Simulation of Lightning Induced Overvoltages
LIOV-EMTP is an EMTP-RV module developed for the calculation of lightning-induced overvoltages on an overhead distribution network.
The LIOV (Lightning-Induced OverVoltage) code allows the calculation of lightning-induced overvoltages on multiconductor lines above a lossy soil as a function of the line geometry, lightning current waveshape and stroke location, return-stroke velocity and soil electrical parameters.
Definition of the geometry for the calculation of the LEMP and its coupling with an overhead line
In order to deal with distribution networks having complex, realistic topology and configuration, the LIOV code has been interfaced with the Electromagnetic Transient Program (EMTP).
The LIOV-EMTP code is a software developed by Alma Mater Studiorum - University of Bologna (Italy), Ecole Polytechnique Fédérale de Lausanne - EPFL (Switzerland), with the support of University of Rome “La Sapienza” and of Centro Elettrotecnico Sperimentale Italiano “G. Motta” CESI S.p.A. (Italy).
The evaluation of lightning induced overvoltages is performed in the following way:
The LIOV code has been experimentally validated by means of several experimental data, related to natural and triggered lightning experiments, and by means of Nuclear Electromagnetic Pulse Simulators and reduced scale models .
Overvoltages on a 10-m high medium voltage line above a 10 mS/m conductiing soil due to a typical subsequent return stroke (12 kA peak).
The analysis of more complex system configurations composed by several lines and power components can be dealt with by using the LIOV-EMTP module based on the interfacing method presented in . An example of a system that can be simulated with the LIOV-EMTP module is shown below, taken from .
Comparison between the overvoltages calculated at the terminals of a 100 kVA transformer T2 due to a typical first return stroke (31 kA peak): a) topology of the distribution network; b) MV side; c) LV side.
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