Naslov
Calculation of earthing and screening effects of compensation conductor laid alongside underground multi-cable power lines

Autori
Medić, Ivan ; Majstrović, Matislav ; Sarajčev, Petar

Vrsta, podvrsta i kategorija rada
Poglavlja u knjigama, znanstveni

Knjiga
Electrical engineering and electromagnetics VI

Urednik/ci
Brebbia, Carlos Alberto ; Poljak, Dragan

Izdavač
Wessex Institute of Technology Press

Grad
Southampton : Boston (MA)

Godina
2003

Raspon stranica
205-214

ISBN
1-85312-981-X

Ključne riječi
Earthing effect, Screening effect, Compensation conductor, Multi-cable power line

Sažetak
Power substations in an urban area are interconnected by high voltage underground power cables, resulting also in interconnections of their earthing grids through cable metallic screens/sheaths. Most modern power cables with XLPE insulated core have metallic screens which are practically insulated from ground. These screens can only be (and susally are) grounded at cable ends and therefore do not act like extra earth electrodes extending from a station. In this case, almost the same positive earthing effects of an extended electrode can be obtained only by extending an auxillary wire in the same trench and routing it closely parallel to the power line. This bare conductor also provides better screening for nearby telecommunication circuits against inductive interference. This paper presents an analytical method to determine the line-to-ground fault current distribution and related voltages in the earthing system which consists of two substation earthings interconnected by insulated metal sheaths of modern XLPE cables and one bare earthing wire laid in parallel in the same cable trench. The analytical expressions, derived by solving a set of differential equations, are based on the assumption of uniformly distributed conductance between the earthing wire and earth. The proposed mathematical model takes into account mutual inductive couplings between all conductors (phases, cable sheaths and the bare conductor). In addition the paper presents a procedure for computing the resulting nominal screening factor of multi-conductor connection between two substations. The earthing and screening effects of one bare conductor laid parallel to double cable power line are numerically illustrated and outlined.

Izvorni jezik
Engleski

Znanstvena područja
Elektrotehnika

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