Methods and locating systems for determining an insulation fault location on an electric conductor of a subsea supply line

A method for determining an insulation fault location (40) on an electric conductor (11) of a subsea supply line (10), which can be filled with seawater (5), comprising the method steps:

• applying electric voltage to ground at the electric conductor (11), an electrochemical reaction taking place at the insulation fault location (40) between a metallic conductor material of the electric conductor (11) and the seawater (5), said electrochemical reaction forming gas, and said electric voltage being formed by a modulated voltage impulse sequence,
• capturing sonic waves (20, 20a, 20b) of a noise made by formed gas bubbles (28), sonic waves (20, 20a, 20b) of the noise being captured outside of the subsea supply line (10) using sonic sensors (18), which are installed at predetermined location in the seawater (5),
• evaluating measuring-signal impulse sequences supplied by the sonic sensors (18) in order to determine the insulation fault location (40).

A method for determining an insulation fault location (40) on an electric conductor (11) of a subsea supply line (10), which comprises an outer casing (9) having through bores (30), comprising the method steps:

• applying electric voltage to ground at the electric conductor (11), an electrochemical reaction taking place at the insulation fault location (40) between a metallic conductor material of the electric conductor (11) and the seawater (5), said electrochemical reaction forming gas, said electric voltage being formed by a modulated voltage impulse sequence,
• capturing gas bubbles (28) exiting from the through bores (30) of the outer casing (9) by optically sampling immediate surroundings along the subsea supply line (10) using an image capturing system (38),
• evaluating image patterns for identifying a gas-bubble image pattern and for determining the insulation fault location (40).

A locating system for determining an insulation fault location (40) on an electric conductor (11) of a subsea supply line (10), which can be filled with seawater (5),

• comprising a voltage generator (14) for generating a modulated voltage impulse sequence, which is grounded to the electric conductor (11);
• comprising sonic sensors (18), which are installed at predetermined locations along the subsea supply line (10) in order to capture sonic waves (20, 20c) propagating within the subsea supply line (10) in the seawater filling (7);
• and comprising an evaluation device (16) for evaluating measuring-signal impulse sequences supplied by the sonic sensors (18) for determining the insulation fault location (40).

A locating system for determining an insulation fault location (40) on an electric conductor (11) of a subsea supply line (10), which can be filled with seawater (5),

• comprising a voltage generator (14) for generating a modulated voltage impulse sequence, which is grounded to the electric conductor (11);
• comprising sonic sensors (18), which are installed at predetermined locations in the seawater (5) surrounding the subsea supply line (10) in order to capture sonic waves (20, 20a, 20b) emitted from the subsea supply line (10) outside of the subsea supply line (10);
• and comprising an evaluation device (16) for evaluating measuring-signal impulse sequences supplied by the sonic sensors (18) for determining the insulation fault location (40).

A tracking device for determining an insulation fault location (40) on an electric conductor (11) of a subsea supply line (10), which comprises an outer casing (9) having through bores (30),

• comprising a voltage generator (14) for generating a modulated voltage impulse sequence, which is grounded to the electric conductor (11);
• comprising an image capturing system (38), which captures gas bubbles (28) being formed at the insulation fault location (40) and exiting from the through bores (30) by optically sampling immediate surroundings of the subsea supply line (10);
• and comprising an image evaluation device (36) for evaluating image patterns in order to identify gas-bubble image patterns and to determine the insulation fault location (40).