Electric transmission line fault early warning method based on discharge phenomenon

Abstract

The invention discloses a power transmission line fault early warning method based on a discharge phenomenon, and the method comprises the steps: setting a triggering time threshold value of a traveling wave current, collecting the traveling wave current of a power transmission line when the triggering time threshold value is reached, and forming a traveling wave pile of the traveling wave current at different triggering moments; and sending a fault early warning signal according to the similarity, periodicity and co-frequency of the traveling wave current at different triggering moments in the traveling wave pile. The power transmission line fault early warning method is not limited by regions, fault early warning of the power transmission line can be effectively achieved without installing a plurality of detection devices, the operation and maintenance cost is reduced, and the fault early warning efficiency is improved. According to the method, the accuracy of fault early warning is ensured, the robustness of safe operation of the power transmission line is improved, and the method has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of power transmission line fault early warning, and in particular to a power transmission line fault early warning method based on a discharge phenomenon. Background Art

[0002] The operation experience of power transmission lines shows that in addition to instantaneous faults such as lightning strikes and external force damage, there are also cracking, pollution flashover, tree barriers, ice cover, etc. Although these faults account for a lower proportion than lightning strikes and external force damage, they are easy to cause tripping and affect the safe operation of the power grid. At present, patrol personnel mainly rely on detection equipment such as infrared monitors, ultrasonic patrol meters, and ultraviolet monitors to conduct fixed-point inspections of these abnormal faults. However, the above detection equipment cannot perform wide-area real-time monitoring, so it cannot effectively realize fault warning of power transmission lines. Summary of the invention

[0003] The main purpose of the present invention is to provide a fault early warning method for a power transmission line based on a discharge phenomenon, so as to realize a wide-area fault early warning for the power transmission line.

[0004] To achieve the above-mentioned purpose, the present invention proposes a fault early warning method for a power transmission line based on a discharge phenomenon, comprising the steps of:

[0005] Setting a trigger time threshold of the traveling wave current, and when the trigger time threshold is reached, collecting the traveling wave current of the transmission line to form a traveling wave pile of traveling wave currents at different triggering moments;

[0006] A fault warning signal is issued according to the similarity, periodicity and same frequency of the traveling wave current at different triggering moments in the traveling wave reactor.

[0007] Optionally, the step of “issuing a fault warning signal according to the similarity, periodicity and frequency co-incidence of the traveling wave currents at different triggering moments in the traveling wave reactor” includes:

[0008] Determine whether the traveling wave currents in the traveling wave reactor have similarity, determine whether the traveling wave currents have periodicity, and determine whether the traveling wave currents have the same frequency;

[0009] When the traveling wave currents at different triggering moments in the traveling wave reactor have similarity, periodicity and co-frequency, a fault warning signal is issued.

[0010] Optionally, the step of “determining whether the traveling wave currents in the traveling wave reactor have similarity” includes:

[0011] The two traveling wave currents are normalized respectively to obtain the normalized two traveling wave currents;

[0012] The similarity is calculated based on the two normalized traveling wave currents, and whether the traveling wave currents in the traveling wave stack have similarity is determined according to the similarity.

[0013] Optionally, in the step of “calculating the similarity based on the normalized two traveling wave currents”, the similarity calculation formula is:

[0014]

[0015] In the formula, ρ represents similarity, i represents current dimension, and I j (i) represents the current in the i-th dimension at the trigger time j, I m (i) represents the current in the i-th dimension at the triggering moment m.

[0016] Optionally, the step of “determining whether the traveling wave currents in the traveling wave reactor have similarity according to the similarity” includes:

[0017] It is determined whether the similarity is greater than 0.7. If the similarity is greater than 0.7, the traveling wave currents have similarity; if the similarity is not greater than 0.7, the traveling wave currents do not have similarity.

[0018] Optionally, the step of “determining whether the traveling wave current has periodicity” includes:

[0019] The time difference between two traveling wave currents at adjacent triggering moments at the same moment is calculated, and whether the traveling wave current has periodicity is determined based on the time difference.

[0020] Optionally, the step of “determining whether the traveling wave current has periodicity according to the time difference” includes:

[0021] Determine whether the time difference satisfies one of the following relationships. If so, it is determined that the traveling wave current has periodicity. If not, it is determined that the traveling wave current does not have periodicity. The relationship is:

[0022] (10-Δt)ms≤|T m -T m-1 |≤(10+Δt)ms;

[0023] (20-Δt)ms≤|T m -T m-1 |≤(20+Δt)ms;

[0024] In the relationship, T m represents the time of the traveling wave current at the triggering moment m; T m-1 It represents the time of the traveling wave current at the triggering moment m-1, Δt represents the time margin parameter, and Δt is not greater than 2ms.

[0025] Optionally, the step of “determining whether the traveling wave current has the same frequency” includes:

[0026] The frequency difference between two traveling wave currents at adjacent triggering moments is calculated, and whether the traveling wave currents have the same frequency is determined based on the frequency difference.

[0027] Optionally, the step of “determining whether the traveling wave current has the same frequency according to the frequency difference” includes:

[0028] Determine whether the frequency difference satisfies the following expression. If so, it is determined that the traveling wave current has the same frequency; if not, it is determined that the traveling wave current does not have the same frequency. The expression is:

[0029] |f m -f m-1 |≤(Δf)Hz;

[0030] In the expression, f m represents the frequency of the traveling wave current at the triggering time m, f m-1 represents the frequency of the traveling wave current at the triggering time m-1, Δf represents the frequency margin parameter, and Δf is not greater than 100 Hz.

[0031] Optionally, the step of “collecting traveling wave current of a transmission line” includes:

[0032] The high-frequency traveling wave signal of the transmission line is collected, and the high-frequency traveling wave signal is extracted to collect the traveling wave current.

[0033] The technical solution of the present invention is based on the commonality of discharge phenomena in the process of abnormal fault state development. The traveling wave current of the transmission line is automatically collected by setting the trigger time threshold of the traveling wave current to form a traveling wave stack of traveling wave currents at different triggering moments. A fault warning signal is issued according to the similarity, periodicity and frequency co-occurrence of the traveling wave currents at different triggering moments in the traveling wave stack, thereby achieving fault warning for various abnormal states (such as cracking, pollution flashover, tree barriers, ice cover, etc.). Since the high-frequency traveling wave current generated by the discharge has a wide area, the present invention is not limited by geographical restrictions, and can effectively realize the fault warning of the transmission line without installing multiple detection equipment, thereby reducing the operation and maintenance cost and improving the efficiency of fault warning. While ensuring the accuracy of fault warning, the present invention improves the robustness of safe operation of the transmission line and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0035] Figure 1 It is a flow chart of the fault early warning method of the power transmission line based on the discharge phenomenon of the present invention;

[0036] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0039] In one embodiment of the present invention, a fault warning method for a power transmission line based on a discharge phenomenon includes the steps of: setting a trigger time threshold of a traveling wave current, collecting the traveling wave current of the transmission line when the trigger time threshold is reached, and forming a traveling wave stack of traveling wave currents at different triggering moments; and issuing a fault warning signal according to the similarity, periodicity and frequency co-occurrence of the traveling wave currents at different triggering moments in the traveling wave stack. It should be noted that the present invention also includes collecting high-frequency traveling wave signals of the transmission line before setting the trigger time threshold of the traveling wave current. When cracking, flashover, tree barriers, ice and other faults occur in the transmission line, abnormal discharge occurs in the transmission line and a high-frequency traveling wave signal is generated. The present invention collects the traveling wave current through the obtained high-frequency traveling wave signal. When the trigger time threshold is reached, the traveling wave current is collected once. The trigger time threshold is the trigger moment at a certain time interval. Of course, the specific interval time can be adjusted as needed, thereby forming a traveling wave stack of traveling wave currents at different triggering moments. Based on the commonality of the traveling wave current of abnormal discharge caused by cracking, flashover, tree barriers, icing and other faults, that is, according to the similarity, periodicity and frequency co-occurrence of the traveling wave current at different triggering moments in the traveling wave reactor, a fault warning signal is issued, thereby achieving fault warning for various abnormal conditions (such as cracking, flashover, tree barriers, icing, etc.), and ensuring the accuracy of fault warning. At the same time, since the high-frequency traveling wave current generated by the discharge has a wide area, the present invention is not limited by geographical restrictions, and can effectively realize fault warning of the transmission line without installing multiple detection equipment, reducing the operation and maintenance cost and improving the efficiency of fault warning. While ensuring the accuracy of fault warning, the present invention improves the robustness of safe operation of the transmission line and has broad application prospects.

[0040] To supplement, the embodiment of the present invention collects traveling wave currents at different triggering moments, and calculates the similarity, periodicity and frequency co-occurrence of two traveling wave currents at different triggering moments in sequence to issue a fault warning signal. Of course, the two calculated traveling wave currents can be the traveling wave current at the current moment and the traveling wave current at any previous moment. The embodiment of the present invention is not limited to this, and the above are all within the protection scope of the embodiment of the present invention.

[0041] In one embodiment of the present invention, the step of "issuing a fault warning signal according to the similarity, periodicity and co-frequency of the traveling wave current at different triggering moments in the traveling wave stack" includes: determining whether the traveling wave current in the traveling wave stack has similarity, determining whether the traveling wave current has periodicity, and determining whether the traveling wave current has co-frequency; when the traveling wave current at different triggering moments in the traveling wave stack has similarity, periodicity and co-frequency, a fault warning signal is issued. It should be noted that if the traveling wave current at different triggering moments has similarity, periodicity and co-frequency, a fault warning signal is generated, otherwise, no fault warning signal is issued. Of course, the embodiment of the present invention can reflect the similarity through similarity, and set a preset value reflecting the similarity. The preset value can be 0.7. When the calculated similarity is greater than 0.7, it is determined that the traveling wave currents at different triggering moments have similarity; when the calculated similarity is not greater than 0.7, it is determined that the traveling wave currents at different triggering moments do not have similarity. Similarly, the periodicity can be reflected by the time difference, and the time parameters reflecting the periodicity are set. When the calculated time difference is within the range of the time parameters, it is determined that the traveling wave current at different triggering moments has periodicity; when the calculated time difference is not within the range of the time parameters, it is determined that the traveling wave current at different triggering moments does not have periodicity. Similarly, the same frequency can be reflected by the frequency difference, and the frequency margin parameter reflecting the same frequency is set. The frequency margin parameter can be 100Hz. Of course, the setting of specific parameters can be adjusted according to actual conditions, and the embodiments of the present invention are not limited thereto. The above are all within the protection scope of the embodiments of the present invention.

[0042] In one embodiment of the present invention, the step of "determining whether the traveling wave currents in the traveling wave stack are similar" includes: normalizing the two traveling wave currents respectively to obtain two normalized traveling wave currents; calculating the similarity based on the two normalized traveling wave currents, and determining whether the traveling wave currents in the traveling wave stack are similar based on the similarity. It should be noted that the two traveling wave currents in the present invention are traveling wave currents at two different triggering times. Of course, they can be two traveling wave currents at adjacent triggering moments, or two traveling wave currents at intervals. The embodiments of the present invention are not limited to this, and all of the above are within the protection scope of the embodiments of the present invention. The present invention calculates the similarity of the normalized traveling wave currents to eliminate the similarity changes caused by non-fault anomalies such as load changes, thereby improving the accuracy of abnormal discharge identification and achieving effective fault warning for transmission lines.

[0043] In one embodiment of the present invention, in the step of “calculating the similarity based on the normalized two traveling wave currents”, the similarity calculation formula is:

[0044]

[0045] In the formula, ρ represents similarity, i represents current dimension, and I j(i) represents the current in the i-th dimension at the trigger time j, I m (i) represents the current in the i-th dimension at the trigger time m. It should be noted that the present invention calculates the similarity by summing the squares of the currents in different dimensions, thereby better analyzing the contribution of the currents in each dimension, thereby obtaining a more accurate measure of similarity, which is conducive to achieving effective fault warning for the transmission line.

[0046] In one embodiment of the present invention, the step of "determining whether the traveling wave currents in the traveling wave stack have similarity according to the similarity" includes: judging whether the similarity is greater than 0.7, if the similarity is greater than 0.7, the traveling wave currents have similarity; if the similarity is not greater than 0.7, the traveling wave currents do not have similarity. In general, the calculated value of the similarity is less than 1, when the similarity is greater than 0.7, the two traveling wave currents are actually correlated, and the two traveling wave currents are similar; when the similarity is not greater than 0.7, the two traveling wave currents are slightly correlated, and the two traveling wave currents are not similar.

[0047] In one embodiment of the present invention, the step of "determining whether the traveling wave current has periodicity" includes: calculating the time difference between two traveling wave currents at adjacent triggering moments at the same moment, and determining whether the traveling wave current has periodicity according to the time difference. It should be noted that the same moment may be a wave head moment, and the time difference between the two traveling wave currents at the wave head moment is calculated to determine whether the traveling wave current has periodicity. Specifically, when the time difference is within the range of the time parameter, it is determined that the traveling wave current has periodicity; when the time difference is not within the range of the time parameter, it is determined that the traveling wave current does not have periodicity.

[0048] In one embodiment of the present invention, the step of "determining whether the traveling wave current has periodicity according to the time difference" includes: determining whether the time difference satisfies one of the following relationship equations, if so, determining that the traveling wave current has periodicity, if not, determining that the traveling wave current does not have periodicity; the relationship equation is:

[0049] (10-Δt)ms≤|T m -T m-1 |≤(10+Δt)ms;

[0050] (20-Δt)ms≤|T m -T m-1 |≤(20+Δt)ms;

[0051] In the relationship, T m represents the time of the traveling wave current at the triggering moment m; T m-1The time of the traveling wave current at the triggering time m-1 is represented by Δt, which is not greater than 2ms. Of course, the present invention can also calculate the time difference between two traveling wave currents at the interval time, and the embodiments of the present invention are not limited thereto, and the above are all within the protection scope of the embodiments of the present invention.

[0052] In one embodiment of the present invention, the step of "determining whether the traveling wave current has the same frequency" includes: calculating the frequency difference between two traveling wave currents at adjacent triggering moments, and determining whether the traveling wave current has the same frequency according to the frequency difference. It should be noted that whether the traveling wave current has the same frequency is determined according to whether the frequency difference is greater than the frequency margin parameter. Specifically, when the frequency difference is not greater than the frequency margin parameter, it is determined that the traveling wave current has the same frequency; when the frequency difference is greater than the frequency margin parameter, it is determined that the traveling wave current does not have the same frequency. Preferably, the frequency margin parameter is 100Hz.

[0053] In one embodiment of the present invention, the step of "determining whether the traveling wave current has the same frequency according to the frequency difference" includes: determining whether the frequency difference satisfies the following expression, if so, determining that the traveling wave current has the same frequency; if not, determining that the traveling wave current does not have the same frequency; the expression is:

[0054] f m -f m-1 |≤(Δf)Hz;

[0055] In the expression, f m represents the frequency of the traveling wave current at the triggering time m, f m-1 represents the frequency of the traveling wave current at the triggering time m-1, Δf represents the frequency margin parameter, Δf≤100Hz. It should be noted that the frequency margin parameter can be adjusted with reference to actual conditions, and the embodiments of the present invention are not limited thereto, and the above are all within the protection scope of the embodiments of the present invention.

[0056] In one embodiment of the present invention, a fault warning method for a power transmission line based on a discharge phenomenon includes the steps of: collecting a high-frequency traveling wave signal of the transmission line, setting a trigger time threshold of the traveling wave current, and when the trigger time threshold is reached, extracting the high-frequency traveling wave signal to collect the traveling wave current, forming a traveling wave stack of traveling wave currents at different triggering moments; and issuing a fault warning signal according to the similarity, periodicity and frequency co-occurrence of the traveling wave currents at different triggering moments in the traveling wave stack. The present invention automatically triggers the automatic collection of the traveling wave current to form a traveling wave stack of traveling wave currents at different triggering moments, thereby automatically warning of faults according to the similarity, periodicity and frequency co-occurrence of the traveling wave currents at different triggering moments, thereby realizing real-time hidden danger monitoring of various abnormal faults of insulators of the transmission line (such as cracking, flashover, tree obstacles, ice covering, etc.), overcoming the problem of a single monitoring object of the abnormal state of traditional hidden danger defects, so as to be applicable to early warning of various faults. While ensuring the accuracy of the fault warning, the present invention improves the robustness of the safe operation of the transmission line, and has a broad application prospect.

[0057] The above descriptions are only optional embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A fault warning method for a power transmission line based on a discharge phenomenon, characterized in that: Includes steps: Setting a trigger time threshold of the traveling wave current, and when the trigger time threshold is reached, collecting the traveling wave current of the transmission line to form a traveling wave pile of traveling wave currents at different triggering moments; A fault warning signal is issued according to the similarity, periodicity and same frequency of the traveling wave current at different triggering moments in the traveling wave reactor.

2. The fault warning method for a power transmission line based on a discharge phenomenon as claimed in claim 1, characterized in that: The step of "issuing a fault warning signal according to the similarity, periodicity and frequency co-incidence of the traveling wave current at different triggering moments in the traveling wave reactor" includes: Determine whether the traveling wave currents in the traveling wave reactor have similarity, determine whether the traveling wave currents have periodicity, and determine whether the traveling wave currents have the same frequency; When the traveling wave currents at different triggering moments in the traveling wave reactor have similarity, periodicity and co-frequency, a fault warning signal is issued.

3. The fault warning method for power transmission lines based on discharge phenomenon as claimed in claim 2, characterized in that: The step of "determining whether the traveling wave currents in the traveling wave reactor have similarity" comprises: The two traveling wave currents are normalized respectively to obtain the normalized two traveling wave currents; The similarity is calculated based on the two normalized traveling wave currents, and whether the traveling wave currents in the traveling wave stack have similarity is determined according to the similarity.

4. The fault warning method for power transmission lines based on discharge phenomenon as claimed in claim 3, characterized in that: In the step of "calculating the similarity based on the normalized two traveling wave currents", the similarity calculation formula is: In the formula, ρ represents similarity, i represents current dimension, and I j (i) represents the current in the i-th dimension at the triggering moment j, I m (i) represents the current in the i-th dimension at the triggering moment m.

5. The fault warning method for power transmission lines based on discharge phenomenon as claimed in claim 4, characterized in that: The step of "determining whether the traveling wave currents in the traveling wave reactor have similarity according to the similarity" comprises: It is determined whether the similarity is greater than 0.

7. If the similarity is greater than 0.7, the traveling wave currents have similarity; if the similarity is not greater than 0.7, the traveling wave currents do not have similarity.

6. The fault warning method for power transmission lines based on discharge phenomenon as claimed in claim 2, characterized in that: The step of "determining whether the traveling wave current has periodicity" comprises: The time difference between two traveling wave currents at adjacent triggering moments at the same moment is calculated, and whether the traveling wave current has periodicity is determined based on the time difference.

7. The method for early warning of power transmission line faults based on discharge phenomenon according to claim 6, characterized in that: The step of "determining whether the traveling wave current has periodicity according to the time difference" comprises: Determine whether the time difference satisfies one of the following relationships. If so, it is determined that the traveling wave current has periodicity. If not, it is determined that the traveling wave current does not have periodicity. The relationship is: (10-Δt)ms≤|Tm-Tm-1|≤(10+Δt)ms; (20-Δt)ms≤|T m -T m-1 |≤(20+Δt)ms; In the relationship, T m represents the time of the traveling wave current at the triggering moment m; T m-1 It represents the time of the traveling wave current at the triggering moment m-1, Δt represents the time margin parameter, and Δt is not greater than 2ms.

8. The method for early warning of power transmission line faults based on discharge phenomenon according to claim 2, characterized in that: The step of "determining whether the traveling wave current has the same frequency" includes: The frequency difference between two traveling wave currents at adjacent triggering moments is calculated, and whether the traveling wave currents have the same frequency is determined based on the frequency difference.

9. The method for early warning of power transmission line faults based on discharge phenomenon according to claim 8, characterized in that: The step of "determining whether the traveling wave current has the same frequency according to the frequency difference" includes: Determine whether the frequency difference satisfies the following expression. If so, it is determined that the traveling wave current has the same frequency; if not, it is determined that the traveling wave current does not have the same frequency. The expression is: f m -f m-1 |≤(Δf)Hz; In the expression, f m represents the frequency of the traveling wave current at the triggering time m, f m-1 represents the frequency of the traveling wave current at the triggering time m-1, Δf represents the frequency margin parameter, and Δf≤100Hz.

10. The method for early warning of a power transmission line fault based on a discharge phenomenon according to any one of claims 1 to 9, characterized in that: The step of "collecting the traveling wave current of the transmission line" includes: The high-frequency traveling wave signal of the transmission line is collected, and the high-frequency traveling wave signal is extracted to collect the traveling wave current.

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