# US 2014/0192458 A1 · Power distribution systems and methods of operating a power distribution system including arc flash detection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0192458 A1 - Document ID: US20140192458A1 - Status: Published application - Kind: A1 - Application number: 13/734,431 - Filed: 2013-01-04 - Published: 2014-07-10 - Earliest claimed: 2013-01-04 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Marcelo Esteban Valdes - Web page: https://patentgrep.com/patent/US20140192458A1 ## CPC - H01H 83/00: Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current - H02H 7/262: {involving transmissions of switching or blocking orders} - H02H 1/0015: {Using arc detectors} - H01H: ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES (contact cables H01B7/10; electrolytic self-interrupters H01G9/18; emergency protective circuit arrangements H02H; switching by electronic means without contact-making H03K17/00) - H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H) ## Abstract An arc flash relay system is described for use in a power distribution system including an arc flash sensor, a first circuit protection device, and a second circuit protection device. The arc flash relay system includes a first input configured to receive a detection signal from the arc flash sensor, a second input configured to receive a blocking signal from the first circuit protection device, and a controller. The controller is configured to determine that an arc flash has occurred based, at least in part, on the detection signal. The controller activates the second circuit protection device in response to the determination that an arc flash has occurred when the controller is not receiving the blocking signal, and delays activation of the second circuit protection device in response to the determination that an arc flash has occurred when the controller is receiving the blocking signal. ## Claims ### Claim 1 A power distribution system comprising: a first distribution bus operatively disposed within a cavity defined by an enclosure; an arc flash sensor configured to detect an arc within the cavity and generate a detection signal; an arc flash relay system communicatively coupled to said arc flash sensor, said arc flash relay system comprising a controller configured to determine an arc flash has occurred based, at least in part, on the detection signal; and a first circuit protection device disposed within the cavity, said first circuit protection device comprising: a trip mechanism configured to interrupt a current flowing through said first distribution bus; and a trip unit operatively coupled to said trip mechanism, said trip unit configured to: determine when a current on said first distribution bus exceeds a protection threshold; and output a blocking signal to said arc flash relay system and output a trip signal to said trip mechanism upon determining that a current on said first distribution bus exceeds the protection threshold. ### Claim 2 (depends on 1) A power distribution system in accordance with claim 1, further comprising a second circuit protection device, and wherein said arc flash relay system is configured to output a trip signal to activate said second circuit protection device in response to determining an arc flash has occurred. ### Claim 3 (depends on 2) A power distribution system in accordance with claim 2, wherein said second circuit protection device comprises an arc flash mitigation device. ### Claim 4 (depends on 2) A power distribution system in accordance with claim 2, further comprising a second distribution bus configured to provide electrical power to at least said first circuit protection device, and wherein said second circuit protection device comprises a circuit breaker configured to interrupt a current flowing through said second distribution bus in response to the trip signal from said arc flash relay system. ### Claim 5 (depends on 2) A power distribution system in accordance with claim 2, wherein said arc flash system is further configured to operate in a restrained mode in response to the blocking signal from said first circuit protection device trip unit. ### Claim 6 (depends on 5) A power distribution system in accordance with claim 5, wherein operating in the restrained mode comprises delaying the output of the trip signal to activate said second circuit protection device for a determined period of time after determining that an arc flash has occurred. ### Claim 7 (depends on 6) A power distribution system in accordance with claim 6, wherein the determined period of time is greater than a length of time required for said first circuit protection device trip mechanism to interrupt the current flowing through said first distribution bus in response to the trip signal from said first circuit protection device trip unit. ### Claim 8 (depends on 5) A power distribution system in accordance with claim 5, wherein said arc flash relay is operable in a normal mode and a maintenance mode, and wherein said arc flash relay is configured to ignore the blocking signal when said arc flash relay is operating in a maintenance mode. ### Claim 9 (depends on 1) A power distribution system in accordance with claim 1, wherein said arc flash sensor comprises at least one of a light sensor, a sound sensor, and a pressure sensor. ### Claim 10 An arc flash relay system for use in a power distribution system including an arc flash sensor, a first circuit protection device, and a second circuit protection device, said arc flash relay system comprising: a first input configured to receive a detection signal from the arc flash sensor; a second input configured to receive a blocking signal from the first circuit protection device; and a controller configured to: determine an arc flash has occurred based, at least in part, on the detection signal; activate the second circuit protection device in response to the determination that an arc flash has occurred when said controller is not receiving the blocking signal; and delay activation of the second circuit protection device in response to the determination that an arc flash has occurred when said controller is receiving the blocking signal. ### Claim 11 (depends on 10) An arc flash relay system in accordance with claim 10, wherein said controller is configured to delay activation of the second circuit protection device for a determined time greater than a length of time for the first circuit protection device to act to protect the first load. ### Claim 12 (depends on 10) An arc flash relay system in accordance with claim 10, further comprising a third input configured to receive a current signal from a current sensor, and wherein said controller is configured to determine that an arc flash has occurred based on the detection signal and the current signal. ### Claim 13 (depends on 10) An arc flash relay system in accordance with claim 10, wherein said controller is selectively operable in a normal mode and a maintenance mode, and wherein said controller is configured to delay activation of the second circuit protection device in response to the determination that an arc flash has occurred when said controller is operating in the normal mode and receiving the blocking signal, and to activate the second circuit protection device, regardless of the blocking signal, in response to the determination that an arc flash has occurred when said controller is operating in the maintenance mode. ### Claim 14 (depends on 10) An arc flash relay system in accordance with claim 10, wherein said controller is configured to delay activation of the second circuit protection device for as long as said controller is receiving the blocking signal. ### Claim 15 A method for use by an arc flash relay system in a power distribution system including a first circuit protection device configured to output a blocking signal, and a second circuit protection device configured to provide arc flash protection, said method comprising: determining an arc flash has occurred within a cavity occupied by the power distribution system; activating the second circuit protection device in response to the determination that an arc flash has occurred when the arc flash relay system is not receiving the blocking signal from the first circuit protection device; and delaying activation of the second circuit protection device in response to the determination that an arc flash has occurred when the arc flash relay system is receiving the blocking signal from the first circuit protection device. ### Claim 16 (depends on 15) A method in accordance with claim 15, wherein delaying activation of the second circuit protection device comprises delaying activation of the second circuit protection device for a determined time greater than a length of time for the first circuit protection device to act to protect the load. ### Claim 17 (depends on 15) A method in accordance with claim 15, further comprising receiving a signal from an arc flash sensor positioned within the cavity occupied by the power distribution system and wherein determining that an arc flash has occurred within a cavity occupied by the power distribution system comprises determining that an arc flash has occurred within a cavity occupied by the power distribution system based, at least in part, on the received signal from the arc flash sensor. ### Claim 18 (depends on 15) A method in accordance with claim 15, wherein said arc flash relay system is selectively operable in a normal mode and a maintenance mode, and wherein delaying activation of the second circuit protection device comprises delaying activation of the second circuit protection device when said controller is operating in the normal mode and receiving the blocking signal. ### Claim 19 (depends on 18) A method in accordance with claim 18, wherein activating a second circuit protection device further comprises activating a second circuit protection device, regardless of the blocking signal, in response to the determination that an arc flash has occurred when the arc flash relay system is operating in the maintenance mode. ### Claim 20 (depends on 15) A method in accordance with claim 15, wherein delaying activation of the second circuit protection device comprises delaying activation of the second circuit protection device for as long as the arc flash relay system is receiving the blocking signal.