 (9-2013)
Abstract
In this article, three new green's functions are presented for a narrow strip line (not a thin wire) inside or on a homogeneous dielectric, supposing quasi-TEM dominant mode. These functions have no singularity in contrast to so far presented ones, so that they can be used easily to determine the capacitance matrix of multi-layer and single-layer homogeneous coupled microstrip lines. To obtain the green’s functions, the Laplace’s equation is solved analytically in Fourier integral or Fourier series expressions, taking into account the boundary conditions including the narrow strip. The validity and accuracy of three presented green’s functions are verified by some examples.
R. Gandotra, K. Pal,
Volume 18, Issue 3 (9-2022)
Abstract
The growing demand increases the maximum utilization of transmission and distribution lines which causes overloading, high losses, instability, contingency, and congestion. To enhance the performance of AC transmission and distribution systems FACTS devices are used. These devices assist in solving different issues of transmission lines such as instability, congestion, power flow, and power losses. Advancement in developed technology leads to the development of special application-based FACTS controllers. The main issues are concerned while placing the FACTS controller in the transmission and distribution lines to maximize the flow of power. Various methods like analytic method, arithmetic programming approaches, meta-heuristic optimization approaches, and hybrid approaches are being employed for the optimal location of FACTS controllers. This paper presents a review of various types of FACTS controllers available with both analytical and meta-heuristic optimization methods for the optimal placement of FACTS controllers. This paper also presents a review of various applications of FACTS devices such as stability improvement, power quality, and congestion management which are the main issues in smart power systems. Today’s smart power systems comprise the smart grids with smart meters and ensure continuous high quality of power to the consumers.
S. P. Ramezanzadeh, M. Mirzaie, M. Shahabi,
Volume 19, Issue 2 (6-2023)
Abstract
Due to the role of renewable energy sources in providing energy in future power systems, multi-terminal HVDC (MTDC) systems have attracted the attention of utilities and decision-makers. The reliability study of MTDC grids is critical for analyzing electrical power systems and providing a reliable power delivery system. Reliability modeling and study of six MTDC transmission networks containing hybrid DC circuit breakers for interrupting transmission line contingencies is presented in this paper. This study incorporates precise reliability models of MTDC grid configurations and describes a step-by-step grid expansion. Considering these reliability models, critical reliability indices of the demand bus of the grid have been obtained to calculate the amount of energy not supplied. Also, the influence of the tapping stations on the demand bus reliability features has been investigated. Since the components' characteristics significantly affect the system's reliability, the impact of the transformer and DC circuit breaker's failure rate and repair time on the reliability features of the demand bus of all MTDC grids have been assessed. The obtained results are employed to forecast the effect of simultaneous change of the repair time and failure rate of the transformer, the most influential component in determining the reliability indices, on the proposed configuration by incorporating multivariate linear regression.
