Effect of shield wires on GICs: Equivalent resistance and induced voltage sources. (December 2022)

• Record Type: Journal Article
• Authors: Santos, Rute; Pais, Maria Alexandra; Alves Ribeiro, Joana; Cardoso, João; Perro, Luís; Santos, André
• Is Part Of: International journal of electrical power & energy systems. Volume 143(2022)
• Publication Date: 2022-12
• Subjects: GICs -- Shield wires -- Transmission lines -- Geomagnetic storms; Electrical engineering -- Periodicals; Electric power systems -- Periodicals; Électrotechnique -- Périodiques; Réseaux électriques (Énergie) -- Périodiques; Electric power systems; Electrical engineering; Periodicals; 621.3
• DOI: 10.1016/j.ijepes.2022.108487
• Languages: English
• ISSNs: 0142-0615

Abstract

Abstract: In transmission power networks and during geomagnetic storms, shield wires can carry induced currents in the same way as phase conductors. Shield wires are not usually considered in the transmission line models used in the study of the impact of geoelectric phenomena in power systems. In this study, the influence of shield wires on GICs in power systems is made clearer. The most simple power system, with one single transmission line connecting two substations and one shield wire, is considered. An analytical expression for the Thévenin equivalent circuit that, in parallel with the substations grounding resistances, produces the same effects on GICs as the complete circuit, is derived. Our model extends the results from previous studies by including the induced voltage along the shield wires. Differences can be relevant in relatively short transmission lines with only some tens of towers, where nevertheless the more simple asymptotic derived expressions may be used. Tests were done using realistic values for the circuit parameters and applied to real transmission lines. Highlights: Derivation of a new model for the single shield wire circuit, taking into account the effect of voltage induced by geomagnetic storms along the shield wire. Derivation of a simple test to find out if a short transmission line may be described by the new model. The new model improves GIC estimations for transmission lines with only a few tens of towers.