A fault protection system of a power system of a dynamically positioned vessel, wherein the power system comprises a power distribution bus comprising three or more bus subsections, electric connections including bus ties, wherein for at least one of said bus subsections, the fault protection system comprises: - a generator circuit breaker for coupling a generator to the bus subsection, - one or more feeder circuit breakers (43, 44, 45) for coupling one or more loads to the bus subsection, - an another circuit breaker via which a first end of the bus subsection is connected to a bus tie, said bus tie providing the electric connection to another bus subsection, the another circuit breaker being a bus tie breaker, - a further circuit breaker for coupling a second end of the bus subsection to a further bus subsection, - protection relays (71, 72, 73, 83) coupled to the circuit breakers (41, 42, 43, 44, 45) for operating the circuit breakers, - communication links between the protection relays (71, 72, 73, 83), the protection relays being configured to exchange information via said communication links, wherein the electric connections connect the bus subsections in a closed ring configuration with closed bus tie circuit breakers and further circuit breakers, and wherein said protection relays (71, 72, 73, 83) are configured to provide at least - a generator protection zone including the generator circuit breaker and a generator, the protection relay coupled to the generator circuit breaker being configured to provide a differential protection for the generator, - a bus tie protection zone including the bus tie breaker, the bus tie and a further bus tie breaker via which the bus tie is coupled to the other bus subsection, wherein protection relays (73, 83) coupled to the bus tie breakers are configured to provide differential protection for the bus tie, and - a bus subsection protection zone including the bus subsection and the circuit breakers coupled to the bus subsection, the protection relays coupled to these circuit breakers being configured to provide a differential protection for the bus subsection. - a generator circuit breaker for coupling a generator to the bus subsection, - one or more feeder circuit breakers (43, 44, 45) for coupling one or more loads to the bus subsection, - an another circuit breaker via which a first end of the bus subsection is connected to a bus tie, said bus tie providing the electric connection to another bus subsection, the another circuit breaker being a bus tie breaker, - a further circuit breaker for coupling a second end of the bus subsection to a further bus subsection, - protection relays (71, 72, 73, 83) coupled to the circuit breakers (41, 42, 43, 44, 45) for operating the circuit breakers, - communication links between the protection relays (71, 72, 73, 83), the protection relays being configured to exchange information via said communication links, wherein the electric connections connect the bus subsections in a closed ring configuration with closed bus tie circuit breakers and further circuit breakers, and wherein said protection relays (71, 72, 73, 83) are configured to provide at least - a generator protection zone including the generator circuit breaker and a generator, the protection relay coupled to the generator circuit breaker being configured to provide a differential protection for the generator, - a bus tie protection zone including the bus tie breaker, the bus tie and a further bus tie breaker via which the bus tie is coupled to the other bus subsection, wherein protection relays (73, 83) coupled to the bus tie breakers are configured to provide differential protection for the bus tie, and - a bus subsection protection zone including the bus subsection and the circuit breakers coupled to the bus subsection, the protection relays coupled to these circuit breakers being configured to provide a differential protection for the bus subsection.