10 Results for the search " method":
Modular Multilevel Matrix Converter for Low-Frequency AC Transmission – modeling and Simulation in EMTP
Description:Authors: Rafael Castillo-Sierra and Giri Venkataramanan
The transmission of power with AC faces limitations both to the stable operation of the electrical system and to the physical properties of... see more the transmission lines. Therefore, alternatives are being sought to mitigate these problems without the need to build new lines or replace existing ones with new, more powerful ones. In this context, a proven method makes it possible to overcome these problems by reducing the frequency at which power is transmitted. This method is known as Low Frequency AC Transmission (LFAC). In this sense, the model presented in this Research Contribution Prize Program EMTP® 2021 shows the implementation of a low-frequency transmission line in a small power system. The model presented shows a new block in EMTP of the AC/AC converter used, the Modular Multilevel Matrix Converter (MMMC) and the controls necessary for its operation. Time domain studies show that the technology is feasible and has the potential to improve the controllability and stability of transmission systems.
Tag(s): AC-AC power conversion, Electromagnetic Transient Studies in EMTP, Low frequency AC transmission, Modular Multilevel Matrix Converter
INDUCED VOLTAGES AND CURRENTS: OVERVIEW AND EVALUATION OF SIMULATION MODELS AND METHODOLOGIES
Description:In this paper induced voltages and currents caused by underground cables are calculated in cable sheaths and nearby metallic pipelines. The performance of several simulation methods and models are inv... see moreestigated in steady-state, considering also different implementations in ATP-EMTP, EMTP-RV and PSCAD/EMTDC. The analysis is extended in the simulation of transient overvoltages in cable systems, evaluating the accuracy of two widely used simulation models. The influence of different parameters is investigated, among them specifically the earth properties. Results reveal that implementing accurate earth representations, earth conduction effects have a significant impact on induced voltages at the power frequency, while for high frequency phenomena the influence is minor.
Tag(s): induced voltages
Tutorial on exported mask (Demonstrated with an exciter)
Description:In this example, a device is placed in a subcircuit. The goal is to be able to modify the parameters of this device from the parent mask.
However, this device is a masked subcircuit and therefore... see more ## are not accepted. Here are two options to achieve this task.
Tag(s): exported, mask, exciter, governor, subcircuit, subnetwork, script, method
Indirect Lightning Performance of a Real Distribution Network with focus on Transformer Protection
Description:The paper applies the Monte Carlo procedure proposed by the Authors to evaluate the indirect lightning performance of a real medium-voltage distribution network, which includes feeders and laterals, p... see moreoles, secondary substations and surge protection devices. Such a procedure allows inferring the amplitude of lightning-induced voltages at any point and any phase of the network. The analysis presented in this paper aims at assessing the expected mean time between failures of each MV/LV transformer caused by indirect lightning strikes.
A heuristic technique has been specifically developed to reduce the computational effort despite the non-linear response of the network enhanced by the presence of surge arresters.
Authors: Alberto Borghetti, Fabio Napolitano, Carlo Alberto Nucci, Fabio Tossani, Gilnei J. G. Dos Santos, Donorvan R. Fagundes, Gustavo P. Lopes, Manuel L. B. Martinez
2014 International Conference on Lightning Protection (ICLP), Shanghai, China
Tag(s): induced voltages; distribution networks; Monte Car lo method; lightning protection; MTBF.
Indirect-Lightning Performance of Overhead Distribution Networks With Complex Topology
Description:The paper deals with the evaluation of the indirect-lightning performance of overhead distribution networks. The novelty of this contribution is that it takes into account the inherent complexity of d... see moreistribution networks. These networks are indeed characterized by a plurality of lines (main feeder and laterals) and also by the presence of typical power components (e.g., transformers and surge arresters); they consequently differ considerably from the straight line configuration generally adopted in this type of studies.
To accomplish such an evaluation we have extended the general procedure already presented in a previous paper based on the use of the LIOV code along with the Monte Carlo method. The extended procedure combines the advantage of the LIOV-EMTP computer code—that allows the calculation of lightning-induced voltages in complex distribution networks—with a heuristic technique specifically developed and integrated in the Monte Carlo routine in order to reduce the computational effort. The application of the proposed procedure to a set of distribution overhead networks characterized by different topologies, but all of the same length, shows that, in general, the usual single straight-line approach may result into a misestimation of the indirect-lightning performance. The paper also analyzes and discusses the influence of both the line terminations, and the position of the line poles.
Authors: Alberto Borghetti, Senior Member, IEEE, Carlo Alberto Nucci, Fellow, IEEE, and Mario Paolone, Member, IEEE
IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 24, NO. 4, OCTOBER 2009
Tag(s): LIOV-EMTP, lightning-induced overvoltages, lightning performance, power quality, distribution systems, overhead power lines.