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In this paper is described the implementation of the frequency-dependent line model (FD-Line) in a real-time digital power system simulator. The main goal with such development is to describe a general procedure to incorporate new realistic models of power system components in modern real-time simulators based on the Electromagnetic Transients Program (EMTP). In this procedure are described, firstly, the steps to obtain the time domain solution of the differential equations that models the electromagnetic behavior in multi-phase transmission lines with frequency dependent parameters. After, the algorithmic solution of the FD-Line model is implemented in Simulink environment, through an S-function programmed in C language, for running off-line simulations of electromagnetic transients. This implementation allows the free assembling of the FD Line model with any element of the Power System Blockset library and also, it can be used to build any network topology. The main advantage of having a power network built in Simulink is that can be executed in real-time by means of the commercial eMEGAsim simulator. Finally, several simulation cases are presented to validate the accuracy and the real-time performance of the FD-Line model.

El presente trabajo muestra la propagación de ondas de interfaz de Scholte en la frontera de un medio acústico (fluido) en contacto con un medio solido elástico, para una gama amplia de materiales sólidos. Se ha demostrado que mediante un análisis de ondas difractadas en un fluido, es posible inferir las propiedades mecánicas del medio solido elástico, específicamente, sus velocidades de propagación. Con este fin, el campo difractado de presiones y desplazamientos, debido a una onda de presión inicial en el fluido, son expresados empleando representaciones integrales de frontera, las cuales satisfacen la ecuación de movimiento. La fuente en el fluido es representada por una función de Hankel de segunda especie y orden cero. La solución a este problema de propagación de onda es obtenida por medio del Método Indirecto de Elementos Frontera, el cual es equivalente al bien conocido teorema de representación de Somigliana. La validación de los resultados se lleva a cabo usando el Método del Número de Onda Discreto y el Método de Elementos Espectrales. Primeramente, presentamos espectros de presiones que ilustran el comportamiento del fluido para cada material solido considerado, después, mediante la aplicación de la Transformada Rápida de Fourier se presentan resultados en el dominio del tiempo, mediante simulaciones numéricas que muestran la emergencia de las ondas de Scholte. doi: https://doi.org/10.1016/S0016-7169(13)71459-4

Abstract The purpose of this study is to obtain numerical estimations of seismic pressures in offshore areas considering the effect of seabed configurations and soil materials. To this end, the Boundary Element Method is used to irradiate waves, so that force densities can be obtained for each boundary element. From this hypothesis, Huygens´ Principle is implemented since the diffracted waves are constructed at the boundary from which they are radiated. Application of boundary conditions allows us to determine a system of integral equations of Fredholm type of second kind and zero order. Various models were analyzed, the first one is used to validate the proposed formulation. Other models of ideal seabed configurations are developed to estimate the seismic pressure profiles at several locations. The influence of P- and SV-wave incidence was also highlighted. In general terms, it was found that soil materials with high wave propagation velocities generate low pressure fields. The difference between the maximum pressure values obtained for a soil material with shear wave velocity of β = 3000 m/s is approximately 9 times lower than those obtained for a material with β = 90 m/s, for the P-wave incidence, and 2.5 times for the case of SV-waves. These results are relevant because the seabed material has direct implications on the field pressure obtained. A relevant finding is that the highest seismic wave pressure due to an offshore earthquake is almost always located at the seafloor.