# US 10,310,017 B2 · Detection of generator stator inter-circuit faults > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,310,017 B2 - Document ID: US10310017B2 - Status: Granted - Kind: B2 - Application number: 15/335,073 - Filed: 2016-10-26 - Published: 2017-03-16 - Granted: 2019-06-04 - Earliest claimed: 2012-09-13 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Shantanu Som; Zeeky Ashiono Bukhala - Web page: https://patentgrep.com/patent/US10310017B2 ## CPC - G01R 31/346: {Testing of armature or field windings} - G01R 19/02: Measuring effective values, i.e. root-mean-square values - G01R 31/343: {in operation} - G01R 31/52: Testing for short-circuits, leakage current or ground faults - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract Aspects of the invention provide a system and method for detecting inter-circuit faults within a generator stator. In one embodiment, a computer system includes: a sampler for sampling phase voltages and phase currents of a generator stator; a plurality of pre-defined blocks for enabling, based on the sampled phase voltages and currents, an inter-circuit fault detection scheme; a level detection block for determining, in response to the enabled inter-circuit fault detection scheme, a plurality of differences between the sampled phase voltages; and a comparison logic device for comparing, in response to the enabled inter-circuit fault detection scheme, each of the differences of the sampled phase voltages and determining, based on the differences, an inter-circuit fault within at least one phase of the generator stator. The system may also include a negative sequence voltage block for detection of inter-circuit fault within a generator stator. ## Claims ### Claim 1 A system comprising: three input voltage lines electrically connected to at least one voltmeter that is electrically connected to a multiphase generator stator to measure a voltage across each phase of the stator; a plurality of pre-defined blocks including at least a ground fault de-sensitizer electrically connected to the input voltage lines and determining based on values received therefrom whether a ground fault has occurred, a phase-phase fault de-sensitizer connected to the input voltage lines and determining therefrom whether a phase-phase fault has occurred, and a multiplier receiving outputs of at least the ground fault de-sensitizer and the phase-phase fault de-sensitizer of the plurality of pre-defined blocks and producing an output signal indicative of a product thereof, the output signal of the multiplier enabling an inter-circuit fault detection (IC-FD) program upon a determination by the ground fault de-sensitizer that no ground fault has occurred and a determination by the phase-phase fault de-sensitizer that no phase-phase fault has occurred; at least one root mean square (RMS) device that receives the input voltages and outputs a signal for each phase representative of a respective RMS phase voltage; at least three difference devices that each receive a pair of RMS phase voltage signals and output a signal indicative of a difference between the received pair of RMS phase voltage signals; at least three absolute value devices that each receive a respective difference from a respective difference device and output an absolute value of the difference as an error signal; a comparison logic that receives the error signals, compares combinations of the error signals, and outputs a logic high value for any phase in which an inter-circuit fault is detected; and an interrupt device responsive to a logic high value from the comparison logic to interrupt operation of the multiphase generator. ### Claim 2 (depends on 1) The system of claim 1, further comprising a negative sequence over-voltage block for determining, based on the sampled phase voltages, a negative sequence voltage and determining if the negative sequence voltage is greater than a threshold. ### Claim 3 (depends on 1) The system of claim 1, wherein the at least three difference devices are included in a level detection block that further includes an unbalance de-sensitizer for comparing the sampled phase voltages and determining if an unbalance between the sampled phase voltages is within a pre-defined limit. ### Claim 4 (depends on 1) The system of claim 1, wherein the plurality of pre-defined blocks includes a directional element for determining, based on the sampled phase voltages and currents, if a fault is within the generator stator. ### Claim 5 (depends on 1) The system of claim 1, wherein the plurality of pre-defined blocks includes a ground fault de-sensitizer for determining, based on the sampled phase voltages, if a fault is a ground fault. ### Claim 6 (depends on 1) The system of claim 1, wherein the plurality of pre-defined blocks includes a phase-to-phase fault de-sensitizer for determining, based on the sampled phase voltages, if a fault is a phase-phase fault. ### Claim 7 A computer program comprising program code embodied in at least one non-transitory computer-readable medium, which when executed, enables a computer system to implement a method of detecting inter-circuit faults within a generator stator, the method comprising: sampling phase voltages of the generator stator; sampling phase currents of the generator stator; enabling, based on the sampled phase voltages and currents, an inter-circuit fault detection scheme; determining, in response to the enabling, a plurality of differences between the sampled phase voltages; and comparing, in response to the enabling, each of the differences of the sampled phase voltages and determining, based on the differences, an inter-circuit fault within at least one phase of the generator stator. ### Claim 8 (depends on 7) The computer program of claim 7, further comprising determining a negative sequence voltage, based on the sampled phase voltages, and determining if the negative sequence voltage is higher than a threshold. ### Claim 9 (depends on 7) The computer program of claim 7, further comprising comparing the sampled phase voltages, and determining if an unbalance between the sampled phase voltages is within a pre-defined limit. ### Claim 10 (depends on 9) The computer program of claim 9, wherein comparing each of the differences of the sampled phase voltages is further in response to determining that the balance between the sampled phase voltages is within the pre-defined limit. ### Claim 11 (depends on 7) The computer program of claim 7, further comprising filtering, using a timer block, to ensure isolation of a generator under a sustained inter-circuit fault. ### Claim 12 (depends on 7) The computer program of claim 7, wherein enabling the inter-circuit fault detection scheme further comprises: determining, based on the sampled phase voltages and current, if a fault is within the generator stator. ### Claim 13 (depends on 7) The computer program of claim 7, wherein enabling the inter-circuit fault detection scheme further comprises: determining, based on the sampled phase voltages, if a fault is a ground fault. ### Claim 14 (depends on 7) The computer program of claim 7, wherein enabling the inter-circuit fault detection scheme further comprises: determining, based on the sampled phase voltages, if a fault is a phase-phase fault. ### Claim 15 A computer-implemented method for detecting inter-circuit faults within a generator stator, the method comprising: sampling phase voltages of the generator stator; sampling phase currents of the generator stator; enabling, based on the sampled phase voltages and phase currents, an inter-circuit fault detection scheme; determining, in response to the enabling, a plurality of differences between the sampled RMS phase voltages; and comparing, in response to the enabling, each of the differences of the sampled phase voltages and determining, based on the differences, an inter-circuit fault within at least one phase of the generator stator. ### Claim 16 (depends on 15) The computer-implemented method of claim 15, further comprising determining a negative sequence voltage, based on the sampled phase voltages, and determining if the negative sequence voltage is higher than a threshold. ### Claim 17 (depends on 15) The computer-implemented method of claim 15, further comprising comparing the sampled phase voltages, and determining if an unbalance between the sampled phase voltages is within a pre-defined limit. ### Claim 18 (depends on 15) The computer-implemented method of claim 15, wherein enabling the inter-circuit fault detection scheme further comprises: determining, based on the sampled phase voltages and current, if a fault is within the generator stator. ### Claim 19 (depends on 15) The computer-implemented method of claim 15, wherein enabling the inter-circuit fault detection scheme further comprises: determining, based on the sampled phase voltages, if a fault is a ground fault. ### Claim 20 (depends on 15) The computer-implemented method of claim 15, wherein enabling the inter-circuit fault detection scheme further comprises: determining, based on the sampled phase voltages, if a fault is a phase-phase fault.