EP0164711A2
Expired / Lapsed
EP
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Method for detection and location of a fault point on a power transmission line and device for carrying out the method
Assignee: ABB Norden Holding AB
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Filing: 1985-06-08
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Granted: —
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Expires: 2005-06-08
Abstract
Abstract Method for detection and location of a fault point on a power transmission line and device for carrying out the method. Method and device are based on voltage waves (u + ) emitted from a measuring point towards a fault point and corresponding waves (u-) reflected from the fault point, which are included in a travelling wave model of the transmission line. The invention comprises a measurement ofthe instantaneous values of the current and the voltage at the end point of the transmission line, for example at a station, at certain regular intervals. Based on these measured values and with the aid of the travelling wave model it is possible to calculate the voltage (u,, u 2 , .... u n ) at a number of control points (d,, d 2 , ... d n ) along the transmission line. If the line is energized and the calculated control voltages at two control points have different signs during a time longer than a time corresponding to normal phase difference between the two voltages, there is a fault on the line between these two points. By interpolation it is possible, based on the distance between the two points and the calculated control voltages, to locate the fault point in case of low resistance faults.
Inventors
- 👤 Gunnar Dipl.-Ing. Nimmersjö
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-10 01:40
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/08; G01R31/081; G01R31/085; H; H02; H02H; H02H7/00; H02H7/26; H02H7/265
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
278 words
Method for detection and location of a fault point on a power transmission line included in a single-phase, three-phase or multi-phase distribution system, whereby the instantaneous values of the current and the voltage are measured in each phase at the end point of the transmission line and the measured values are stored in a shift register, characterized in that a control voltage (u 1 , u 2 , ... u j , ... u n ) at a number of control points (1, 2, ... j, ... n) along the transmission line is calculated by means of a formula, derived from the travelling wave theory according to where D j = attenuation factor of the travelling wave, τ j = transit time of the travelling wave, u O = voltage at end point of the transmission line i O = current at end point of the transmission line Z = wave impedance that the calculated control voltages along the transmission line and their conceived extension at the two end points are used for detecting and locating a fault point on the transmission line, that a fault is determined if the control voltages at two consecutive control points (j, k) constantly have different signs this fault being located on the transmission line between said two points, that the exact location of the fault on the transmission line is determined as that point on the transmission line where the control voltage is constantly zero, this fault point (f) being obtained by interpolation in such a way that the distance between said control points (j, k) is divided in relation to the calculated control voltages (u j , u k ).
Claim 2
Dependent Claim
278 words
Method for detection and location of a fault point on a power transmission line included in a single-phase, three-phase or multi-phase distribution system, whereby the instantaneous values of the current and the voltage are measured in each phase at the end point of the transmission line and the measured values are stored in a shift register, characterized in that a control voltage (u 1 , u 2 , ... u j , ... u n ) at a number of control points (1, 2, ... j, ... n) along the transmission line is calculated by means of a formula, derived from the travelling wave theory according to where D j = attenuation factor of the travelling wave, τ j = transit time of the travelling wave, u O = voltage at end point of the transmission line i O = current at end point of the transmission line Z = wave impedance that the calculated control voltages along the transmission line and their conceived extension at the two end points are used for detecting and locating a fault point on the transmission line, that a fault is determined if the control voltages at two consecutive control points (j, k) constantly have different signs this fault being located on the transmission line between said two points, that the exact location of the fault on the transmission line is determined as that point on the transmission line where the control voltage is constantly zero, this fault point (f) being obtained by interpolation in such a way that the distance between said control points (j, k) is divided in relation to the calculated control voltages (u j , u k ).
Claim 3
Dependent Claim
65 words
Method according to claim 1, characterized in that in the calculations of the control voltages there are used measured current and voltage values at the times t + τ k and t - τ k , where ^Ck is the transit time of a wave -on the transmission line from the measuring point to the control point k, with k running from 0 to n.
Claim 4
Dependent Claim
44 words
Method according to claim 1 or 2, characteriz-ed in that for three-phase and multi-phase systems, the measured current and voltage values are transformed to independent modal values, which are used when calculating the control voltages in accordance with the formula stated in claim 1.
Claim 5
Dependent Claim
25 words
Method according to any of the preceding claims, cha-racterized in that the modally calculated voltages are returned by inverse transformation to their respective original systems.
Claim 6
Dependent Claim
32 words
Method according to any of the preceding claims, cha-racterized in that the method is used for distance protection by supplementing the distance-measuring protection device with a directional wave detector of known type.
Claim 7
Dependent Claim
213 words
Device for carrying out the method according to any of the preceding claims comprising units (L1, K1) for transformation, shift registers (S3, S4), calculating units (A3), units for inverse transformation (K2) and a fault logic unit (FL) and having access to current and voltage values via the end of the transmission line, characterized in that the transformation units (L1, K1) are arranged to transform measured current and voltage values to modal values, that these transformed values are arranged to be consecutively supplied to the shift registers (S3, S4), from which the values are adapted to be supplied to the calculat- ing units (A3) for calculation of control voltages according to the forlmula where D j = attenuation factor of the travelling wave, τ j = transit time of the travelling wave, u O = voltage at end point of the transmission line i O = current at end point of the transmission line Z = wave impedance, that the units for inverse transformation (K2) are arranged to transform the calculated control voltages to correspond- .ing values in the original systems, and that these values are adapted to be supplied to the fault logic unit (FL) for determining whether a fault exists and for calculating the distance to the fault from the measuring point.
Claim 8
Dependent Claim
17 words
Device according to claim 6, characterized in that the fault logic unit is constructed in analog technique.
Claim 9
Dependent Claim
18 words
Device according to claim 6, character-ized in that the fault detection logic unit is constructed in digital technique.
Claim 10
Dependent Claim
33 words
Device according to any of claim 6 to 8, charac-terized in that the distance-measuring protection device is supplemented with a directional wave detector of known type, thus together forming a distance protection device.
Claim 11
Dependent Claim
28 words
Device according to any of claim 6, 8 or 9 charac-terized in that transformation matrices, shift registers and calculating units consist of programs in one or more microprocessors.
References Cited (Backward Citations)
No citation records indexed.
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