@article{ca3edd9a6cd54221866eb68bf5ef2f1f,
title = "A New Standalone Tool for DC-Equivalent Network Generation and GIC Calculation in Power Grids With Multiple Voltage Levels",
abstract = "Space Weather phenomena pose a major socio-economic threat due, in part, to the vulnerability of power network transformers to geomagnetically induced currents (GIC). In 1985, Lehtinen and Pirjola (LP) provided a method to calculate GICs in a single-voltage-level network. The need to account for lower voltages has caused the proliferation of GIC risk assessments applied to power grids with multiple voltages. We hereby present a tool to systematically generate the direct currents (DC)-equivalent of a multiple-voltage-level network. The LP and Nodal Admittance Matrix methods are the most popular schemes to compute the GIC from the resulting equivalent network by solving the circuit laws for the earthing current or the voltage at each node, respectively. A new scheme is presented here that solves the circuit laws for the current flowing between the bus nodes and the neutral point which, unlike LP, requires no (infinite-resistance) earth connections for the buses. The number of equations/unknowns of the resulting GIC matrix equation is reduced compared to the traditional methods, thus optimizing the computational cost -an advantage that becomes important for large networks-, while keeping a good condition of the design matrix associated with the inversion. Examples are shown for different test cases and a standalone computationally efficient code is provided.",
keywords = "GIC, geomagnetically induced currents, natural hazards, power networks, space weather, vulnerability",
author = "S. Marsal and Torta, {J. M.} and V. Canillas-P{\'e}rez and Curto, {J. J.}",
note = "Funding Information: These results are part of the projects CGL2017-82169-C2-1-R, funded by FEDER/Ministerio de Ciencia, Innovaci{\'o}n y Universidades – Agencia Estatal de Investigaci{\'o}n-, and PID2020-113135RB-C32, funded by Ministerio de Ciencia e Innovaci{\'o}n. The research that led to these results was also in part carried out using funds from “la Caixa” Foundation. The authors would like to thank Red El{\'e}ctrica de Espa{\~n}a (REE) for supporting this study. REE provided us with the DC characteristics of the Spanish electrical transmission network under caveats and restrictions and attended to many questions concerning them. This research is also part of POLARCSIC activities. The authors are indebted to Dr. D. Boteler who, as a reviewer, contributed greatly to improving this manuscript. They are also grateful to an anonymous reviewer. The authors declare no conflicts of interest. Funding Information: These results are part of the projects CGL2017‐82169‐C2‐1‐R, funded by FEDER/Ministerio de Ciencia, Innovaci{\'o}n y Universidades – Agencia Estatal de Investigaci{\'o}n‐, and PID2020‐113135RB‐C32, funded by Ministerio de Ciencia e Innovaci{\'o}n. The research that led to these results was also in part carried out using funds from “la Caixa” Foundation. The authors would like to thank Red El{\'e}ctrica de Espa{\~n}a (REE) for supporting this study. REE provided us with the DC characteristics of the Spanish electrical transmission network under caveats and restrictions and attended to many questions concerning them. This research is also part of POLARCSIC activities. The authors are indebted to Dr. D. Boteler who, as a reviewer, contributed greatly to improving this manuscript. They are also grateful to an anonymous reviewer. The authors declare no conflicts of interest. Publisher Copyright: {\textcopyright} 2022. The Authors.",
year = "2022",
month = mar,
doi = "10.1029/2021SW002984",
language = "English",
volume = "20",
journal = "Space Weather",
issn = "1542-7390",
publisher = "Wiley-Blackwell",
number = "3",
}