# US 2019/0245340 A1 ยท Flux based utility disturbance detector > Agents: this data is available as JSON from the patentgrep API and MCP server โ€” see https://patentgrep.com/llms.txt - Number: US 2019/0245340 A1 - Document ID: US20190245340A1 - Status: Published application - Kind: A1 - Application number: 16/224,986 - Filed: 2018-12-19 - Published: 2019-08-08 - Earliest claimed: 2018-02-03 - Assignees: S&C Electric Company - Applicants: S&C Electric Company - Inventors: David Glenn Porter - Web page: https://patentgrep.com/patent/US20190245340A1 ## CPC - H02H 3/207: {also responsive to under-voltage (window comparators for indication G01R19/165)} - G01R 19/16547: {voltage or current in AC supplies (switching for protection H02H; circuits for emergency power supply H02J9/00)} - G01R 31/42: AC power supplies - G01R 33/02: Measuring direction or magnitude of magnetic fields or magnetic flux (G01R33/20 takes precedence) - H02J 9/06: with automatic change-over {, e.g. UPS systems} - G01R 19/02: Measuring effective values, i.e. root-mean-square values - G01R 19/2513: {Arrangements for monitoring electric power systems, e.g. power lines or loads; Logging} - 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) - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY ## Abstract A method for detecting a voltage disturbance on an electrical line coupled to a utility that provides three-phase electrical AC power signals to a critical load that includes a transformer. The method includes reading instantaneous voltage measurements at a high sample rate of each of the three-phase power signals, and calculating a flux in the transformer at the sample rate for each of three-phase power signals by adding the instantaneous voltage measurements at the current sample point and at a previous sample point. The method includes calculating a flux error for each of the three-phase signals at the sample rate as a difference between the newly calculated flux and the oldest calculated flux. The method determines whether the flux error for any of the three-phase power signals is greater than a first predetermined percentage or less than a second predetermined percentage, and if so, identifies a voltage disturbance. ## Claims ### Claim 1 A method for detecting a voltage disturbance on an electrical line coupled to a utility, where the utility provides three-phase electrical AC power signals on the line to an electrical system, said electrical system including a transformer, said method comprising: reading instantaneous voltage measurements for each of the three-phase power signals on the electrical line at a predetermined sample rate; calculating a flux value in the transformer at the sample rate for each of the three-phase power signals using the instantaneous voltage measurements at a current sample point and at a previous sample point; storing the calculated flux value at each sample point over a predetermined sample period where a newly calculated flux value replaces an oldest calculated flux value; calculating a flux error value for each of the three-phase power signals at the sample rate as a difference between the newly calculated flux value and the oldest calculated flux value; determining whether the flux error value of any of the three-phase power signals is greater than a first predetermined percentage; determining whether the flux error value of any for the three-phase power signals is less than a second predetermined percentage; and detecting the voltage disturbance if any of the flux error values is greater than the first predetermined percentage or less than the second predetermined percentage. ### Claim 2 (depends on 1) The method according to claim 1 wherein calculating a flux value of the transformer includes adding the instantaneous voltage measurements at the current sample point and at the previous sample point. ### Claim 3 (depends on 2) The method according to claim 2 further comprising calculating an average flux value over the sample period using the stored flux values for each of the three-phase power signals, wherein calculating a flux value of the transformer includes removing a DC flux offset of each three-phase power signal that is determined using the average flux value. ### Claim 4 The method according to clam 3 wherein removing the DC flux offset includes multiplying the average flux value by a proportional flux term defined by asymmetrical losses in a transformer core due to asymmetrical voltages on the core. ### Claim 5 (depends on 1) The method according to claim 1 wherein the predetermined sample rate is 4800 samples per second. ### Claim 6 (depends on 1) The method according to claim 1 wherein the predetermined sample period is a full AC cycle of the three-phase power signals. ### Claim 7 (depends on 1) The method according to claim 1 wherein the first predetermined percentage is 10% and the second predetermined percentage is โˆ’10%. ### Claim 8 (depends on 1) The method according to claim 1 wherein the electrical system is a critical load or a micro-grid. ### Claim 9 (depends on 1) The method according to claim 1 further comprising disconnecting the electrical system from the utility if the voltage disturbance is detected. ### Claim 10 A method for detecting a voltage disturbance on an electrical line coupled to a utility, where the utility provides an electrical AC power signal on the line to an electrical system, said electrical system including a transformer, said method comprising: reading instantaneous voltage measurements of the power signal on the electrical line at a predetermined sample rate; calculating a flux value in the transformer at the sample rate for the power signal by adding the instantaneous voltage measurements at a current sample point and at a previous sample point; storing the calculated flux values at each sample point over a predetermined sample period where a newly calculated flux value replaces an oldest calculated flux value; calculating a flux error value for the power signal at the sample rate as a difference between the newly calculated flux value and the oldest calculated flux value; determining whether the flux error value of the power signal is greater than a first predetermined percentage; determining whether the flux error value of the power signal is less than a second predetermined percentage; and detecting the voltage disturbance if the flux error value is greater than the first predetermined percentage or less than the second predetermined percentage. ### Claim 11 (depends on 10) The method according to claim 10 further comprising calculating an average flux value over the sample period using the stored flux value of the power signal, wherein calculating a flux value of the transformer includes removing a DC flux offset of the power signal that is determined using the average flux. ### Claim 12 The method according to clam 11 wherein removing the DC flux offset includes multiplying the average flux value by a proportional flux term defined by asymmetrical losses in a transformer core due to asymmetrical voltages on the core. ### Claim 13 (depends on 10) The method according to claim 10 wherein the predetermined sample rate is 4800 samples per second. ### Claim 14 (depends on 10) The method according to claim 10 wherein the predetermined sample period is a full AC cycle of the power signal. ### Claim 15 (depends on 10) The method according to claim 10 wherein the first predetermined percentage is 10% and the second predetermined percentage is -10%. ### Claim 16 (depends on 10) The method according to claim 10 wherein the electrical system is a critical load or a micro-grid. ### Claim 17 (depends on 16) The method according to claim 16 further comprising disconnecting the electrical system from the utility if the voltage disturbance is detected. ### Claim 18 A method for detecting a voltage disturbance on an electrical line coupled to a utility, where the utility provides three-phase electrical AC power signals on the line to an electrical system, said electrical system including a transformer, said method comprising: reading instantaneous voltage measurements for each of the three-phase power signals on the electrical line at a predetermined sample rate of 4800 samples per second; calculating a flux value in the transformer at the sample rate for each of the three-phase power signals by adding the instantaneous voltage measurements at a current sample point and at a previous sample point, wherein calculating the flux value includes removing a DC flux offset; storing the calculated flux value at each sample point over a predetermined sample period of one AC cycle where a newly calculated flux value replaces an oldest calculated flux value; calculating an average flux value over the sample period using the stored flux values for each of the three-phase power signals, wherein removing the DC flux offset includes multiplying the average flux value by a proportional flux term defined by asymmetrical losses in a transformer core due to asymmetrical voltages on the core; calculating a flux error value for each of the three-phase signals at the sample rate as a difference between the newly calculated flux value and the oldest calculated flux value; determining whether the flux error value of any of the three-phase power signals is greater than a first predetermined percentage of 10%; determining whether the flux error value of any of the three-phase power signals is less than a second predetermined percentage of โˆ’10%; detecting the voltage disturbance if any of the flux error values is greater than the first predetermined percentage or less than the second predetermined percentage; and disconnecting the electrical system from the utility if the voltage disturbance is detected. ### Claim 19 (depends on 18) The method according to claim 18 wherein the electrical system is a critical load or a micro-grid. ### Claim 20 (depends on 18) The method according to claim 18 further comprising disconnecting the electrical system from the utility if the voltage disturbance is detected.