# US 11,307,237 B2 · Method for fault location to single-terminal traveling wave > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,307,237 B2 - Document ID: US11307237B2 - Status: Granted - Kind: B2 - Application number: 17/013,881 - Filed: 2020-09-08 - Published: 2021-05-27 - Granted: 2022-04-19 - Earliest claimed: 2019-11-25 - Assignees: Shandong University of Technology - Applicants: Shandong University of Technology - Inventors: Yu Chen; Jinghua Wang; Bingyin Xu; Ke Peng; Wei Wang - Web page: https://patentgrep.com/patent/US11307237B2 ## CPC - G01R 31/088: {Aspects of digital computing} - G01R 31/085: {in power transmission or distribution lines, e.g. overhead} - G01R 31/11: using pulse reflection methods - H02H 7/265: {making use of travelling wave theory} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - 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) ## Abstract A method for fault location to single-terminal traveling wave includes steps as follows. Step (a): recording a waveform of a traveling wave signal of disturbance by a traveling wave device when a line disturbance occurs. Step (b): performing a phase mode transformation on the waveform recorded by the step (a), so as to obtain components of line mode and zero mode of a fault initial traveling wave, and performing a wavelet transform to decompose the components of the line mode to obtain singularities in the waveform of the traveling wave. Step (c): calculating a wavefront slope k of the components of the line mode of the fault initial traveling wave. Step (d): computing a preliminary fault distance D according to the slope k computed in the step (c). Step (e): confirming a fault point according to the preliminary fault distance and wavelet singularities of the components of the line mode. Step (f): end. ## Claims ### Claim 1 A single-terminal traveling wave based fault locating method comprising steps operated by a main site and a plurality of electrical substations connected to the main site via a communication network, each of the electrical substations equipped with a traveling wave recording system, the method comprising: step (a): recording a waveform of a traveling wave signal of a line disturbance by a traveling wave device when the line disturbance occurs; step (b): performing a phase mode transformation on the waveform recorded by the step (a), so as to obtain components of line mode and zero mode of a fault initial traveling wave, and performing a wavelet transform to decompose the components of the line mode to obtain wavelet singularities in the waveform of the traveling wave; step (c): calculating a wavefront slope k of the components of the line mode of the fault initial traveling wave, wherein calculating the wavefront slope k of the components of the line mode of the fault initial traveling wave during the step (c) comprises: defining a wave head corresponding to a maximum value of a first mode which is detected after the wavelet transform of the step (b) as the disturbance initial traveling wave, and normalizing the components of the zero mode of the wave head such that the collected components of the zero mode of the wave head is amplified to a reference value, and rest of values are scaled up, wherein the reference value is 0.5 kA, and wherein the slope of the normalized wave head is computed by selecting points thereof, which is performed by selecting three sampling points from an initial point and linearly fitting the three selected sampling points with a least square method to obtain the slope k; step (d): computing a preliminary fault distance D according to the slope k computed in the step (c); step (e): confirming a fault point according to the preliminary fault distance and the wavelet singularities of the components of the line mode; and step (f): ending the steps. ### Claim 2 (depends on 1) The single-terminal traveling wave based fault locating method of claim 1, wherein the phase mode transformation in the step (b) is performed by applying a Karen Boolean transformation, which has a phase mode transformation matrix as: S = [ 1 1 1 1 - 2 1 1 1 - 2 ] ; S - 1 = 1 3 ⁡ [ 1 1 1 1 - 1 0 1 0 - 1 ] . ### Claim 3 (depends on 1) The single-terminal traveling wave based fault locating method of claim 1, wherein the wavelet transform performed on the components of the line mode is implemented by: { S 2 j ⁢ f ⁡ ( n ) = ∑ k ⁢ h k ⁢ S 2 j ⁢ - 1 ⁢ f ⁡ ( n - 2 j - 1 ⁢ k ) W 2 j ⁢ f ⁡ ( n ) = ∑ k ⁢ g k ⁢ S 2 j - 1 ⁢ f ⁡ ( n - 2 j - 1 ⁢ k ) , where j∈[1, ∞]; S2jf(n) is an approximation component of a result of the wavelet transform; W2jf(n) is a wavelet components of the result of the wavelet transform; {hk}={0.125, 0.375, 0.375, 0.125} (k=−1, 0, 1, 2); and {gk}={−2, 2} (k=0, 1). ### Claim 4 (depends on 1) The single-terminal traveling wave based fault locating method of claim 1, wherein the selecting the initial point comprises: setting a threshold value as 0.1 kA with respect to the components of the zero mode of the wave head of the normalized disturbance initial traveling wave, wherein the initial point is a first point that is greater than the threshold value. ### Claim 5 (depends on 1) The single-terminal traveling wave based fault locating method of claim 1, wherein the least square method is performed by formulas: { y = k ⁢ ⁢ x + b 3 ⁢ b + k ⁢ ∑ i = 1 3 ⁢ x i = ∑ i = 1 3 ⁢ y i b ⁢ ∑ i = 1 3 ⁢ x i + k ⁢ ∑ i = 1 3 ⁢ x i 2 = ∑ i = 1 3 ⁢ y i ⁢ x i . ### Claim 6 (depends on 1) The single-terminal traveling wave based fault locating method of claim 1, wherein computing the preliminary fault distance D in the step (d) is performed by formulas: k = 2 ⁢ 7 ⁢ 0 ⁢ 0 ⁢ D ( - 0.9990 + 0.013 ⁢ 6 ⁢ ρ ) ⁡ ( ρ 1 ⁢ 0 ⁢ 0 ) - 0.4568 , where k is the wavefront slope, D is the fault distance, and ρ is soil resistivity. ### Claim 7 (depends on 1) The single-terminal traveling wave based fault locating method of claim 1, wherein confirming the fault point in the step (e) comprises: according to the preliminary fault distance D computed in the step (d) and the wavelet singularities of the components of the line mode obtained in the step (b), taking D as a center and setting a range as the center ±D*20%, and selecting a wave head of the traveling wave from the range such that a fault distance is obtained by multiplying a time difference between the fault initial traveling wave and a fault point reflection wave by traveling wave propagation velocity, wherein if there is more than one wave head, min(|D−d|) is applied to, and wherein d is disturbance point distance corresponding to the wave head, and then the fault distance is obtained by multiplying the time difference between the fault initial traveling wave and the fault point reflection wave by the traveling wave propagation velocity.