Method for positioning occurrence position of cable external damage event

Abstract

The invention discloses a method for positioning the occurrence position of a cable external damage event, and belongs to the technical field of electric power safety monitoring. According to the method, the positions and the number of the intelligent ground nails are set, the reference ground nails are set, the intelligent ground nails synchronously collect vibration data of a cable external damage event, an area where the external damage event possibly occurs near the cable is gridded, distance vectors between each grid node and all the intelligent ground nails and difference vectors of distances between the grid nodes and the reference ground nails are calculated respectively, and the vibration data of the cable external damage event are acquired. Calculating an auto-covariance matrix of the external damage event vibration data, calculating a phase delay focusing direction vector of each grid node by using the distance difference vector, and calculating an external damage event vibration power matrix corresponding to each grid node by using the auto-covariance matrix of the external damage event vibration data and the phase delay focusing direction vector of each grid node; the grid node where the maximum vibration power is located in the external damage event vibration power matrix is the occurrence position of the cable external damage event, and the defect that an existing monitoring device cannot achieve external damage positioning is overcome.

Description

Technical Field

[0001] The invention specifically relates to a method for locating the position where a cable external damage event occurs, and belongs to the technical field of power safety monitoring. Background Art

[0002] Cables are responsible for the important task of transmitting electric energy. They are usually sheathed or directly buried underground. If there are no warning signs or personnel are negligent, they are easily damaged by external forces from construction machinery during construction, causing large-scale power outages and potential safety hazards for personnel. Therefore, it is of great significance to locate the location of cable damage events.

[0003] At present, the methods for discovering cable external damage events mainly include manual inspection and monitoring device detection. Manual inspection identification is time-consuming and labor-intensive, with low identification efficiency, and it is difficult to cover a large number of cable lines. The monitoring device identification method mainly uses the vibration amplitude to determine whether an external damage event has occurred, and it is impossible to accurately locate the location of the cable external damage event. Summary of the invention

[0004] The technical problem to be solved by the present invention is how to accurately locate the location where a cable external damage event occurs.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is: a method for locating the location of a cable external damage event, comprising the following steps:

[0006] Step 1: Set n smart ground nails above the cable, and use the first smart ground nail as the reference ground nail; the n smart ground nails should cover at least ten vibration wavelengths of engineering machinery impact and external damage; the spacing between the smart ground nails should exceed at least one vibration wavelength of engineering machinery impact and external damage; set the sampling frequency of the smart ground nails according to the vibration frequency f of engineering machinery impact and external damage, the vibration propagation speed c in the soil and the vibration propagation attenuation and sampling time t;

[0007] When an external damage vibration occurs due to an impact of an engineering machine, the n smart ground nails synchronously collect the external damage event vibration data and form an external damage event vibration data matrix A, as shown in the following formula (1):

[0008] (1)

[0009] In formula (1), L is the length of the smart ground nail for synchronously collecting vibration data of external damage events; The first external breakage event vibration data, the second external breakage event vibration data to the Lth external breakage event vibration data synchronously collected by the first smart ground nail among the n smart ground nails; The first external break event vibration data, the second external break event vibration data to the Lth external break event vibration data synchronously collected by the second smart ground nail among the n smart ground nails; The first external breakage event vibration data, the second external breakage event vibration data to the Lth external breakage event vibration data synchronously collected by the nth smart ground nail among the n smart ground nails;

[0010] Step 2: Divide the cable plane where the cable is located along the xz coordinate axis to form the ground nail arrangement plane. The area where the external damage event may occur on the ground nail arrangement plane is gridded by an equidistant method to form m grid nodes. The distance vectors between the n smart ground nails and the m grid nodes are calculated according to the following formula (2):

[0011] (2)

[0012] In formula (2), d is the distance vector; is the x-axis coordinate of the smart ground pin in the cable plane; is the x-axis coordinate of the grid node in the cable plane; is the z-axis coordinate of the smart ground pin in the cable plane; is the z-axis coordinate of the grid node in the cable plane;

[0013] The distance vectors between the n smart pins and the m grid nodes are collected to form a distance vector set D, as shown in the following formula (3):

[0014] (3)

[0015] In formula (3), is a distance vector sequence from the first smart ground pin among the n smart ground pins to the m grid nodes; are respectively the distance vectors from the first smart ground pin of the n smart ground pins to the m grid nodes in sequence; is a vector distance sequence from the second smart ground pin among the n smart ground pins to the m grid nodes; are respectively the distance vectors from the second smart ground pin among the n smart ground pins to the m grid nodes in sequence; is a vector distance sequence from the nth smart ground pin among the n smart ground pins to the m grid nodes; are respectively the distance vectors from the nth smart ground nail among the n smart ground nails to the m grid nodes in sequence;

[0016] According to the distance vector set D, a difference vector set of the distances between the m grid points and the reference ground nail is obtained by transformation , as shown in the following formula (4),

[0017] (4);

[0018] Step 3: Calculate the autocovariance matrix R of the vibration data of the external damage event according to the following formula (5):

[0019] (5)

[0020] In formula (5), is the transpose of the vibration data matrix A of the external damage event;

[0021] According to the difference vector set The phase delay focusing direction vector matrix B of the m grid nodes is calculated as shown in the following formula (6):

[0022] (6)

[0023] Step 4: Calculate the external-break vibration power matrix P corresponding to the m grid nodes according to the autocovariance matrix R of the external-break event vibration data and the phase-delay focusing direction vector matrix B, as shown in the following formula (7):

[0024] (7)

[0025] The external damage vibration power matrix P is normalized, and the grid node where the maximum vibration power is located in the external damage vibration power matrix P after the normalization is found to be the location where the cable external damage event occurs.

[0026] The beneficial effects of the present invention are as follows: the present invention sets the position and number of smart ground nails and sets reference ground nails. The smart ground nails synchronously collect vibration data of cable external break events, grid the areas where external break events may occur near the cable, respectively calculate the distance vectors between each grid node and all smart ground nails, and the difference vectors of the distances with the reference ground nails, calculate the autocovariance matrix of the vibration data of the external break event, use the distance difference vectors to the reference ground nails to calculate the phase delay focusing direction vector of each grid node, use the autocovariance matrix of the vibration data of the external break event and the phase delay focusing direction vector of each grid node to calculate the vibration power matrix of the external break event corresponding to each grid node, find the grid node with the maximum vibration power in the vibration power matrix of the external break event, that is, the location where the cable external break event occurs, overcome the deficiency that the existing monitoring device cannot realize external break positioning, the method is simple, easy to program and realize, and has high positioning accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a flow chart of a method for locating the location of a cable external rupture event of the present invention.

[0028] Figure 2 It is a three-dimensional cloud diagram of the normalized result of the vibration power matrix of the external damage event in the embodiment of the present invention.

[0029] Figure 3 It is an xz plane cloud diagram of the normalized result of the vibration power matrix of the external damage event in the embodiment of the present invention. DETAILED DESCRIPTION

[0030] Example

[0031] The following is a further description of a method for locating a cable external break position according to the present invention in conjunction with the accompanying drawings and specific embodiments.

[0032] The method for locating the location of the cable break event in this embodiment is as follows: Figure 1 As shown, the following steps are included;

[0033] Step 1: Set n smart ground nails above the cable, and use the first smart ground nail as the reference ground nail; n smart ground nails should cover at least ten vibration wavelengths of engineering machinery impact and external damage; the spacing between smart ground nails should exceed at least one vibration wavelength of engineering machinery impact and external damage; set the sampling frequency of smart ground nails according to the vibration frequency f of engineering machinery impact and external damage, the vibration propagation speed c in the soil, and the vibration propagation attenuation and sampling time t;

[0034] In this embodiment, 15 smart ground nails are set next to the cable, and the interval between the smart ground nails is 2m; since the vibration frequency f of the external impact of the construction machinery is 3kHz, and the propagation speed c of the vibration in the soil is 320m / s, the sampling frequency of the smart ground nails is set is 48kHz, sampling time t is 0.1s;

[0035] When an external damage vibration occurs due to an impact of an engineering machine, the n smart ground nails synchronously collect the external damage event vibration data and form an external damage event vibration data matrix A, as shown in the following formula (1):

[0036] (1)

[0037] In formula (1), L is the length of the smart ground nail for synchronously collecting vibration data of external damage events; The first external breakage event vibration data, the second external breakage event vibration data to the Lth external breakage event vibration data synchronously collected by the first smart ground nail among the n smart ground nails; The first external break event vibration data, the second external break event vibration data to the Lth external break event vibration data synchronously collected by the second smart ground nail among the n smart ground nails; The first external breakage event vibration data, the second external breakage event vibration data to the Lth external breakage event vibration data synchronously collected by the nth smart ground nail among the n smart ground nails;

[0038] Step 2: Divide the cable plane where the cable is located along the xz coordinate axis to form the ground nail arrangement plane, and mesh the area where the external damage event may occur on the ground nail arrangement plane by an equidistant method to form m grid nodes. In this embodiment, the plane is the xz plane, the x value range is [-5m, 5m], the z value range is [-10m, 10m], and the xz plane is divided into 201*101 grid nodes at 0.1m intervals.

[0039] According to the following formula (2), the distance vectors between n smart ground pins and m grid nodes are calculated:

[0040] (2)

[0041] In formula (2), d is the distance vector; is the x-axis coordinate of the cable plane nailed intelligently; is the x-axis coordinate of the grid node in the cable plane; is the z-axis coordinate of the cable plane pinned intelligently; is the z-axis coordinate of the grid node in the cable plane;

[0042] The distance vectors between n smart pins and m grid nodes are collected to form a distance vector set D, as shown in the following formula (3):

[0043] (3)

[0044] In formula (3), is the distance vector sequence from the first of the n smart pins to the m grid nodes; are the distance vectors from the first smart ground pin among the n smart ground pins to the m grid nodes in sequence; is the vector distance sequence from the second smart pin among the n smart pins to the m grid nodes; are the distance vectors from the second smart ground nail among the n smart ground nails to the m grid nodes in sequence; is the vector distance sequence from the nth smart ground pin to the m grid nodes among the n smart ground pins; are the distance vectors from the nth smart ground nail to the m grid nodes in sequence;

[0045] In this embodiment, the grid node (-5, -10) is selected, and the xz plane coordinates of the 15 ground pins are (0, 0), (2, 0), (4, 0), ..., (28, 0). The distance vector D between the grid node and the 15 smart ground pins is calculated. 1,15 =[11.18,12.21, 13.45, 14.87, 16.40, 18.03, 19.72, 21.47, 23.26, 25.08, 26.93, 28.79,30.68, 32.57, 34.48],

[0046] According to the distance vector set D, the difference vector set of the distance between m grid points and the reference ground nail is obtained by transformation , as shown in the following formula (4),

[0047] (4);

[0048] Step 3: Calculate the autocovariance matrix R of the external damage event vibration data according to the following formula (5):

[0049] (5)

[0050] In formula (5), is the transpose of the vibration data matrix A of the external breaking event;

[0051] According to the difference vector set Calculate the phase delay focusing direction vector matrix B of m grid nodes. The calculation formula is shown in the following equation (6):

[0052] (6)

[0053] In formula (6), f is the vibration frequency of the external damage of the construction machinery, and c is the propagation speed of the vibration in the soil;

[0054] Step 4: According to the autocovariance matrix R of the vibration data of the external damage event and the phase delay focusing direction vector matrix B, the corresponding external damage vibration power matrix P of the m grid nodes is calculated, as shown in the following formula (7):

[0055] (7)

[0056] The external damage vibration power matrix P is normalized, and the grid node where the maximum vibration power is located in the normalized external damage vibration power matrix P is found, and the location of the cable external damage event is determined in combination with the possible direction of the cable external damage event.

[0057] In this embodiment, the distribution result after normalizing the external vibration power matrix P is as follows: Figure 2 As shown, drawn in the xz plane Figure 2 The contour map of Figure 3 As shown, the maximum vibration power occurs at positions (1, 5) and (1, -5) in the xz plane. In this embodiment, the possible direction of cable external failure is the positive semi-axis direction of the z-axis. Therefore, the location of the cable external failure event is (1, 5).

Claims

1. A method for locating the location of a cable damage event, characterized in that: The steps include: Step 1: Set n smart ground nails above the cable, and use the first smart ground nail as the reference ground nail; the n smart ground nails should cover at least ten vibration wavelengths of engineering machinery impact and external damage; the spacing between the smart ground nails should exceed at least one vibration wavelength of engineering machinery impact and external damage; set the sampling frequency of the smart ground nails according to the vibration frequency f of engineering machinery impact and external damage, the vibration propagation speed c in the soil and the vibration propagation attenuation and sampling time t; When an external damage vibration occurs due to an impact of an engineering machine, the n smart ground nails synchronously collect the external damage event vibration data and form an external damage event vibration data matrix A, as shown in the following formula (1): （1） In formula (1), L is the length of the smart ground nail for synchronously collecting vibration data of external damage events; The first external breakage event vibration data, the second external breakage event vibration data to the Lth external breakage event vibration data synchronously collected by the first smart ground nail among the n smart ground nails; The first external break event vibration data, the second external break event vibration data to the Lth external break event vibration data synchronously collected by the second smart ground nail among the n smart ground nails; The first external breakage event vibration data, the second external breakage event vibration data to the Lth external breakage event vibration data synchronously collected by the nth smart ground nail among the n smart ground nails; Step 2: Divide the cable plane where the cable is located along the xz coordinate axis to form the ground nail arrangement plane. The area where the external damage event may occur on the ground nail arrangement plane is gridded by an equidistant method to form m grid nodes. The distance vectors between the n smart ground nails and the m grid nodes are calculated according to the following formula (2): （2） In formula (2), d is the distance vector; is the x-axis coordinate of the smart ground pin in the cable plane; is the x-axis coordinate of the grid node in the cable plane; is the z-axis coordinate of the smart pin in the cable plane; is the z-axis coordinate of the grid node in the cable plane; The distance vectors between the n smart pins and the m grid nodes are collected to form a distance vector set D, as shown in the following formula (3): （3） In formula (3), is a distance vector sequence from the first smart ground pin among the n smart ground pins to the m grid nodes; are respectively the distance vectors from the first smart ground pin of the n smart ground pins to the m grid nodes in sequence; is a vector distance sequence from the second smart ground pin among the n smart ground pins to the m grid nodes; are respectively the distance vectors from the second smart ground pin among the n smart ground pins to the m grid nodes in sequence; is a vector distance sequence from the nth smart ground pin among the n smart ground pins to the m grid nodes; are respectively the distance vectors from the nth smart ground nail among the n smart ground nails to the m grid nodes in sequence; According to the distance vector set D, a difference vector set of the distances between m grid points and the reference ground nail is obtained by transformation , as shown in the following formula (4), （4）； Step 3: Calculate the autocovariance matrix R of the vibration data of the external damage event according to the following formula (5): （5） In formula (5), is the transpose of the vibration data matrix A of the external damage event; According to the difference vector set The phase delay focusing direction vector matrix B of the m grid nodes is calculated as shown in the following formula (6): （6） Step 4: Calculate the external-break vibration power matrix P corresponding to the m grid nodes according to the autocovariance matrix R of the external-break event vibration data and the phase-delay focusing direction vector matrix B, as shown in the following formula (7): （7） The external damage vibration power matrix P is normalized, and the grid node where the maximum vibration power is located in the external damage vibration power matrix P after the normalization is found to be the location where the cable external damage event occurs.

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