Active arc suppression method for stator ground fault in multi-generator common-bus system on offshore oil platforms

• The proposed method injects dual-frequency compensation at generator terminal, enabling a single device to suppress ground faults for multiple generators. • A selective fault location criterion is proposed, which utilizes the variation of terminal zero-sequence current before and after arc suppression to identify the faulty generator. • Simulation and experiment results confirm the method's robustness against different fault conditions, demonstrating strong engineering applicability. Generators on offshore oil platforms are often subjected to vibrations caused by wave impacts, which lead to frequent stator ground faults and arc generation. The generator system typically adopts a multi-generator common-bus configuration. If the conventional active arc suppression method based on neutral-point voltage regulation is used, high equipment cost and maintenance complexity are introduced. An active arc suppression method based on terminal voltage regulation is proposed in this paper. The arc suppression device is installed at the terminal side bus. When the stator ground fault occurs in any generator, the fault point voltage is regulated to zero by controlling the terminal voltage of the generator. Reliable arc suppression can thus be achieved, while significantly reducing the total installed capacity and the number of configured devices required for arc suppression. A selective fault location criterion based on the phase of the variation of terminal zero-sequence current before and after arc suppression is also proposed. The faulty generator can be identified after arc suppression. The effectiveness of the proposed method is verified through simulation and experimental results.