Technical gazette, Vol. 17 No. 3, 2010.
Original scientific paper
Calculation of grounding effects of bare conductors laid alongside underground multi-cable power lines by using analytical equations
Ivan Medić
orcid.org/0000-0002-2243-0170
; University of Split; Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture; Ruđera Boškovića b.b., 21000 Split, Croatia
Davor Bajs
; Energy Institute "Hrvoje Požar", Savska cesta 163, 10000 Zagreb, Croatia
Elis Sutlović
; University of Split; Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture; Ruđera Boškovića b.b., 21000 Split, Croatia
Abstract
This paper presents a mathematical model to determine the fault current and voltage distribution in power cable screening conductors and bare earthing wires laid in parallel in the same cable trench. The analytical expressions for voltages and currents are derived by solving a set of differential equations. They are based on the assumption of uniformly distributed self and mutual conductances to ground of earthing wires. The earthing system under consideration includes also impedances of two adjacent substation groundings on which the earthing wires and cable screens terminate.The proposed mathematical model also takes into account mutual inductive couplings between all conductors in the trench (phases, cable screens and bare earthing wires). Particularly, in the case of a single-circuit cable line with an earthing conductor in trench, a set of generalized equations for currents and voltages along the related neutral conductors are derived in detail. An illustrative and practical example is presented too.
Keywords
earthing; earthing wire; fault-current distribution; power cables; substation grounding potential
Hrčak ID:
59642
URI
Publication date:
30.9.2010.
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