A fault protection system of a power system of a dynamically positioned vessel, wherein the power system is separated into two or more power system sections each comprising a bus section of a power distribution bus, characterised in that the bus sections are connected by bus ties in a ring configuration, and wherein each power system section comprises two or more power system subsections each comprising a bus subsection of the power distribution bus, the bus subsections of the same power system section being connected by one or more bus couplers, wherein each bus section comprises a connection to a generator and a connection to a thruster drive of the dynamically positioned vessel, wherein the fault protection system comprises - a fault isolation system including for each power system section a bus tie circuit breaker for breaking the connection provided by the bus tie and one or more bus coupler circuit breakers for breaking the connection provided by the one or more bus couplers, the fault isolation system being configured to implement a differential over-current protection scheme for operating at least the bus tie circuit breaker and the bus coupler circuit breaker, - a generator ride through system comprising for each power system section an excitation limiter for the generator coupled to the respective bus section, the generator ride through system being adapted to limit the excitation field current provided to the generator upon occurrence of a fault, - a thruster drive ride through system configured to provide electric energy to a DC bus of a variable frequency drive of the thruster drive of each power system section upon occurrence of a fault so as to maintain the voltage on the DC bus above a predetermined voltage threshold, wherein the electric energy is provided from a power storage device, such as a battery, or kinetic energy recovery, using kinetic energy of the rotor of the thruster drive or propeller. wherein the fault protection system is configured, upon the occurrence of a fault in the power system, to isolate the fault by tripping the component of the power system in which the fault occurred and/or by opening one or more circuit breakers (41, 42, 25, 35) in the power system subsection in which the fault is located, and to continue operation of the power system with the remaining bus tie circuit breakers and bus coupler circuit breakers closed. - a fault isolation system including for each power system section a bus tie circuit breaker for breaking the connection provided by the bus tie and one or more bus coupler circuit breakers for breaking the connection provided by the one or more bus couplers, the fault isolation system being configured to implement a differential over-current protection scheme for operating at least the bus tie circuit breaker and the bus coupler circuit breaker, - a generator ride through system comprising for each power system section an excitation limiter for the generator coupled to the respective bus section, the generator ride through system being adapted to limit the excitation field current provided to the generator upon occurrence of a fault, - a thruster drive ride through system configured to provide electric energy to a DC bus of a variable frequency drive of the thruster drive of each power system section upon occurrence of a fault so as to maintain the voltage on the DC bus above a predetermined voltage threshold, wherein the electric energy is provided from a power storage device, such as a battery, or kinetic energy recovery, using kinetic energy of the rotor of the thruster drive or propeller.