# US 2025/0096707 A1 · Medium voltage inrush current regulation and interconnection control system and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0096707 A1 - Document ID: US20250096707A1 - Status: Published application - Kind: A1 - Application number: 18/967,644 - Filed: 2024-12-03 - Published: 2025-03-20 - Earliest claimed: 2021-06-09 - Assignees: Aderis Energy, LLC - Applicants: Aderis Energy, LLC - Inventors: Adam Will FOODMAN; Bradley Allan MICALLEF; Olee Joel OLSEN, Jr. - Web page: https://patentgrep.com/patent/US20250096707A1 ## CPC - H02P 9/08: Control of generator circuit during starting or stopping of driving means, e.g. for initiating excitation - H02H 9/002: {limiting inrush current on switching on of inductive loads subjected to remanence, e.g. transformers} - H02H 9/02: responsive to excess current {(current limitation for voltage regulators G05F1/573; disconnection after limiting H02H3/025)} - H02J 3/381: {Dispersed generators} - H02J 2101/24: Photovoltaics - Y02E 10/56: Power conversion systems, e.g. maximum power point trackers - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS - 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) - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A medium voltage inrush current (MVIC) regulator and interconnection control system for interposing between a distributed power generation facility and a utility grid. The facility has a designated generator step-up (GSU) transformer and is connected to the utility grid at a point of interconnect. The system includes a pre-insertion impedance injection transformer, a low voltage first switch connected between the pre-insertion transformer and secondary coils of the designated GSU transformer, a medium voltage second switch connected inline between the pre-insertion transformer and primary coils of the designated GSU transformer, and a controller. In response to restoration of the utility grid following a loss-of-grid event, the controller opens and closes the first and second switches according to an automated pre-energization switching sequence such that magnetic flux in the designated GSU transformer occurs at a reduced rate, thereby reducing inrush of current and undesirable power quality phenomena. ## Claims ### Claim 1 A medium voltage inrush current (MVIC) regulator and interconnection control system for interposing between a distributed power generation facility, having a designated generator step-up (GSU) transformer, and a utility grid, the distributed power generation facility being connected to the utility grid at a point of interconnect, comprising: (a) a pre-insertion impedance injection transformer; (b) a first switch connected between the pre-insertion transformer and secondary coils of the designated GSU transformer, the first switch being a low voltage switch; (c) a second switch connected inline between the pre-insertion transformer and primary coils of the designated GSU transformer, the second switch being a medium voltage switch; and (d) a controller adapted, in response to restoration of the utility grid following a loss-of-grid event, to open and close the first and second switches according to an automated pre-energization switching sequence such that magnetic flux in the designated GSU transformer occurs at a reduced rate, thereby reducing inrush of current and undesirable power quality phenomena. ### Claim 2 (depends on 1) The MVIC regulator and interconnection control system of claim 1, wherein the distributed power generation facility is a photovoltaic power station. ### Claim 3 (depends on 2) The MVIC regulator and interconnection control system of claim 2, wherein the pre-insertion transformer has a higher impedance, a very low kVA size, and a significantly lower inrush current rating than the designated GSU transformer. ### Claim 4 (depends on 3) The MVIC regulator and interconnection control system of claim 3, wherein the pre-insertion transformer is a three-phase 600 V/3 kVA transformer. ### Claim 5 (depends on 2) The MVIC regulator and interconnection control system of claim 2, wherein the controller, in carrying out the automated pre-energization switching sequence, closes the low voltage switch, a first predetermined period of time after initial energization of the utility grid at the point of interconnect, to energize the secondary coil of the designated GSU transformer, then after a second predetermined period of time closes the medium voltage switch to cause the designated GSU transformer to be connected in parallel to the pre-insertion transformer to provide full distribution voltage to the designated GSU transformer, and then after a third predetermined period of time opens the low voltage switch to remove the pre-insertion transformer from the parallel circuit. ### Claim 6 (depends on 5) The MVIC regulator and interconnection control system of claim 5, wherein the controller, in carrying out the automated pre-energization switching sequence, opens the first and second switches before the initial energization of the utility grid at the point of interconnect. ### Claim 7 (depends on 6) The MVIC regulator and interconnection control system of claim 6, further comprising one or more metering relay, wherein execution of the automated pre-energization switching sequence is contingent upon input to the controller from the one or more metering relay. ### Claim 8 (depends on 6) The MVIC regulator and interconnection control system of claim 6, further comprising one or more protective relay, wherein execution of the automated pre-energization switching sequence is contingent upon input to the controller from the one or more protective relay. ### Claim 9 (depends on 6) The MVIC regulator and interconnection control system of claim 6, further comprising an uninterruptible power supply and battery to provide power to the controller during the automated pre-energization switching sequence. ### Claim 10 (depends on 9) The MVIC regulator and interconnection control system of claim 9, wherein execution of the automated pre-energization switching sequence is contingent upon input to the controller from the uninterruptible power supply and battery. ### Claim 11 (depends on 5) The MVIC regulator and interconnection control system of claim 5, wherein the first predetermined period of time has a magnitude designed to ensure that the grid is stable and the designated GSU transformer and the elements of the system are available to operate. ### Claim 12 (depends on 11) The MVIC regulator and interconnection control system of claim 11, wherein the first predetermined period of time is in the range of 3-15 seconds, inclusive. ### Claim 13 (depends on 12) The MVIC regulator and interconnection control system of claim 12, wherein the first predetermined period of time is in the range of 5-10 seconds, inclusive. ### Claim 14 (depends on 5) The MVIC regulator and interconnection control system of claim 5, wherein the second predetermined period of time has a magnitude designed to ensure that oscillation is reduced sufficiently relative to steady state. ### Claim 15 (depends on 14) The MVIC regulator and interconnection control system of claim 14, wherein the second predetermined period of time is in the range of 5-15 seconds, inclusive. ### Claim 16 (depends on 15) The MVIC regulator and interconnection control system of claim 15, wherein the second predetermined period of time is in the range of 10-12 seconds, inclusive. ### Claim 17 (depends on 14) The MVIC regulator and interconnection control system of claim 14, wherein the magnitude is designed to ensure that oscillation is reduced to within 2% of steady state. ### Claim 18 (depends on 5) The MVIC regulator and interconnection control system of claim 5, wherein the third predetermined period of time has a magnitude designed to ensure that the voltage grid is stable and the designated GSU transformer and the elements of the system are available to operate. ### Claim 19 (depends on 18) The MVIC regulator and interconnection control system of claim 18, wherein the third predetermined period of time is in the range of 1-5 seconds, inclusive. ### Claim 20 (depends on 19) The MVIC regulator and interconnection control system of claim 19, wherein the third predetermined period of time is in the range of 1.0-2.5 seconds, inclusive. ### Claim 21 (depends on 5) The MVIC regulator and interconnection control system of claim 5, wherein one or more of the first, second, and third predetermined periods of time has a magnitude that is customized based on specific characteristics of the photovoltaic power station where the system is installed. ### Claim 22 (depends on 5) The MVIC regulator and interconnection control system of claim 5, further comprising a user interface that displays real-time status information during, and based upon, the automated pre-energization switching sequence. ### Claim 23 (depends on 2) The MVIC regulator and interconnection control system of claim 2, wherein the controller includes a programmable logic controller (PLC) programmed to execute the automated pre-energization switching sequence. ### Claim 24 (depends on 2) The MVIC regulator and interconnection control system of claim 2, further comprising real-time operator interface software communicatively connected to the controller via a wireless communication link, the real-time operator interface software providing a remote operator with the capability to adjust parameters and timing sequence settings without physically going on site. ### Claim 25 (depends on 24) The MVIC regulator and interconnection control system of claim 24, wherein the real-time operator interface software further provides the remote operator with the ability to remotely issue a command to trigger the automated pre-energization switching sequence or to clear a trip event prior to initiating the automated pre-energization switching sequence. ### Claim 26 (depends on 2) The MVIC regulator and interconnection control system of claim 2, the designated GSU transformer is one transformer out of a plurality of GSU transformers in the distributed power generation facility, the plurality of GSU transformers being chained together. ### Claim 27 (depends on 2) The MVIC regulator and interconnection control system of claim 2, further comprising a primary voltage cabinet that houses the pre-insertion impedance injection transformer, the first and second switches, the controller, and a user interface, wherein the primary voltage cabinet, the pre-insertion impedance injection transformer, the first and second switches, the controller, and the user interface being part of a self-contained assembly. ### Claim 28 (depends on 27) The MVIC regulator and interconnection control system of claim 27, wherein the user interface is housed in a side compartment, of the primary voltage cabinet, that is separated from the rest of an interior of the primary voltage cabinet but is accessible by an exterior door. ### Claim 29 A distributed power generation facility equipped with a medium voltage inrush current (MVIC) regulator and interconnection control system, comprising: (a) one or more generator step-up (GSU) transformers, at least one of the one or more GSU transformers being a designated GSU transformer, the one or more GSU transformers being connected to a utility grid at a point of interconnect; and (b) a MVIC regulator and interconnection control system interposed between the one or more GSU transformers and the utility grid point of interconnect, including: (i) a pre-insertion impedance injection transformer, (ii) a first switch connected between the pre-insertion transformer and secondary coils of the designated GSU transformer, the first switch being a low voltage switch, (iii) a second switch connected inline between the pre-insertion transformer and primary coils of the designated GSU transformer, the second switch being a medium voltage switch, and (iv) a controller adapted, in response to restoration of the utility grid following a loss-of-grid event, to open and close the first and second switches according to an automated pre-energization switching sequence such that magnetic flux in the designated GSU transformer occurs at a reduced rate, thereby reducing inrush of current and undesirable power quality phenomena. ### Claim 30 (depends on 29) The distributed power generation facility of claim 29, wherein the distributed power generation facility is a photovoltaic power station. ### Claim 31 (depends on 30) The distributed power generation facility of claim 30, wherein the pre-insertion transformer has a higher impedance, a very low kVA size, and a significantly lower inrush current rating than the designated GSU transformer. ### Claim 32 (depends on 31) The distributed power generation facility of claim 31, wherein the pre-insertion transformer is a three-phase 600 V/3 kVA transformer. ### Claim 33 (depends on 30) The distributed power generation facility of claim 30, wherein the controller, in carrying out the automated pre-energization switching sequence, closes the low voltage switch, a first predetermined period of time after initial energization of the utility grid at the point of interconnect, to energize the secondary coil of the designated GSU transformer, then after a second predetermined period of time closes the medium voltage switch to cause the designated GSU transformer to be connected in parallel to the pre-insertion transformer to provide full distribution voltage to the designated GSU transformer, and then after a third predetermined period of time opens the low voltage switch to remove the pre-insertion transformer from the parallel circuit. ### Claim 34 (depends on 33) The distributed power generation facility of claim 33, wherein the controller, in carrying out the automated pre-energization switching sequence, opens the first and second switches before the initial energization of the utility grid at the point of interconnect. ### Claim 35 (depends on 34) The distributed power generation facility of claim 34, wherein the MVIC regulator and interconnection control system further includes one or more metering relay, and wherein execution of the automated pre-energization switching sequence is contingent upon input to the controller from the one or more metering relay. ### Claim 36 (depends on 34) The distributed power generation facility of claim 34, wherein the MVIC regulator and interconnection control system further includes one or more protective relay, and wherein execution of the automated pre-energization switching sequence is contingent upon input to the controller from the one or more protective relay. ### Claim 37 (depends on 34) The distributed power generation facility of claim 34, wherein the MVIC regulator and interconnection control system further includes an uninterruptible power supply and battery to provide power to the controller during the automated pre-energization switching sequence. ### Claim 38 (depends on 37) The distributed power generation facility of claim 37, wherein execution of the automated pre-energization switching sequence is contingent upon input to the controller from the uninterruptible power supply and battery. ### Claim 39 (depends on 33) The distributed power generation facility of claim 33, wherein the first predetermined period of time has a magnitude designed to ensure that the grid is stable and the designated GSU transformer and the elements of the system are available to operate. ### Claim 40 (depends on 39) The distributed power generation facility of claim 39, wherein the first predetermined period of time is in the range of 3-15 seconds, inclusive. ### Claim 41 (depends on 40) The distributed power generation facility of claim 40, wherein the first predetermined period of time is in the range of 5-10 seconds, inclusive. ### Claim 42 (depends on 33) The distributed power generation facility of claim 33, wherein the second predetermined period of time has a magnitude designed to ensure that oscillation is reduced sufficiently relative to steady state. ### Claim 43 (depends on 42) The distributed power generation facility of claim 42, wherein the second predetermined period of time is in the range of 5-15 seconds, inclusive. ### Claim 44 (depends on 43) The distributed power generation facility of claim 43, wherein the second predetermined period of time is in the range of 10-12 seconds, inclusive. ### Claim 45 (depends on 42) The distributed power generation facility of claim 42, wherein the magnitude is designed to ensure that oscillation is reduced to within 2% of steady state. ### Claim 46 (depends on 33) The distributed power generation facility of claim 33, wherein the third predetermined period of time has a magnitude designed to ensure that the voltage grid is stable and the designated GSU transformer and the elements of the system are available to operate. ### Claim 47 (depends on 46) The distributed power generation facility of claim 46, wherein the third predetermined period of time is in the range of 1-5 seconds, inclusive. ### Claim 48 (depends on 47) The distributed power generation facility of claim 47, wherein the third predetermined period of time is in the range of 1.0-2.5 seconds, inclusive. ### Claim 49 (depends on 33) The distributed power generation facility of claim 33, wherein one or more of the first, second, and third predetermined periods of time has a magnitude that is customized based on specific characteristics of the photovoltaic power station where the system is installed. ### Claim 50 (depends on 33) The distributed power generation facility of claim 33, wherein the MVIC regulator and interconnection control system further includes a user interface that displays real-time status information during, and based upon, the automated pre-energization switching sequence. ### Claim 51 (depends on 30) The distributed power generation facility of claim 30, wherein the controller includes a programmable logic controller (PLC) programmed to execute the automated pre-energization switching sequence. ### Claim 52 (depends on 30) The distributed power generation facility of claim 30, further comprising real-time operator interface software communicatively connected to the controller via a wireless communication link, the real-time operator interface software providing a remote operator with the capability to adjust parameters and timing sequence settings without physically going on site. ### Claim 53 (depends on 52) The distributed power generation facility of claim 52, wherein the real-time operator interface software further provides the remote operator with the ability to remotely issue a command to trigger the automated pre-energization switching sequence or to clear a trip event prior to initiating the automated pre-energization switching sequence. ### Claim 54 (depends on 30) The distributed power generation facility of claim 30, the designated GSU transformer is one transformer out of a plurality of GSU transformers in the distributed power generation facility, the plurality of GSU transformers being chained together. ### Claim 55 (depends on 30) The distributed power generation facility of claim 30, wherein the MVIC regulator and interconnection control system further includes a primary voltage cabinet that houses the pre-insertion impedance injection transformer, the first and second switches, the controller, and a user interface, and wherein the primary voltage cabinet, the pre-insertion impedance injection transformer, the first and second switches, the controller, and the user interface being part of a self-contained assembly. ### Claim 56 (depends on 55) The distributed power generation facility of claim 55, wherein the user interface is housed in a side compartment, of the primary voltage cabinet, that is separated from the rest of an interior of the primary voltage cabinet but is accessible by an exterior door. ### Claim 57 A method of reducing inrush current using a medium voltage inrush current (MVIC) regulator and interconnection control system interposed between a distributed power generation facility, having a designated generator step-up (GSU) transformer, and a utility grid, the distributed power generation facility being connected to the utility grid at a point of interconnect, the MVIC regulator and interconnection control system having a pre-insertion impedance injection transformer, a low voltage first switch connected between the pre-insertion transformer and secondary coils of the designated GSU transformer, a medium voltage second switch connected inline between the pre-insertion transformer and primary coils of the designated GSU transformer, and a controller, the method comprising the steps of: (a) following a loss-of-grid event, ensuring that the first and second switches are open; (b) via the controller, and in response to restoration of the utility grid following the loss-of-grid event, opening and closing the first and second switches according to an automated pre-energization switching sequence such that magnetic flux in the designated GSU transformer occurs at a reduced rate, thereby reducing inrush of current and undesirable power quality phenomena. ### Claim 58 (depends on 57) The method of claim 57, wherein the controller carries out the automated pre-energization switching sequence by: (c) closing the low voltage switch, starting at a first predetermined period of time after initial energization of the utility grid at the point of interconnect, to energize the secondary coil of the designated GSU transformer; (d) then, after a second predetermined period of time, closing the medium voltage switch to cause the designated GSU transformer to be connected in parallel to the pre-insertion transformer to provide full distribution voltage to the designated GSU transformer; and (e) then, after a third predetermined period of time, opening the low voltage switch to remove the pre-insertion transformer from the parallel circuit. ### Claim 59 (depends on 58) The method of claim 58, wherein ensuring that the first and second switches are open includes, via the controller, opening the first and second switches before the initial energization of the utility grid at the point of interconnect. ### Claim 60 (depends on 59) The method of claim 59, wherein the MVIC regulator and interconnection control system includes one or more metering relay, and wherein execution of the automated pre-energization switching sequence is contingent upon input received by the controller from the one or more metering relay. ### Claim 61 (depends on 59) The method of claim 59, wherein the MVIC regulator and interconnection control system includes one or more protective relay, and wherein execution of the automated pre-energization switching sequence is contingent upon input received by the controller from the one or more protective relay. ### Claim 62 (depends on 59) The method of claim 59, wherein the MVIC regulator and interconnection control system includes an uninterruptible power supply and a battery, and wherein the controller carries out the automated pre-energization switching sequence using power provided by the uninterruptible power supply and battery. ### Claim 63 (depends on 62) The method of claim 62, wherein execution of the automated pre-energization switching sequence is contingent upon input received by the controller from the uninterruptible power supply and battery. ### Claim 64 (depends on 58) The method of claim 58, wherein the first predetermined period of time has a magnitude designed to ensure that the grid is stable and the designated GSU transformer and the elements of the system are available to operate. ### Claim 65 (depends on 64) The method of claim 64, wherein the first predetermined period of time is in the range of 3-15 seconds, inclusive. ### Claim 66 (depends on 65) The method of claim 65, wherein the first predetermined period of time is in the range of 5-10 seconds, inclusive. ### Claim 67 (depends on 58) The method of claim 58, wherein the second predetermined period of time has a magnitude designed to ensure that oscillation is reduced sufficiently relative to steady state. ### Claim 68 (depends on 67) The method of claim 67, wherein the second predetermined period of time is in the range of 5-15 seconds, inclusive. ### Claim 69 (depends on 68) The method of claim 68, wherein the second predetermined period of time is in the range of 10-12 seconds, inclusive. ### Claim 70 (depends on 67) The method of claim 67, wherein the magnitude is designed to ensure that oscillation is reduced to within 2% of steady state. ### Claim 71 (depends on 58) The method of claim 58, wherein the third predetermined period of time has a magnitude designed to ensure that the voltage grid is stable and the designated GSU transformer and the elements of the system are available to operate. ### Claim 72 (depends on 71) The method of claim 71, wherein the third predetermined period of time is in the range of 1-5 seconds, inclusive. ### Claim 73 (depends on 72) The method of claim 72, wherein the third predetermined period of time is in the range of 1.0-2.5 seconds, inclusive. ### Claim 74 (depends on 58) The method of claim 58, further comprising a step of customizing a magnitude of one or more of the first, second, and third predetermined periods of time based on specific characteristics of the photovoltaic power station where the system is installed. ### Claim 75 (depends on 58) The method of claim 58, further comprising a step of displaying, via a user interface, real-time status information during, and based upon, the automated pre-energization switching sequence. ### Claim 76 (depends on 57) The method of claim 57, wherein the controller opens and closes the first and second switches according to the automated pre-energization switching sequence via a programmable logic controller (PLC) programmed to execute the automated pre-energization switching sequence. ### Claim 77 (depends on 57) The method of claim 57, further comprising the steps of: (c) via the controller, communicating, via a wireless communication link, with real-time operator interface software; and (d) providing, via the real-time operator interface software, a remote operator with the capability to adjust parameters and timing sequence settings without physically going on site. ### Claim 78 (depends on 77) The method of claim 77, wherein providing a remote operator with the capability to adjust parameters and timing sequence settings without physically going on site includes providing the remote operator with the ability to remotely issue a command to trigger the automated pre-energization switching sequence or to clear a trip event prior to initiating the automated pre-energization switching sequence. ### Claim 79 (depends on 57) The method of claim 57, wherein the designated GSU transformer is one transformer out of a plurality of GSU transformers that are chained together in the distributed power generation facility, and wherein the method further comprises the step of reducing inrush current to the chained GSU transformers using the medium voltage inrush current (MVIC) regulator and interconnection control system and the automated pre-energization switching sequence. ### Claim 80 (depends on 57) The method of claim 57, further comprising a step of housing the pre-insertion impedance injection transformer, the first and second switches, the controller, and a user interface in a primary voltage cabinet, wherein the pre-insertion impedance injection transformer, the first and second switches, the controller, and the user interface are part of a self-contained assembly. ### Claim 81 (depends on 80) The method of claim 80, further comprising a step of housing the user interface is housed in a side compartment, of the primary voltage cabinet, that is separated from the rest of an interior of the primary voltage cabinet but is accessible by an exterior door. ### Claim 82 (depends on 57) The method of claim 57, further comprising a step of installing the MVIC regulator and interconnection control system at a distributed power generation facility that is a photovoltaic power station. ### Claim 83 (depends on 82) The method of claim 82, wherein the pre-insertion transformer has a higher impedance, a very low kVA size, and a significantly lower inrush current rating than the designated GSU transformer. ### Claim 84 (depends on 83) The method of claim 83, wherein the pre-insertion transformer is three-phase 600 V/3 kVA transformer.