Method for controlling stray currents in a marine electrical supply system and a marine vessel comprising a marine electrical supply system
AssigneeAB Volvo Penta
InventorSimon Lannetoft
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Abstract
A method and a system for cancelling stray currents in a marine electrical supply system, which system comprises a protective earth circuit connecting a vessel to ground when a source of power is connected to the vessel is described. The method involves the steps of monitoring the current in the protective earth circuit using a current sensor; determining if a stray current is detected by the current sensor, and, if a stray current is detected, counteracting the stray current in the protective earth circuit to reduce the stray current to a value at or near zero current.
Claims11
A method for cancelling stray currents in a marine electrical supply system, which system comprises a protective earth circuit connecting a vessel to ground when a source of power is connected to the vessel, wherein the method involves the steps of:
- monitoring the current in the protective earth circuit using a current sensor;
- determining when a stray current is detected by the current sensor, and when a stray current is detected,
- counteracting the stray current in the protective earth circuit by arranging a controllable induction coil to induce a counter-current into the protected earth circuit to reduce the stray current to a value at or near zero current.
A marine electrical supply system to connect a marine vessel to a source of shore power, wherein the electrical supply system has a protective earth circuit comprising
- a first positive earth connection extending from the shore power source to a vessel connector;
- a second positive earth connection extending from the vessel connector to a ground bus bar;
- and
- a third positive earth connection extending from the ground bus bar to one or more vessel loads;
- wherein the second positive earth connection comprises
- a current sensor arranged to detect a stray current in the protective earth circuit and to emit a signal proportional to the detected current;
- a control unit arranged to receive the emitted signal and to generate and transmit a control signal;
- and
- a controllable induction coil for counteracting the stray current in the protective earth circuit in response to the transmitted control signal, whereby the controllable induction coil is configured to induce a counter-current into the protected earth circuit to reduce the stray current to a value at or near zero current.
Dependencies are inferred from the claim text.