S. Bogarra (ES), Surge arrester's location using fuzzy logic techniques (Q2.4)
(Universitat Politècnica de Catalunya, Bogarra@ee.upc.es ; co-authors A.L. Orille, Orille@ee.upc.es,
M. Angela Grau, Angela@ma2.upc.es)
The calculation of the best location for surge arresters needs the input of all the characteristics of the analyzed
network to obtain some practical guidelines, but also needs powerful tools to calculate the lightning
overvoltages. The calculation of lightning overvoltages is very difficult, even if the analyzed network is
simplified and the models used for the network components are not sophisticated [1]-[5]. It is extremely
complicated to analyze the surge effects in distribution networks as the dimension of the networks increases or
when the random nature of lightning is taken into account.
This paper don’t draw practical guidelines, the aim of this work is to establish a method for selecting power
system protection schemes that guard against lightning overvoltages. The method is based on statistical analysis
of surges and fuzzy logic techniques. The implemented algorithms optimize the surge arrester location, working
with known risks of failure.
The method of calculating the location of surge arresters in order to limit the risk of failure can be applied for
any network configuration, thus permitting the development of a useful computer application that facilitates the
design and analysis of power networks.
Practical guidelines can be obtained if the method developed in order to establish the surge arrester’s location is
applied for practical cases. We can reach important conclusions of the network protection using simplified
models in the analysis, but we can lead more significant conclusions if the models represent the network
components and the lightning with enough accuracy.
The numerical solution obtained by simulation using programs like EMTP/ATP and PSpice is based on the
application of the trapezium rule if the model used for the network component have lumped parameters, and the
Bergeron’s method if the model used for the netowork componente have distributed parameters [6].
The application of the trapezium rule and the Bergeron's method show errors that must be taken into account.
The simulation results show errors that are not due to the simulation model representing the network
components. They result from the limitations of the used methods of the simulation programs; otherwise
programs like Matlab, Simulink and Powersys use high order integration rules that provide bigger stability and
calculation accuracy while running the simulation [7].
Previous studies, in order to establish a selection method of the component models of power networks [8]-[9],
allow the determination of the accuracy degree that can be obtained at the simulations using the models
implemented in the EMTP/ATP program [10]-[11]. The EMTP/ATP program presents serious limitations, in
spite of the high number of options and available models. These limitations are related mainly with the
transformers, it doesn't exist acceptable models for any group of frequencies, according to the classification
proposed by CIGRE, so that usually the models must be incorporated in the transients simulation program by
the user [12]-[13].
The component models of power networks can be easily implemented using the Matlab software and their
modules, such as Simulink and Powersys, which also allow to reduce the developing time of a new computer
application.
The Matlab is becoming a powerful tool in the environment of the engineering, not only for their modules but
also for its own calculation power and the simplicity to develop new applications.
REFERENCES
[1]
S. Bogarra, 1999, “Programa de cálculo de sobretensiones atmosféricas basado en las reflexiones/ refracciones de ondas viajeras”,
1ª Jornada Técnica sobre Coordinación de Aislamiento, CIGRE, pp. 1-6.
[2]
A. L. Orille, S. Bogarra, J. Iglesias, 2000, “Método alternativo de cálculo de sobretensiones atmosféricas basado en las
reflexiones/refracciones de ondas viajeras”, X Reunión de Grupos de Investigación en Ingeniería Eléctrica, pp. 1-7.
[3]
A. L. Orille, S. Bogarra, J. Iglesias, M.A. Grau, 2000, “Enfoque sistemático del cálculo de reflexiones y refracciones de ondas en
líneas de transmisión”, International Conference Telec 2000, pp. 1-6.
[4]
A. L. Orille, S. Bogarra, J. Iglesias, M.A. Grau, 2001, “Implementación de un programa de cálculo de sobretensiones en redes
eléctricas”, XI Reunión de Grupos de Investigación en Ingeniería Eléctrica, pp.1-6.
[5]
S. Bogarra, J. Iglesias, A.L. Orille, M.A. Grau, 2001, “Cálculo de sobretensiones atmosféricas en una red con pararrayos
autoválvula basado en la aplicación del método gráfico de Bewley”, VII Jornadas Hispano-Lusas de Ingeniería Eléctrica, pp. 225-230.
[6]
H.W. Dommel, 1986, EMTP theory book, BPA, Portland.
[7]
The MathWorks Inc., Help pdf-doc: Matlab, Simulink y Power System Blockset, 1984-1998.
[8]
J.A. Martínez, S. Bogarra, 1995, “Modelización de redes de distribución para el cálculo de sobretensiones”, IV Jornadas HispanoLusas de Ingeniería Eléctrica, pp. 829-838, Vol. 2.
[9]
J.A. Martínez, S. Bogarra, 1995, “Sobretensiones en redes de distribución”, V Jornadas Internacionales de Aislamiento Eléctrico,
pp. 1-6.
[10]
J.A. Martínez, S. Bogarra, 1996, “Coordinación de aislamiento en redes de distribución”, 4as Jornadas Técnicas de Redes
Eléctricas de Distribución e Instalaciones de Clientes, pp. 177-188, Vol. 1.
[11]
J.A. Martínez, S. Bogarra, 1996, “Surge protection of underground networks with metal-oxide arresters”, Universities Power
Engineering Conference, pp. 1-6.
[12]
S. Bogarra, R. López, 1998, “Modelización de transformadores de distribución de tres columnas mediante Pspice”, 2as Jornadas
Técnicas sobre Energía, pp. 143-149.
[13]
A.L.Orille, S. Bogarra, J.A. Valencia, R. López, J. Iglesias, 1999, “Modelización de transformadores de tres columnas para el
diseño de protecciones digitales”, VI Jornadas Hispano-Lusas de Ingeniería Eléctrica, pp.1-6.