# US 2013/0155734 A1 · Method and system for islanding detection and protection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0155734 A1 - Document ID: US20130155734A1 - Status: Published application - Kind: A1 - Application number: 13/325,246 - Filed: 2011-12-14 - Published: 2013-06-20 - Earliest claimed: 2011-12-14 - Assignees: General Electric Company - Inventors: Said Farouk Said El-Barbari; Simon Herbert Schramm; Ara Panosyan - Web page: https://patentgrep.com/patent/US20130155734A1 ## CPC - H02J 3/381: {Dispersed generators} - H02H 7/122: for inverters, i.e. DC/AC converters - H02J 3/388: Arrangements for the handling of islanding, e.g. for disconnection or for avoiding the disconnection of power - H02J 2101/24: Photovoltaics - Y02E 10/56: Power conversion systems, e.g. maximum power point trackers - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC 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) - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A method and system for detecting an islanding condition in a grid is provided. The method comprises detecting a potential islanding condition in a grid; and, in response to the detected potential islanding condition, ramping up an amount of reactive power, active power, or a combination of active and reactive power that is generated from a power conversion system until the earlier of the power conversion system shutting down or a threshold condition being reached. ## Claims ### Claim 1 A method comprising: detecting a potential islanding condition in a grid; and in response to the detected potential islanding condition, ramping up an amount of reactive power, active power, or a combination of active and reactive power that is generated from a power conversion system until the earlier of the power conversion system shutting down or a threshold condition being reached. ### Claim 2 (depends on 1) The method of claim 1, wherein detecting the potential islanding condition comprises obtaining a line parameter value. ### Claim 3 (depends on 2) The method of claim 2, wherein the line parameter value and a corresponding result of ramping up the amount of reactive power, active power, or a combination of active and reactive power is stored in a database learning system. ### Claim 4 (depends on 2) The method of claim 2, wherein the line parameter value comprises a voltage, a current, a frequency, an impedance, or combinations thereof. ### Claim 5 (depends on 1) The method of claim 1, wherein ramping up comprises ramping up with a varying ramp rate. ### Claim 6 (depends on 5) The method of claim 5, wherein the varying ramp rate comprises a progressively increasing ramp rate. ### Claim 7 (depends on 1) The method of claim 1, further comprising, if the threshold condition is reached, resetting the amount of reactive power, active power, or the combination of active and reactive power. ### Claim 8 (depends on 1) The method of claim 1, wherein the threshold condition comprises a predetermined time period. ### Claim 9 (depends on 1) The method of claim 1, wherein a zero amount of reactive power is injected during normal operating conditions of the power conversion system, and wherein ramping up the amount of reactive power, active power, or a combination of active and reactive power comprises ramping up an amount of reactive power from zero. ### Claim 10 A grid protection system comprising: a detection unit for detecting a potential islanding condition in a grid; and a variable ramp rate generation unit for, upon detection of a potential islanding condition, ramping up an amount of reactive power, active power, or a combination of active and reactive power that is generated from a power conversion system until the earlier of the power conversion system shutting down or a threshold condition being reached. ### Claim 11 (depends on 10) The system of claim 10, further comprising a sensor for obtaining a line parameter value at a point of common coupling for use by the detection unit for detecting the potential islanding condition. ### Claim 12 (depends on 10) The system of claim 10, further comprising a database learning system for storing past line parameter values and corresponding past results from the ramping, wherein the past line parameter values and the corresponding past results from the ramping are used to adjust a present ramping profile. ### Claim 13 (depends on 10) The system of claim 10, further comprising a relay for shutting down the power conversion system when a line parameter value deviates from a trip range. ### Claim 14 A solar power generation system comprising: a power converter for receiving power from a solar power source; a detection unit for measuring a line parameter value and using the line parameter value for identifying a potential islanding condition in a grid fed by the a power converter; and a variable ramp rate generation unit for ramping up an amount of reactive power, active power, or a combination of active and reactive power generated from the power converter in response to an identified potential islanding condition. ### Claim 15 (depends on 14) The system of claim 14, wherein the solar power generation system is configured for injecting zero reactive power during normal operating conditions of the power conversion system, and wherein the variable ramp rate generation unit is configured for ramping up the amount of reactive power from zero in response to the identified potential islanding condition. ### Claim 16 (depends on 14) The system of claim 14, wherein the line parameter value comprises a voltage at a point of common coupling. ### Claim 17 (depends on 14) The system of claim 14, further comprising a database learning system wherein the line parameter value and a corresponding result of ramping up the amount of reactive power, active power, or a combination of active and reactive power are stored in the database learning system. ### Claim 18 (depends on 14) The system of claim 14, wherein the line parameter value comprises a voltage, a current, a frequency, an impedance, or combinations thereof. ### Claim 19 (depends on 14) The system of claim 14, wherein the power converter comprises a plurality of power converters and wherein the variable ramp rate generation unit is coupled for transmitting a common power ramp control signal to the plurality of power converters.