# US 2018/0026448 A1 · Method for connecting an energy generation installation to a medium voltage network and energy generation installation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0026448 A1 - Document ID: US20180026448A1 - Status: Published application - Kind: A1 - Application number: 15/715,573 - Filed: 2017-09-26 - Published: 2018-01-25 - Earliest claimed: 2015-03-27 - Assignees: SMA Solar Technology AG - Applicants: SMA Solar Technology AG - Inventors: Andreas Falk - Web page: https://patentgrep.com/patent/US20180026448A1 ## CPC - H02J 3/381: {Dispersed generators} - H02M 7/54: by dynamic converters - G05F 1/10: Regulating voltage or current (G05F1/02 takes precedence) - H02J 3/42: with automatic parallel connection when synchronisation is achieved - H02J 2101/24: Photovoltaics - Y02B 70/3225: Demand response systems, e.g. load shedding, peak shaving - Y02E 10/56: Power conversion systems, e.g. maximum power point trackers - Y04S 20/222: Demand response systems, e.g. load shedding, peak shaving - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) - G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y04S: SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS ## Abstract A method for connecting an energy generation installation to a medium-voltage grid includes determining a calibration factor for adjusting first voltage values to second voltage values by a controller of the energy generation installation. During an idle state of a medium-voltage transformer, the first voltage values are detected at a capacitive voltage divider, arranged on the medium-voltage side of the medium-voltage transformer, and the second voltage values are detected by a voltage detection means, arranged on the low-voltage side of the medium-voltage transformer. The method further includes closing a circuit breaker arranged on the medium-voltage side of the medium-voltage transformer by the controller of the energy generation installation, when voltage values determined at the capacitive voltage divider exceed a first threshold value after the calibration factor has been applied. ## Claims ### Claim 1 A method for connecting an energy generation installation to a medium-voltage grid, comprising: determining a calibration factor for adjusting first voltage values to second voltage values by a controller of the energy generation installation, wherein, during an idle state of a medium-voltage transformer, the first voltage values are detected at a capacitive voltage divider, arranged on the medium-voltage side of the medium-voltage transformer, and the second voltage values are detected by a voltage detection means, arranged on the low-voltage side of the medium-voltage transformer, and closing a circuit breaker arranged on the medium-voltage side of the medium-voltage transformer by the controller of the energy generation installation, when voltage values determined at the capacitive voltage divider exceed a first threshold value after the calibration factor has been applied. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein the first voltage values are amplified by means of an amplifier. ### Claim 3 (depends on 2) The method as claimed in claim 2, wherein the amplified first voltage values are transmitted to the controller of the energy generation installation by means of an analog data transmission circuit. ### Claim 4 A photovoltaic installation, comprising: a photovoltaic (PV) inverter connected on an input side thereof to a photovoltaic generator and its output connected without a switch in-between to a low-voltage side of a medium-voltage transformer, a capacitive voltage divider arranged on a medium-voltage side of the medium-voltage transformer configured to detect first voltage values, a voltage detection means arranged on the low-voltage side of the medium-voltage transformer for detecting second voltage values, a circuit breaker arranged on the medium-voltage side of the medium-voltage transformer and configured to connect the output of the PV inverter to a medium-voltage grid, a calibration unit configured to adjust the first voltage values to the second voltage values during the idle state of the medium-voltage transformer, a controller configured to actuate the circuit breaker when voltage values detected at the capacitive voltage divider and adjusted by the calibration unit exceed a first threshold value. ### Claim 5 (depends on 4) The photovoltaic installation as claimed in claim 4, further comprising an amplifier configured to amplify the first voltage values. ### Claim 6 (depends on 5) The photovoltaic installation as claimed in claim 5, further comprising an analog data transmission circuit configured to transmit the amplified first voltage values to the controller of the photovoltaic installation. ### Claim 7 (depends on 4) The photovoltaic installation as claimed in claim 4, wherein the controller comprises the calibration unit.