TY - JOUR
T1 - Improvement of the lightning shielding performance of overhead transmission lines by passive shield wires
AU - Metwally, Ibrahim A.
AU - Heidler, Fridolin H.
N1 - Funding Information:
Manuscript received February 5, 2002; revised December 4, 2002. The work of I. A. Metwally was supported in part by the Alexander von Humboldt Foundation and in part by the University of the Federal Armed Forces Munich, Germany.
PY - 2003/5
Y1 - 2003/5
N2 - This paper addresses a numerical electromagnetic analysis of the influence of installing passive shield wires "extra ground wires" (EGW) underneath the bottom phase conductor on the lightning shielding performance of 765-kV, 3-phase, double-circuit transmission lines. The method of moment (MOM) is employed to model the whole structure in three dimensions except the lightning channel. The lightning channel is simulated by the well-known transmission-line model (TLM), where the influence of the lightning-channel-generated electric and magnetic fields (EMF) are taken into account. The lightning shielding performance with and without EGW is introduced and discussed, without ac energization and due to three distinct lightning strokes, namely, the negative first, the negative subsequent and the positive strokes. The produced voltages and currents in the phase conductors and ground wires as well as the voltage across the insulators are computed, with and without the EGW, due to different lightning current waveforms, locations and inclination of the lightning channel, and return-stroke velocities. The introduction of such EGW results in a significant improvement of the shielding effectiveness by reducing the lightning-produced voltages and currents in the phase conductors as well as the voltage across the insulators. Accordingly, a much lower transient overvoltages can be expected with less inadvertent outages of the lines, where the probabilities of flashover and back-flashover decrease, and the reliability enhances.
AB - This paper addresses a numerical electromagnetic analysis of the influence of installing passive shield wires "extra ground wires" (EGW) underneath the bottom phase conductor on the lightning shielding performance of 765-kV, 3-phase, double-circuit transmission lines. The method of moment (MOM) is employed to model the whole structure in three dimensions except the lightning channel. The lightning channel is simulated by the well-known transmission-line model (TLM), where the influence of the lightning-channel-generated electric and magnetic fields (EMF) are taken into account. The lightning shielding performance with and without EGW is introduced and discussed, without ac energization and due to three distinct lightning strokes, namely, the negative first, the negative subsequent and the positive strokes. The produced voltages and currents in the phase conductors and ground wires as well as the voltage across the insulators are computed, with and without the EGW, due to different lightning current waveforms, locations and inclination of the lightning channel, and return-stroke velocities. The introduction of such EGW results in a significant improvement of the shielding effectiveness by reducing the lightning-produced voltages and currents in the phase conductors as well as the voltage across the insulators. Accordingly, a much lower transient overvoltages can be expected with less inadvertent outages of the lines, where the probabilities of flashover and back-flashover decrease, and the reliability enhances.
KW - Electric and magnetic fields (EMF)
KW - Extra ground wires (EGWs)
KW - Insulator voltage
KW - Lightning shielding
KW - Numerical electromagnetic transient
UR - http://www.scopus.com/inward/record.url?scp=0037505633&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0037505633&partnerID=8YFLogxK
U2 - 10.1109/TEMC.2003.811300
DO - 10.1109/TEMC.2003.811300
M3 - Article
AN - SCOPUS:0037505633
SN - 0018-9375
VL - 45
SP - 378
EP - 392
JO - IEEE Transactions on Electromagnetic Compatibility
JF - IEEE Transactions on Electromagnetic Compatibility
IS - 2
ER -