	US 12,339,306 B2
	Method for locating a fault point on a high-voltage three-phase AC cable, and system for locating a fault point
Francisco Javier Bengoechea De La Llera, Derio (ES)
Assigned to LUMIKER APLICACIONES TECNOLOGICAS S.L., Derio (ES)
Filed by LUMIKER APLICACIONES TECNOLOGICAS S.L., Derio (ES)
Filed on Mar. 31, 2023, as Appl. No. 18/129,342.
Claims priority of application No. 22382331 (EP), filed on Apr. 6, 2022.
Prior Publication US 2023/0324449 A1, Oct. 12, 2023
Int. Cl. G01R 31/08 (2020.01)

CPC G01R 31/083 (2013.01)

12 Claims

1. A method for locating a fault point (F) on a high-voltage three-phase AC cable (1) comprising a first end (10), a second end (11), and at least one section (P₁, P₂) extending between the first and second ends (10, 11), the cable (1) comprising first, second and third conductors (R, S, T) and respective first, second and third shields (S_R, S_S, S_T), the first, second and third shields (S_R, S_S, S_T) being connected to a surge arrester device (3,4) connected to ground (G) at one end of the at least one section (P₁, P₂), the first, second and third shields (S_R, S_S, S_T) being connected to a grounding element (2) at the other end of said at least one section (P1, P2), the grounding element (2) being connected to the ground (G) through a ground connection (20), the surge arrester device (3,4) being connected to the ground (G) through a ground connection (30,40), the cable (1) comprising an earth continuity conductor (ECC) connecting the ground connections (20, 30, 40), the method comprising:

measuring a conductor current (I_R1, I_S1, I_T1, I_R2, I_S2, I_T2) circulating through each of the first, second and third conductors (R, S, T) both at the first end (10) and at the second end (11) of the cable (1);

measuring a shield current (I_SR1, I_SS1, I_ST1, I_SR2, I_SS2, I_ST2) circulating through each of the first, second and third shields (S_R, S_S, S_T) in each section (P₁, P₂) at a first point close to the grounding element;

measuring an earth continuity conductor current (I_ECC1, I_ECC2) circulating through each section (P₁, P₂) at the first point close to the grounding element or at a second point close to the grounding element;

determining a fault in one of the first, second and third conductor (R, S, T) based on the previously measured conductor currents (I_R1, I_S1, I_T1, I_R2, I_S2, I_T2);

in the event that the cable (1) comprises more than one section (P₁, P₂), determining section (P₁, P₂) in fault based on the previously measured shield currents (I_SR1, I_SS1, I_ST1, I_SR2, I_SS2, I_ST2); and

locating a fault point (F) by means of a model of section (P₁, P₂) in fault of the earth continuity conductor (ECC), the only unknown being the distance (x) to the fault point (F) from an end of said section (P₁, P₂) in fault.