Power system protection system, power system protector, and power system protection method

A power system protection system comprising:

• a system circuit breaker installed on a power transmission line, the power transmission line connecting a power generator and a load, the load being to be supplied with power from the power generator, the system circuit breaker being to interrupt a current flowing through the power transmission line upon occurrence of an anomaly on the power transmission line;
• a commutator connected to a section between the system circuit breaker and the load, of the power transmission line, and connected to a ground, the commutator being to isolate the power transmission line from the ground when in an “off” state, and to cause the power transmission line to conduct to the ground when in an “on” state;
• and
• a controller adapted to control on-off switching of the commutator and of the system circuit breaker, wherein
• upon detection of an accident of a ground fault or short circuit occurred on the power transmission line, the power system protection system is adapted to turn on the commutator to redirect the current flowing through the power transmission line to the ground before the system circuit breaker interrupts the current flowing through the power transmission line, wherein
• the controller is adapted to determine whether the accident has been eliminated based on a result of an accident elimination verification operation, wherein
• in the accident elimination verification operation, the commutator is turned on when the accident is detected upon turning off of the commutator after a predetermined time period has elapsed since turning on of the commutator.

A power system protector to be installed in a section between a system circuit breaker and a load, of a power transmission line, the power transmission line connecting a power generator and the load, the load being to be supplied with power from the power generator, the power system protector comprising:

• a commutator connected to the section between the system circuit breaker and the load, of the power transmission line, and connected to a ground, the commutator is adapted to isolate the power transmission line from the ground when in an “off” state, and adapted to cause the power transmission line to conduct to the ground when in an “on” state;
• and
• a controller adapted to control on-off switching of the commutator, wherein
• upon detection of an accident caused by a ground fault or short circuit occurred on the power transmission line, the power system protector is adapted to turn on the commutator to redirect a current flowing through the power transmission line to the ground, wherein
• the controller is adapted to determine whether the accident has been eliminated based on a result of an accident elimination verification operation, wherein
• in the accident elimination verification operation, the commutator is turned on when the accident is detected upon turning off of the commutator after a predetermined time period has elapsed since turning on of the commutator.

A power system protection method for use in a power system protection system comprising:

• a system circuit breaker being installed on a power transmission line, the power transmission line connecting a power generator and a load, the load being to be supplied with power from the power generator;
• and
• a commutator being connected to a section between the system circuit breaker and the load, of the power transmission line, and connected to a ground, the commutator being to isolate the power transmission line from the ground when in an “off” state, and to cause the power transmission line to conduct to the ground when in an “on” state, the power system protection method comprising:
• determining whether an accident caused by a ground fault or short circuit has occurred on the power transmission line;
• redirecting a current flowing through the power transmission line to the ground by turning on the commutator, upon determination that the accident has occurred;
• and
• determining whether the accident has been eliminated based on a result of an accident elimination verification operation of turning on the commutator when the accident is detected upon turning off of the commutator after a predetermined time period has elapsed since turning on of the commutator.