# US 2014/0195177 A1 · Noise propagation immunity of a multi-string arc fault detection device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0195177 A1 - Document ID: US20140195177A1 - Status: Published application - Kind: A1 - Application number: 14/138,575 - Filed: 2013-12-23 - Published: 2014-07-10 - Earliest claimed: 2012-11-16 - Assignees: Sensata Technologies, Inc. - Inventors: Jianhong Kang; Christian V. Pellon; Lee Martin; Keith W. Kawate - Web page: https://patentgrep.com/patent/US20140195177A1 ## CPC - H02H 3/445: {of DC quantities} - G01R 31/1227: {of components, parts or materials (G01R31/1209, G01R31/1218, G01R31/18 take precedence; circuits therefor G01R31/14; testing vessels of electrodes G01R31/16)} - H02H 1/0015: {Using arc detectors} - H02S 50/00: Monitoring or testing of PV systems, e.g. load balancing or fault identification - H02S 50/10: Testing of PV devices, e.g. of PV modules or single PV cells (testing of semiconductor devices during manufacturing {H10P74/00}) - G01R 31/085: {in power transmission or distribution lines, e.g. overhead} - G01R 31/40: Testing power supplies (testing photovoltaic devices H02S50/10) - G16Z 99/00: Subject matter not provided for in other main groups of this subclass - Y02E 10/50: Photovoltaic [PV] energy - 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) - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - H02S: GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES (obtaining electrical energy from radioactive sources G21H1/12; light sensitive inorganic semiconductor devices H10F; light sensitive organic semiconductor devices H10K30/00; thermoelectric devices H10N10/00; pyroelectric devices H10N15/00) - G16Z: INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS, NOT OTHERWISE PROVIDED FOR - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract Systems and methods of detecting arcing in a DC power system that can provide improved noise propagation immunity. The system includes at least two current sensors for monitoring at least two current outputs, respectively. The current sensors have reverse polarities, and are configured and arranged in parallel to provide a combined current output signal. The current sensors monitor the respective current outputs, which are provided for monitoring by the current sensors over at least two adjacent conductors. If arcing occurs at a location on a first conductor, then arcing (adjacent conductor crosstalk), having an arc current signature like that of the arcing on the first conductor, can occur at a location on the other adjacent conductor. The system can effectively cancel out such adjacent conductor crosstalk within a photovoltaic (PV) system, thereby improving the capability of an arc fault detection device for detecting arcing at the PV string level. ## Claims ### Claim 1 A method of detecting arcing in a DC power system, comprising the steps of: monitoring at least two current outputs by at least two current sensors, respectively, the at least two current sensors having reverse polarities, the at least two current outputs being provided for monitoring by the respective current sensors over at least two adjacent conductors, respectively, in the DC power system; combining the at least two current outputs to provide a combined current output; generating one or more pulses in response to at least one change in the combined current output over time (di/dt); processing, by a processor, the respective pulses to determine a presence of arcing in the DC power system; and generating, by the processor, an output indicative of the presence of arcing in the DC power system. ### Claim 2 (depends on 1) The method of claim 1 wherein the respective pulses have associated durations, and wherein the method further comprises: counting, by a processor, the number of pulses in at least one predetermined time interval to provide a pulse count for the predetermined time interval; measuring, by the processor, a fluctuation in the durations of the respective pulses in the predetermined time interval; calculating, by the processor, a first ratio of the fluctuation in the durations of the respective pulses to the pulse count; determining, by the processor, a presence of arcing in the DC power system based at least in part on the first ratio; and generating, by the processor, an output indicative of the presence of arcing in the DC power system. ### Claim 3 (depends on 2) The method of claim 2 wherein the determining of the presence of arcing includes determining that the first ratio exceeds a first specified threshold value. ### Claim 4 (depends on 2) The method of claim 2 wherein the counting of the number of pulses includes counting the number of pulses in each of a plurality of predetermined time intervals to provide pulse counts for the respective predetermined time intervals, and wherein the measuring of the fluctuation in the durations of the respective pulses includes measuring fluctuations in the durations of the respective pulses in the respective predetermined time intervals. ### Claim 5 (depends on 4) The method of claim 4 wherein the calculating of the first ratio includes calculating an average of the pulse counts after each predetermined time interval, calculating an average of the fluctuations in the durations of the respective pulses after each predetermined time interval, and calculating the first ratio based on the average of the fluctuations in the durations of the respective pulses and the average of the pulse counts. ### Claim 6 (depends on 2) The method of claim 2 further comprising: measuring, by the processor, a modulation of the durations of the respective pulses in the predetermined time interval. ### Claim 7 (depends on 6) The method of claim 6 further comprising: calculating, by the processor, a second ratio of the fluctuation in the durations of the respective pulses to the modulation of the durations of the respective pulses. ### Claim 8 (depends on 7) The method of claim 7 wherein the determining of the presence of arcing includes determining the presence of arcing in the DC power system based at least in part on the first ratio and the second ratio. ### Claim 9 (depends on 8) The method of claim 8 wherein the determining of the presence of arcing includes determining that the first ratio exceeds a first specified threshold value, and determining that the second ratio exceeds a second specified threshold value. ### Claim 10 (depends on 7) The method of claim 7 wherein the measuring of the fluctuation in the durations of the respective pulses includes measuring fluctuations in the durations of the respective pulses for a plurality of predetermined time intervals, and wherein the measuring of the modulation of the durations of the respective pulses includes measuring modulations of the durations of the respective pulses for the plurality of predetermined time intervals. ### Claim 11 (depends on 10) The method of claim 10 wherein the calculating of the second ratio includes calculating an average of the fluctuations in the durations of the respective pulses after each predetermined time interval, calculating an average of the modulations of the durations of the respective pulses after each predetermined time interval, and calculating the second ratio based on the average of the fluctuations in the durations of the respective pulses and the average of the modulations of the durations of the respective pulses. ### Claim 12 (depends on 7) The method of claim 7 further comprising: measuring, by the processor, a fluctuation in the pulse count for the predetermined time interval. ### Claim 13 (depends on 12) The method of claim 12 further comprising: calculating, by the processor, one or more of a third ratio of the fluctuation in the pulse count to the pulse count, and a fourth ratio of the fluctuation in the durations of the respective pulses to the durations of the respective pulses. ### Claim 14 (depends on 13) The method of claim 13 wherein the determining of the presence of arcing includes determining the presence of arcing in the DC power system based at least in part on the first ratio, and one or more of the second ratio, the third ratio, and the fourth ratio. ### Claim 15 (depends on 14) The method of claim 14 wherein the determining of the presence of arcing includes determining that the first ratio exceeds a first specified threshold value, determining that the second ratio exceeds a second specified threshold value, determining that the third ratio exceeds a third specified threshold value, and determining that the fourth ratio exceeds a fourth specified threshold value. ### Claim 16 (depends on 15) The method of claim 15 wherein the determining of the presence of arcing further includes determining that the pulse count exceeds a fifth specified threshold value, and determining that the durations of the respective pulses exceed a sixth specified threshold value. ### Claim 17 (depends on 16) The method of claim 16 wherein the measuring of the fluctuation in the pulse count includes measuring fluctuations in the pulse counts for a plurality of predetermined time intervals, and wherein the measuring of the fluctuation of the durations of the respective pulses includes measuring fluctuations of the durations of the respective pulses for the plurality of predetermined time intervals. ### Claim 18 (depends on 17) The method of claim 17 wherein the calculating of the third ratio includes calculating an average of the fluctuations in the pulse counts after each predetermined time interval, calculating an average of the pulse counts after each predetermined time interval, and calculating the third ratio based on the average of the fluctuations in the pulse counts and the average of the pulse counts. ### Claim 19 (depends on 17) The method of claim 17 wherein the calculating of the fourth ratio includes calculating an average of the fluctuations of the durations of the respective pulses after each predetermined time interval, calculating an average of the durations of the respective pulses after each predetermined time interval, and calculating the fourth ratio based on the average of the fluctuations of the durations of the respective pulses and the average of the durations of the respective pulses. ### Claim 20 A system for detecting arcing in a DC power system, comprising: at least two current sensors operative to monitor at least two current outputs, respectively, the at least two current sensors being configured and arranged to provide a combined current output, wherein the at least two current sensors have reverse polarities, and wherein the at least two current outputs are provided for monitoring by the respective current sensors over at least two adjacent conductors, respectively, in the DC power system; a comparator operative to generate one or more pulses in response to at least one change in the combined current output over time (di/dt); and a processor operative to process the respective pulses to determine a presence of arcing in the DC power system, and to generate an output indicative of the presence of arcing in the DC power system. ### Claim 21 A system for detecting arcing in a DC power system, comprising: at least two current sensors operative to monitor at least two current outputs, respectively, the at least two current sensors being configured and arranged to provide a combined current output, wherein the at least two current outputs are provided for monitoring by the respective current sensors over at least two adjacent conductors, respectively, in the DC power system, the at least two adjacent conductors being configured and arranged to provide the at least two current outputs in opposing directions; a comparator operative to generate one or more pulses in response to at least one change in the combined current output over time (di/dt); and a processor operative to process the respective pulses to determine a presence of arcing in the DC power system, and to generate an output indicative of the presence of arcing in the DC power system.