CN102967803B - Fault positioning method of power distribution network based on D type traveling wave principle - Google Patents

Abstract

The invention provides a fault positioning method of a power distribution network based on a D type traveling wave principle. The fault positioning method of the power distribution network comprises the following steps: firstly, selecting a measuring point where the initial fault traveling wave arrives first as the reference measuring point; carrying out fault positioning at a plurality of times through the reference measuring point and other measuring points with the fault traveling wave signals received based on the D type traveling wave distance measuring principle; and thirdly, selecting the maximum value from the results of the plurality of fault positioning actions as the final fault positioning result. Compared with the conventional method, the fault positioning method of the power distribution network has the advantages that the fault section does not need to be determined, and the fault positioning of the whole power distribution network is directly carried out based on the D type traveling wave distance measuring principle, so that the accuracy and reliability in fault positioning can be improved; and once fault occurs in a circuit, little time is spent in finding out and determining the fault point, and therefore, the reliability in power supply is improved; and the fault positioning method of the power distribution network based on D type traveling wave principle has a wide application prospect.

Description

Distribution network fault location method based on D-type traveling wave principle

technical field

The invention belongs to the technical field of electric power system protection, and in particular relates to a fault location method of a distribution network based on a D-type traveling wave principle.

Background technique

Quickly and accurately determining the location of the fault point of the distribution line can speed up the repair of permanent faults, eliminate hidden dangers in time to avoid the recurrence of a large number of transient faults, and is of great significance to ensure the safety, stability and economic operation of the power system.

At present, many methods have been proposed at home and abroad for the fault location of distribution network, mainly including impedance method, S injection method, intelligent method, "fault indicator" technology, feeder automation technology and traveling wave method. The impedance method is greatly affected by line impedance, load and power supply parameters. For distribution lines with multiple branches, the impedance method cannot exclude false fault points. The energy of the injected signal of the S-injection method is limited. If the fault point is grounded through a large resistance, or the fault point is far away from the beginning of the line, the signal will be very weak and cannot be accurately measured. Smart methods are greatly influenced by the knowledge base and network structure. Although the "fault indicator" technology has been put into practical use, the effect of the ground fault indicator is not very satisfactory, the accuracy rate is not high, and there is often no response when a single-phase ground fault occurs in the power grid. Feeder automation technology cannot accurately locate faults, and the interval of fault location is affected by the installation density of feeder automation equipment.

The principle of traveling wave method can be divided into single-ended principle and double-ended principle. The single-ended principle distance measurement uses the time difference between the reflected wave and the incident wave to calculate the fault distance. However, in the distribution network, due to its many branches, after a fault occurs, the fault traveling wave will undergo complex refraction and reflection in the line, and it is impossible to distinguish the reflected traveling wave at the fault point and the branch point of the line. At present, the principle of single-ended traveling wave ranging is still difficult to automatically give correct ranging results, and it still cannot be used alone in the distribution network. The distance measurement of the double-terminal principle is to calculate the fault location by calculating the time difference between the arrival of the fault traveling wave at both ends of the line. The distance measurement accuracy is basically not affected by the fault location, fault type, line length, grounding resistance and other factors of the line. However, theoretical analysis and practical application show that although the double-terminal traveling wave principle can automatically give fault location results online, the reliability and accuracy are affected by the error of the given line length and the timing system. When there is a large error in the given line length or the timing system is not working properly, the ranging result of the double-terminal principle is not credible.

Contents of the invention

The purpose of the present invention is to provide a distribution network fault location method based on the D-type traveling wave principle that can overcome the above-mentioned defects and is suitable for distribution lines. The technical solution is:

(1) Select reference measurement points: use i=1,2,3,...,m,...,n to represent the measurement points located at the end of each feeder line in the distribution network, and T _i represents the time synchronization received when a fault occurs The fault initial traveling wave time; where m is the measurement point where the fault initial traveling wave arrives first, and the arrival time of the fault initial traveling wave corresponding to this point is T _m , which is selected as the reference measurement point;

(2) Preliminary fault location: k represents the fault point of the distribution network. After selecting the reference measurement point m, based on the D-type traveling wave principle, the possible location of the fault point is calculated by using the reference measurement point and the line where the measurement point i is located, namely Distance l _ki from fault point k to reference measurement point: Where l _mi is the length of the line from the reference measurement point to the measurement point i, and v is the propagation velocity of the traveling wave in the line;

(3) Determination of the fault location result: the maximum value can be selected from the preliminary fault location result as the final precise fault location result, that is, the distance l _km from the fault point k to the reference measurement point is: l _km = max(l _ki ).

The working principle is: According to the propagation path of the fault traveling wave, when a fault occurs in the distribution network, the first fault traveling wave received by the measurement point at the end of each feeder should be the initial fault traveling wave sent by the fault point, and the time is accurate In the case of synchronization, it corresponds to the arrival time of the fault initial traveling wave, and the measurement point at the end of the feeder closest to the fault point first detects the fault initial traveling wave signal. If this measurement point is used as a reference, based on the D-type traveling wave principle, the possible distance from the fault point to the reference measurement point can be calculated by using the reference measurement point and the line where the rest of the measurement points where the fault initial traveling wave signal is detected are located. According to the propagation process of traveling waves, it can be seen that when the fault point is not on the line using the D-type traveling wave principle, the calculated distance from the fault point to the reference measurement point must be smaller than that of the fault point on the line using the D-type traveling wave principle The calculated distance from the fault point to the reference measurement point. Obviously, the maximum value among all the calculated distances from the fault point to the reference measurement point is the distance from the final fault point to the reference measurement point. In this way, the traveling wave fault location of the distribution network is realized.

Compared with the prior art, the present invention has the advantages that: the final fault location result can be given by the double-ended principle, and the influence of the branch line in the distribution network on the single-ended principle fault location can be eliminated, the calculation is simple, and the consistency of the method is good , there is no need to judge the fault branch, the fault location accuracy is improved, and the reliability and accuracy of the power line traveling wave fault location are greatly improved. When a line fails, the fault point can be determined without spending a lot of time, which improves the reliability of power supply and has broad application prospects.

Description of drawings

Fig. 1 is a schematic diagram of the propagation process of the fault transient traveling wave in the topology diagram of the distribution network according to the present invention.

In the figure: 1 is the measurement point at the power supply end, and the length of the branch line where it is located is _l1 ; measurement point 2, measurement point 3, ..., measurement point 13, and measurement point 14 are the measurement points at the end of each line in the distribution network, where The lengths of the branch lines are l ₂ , l ₃ , ..., l ₁₃ , l ₁₄ ; A, B, C, ..., J, K are the branch points of the line, and the distances between the two adjacent points are l _AB , l _BC ,..., l _IJ , l _JK ; S is the power access point, and the distances from branch point A and branch point F are l _SA and l _SF respectively; k is the fault point; the direction of the arrow in the figure represents the propagation of the fault initial traveling wave path and direction of propagation.

Detailed ways

Below in conjunction with accompanying drawing, the present invention is described as follows with certain simulation example:

Embodiment 1: the voltage level is 10kV, the measurement point 1 is the measurement point of the power supply end, and the length of the branch line where it is located is l ₁ =100m; the measurement point 2, the measurement point 3, the measurement point 4, the measurement point 5, the measurement point 6, Measuring point 7, measuring point 8, measuring point 9, measuring point 10, measuring point 11, measuring point 12, measuring point 13, and measuring point 14 are the measuring points at the end of each line in the distribution network, and the lengths of the branch lines where they are located are respectively l ₂ =100m, l ₃ =150m, l ₄ =100m, l ₅ =200m, l ₆ =300m, l ₇ =200m, l ₈ =100m, l ₉ =100m, l ₁₀ =200m, l ₁₁ =200m, l ₁₂ = 200m, l ₁₃ = 200m, l ₁₄ = 400m; A, B, C, ..., J, K are the branch points of the line, and the distances between the two adjacent points are l _AB = 500m, l _BC = 800m, l _CD ＝1500m, l _DE ＝1000m, l _FG ＝500m, l _GH ＝100m, l _GI ＝1500m, l _IJ ＝1000m, l _JK ＝100m; The distances are l _SA = 1500m and l _SF = 500m; the distance from the actual fault point k to the measurement point 2 is 50m, and the wave velocity of the traveling wave in the transmission line is v = 3×10 ⁸ m/s. A fault occurs at t=0.025s.

Step 1. Select the reference measurement point: After the fault occurs, the initial travel time of the fault received by each measurement point under the condition of time synchronization is: T ₁ = 25005.5μs, T ₂ = 25000.2μs, T ₃ = 25002.4μs, T ₄ =25004.9 μs, T ₅ =25010.2 μs, T ₆ =25013.9 μs, T ₇ =25013.6 μs, T ₈ =25007.2 μs, T ₉ =25009.2 μs, T ₁₀ =25009.5 μs, T ₁₁ =25014.2 μs, T _017.5 =25 μs, T ₁₃ =25017.9μs, T ₁₄ =25018.5μs; From the above, it can be seen that the measurement point 2 is the measurement point where the fault initial traveling wave arrives first, and the arrival time of the fault initial traveling wave corresponding to this point is T ₂ =25000.2μs , so this point is selected as the reference measurement point;

Step 2. Preliminary fault location: After selecting measurement point 2 as the reference measurement point, based on the D-type traveling wave principle, use the reference measurement point and the line where measurement point 1 is located to calculate the possible location of the fault point, that is, the distance from the fault point to the measurement point l _k1 : $l_{k1}=\frac{l_{\mathrm{twenty\; one}}+v(T_2-T_1)}{2}=\frac{l_1+l_2+l_{\mathrm{SA}}+v(T_2-T_1)}{2}=55m,$ Wherein l ₂₁ is the length of the line where the reference measurement point and measurement point 1 are located; the same method can be used to calculate the distance from the fault point to the measurement point 2 by using the same method from the reference measurement point to the line where other measurement points are located: l _k2 = 0m, l _k3 = 45m, l _k4 = 45m, l _k5 = 50m, l _k6 = 45m, l _k7 = 40m, l _k8 = 50m, l _k9 = 50m, l _k10 = 55m, l _k11 = 50m, l _k12 = 55m, l _k13 = 45m, l _k14 = 55m;

Step 3. Determination of fault location results: select the maximum value from the preliminary fault location results as the final precise fault location result, that is, the distance l _k2 from the fault point to the reference measurement point is: l _k2 = max(l _ki ) = l _k1 =55m, the fault point is positioned at measuring point 2 and the distance of measuring point 1 place line to the reference measuring point is 55m like this, compared with actual fault point, the measuring error of the present invention is 5m.

Embodiment 2: the voltage level is 10kV, the measurement point 1 is the measurement point of the power supply end, and the length of the branch line where it is located is l ₁ =100m; the measurement point 2, the measurement point 3, the measurement point 4, the measurement point 5, the measurement point 6, Measuring point 7, measuring point 8, measuring point 9, measuring point 10, measuring point 11, measuring point 12, measuring point 13, and measuring point 14 are the measuring points at the end of each line in the distribution network, and the lengths of the branch lines where they are located are respectively l ₂ =100m, l ₃ =150m, l ₄ =100m, l ₅ =200m, l ₆ =300m, l ₇ =200m, l ₈ =100m, l ₉ =100m, l ₁₀ =200m, l ₁₁ =200m, l ₁₂ = 200m, l ₁₃ = 200m, l ₁₄ = 400m; A, B, C, ..., J, K are the branch points of the line, and the distances between the two adjacent points are l _AB = 500m, l _BC = 800m, l _CD ＝1500m, l _DE ＝1000m, l _FG ＝500m, l _GH ＝100m, l _GI ＝1500m, l _IJ ＝1000m, l _JK ＝100m; The distances are l _SA = 1500m and l _SF = 500m; the actual fault point k is located in the AB section and the distance from measurement point 2 is 300m, and the wave velocity v = 3×10 ⁸ m/s. A fault occurs at t=0.025s.

Step 1. Select the reference measurement point: After the fault occurs, the initial travel time of the fault received by each measurement point under the condition of time synchronization is: T ₁ = 25006.0μs, T ₂ = 25001.0μs, T ₃ = 25001.5μs, T ₄ =25004.0μs, T ₅ =25009.4μs, T ₆ =25013.0μs, T ₇ =25012.7μs, T ₈ =25007.7μs, T ₉ =25009.7μs, T ₁₀ =25010.0μs, T ₁₁ =25014.7μs, T _018.012 =25 μs, T ₁₃ =25018.4μs, T ₁₄ =25019.0μs; From the above, it can be seen that the measurement point 2 is the measurement point where the fault initial traveling wave arrives first, and the arrival time of the fault initial traveling wave corresponding to this point is T ₂ =25001.0μs , so this point is selected as the reference measurement point;

Step 2. Preliminary fault location: After selecting measurement point 2 as the reference measurement point, based on the D-type traveling wave principle, use the reference measurement point and the line where measurement point 1 is located to calculate the possible location of the fault point, that is, the distance l from the fault point to the measurement point _k1 : $l_{k1}=\frac{l_{\mathrm{twenty\; one}}+v(T_2-T_1)}{2}=\frac{l_1+l_2+l_{\mathrm{SA}}+v(T_2-T_1)}{2}=100m,$ Wherein l ₂₁ is the length of the line at measuring point 2 and measuring point 1; use the same method to calculate the distance from the fault point to measuring point 2 by using the same method from the reference measuring point to the line at other measuring points: l _k2 = 0m, l _k3 = 300m, l _k4 = 300m, l _k5 = 290m, l _k6 = 300m, l _k7 = 295m, l _k8 = 95m, l _k9 = 95m, l _k10 = 100m, l _k11 = 95m, l _k12 = 100m, l _k13 = 90m, l _k14 = 100m;

Step 3. Determination of the fault location result: the maximum value can be selected from the preliminary fault location result as the final precise fault location result, that is, the distance l _k2 from the fault point to the measurement point 2 is: l _k2 =max(l _ki )=l _k3 =300m, fault point is positioned at measuring point 2 and the distance of measuring point 3 place line to measuring point 2 is 300m like this, compared with actual fault point, the measuring error of the present invention is 0m.

Embodiment 3: the voltage level is 10kV, 1 is the measurement point at the power supply end, and the length of the branch line where it is located is l ₁ =100m; 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 and 14 are the measurement points at the end of each line in the distribution network, and the lengths of the branch lines where they are located are l ₂ =100m, l ₃ =150m, l ₄ =100m, l ₅ =200m, l ₆ =300m, l ₇ = 200m, l ₈ =100m, l ₉ =100m, l ₁₀ =200m, l ₁₁ =200m, l ₁₂ =200m, l ₁₃ =200m, l ₁₄ =400m; A, B, C, ..., J, K are lines , the distance between two adjacent points is l _AB =500m, l _BC =800m, l _CD =1500m, l _DE =1000m, l _FG =500m, l _GH =100m, l _GI =1500m, l _IJ = 1000m, l _JK = 100m; S is the power access point, and the distances from branch point A and branch point F are l _SA = 1500m and l _SF = 500m; the actual fault point k is located in branch point B, and the traveling wave is in the transmission line The wave velocity in v=3×10 ⁸ m/s. A fault occurs at t=0.025s.

Step 1. Select the reference measurement point: After the fault occurs, the initial travel time of the fault received by each measurement point under the condition of time synchronization is: T ₁ = 25007.0μs, T ₂ = 25002.0μs, T ₃ = 25000.5μs, T ₄ =25003.0 μs, T ₅ =25008.4 μs, T ₆ =25012.0 μs, T ₇ =25011.7 μs, T ₈ =25008.7 μs, T ₉ =25010.7 μs, T ₁₀ =25011.0 μs, T ₁₁ =25015.7 μs, T _019.05 =25 μs, T ₁₃ =25019.4μs, T ₁₄ =25020.0μs; From the above, it can be seen that the measurement point 3 is the measurement point where the fault initial traveling wave arrives first, and the arrival time of the fault initial traveling wave corresponding to this point is T ₃ =25000.5μs , so this point is selected as the reference measurement point;

Step 2. Preliminary fault location: After selecting measurement point 3 as the reference measurement point, based on the D-type traveling wave principle, use the reference measurement point and the line where measurement point 1 is located to calculate the possible location of the fault point, that is, the distance from the fault point to measurement point 3 l _k31 : $l_{k31}=\frac{l_{31}+v(T_3-T_1)}{2}=\frac{l_1+l_3+l_{\mathrm{SA}}+l_{\mathrm{AB}}+v(T_3-T_1)}{2}=150m,$ Wherein l ₃₁ is the length of the line at measuring point 3 and measuring point 1; use the same method to calculate the distance from the fault point to measuring point 3 by using the same method from the reference measuring point to the line at other measuring points: l _k = 150m, l _k33 = 0m, l _k34 = 150m, l _k35 = 140m, l _k36 = 150m, l _{k37 = 145m, l k38 =} 145m, l _k39 = 145m, l _k310 = 150m, l _k311 = 145m, l _k312 = 150m, l _k313 = 140m, l _k314 = 150m;

Step 3. Determination of the fault location result: the maximum value can be selected from the preliminary fault location result as the final precise fault location result, that is, the distance l _k3 from the fault point to the measurement point 3 is: l _k3 =max(l _k3i )=l _k31 =150m, fault point is positioned at measuring point 3 and the distance of measuring point 1 place line to measuring point 3 is 150m like this, compared with actual fault point, the measurement error of the present invention is 0m.

Claims (1)

1., based on an electrical power distribution network fault location method for the capable ripple principle of D type, it is characterized in that adopting following steps:

(1) reference measure point is chosen: with i=1,2,3 ..., m ..., n represents the measurement point being positioned at each feeder terminal of power distribution network, T _ithe fault initial row ripple time that when representing that fault occurs, it receives in time synchronized situation; Wherein m is the measurement point that fault initial row ripple arrives at first, and fault initial row ripple time of arrival of this some correspondence is T _m, choosing this point is reference measure point;

(2) preliminary localization of fault: k represents distribution network failure point, after choosing reference measure point m, based on the capable ripple principle of D type, utilize reference measure point and measurement point i place routine calculation to be out of order apart from possible position respectively, namely trouble spot k is to the distance l of reference measure point _ki: wherein l _mibe the line length of reference measure point to measurement point i, v is row ripple velocity of propagation in the line;

(3) localization of fault result is determined: from preliminary localization of fault result, choose maximal value namely can be used as the accurate positioning result of final fault, namely trouble spot k is to the distance l of reference measure point _kmfor: l _km=max (l _ki).