Protection method and protection system of ship's power distribution system
A protection system of ship's power distribution system, when a fault occurs in the feeder preset to be in charge of the third circuit breaker module, the relay of the third circuit breaker module trips the circuit breaker based on a magnitude and a direction of a fault current, and to transmit a power distribution maintenance signal to the relay of the second circuit breaker module. When a fault occurs in the switchboard preset to be in charge of the second circuit breaker module, the relays of the second and third circuit breaker modules trip the circuit breaker based on a magnitude and a direction of a fault current and the relay of the second circuit breaker module transmit a power distribution maintenance signal to the relay of the third circuit breaker module preset based on the magnitude and direction of the fault current.
1 . A system for protecting a power distribution system of a ship, the system comprising:
a plurality of first circuit breaker modules, wherein each first circuit breaker module has a circuit breaker disposed between a generator and one of a plurality of buses of a switchboard to block transmitted power and a relay configured to control an operation of the corresponding circuit breaker of the first circuit breaker module;
a plurality of second circuit breaker modules, wherein each second circuit breaker module has a circuit breaker disposed between the plurality of buses of the switchboard to block transmitted power and a relay configured to control an operation of the corresponding circuit breaker of the second circuit breaker module; and
a plurality of third circuit breaker modules, wherein each third circuit breaker module has a circuit breaker disposed between one of the plurality of buses of the switchboard and a feeder to block transmitted power and a relay configured to control an operation of the corresponding circuit breaker of the third circuit breaker module, wherein the relay of each of the plurality of second circuit breaker modules and the relay of each of the plurality of third circuit breaker modules have the same delay time, when a fault occurs in the feeder preset to be in charge of one of the plurality of third circuit breaker modules, the relay of the one of the plurality of third circuit breaker module is configured to trip the corresponding circuit breaker of the one of the third circuit breaker module based on a magnitude and a direction of a fault current, and to transmit a power distribution maintenance signal to the relay of one of the plurality of the second circuit breaker modules, and when a fault occurs in one bus of the switchboard preset to be in charge of one of the plurality of second circuit breaker modules, the relays of the second and third circuit breaker modules are configured to trip the corresponding circuit breakers of the second and third circuit breaker modules based on a magnitude and a direction of a fault current, and the relay of the second circuit breaker module is configured to transmit a power distribution maintenance signal to the relay of the third circuit breaker module preset based on the magnitude and direction of the fault current; and
wherein, in case that at least one of the plurality of the buses of the switchboard fails, each of the relays of the plurality of the second circuit breaker modules transmits, in response to the bus fault and based on the direction of the fault current between the plurality of the buses of the switchboard, the power distribution maintenance signal to a relay of a third circuit breaker module connected to a bus of the switchboard that is adjacent to a reverse direction of the fault current among the plurality of buses of the switchboard, and a relay of a second circuit breaker module with an open circuit breaker does not transmit the power distribution maintenance signal to the relays of the third circuit breaker modules.
2 . The system of claim 1 , wherein the relays of the plurality of first circuit breaker modules, the relays of the plurality of second circuit breaker modules, and the relays of the plurality of third circuit breaker modules are configured to communicate with each other to identify a position and a direction of a fault current.
3 . The system of claim 1 , wherein a delay time of the relays of the plurality of first circuit breaker modules is longer than delay times of the relays of the plurality of second circuit breaker modules and the relays of the plurality of third circuit breaker modules.
4 . The system of claim 1 , wherein the plurality of second circuit breaker modules include at least one circuit breaker disposed between adjacent buses among a plurality of buses of the switchboard, and a relay configured to control an operation of the at least one circuit breaker for each space between the adjacent buses among the plurality of buses of the switchboard.
5 . The system of claim 1 , wherein the plurality of second circuit breaker modules include two circuit breakers disposed between adjacent buses among a plurality of buses of the switchboard, and two relays configured to respectively control operations of the two circuit breakers for each space between the adjacent buses among the plurality of buses of the switchboard.
6 . A method for protecting a power distribution system of a ship, the method comprising:
a first operation in which each of a plurality of first circuit breaker modules having a circuit breaker disposed between a generator and one of a plurality of buses of a switchboard to block transmitted power and a relay configured to control an operation of the corresponding circuit breaker of the first circuit breaker module, each of a plurality of second circuit breaker modules having a circuit breaker disposed between one of the plurality of buses of the switchboard to block transmitted power and a relay configured to control an operation of the corresponding circuit breaker of the second circuit breaker module, and each of a plurality of third circuit breaker modules having a circuit breaker disposed between one of the plurality of buses of the switchboard and a feeder to block transmitted power and a relay configured to control an operation of the corresponding circuit breaker of the third circuit breaker module, relays of the plurality of the first circuit breaker modules, the plurality of the second circuit breaker modules, and the plurality of the third circuit breaker modules communicate with each other to identify a magnitude and a direction of a fault current when a fault occurs in the power distribution system of the ship;
a second operation in which a corresponding circuit breaker module is instantaneously tripped when the identified magnitude and direction of the fault current correspond to a preset differential protection fault;
a third operation in which the relay of one of the plurality of third circuit breaker modules trips the corresponding circuit breaker and transmits a power distribution maintenance signal to the relay of one of the plurality of the second circuit breaker modules when the identified magnitude and direction of the fault current do not correspond to the differential protection fault and correspond to a preset feeder fault;
a fourth operation in which a fault location is identified based on the identified magnitude and direction of the fault current when the identified magnitude and direction of the fault current do not correspond to the differential protection fault and the feeder fault, the relays of the second and third circuit breaker modules connected to the switchboard in which a fault occurs are configured to trip corresponding circuit breakers, when the fault occurs in the switchboard preset to be in charge of one of the plurality of the second circuit breaker modules, and the relay of the one of the plurality of the second circuit breaker modules is configured to transmit a power distribution maintenance signal to the relay of the third circuit breaker module preset based on the magnitude and direction of the fault current; and
a fifth operation in which the corresponding circuit breaker of one of the plurality of the first circuit breaker modules of the switchboard in which the fault occurs is tripped;
wherein, in the first operation, the relays of the plurality of second circuit breaker modules and the relays of the plurality of third circuit breaker modules have the same delay time;
wherein, in case that at least one of the plurality of the buses of the switchboard fails, each of the relays of the plurality of second circuit breaker modules transmits, in response to the bus fault and based on the direction of the fault current between the plurality of the buses of the switchboard, the power distribution maintenance signal to a relay of a third circuit breaker module connected to a bus of the switchboard that is adjacent to a reverse direction of the fault current among the plurality of buses of the switchboard, and a relay of a second circuit breaker module with an open circuit breaker does not transmit the power distribution maintenance signal to the relays of the third circuit breaker modules.
7 . The method of claim 6 , wherein in the first operation, a delay time of the relay of the first circuit breaker module is set to be slower than delay times of the relay of the second circuit breaker module and the relay of the third circuit breaker module.