# US 9,520,713 B2 · Fast switch fault current limiter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,713 B2 - Document ID: US9520713B2 - Status: Granted - Kind: B2 - Application number: 14/462,132 - Filed: 2014-08-18 - Published: 2015-02-26 - Granted: 2016-12-13 - Earliest claimed: 2013-08-22 - Assignees: Varian Semiconductor Equipment Associates, Inc. - Applicants: Varian Semiconductor Equipment Associates, Inc. - Inventors: Kasegn D. Tekletsadik; Charles L. Stanley - Web page: https://patentgrep.com/patent/US9520713B2 ## CPC - H02H 9/005: {avoiding undesired transient conditions} - H01H 71/10: Operating or release mechanisms - H01H 71/2409: {combined with an electromagnetic current limiting mechanism} - H02H 9/021: {Current limitation using saturable reactors (H02H9/023 takes precedence)} - H01H 71/2463: {with plunger type armatures} - H01H 83/02: operated by earth fault currents (H01H83/14 takes precedence) - 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) - H01H: ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES (contact cables H01B7/10; electrolytic self-interrupters H01G9/18; emergency protective circuit arrangements H02H; switching by electronic means without contact-making H03K17/00) ## Abstract A fault current limiter circuit including a fast switch fault current limiter (FSFCL) and a voltage control reactor (VCR) operative to conduct load current during a steady state operation and limit load current when the load current exceeds fault current limits. The FSFCL may include a breaker having electrical contacts, a coil electrically coupled to the electrical breaker contacts, a plunger mechanically coupled to the electrical breaker contacts, a parallel voltage control (VCR), a transient overvoltage control circuit (TOCC), wherein when current greater than a threshold level flows through the coil, a magnetic field having strength to move the plunger is generated, the movement of the plunger operates to open the contacts in the breaker and transfer fault current to VCR and TOCC and limit the overall system fault current. ## Claims ### Claim 1 A fast switch fault current limiter, comprising: a breaker having electrical breaker contacts; a coil electrically coupled to the electrical breaker contacts; and a plunger mechanically coupled to the electrical breaker contacts, the plunger configured to open the electrical breaker contacts, wherein when current greater than a threshold level flows through the coil, a magnetic field having strength to move the plunger is generated, the movement of the plunger operates to open the contacts in the breaker; and a voltage control reactor (VCR) connected in parallel to the coil, wherein VCR is configured to receive the current in response to a break in the current flowing through the coil. ### Claim 2 (depends on 1) The fast switch fault current limiter of claim 1, wherein the electrical breaker contacts are configured to break the current flowing through the coil by the movement of the plunger. ### Claim 3 (depends on 1) The fast switch fault current limiter of claim 1, further comprising a current splitting reactor (CSR) electrically connected to the coil, the CSR used for current limiting, and the CSR and the VCR used to limit or control a voltage. ### Claim 4 (depends on 1) The fast switch fault current limiter of claim 1, the plunger further comprising a lever arm, the lever arm operates to open the electrical breaker contacts. ### Claim 5 (depends on 1) The fast switch fault current limiter of claim 1, further comprising a timing circuit, having electromagnetic force control mechanisms, electrically coupled to the electrical breaker contacts for closing the electrical breaker contacts. ### Claim 6 (depends on 5) The fast switch fault current limiter of claim 5, wherein the electromagnetic force control mechanisms includes an air cylinder and a spring mechanism, wherein the timing circuit instantaneously closes the contacts in the breaker after a fault current is cleared, or closes the electrical breaker contacts after the fault current is detected following a predefined time delay. ### Claim 7 (depends on 1) The fast switch fault current limiter of claim 1, further includes a transient overvoltage control circuit connected to the coil, the transient overvoltage control circuit to limit overvoltages. ### Claim 8 A current limiter system comprising: a fast switch fault current limiter having electrical breaker contacts, a coil electrically coupled to the electrical breaker contacts, and a plunger mechanically coupled to the electrical breaker contacts, wherein when current greater than a threshold level flows through the coil, a magnetic field having strength to move the plunger is generated, the movement of the plunger operates to open the electrical breaker contacts; a voltage control reactor connected in parallel to the fast switch fault current limiter; and a transient overvoltage control circuit connected in parallel to the fast switch fault current limiter and the voltage control reactor, wherein when the current flowing through the coil is greater than the threshold level, the current transfers to the voltage control reactor and the transient overvoltage control circuit to limit a fault current. ### Claim 9 (depends on 8) The current limiter system of claim 8, the movement of the plunger operates to break the current flowing through the coil. ### Claim 10 (depends on 8) The current limiter system of claim 8, wherein the electrical breaker contacts are configured to break the current flowing through the coil by the movement of the plunger. ### Claim 11 (depends on 8) The current limiter system of claim 8, further comprising a current splitting reactor electrically connected to the fast switch fault current limiter, the current splitting reactor used to limit or control the current. ### Claim 12 (depends on 8) The current limiter system of claim 8, the plunger further comprising a lever arm, the lever arm operates to open the electrical breaker contacts. ### Claim 13 (depends on 8) The current limiter system of claim 8, further comprising a timing circuit, having electromagnetic force control mechanisms, electrically coupled to the electrical breaker contacts for closing the electrical breaker contacts. ### Claim 14 (depends on 13) The current limiter system of claim 13, wherein the electromagnetic force control mechanisms includes an air cylinder and a spring mechanism, wherein the timing circuit either instantaneously closes the contacts in the breaker after a fault current is cleared, or closes the electrical breaker contacts after the fault current is detected following a predefined time delay. ### Claim 15 A fast switch fault current limiting system, comprising: a fast switch, the fast switch having a breaker having electrical breaker contacts and a coil electrically coupled to the electrical breaker contacts, wherein the fast switch produces a magnetic field; and a plunger mechanically coupled to the fast switch, the plunger configured to open the electrical breaker contacts, wherein when current greater than a threshold level flows through the fast switch, a magnetic field produced by the fast switch having strength to move the plunger is generated, the movement of the plunger operates to open the contacts in the breaker and break the current flowing through the fast switch; and a voltage control reactor (VCR) connected in parallel to the fast switch, wherein the current is forced through the VCR in response to a break in the current flowing through the fast switch. ### Claim 16 (depends on 15) The fast switch fault current limiting system of claim 15, further comprising: a current splitting reactor (CSR) electrically connected to the coil, the CSR used for current limiting, and the CSR and the VCR used to limit or control a voltage, and a timing circuit electrically coupled to the fast switch for closing the electrical breaker contacts. ### Claim 17 (depends on 15) The fast switch fault current limiting system of claim 15, further comprising a transient overvoltage control circuit, having a parallel connection of a series resistance and capacitance (RC) circuit and a resistance connected in parallel to the fast switch and the voltage control reactor for limiting a fault current. ### Claim 18 (depends on 15) The fast switch fault current limiting system of claim 15, wherein the fast switch is configured as a fast interrupter of the fault current.