Wire vibration mode test system

Abstract

The invention discloses a wire vibration mode test system. The system comprises a cross arm, an acceleration sensor, a suspension clamp, a tension sensor, a winch, a first tower, a second tower and an upper computer, one end of the cross arm is connected with the first tower, and the other end is connected with the second tower; the hanging rack of the suspension clamp is clamped on the to-be-tested lead through the insulation part and the pressing strip of the suspension clamp hung on the cross arm; the acceleration sensor is arranged on the wire at the outlet of the suspension clamp; the winch is fixed on the first tower, one end of the tension sensor is connected with the winch, the other end is connected with the first end of the to-be-tested wire, and the second end of the to-be-tested wire is connected with the second tower; the winch is used for pulling a to-be-tested wire; and the upper computer obtains the vibration acceleration of the to-be-tested wire, and calculates a vibration modal analysis result of the to-be-tested wire according to the vibration acceleration and preset impact excitation. According to the invention, the vibration mode of the wire at the suspension clamp can be tested and analyzed.

Description

Technical Field

[0001] The invention relates to the field of wire vibration modal testing, and in particular to a wire vibration modal testing system. Background Art

[0002] Modal analysis is a structural dynamics analysis method that extracts the change characteristics of structural modal parameters (such as modal natural frequency and modal damping) through structural vibration response. In the process of modal analysis, the change of structural modal parameters can characterize the damage characteristics of the system structure to a certain extent. In the modal analysis of overhead wires, the detection and identification of overhead wire damage is mainly based on the change of modal frequency or modal damping ratio before and after the wire strand is broken.

[0003] Due to the complex forces on the conductors at the suspension clamps, there is currently no method for performing vibration modal test analysis on the conductors at the suspension clamps. Summary of the invention

[0004] The invention provides a conductor vibration modal test system, which can test and perform modal analysis on the vibration modal of a conductor at a suspension clamp.

[0005] An embodiment of the present invention provides a conductor vibration modal test system, comprising: a cross arm, an acceleration sensor, a suspension wire clamp, a tension sensor, a winch, a first pole tower, a second pole tower and a host computer;

[0006] One end of the cross arm is connected to the first pole tower, and the other end of the cross arm is connected to the second pole tower;

[0007] The hanging bracket of the suspension clamp is connected to the cross arm through an insulating component, and the pressure strip of the suspension clamp is clamped on the wire to be tested; the acceleration sensor is arranged on the wire area at the outlet of the suspension clamp;

[0008] The hoist is fixed on the first pole tower, one end of the tension sensor is connected to the hoist, the other end of the tension sensor is connected to the first end of the wire to be measured, and the second end of the wire to be measured is connected to the second pole tower;

[0009] The hoist is used to pull the wire to be tested until the readings of the acceleration sensor and the tension sensor are stable;

[0010] The host computer is used to obtain the vibration acceleration of the conductor to be measured by the acceleration sensor, and calculate the vibration modal analysis result of the conductor to be measured according to the vibration acceleration and the preset impact excitation; wherein, after the readings of the acceleration sensor and the tension sensor are stable, the conductor to be measured is struck according to the preset impact excitation at a preset distance from the acceleration sensor, so that the acceleration sensor measures the vibration acceleration of the conductor to be measured.

[0011] Furthermore, the insulating component is a suspension insulator;

[0012] One end of the suspension insulator is connected to the cross arm through a hanging ring, and the other end of the suspension insulator is connected to the hanging bracket of the suspension wire clamp through a hanging ring.

[0013] Furthermore, it also includes: a first tension clamp and a second tension clamp;

[0014] The conductor to be tested is connected to the tension sensor via the first tension clamp;

[0015] The conductor to be tested is connected to the second tower via the second tension clamp.

[0016] Furthermore, it also includes: a first shock absorbing fixture and a second shock absorbing fixture;

[0017] The conductor to be tested is provided with a first damping area and a second damping area; the first damping area is the right side of the suspension clamp, and is the area with the maximum amplitude of the superimposed vibration of the conductor to be tested; the second damping area is the left side of the suspension clamp, and is the area with the maximum amplitude of the superimposed vibration of the conductor to be tested;

[0018] The first shock absorbing fixture is clamped on the first shock absorbing area of ​​the conductor to be tested, and the second shock absorbing fixture is clamped on the second shock absorbing area of ​​the conductor to be tested.

[0019] Furthermore, the determination of the maximum amplitude region includes:

[0020] Obtain the maximum tension of the conductor to be tested at the lowest point of the sag, the conductor design safety factor, the line density of the conductor to be tested, and the span length;

[0021] Calculate the rated breaking force of the conductor to be tested according to the product of the maximum tension and the conductor design safety factor;

[0022] Calculating the tension of the conductor to be tested according to the rated breaking force;

[0023] Calculating the first-order vibration wavelength and the second-order vibration wavelength of the conductor to be tested according to the tension, the line density and the span length;

[0024] The maximum amplitude position of the conductor to be measured is determined according to the first-order vibration wavelength and the second-order vibration wavelength.

[0025] Furthermore, after calculating the tension of the conductor to be tested according to the rated breaking force, the method further includes:

[0026] Determine the maximum bearing capacity of the first pole tower and the second pole tower according to the tension; wherein the maximum bearing capacity is higher than the tension;

[0027] According to the maximum bearing capacity and the preset conductor installation height, the maximum bearing capacity bending moment of the first pole tower and the second pole tower is calculated;

[0028] The models of the first pole tower and the second pole tower are determined according to the maximum bearing capacity bending moment.

[0029] Furthermore, it also includes: a first metal support frame and a second metal support frame;

[0030] One end of the first metal support frame is fixed on the ground, and the other end of the first metal support frame is fixed on the first shock-absorbing fixture;

[0031] One end of the second metal support frame is fixed on the ground, and the other end of the second metal support frame is fixed on the second shock-absorbing fixture.

[0032] Further, the vibration modal analysis result of the conductor to be tested is calculated according to the vibration acceleration and the preset impact excitation, including:

[0033] Preprocessing the vibration acceleration to obtain a target vibration acceleration set, and performing Fourier transform on the target vibration acceleration set to obtain frequency domain vibration acceleration;

[0034] Performing Fourier transform on the impact excitation to obtain frequency domain impact excitation;

[0035] Calculating the vibration frequency response function of the conductor to be tested according to the quotient of the frequency domain vibration acceleration and the frequency domain impact excitation;

[0036] A vibration modal analysis result of the conductor to be tested is determined according to the vibration frequency response function.

[0037] Further, the vibration acceleration is preprocessed to obtain a target vibration acceleration set, including:

[0038] Calculating an average value of the vibration acceleration, and calculating a standard deviation of the vibration acceleration based on the vibration acceleration and the average value;

[0039] Calculating the difference between each vibration acceleration and the standard deviation;

[0040] Retain the vibration accelerations whose differences are not greater than a preset threshold to obtain a first vibration acceleration set;

[0041] Deduplicating the first vibration acceleration set to obtain a deduplicated second vibration acceleration set;

[0042] The second vibration acceleration set is complemented by a linear interpolation method to obtain the target vibration acceleration set.

[0043] Further, determining the vibration modal analysis result of the conductor to be tested according to the vibration frequency response function includes:

[0044] Obtaining a vibration amplitude-frequency curve of the conductor to be tested according to the vibration frequency response function;

[0045] The frequency corresponding to the peak point of the vibration amplitude-frequency curve is used as the natural frequency of the conductor to be tested;

[0046] According to the half power spectrum method and the vibration amplitude-frequency curve, the modal damping ratios of each order of the conductor to be tested are calculated;

[0047] The vibration modal analysis result of the conductor to be tested is obtained according to the natural frequency and the modal damping ratios of each order.

[0048] The embodiments of the present invention have the following beneficial effects:

[0049] The present invention provides a conductor vibration modal test system. The above system includes: a cross arm, an acceleration sensor, a suspension wire clamp, a tension sensor, a winch, a first pole tower, a second pole tower and a host computer; one end of the cross arm is connected to the first pole tower, and the other end of the cross arm is connected to the second pole tower; the hanger of the suspension wire clamp is hung with the cross arm through an insulating component, and the pressure strip of the suspension wire clamp is clamped on the conductor to be tested; the acceleration sensor is arranged on the conductor area at the outlet of the suspension wire clamp; the winch is fixed on the first pole tower, one end of the tension sensor is connected to the winch, and the other end of the tension sensor is connected to the first end of the conductor to be tested, The second end of the conductor to be tested is connected to the second pole tower; the hoist is used to pull the conductor to be tested until the readings of the acceleration sensor and the tension sensor are stable; the host computer is used to obtain the vibration acceleration of the conductor to be tested measured by the acceleration sensor, and calculate the vibration modal analysis result of the conductor to be tested according to the vibration acceleration and the preset impact excitation; wherein, after the readings of the acceleration sensor and the tension sensor are stable, the conductor to be tested is struck at a preset distance from the acceleration sensor according to the preset impact excitation, so that the acceleration sensor measures the vibration acceleration of the conductor to be tested. Therefore, the present invention designs a conductor vibration modal test system for conductor vibration modal analysis, and a suspension wire clamp is installed on the conductor vibration modal test system, and the vibration acceleration data of the conductor to be tested at the outlet of the suspension wire clamp is measured by the test system, and then according to the vibration acceleration data and the preset impact excitation applied to the conductor to be tested, the vibration modal analysis of the conductor to be tested at the suspension wire clamp is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 The present invention is a schematic diagram of the structure of a conductor vibration modal test system provided by an embodiment of the present invention.

[0051] Figure 2 This is a schematic diagram of a bolt-type EPDM rubber shock-absorbing clamp provided by an embodiment of the present invention.

[0052] Figure 3 It is a schematic diagram of the installation position of the first shock-absorbing clamp provided in one embodiment of the present invention.

[0053] Figure 4 It is a schematic diagram of tower force analysis provided by one embodiment of the present invention.

[0054] Figure 5 It is a schematic diagram of a vibration amplitude-frequency curve provided by an embodiment of the present invention.

[0055] Explanation of the reference numerals: first pole tower 1, second pole tower 2, tension clamp 3, conductor to be tested 4, cross arm 5, suspension insulator 6, acceleration sensor 7, suspension clamp 8, first shock absorbing clamp 9, second shock absorbing clamp 10, first metal support frame 11, second metal support frame 12, tension sensor 13 and winch 14. DETAILED DESCRIPTION

[0056] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings 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.

[0057] like Figure 1 As shown, a conductor vibration modal test system provided by an embodiment of the present invention comprises: a cross arm 5, an acceleration sensor 7, a suspension clamp 8, a tension sensor 13, a winch 14, a first pole tower 1, a second pole tower 2 and a host computer (not shown in FIG. Figure 1 (in the bid);

[0058] One end of the cross arm 5 is connected to the first pole tower 1, and the other end of the cross arm 5 is connected to the second pole tower 2;

[0059] Specifically, Figure 1 As shown, the distance between the first pole tower 1 and the second pole tower 2 is 12 m. The heights of the first pole tower and the second pole tower are both 1.8 m.

[0060] The hanging bracket of the suspension clamp 8 is connected to the cross arm 5 through an insulating component, and the pressure strip of the suspension clamp 8 is clamped on the wire to be tested 4; the acceleration sensor 7 is arranged on the wire area at the outlet of the suspension clamp 8;

[0061] Specifically, the cross arm 5 is a metal cross arm 5, which is installed in the center of the span of the conductor 4 to be tested, and is used to stabilize the suspension insulator 6 and the suspension clamp 8. In order to ensure the stability of the cross arm 5, it is fixed to the ground through the first tower 1 and the second tower 2 by cement pouring.

[0062] Specifically, the acceleration sensor 7 is a three-axis acceleration sensor 7, which is fixed to the wire area at the exit of the suspension clamp 8 by a binding tape and a theater tape, and the acceleration sensor 7 and the wire to be measured 4 need to be tightly fitted and fixed to avoid relative displacement between the acceleration sensor 7 and the wire to be measured 4 to affect the measurement accuracy. Among them, the z-axis measurement direction of the acceleration sensor 7 should be perpendicular to the surface of the wire to be measured 4.

[0063] Preferably, after installing the acceleration sensor 7, gently shake the wire 4 to be tested to observe whether the response of the acceleration sensor 7 is stable and continuous. If the acceleration sensor 7 can accurately and quickly capture the vibration acceleration change of the wire 4 to be tested, it means that the acceleration sensor 7 and the wire 4 to be tested have a good fit.

[0064] The hoist 14 is fixed on the first pole tower 1, one end of the tension sensor 13 is connected to the hoist 14, the other end of the tension sensor 13 is connected to the first end of the wire to be measured 4, and the second end of the wire to be measured 4 is connected to the second pole tower 2;

[0065] Specifically, the tension sensor 13 is connected to the hoist 14 via a hook lock on the hoist 14 .

[0066] The hoist 14 is used to pull the wire 4 to be tested until the readings of the acceleration sensor 7 and the tension sensor 13 are stable;

[0067] Specifically, when the hoist 14 is adjusted to pull the wire 4 to be tested, the tension sensor 13 detects the tension exerted on the wire in real time.

[0068] The host computer is used to obtain the vibration acceleration of the conductor 4 to be tested measured by the acceleration sensor 7, and calculate the vibration modal analysis result of the conductor 4 to be tested according to the vibration acceleration and the preset impact excitation; wherein, after the readings of the acceleration sensor 7 and the tension sensor 13 are stable, the conductor 4 to be tested is struck at a preset distance from the acceleration sensor 7 according to the preset impact excitation, so that the acceleration sensor 7 measures the vibration acceleration of the conductor 4 to be tested.

[0069] Preferably, a constant impact excitation is applied to the position of the conductor 4 to be measured which is about 89 cm away from the acceleration sensor 7, so that the conductor 4 to be measured enters a free decay vibration state.

[0070] Preferably, before actually measuring the vibration acceleration of the above-mentioned conductor 4 to be tested, a preliminary experiment is first conducted. During the preliminary experiment, the vibration spectrum of the conductor is observed by continuously changing the application position of the impact excitation. It is found that when the impact excitation is applied to the conductor at a distance of about 89 cm from the acceleration sensor 7, the natural frequency level of the amplitude-frequency image obtained is the most obvious. Therefore, the impact excitation is applied to the conductor 4 to be tested at a distance of 89 cm from the sensor. In the preliminary experiment, each time the application position of the impact excitation is changed, the tension of the conductor is recalibrated using the winch 14, the tension sensor 13 and the acceleration sensor 7 until the reading of the tension sensor 13 returns to the value before the experiment.

[0071] Specifically, an impact hammer is used to strike the conductor 4 to be tested according to a preset impact excitation.

[0072] Specifically, after the impact excitation is applied, the host computer of the acceleration sensor 7 is started to collect the vibration acceleration, and the digital display screen can monitor the vibration acceleration data of the wire to be tested 4 in real time. When the acceleration data on the digital display screen is close to 0 and tends to be stable, the collection is stopped.

[0073] In this embodiment, the vibration acceleration of the conductor 4 to be tested under a preset impact excitation is acquired by the acceleration sensor 7, and then the vibration modal analysis result of the conductor 4 to be tested is obtained according to the vibration acceleration and the preset impact excitation.

[0074] In a preferred embodiment, the above-mentioned insulating component is a suspension insulator 6;

[0075] One end of the suspension insulator 6 is connected to the cross arm 5 via a hanging ring, and the other end of the suspension insulator 6 is connected to the hanging bracket of the suspension wire clamp 8 via a hanging ring.

[0076] Specifically, the suspension insulator 6 is a glass insulator, and a U-shaped hanging ring is welded on the cross arm 5. Therefore, one end of the suspension insulator 6 is connected to the cross arm 5 through the U-shaped hanging ring, and the other end of the suspension insulator 6 is also connected to the suspension wire clamp 8 through the U-shaped hanging ring.

[0077] In this embodiment, two ends of the suspension insulator 6 are connected to the cross arm 5 and the suspension clamp 8 respectively through hanging rings.

[0078] In another preferred embodiment, it further comprises: a first tension clamp 3 and a second tension clamp 3;

[0079] The conductor 4 to be tested is connected to the tension sensor 13 via the first tension clamp 3;

[0080] The conductor 4 to be tested is connected to the second tower 2 via the second tension clamp 3 .

[0081] Specifically, the tension clamp 3 is a crimped tension clamp 3, and the conductor 4 to be tested is fixed by the first tension clamp 3, the second tension clamp 3 and the suspension clamp 8. The tension sensor 13 is located between the hook lock of the winch 14 and the first tension clamp 3, and is used to monitor the tension on the conductor 4 to be tested.

[0082] In this preferred embodiment, the conductor and the tension sensor 13 are connected via the first tension clamp 3 , and the conductor to be measured 4 and the second tower 2 are connected via the second tension clamp 3 .

[0083] In another preferred embodiment, it further comprises: a first shock absorbing fixture 9 and a second shock absorbing fixture 10;

[0084] The above-mentioned conductor 4 to be tested is provided with a first damping area and a second damping area; the above-mentioned first damping area is the right side of the suspension clamp 8, and is the area with the maximum amplitude of the superimposed vibration of the conductor 4 to be tested; the above-mentioned second damping area is the left side of the suspension clamp 8, and is the area with the maximum amplitude of the superimposed vibration of the conductor 4 to be tested;

[0085] The first shock absorbing fixture 9 is clamped on the first shock absorbing area of ​​the conductor 4 to be tested, and the second shock absorbing fixture 10 is clamped on the second shock absorbing area of ​​the conductor 4 to be tested.

[0086] Specifically, a bolt-type EPDM rubber shock-absorbing clamp is selected as the first shock-absorbing clamp 9 and the second shock-absorbing clamp 10. The bolt-type EPDM rubber shock-absorbing clamp is filled with EPDM rubber in a traditional aluminum alloy clamp to block and reflect the vibration energy of the wire. Schematically, the schematic diagram of the bolt-type EPDM rubber shock-absorbing clamp is as shown in FIG. Figure 2 shown.

[0087] Preferably, in order to study the vibration characteristics of the conductor 4 to be tested at the position of the suspension clamp 8 and effectively reduce the energy loss caused by the vibration energy propagating through the conductor 4 to be tested to the first tension clamp 3 and the second tension clamp 3 on both sides, a vibration energy isolation device is provided on both sides of the suspension clamp 8 to confine the vibration signal to the local range of the suspension clamp 8, thereby realizing the isolation and control of the vibration signal.

[0088] In this preferred embodiment, by arranging the first shock absorbing clamp 9 and the second shock absorbing clamp 10 on the first shock absorbing area and the second shock absorbing area of ​​the conductor 4 to be tested, the vibration energy loss of the conductor 4 to be tested is reduced.

[0089] In another preferred embodiment, the determination of the maximum amplitude region includes:

[0090] Obtain the maximum tension of the conductor 4 to be tested at the lowest point of the sag, the conductor design safety factor, the line density of the conductor 4 to be tested, and the span length;

[0091] Specifically, the above-mentioned maximum tension, conductor design safety factor and line density can all be obtained by looking up a table, and the span length can be obtained by measurement.

[0092] The rated breaking force of the conductor 4 to be tested is calculated based on the product of the maximum tension and the conductor design safety factor.

[0093] Specifically, the rated breaking force is calculated by the following formula:

[0094] T p =T max k c

[0095] Where, T pIndicates the rated breaking force, T max Indicates the maximum tension in N, k c Indicates the conductor design safety factor.

[0096] The tension of the conductor 4 to be tested is calculated based on the rated breaking force;

[0097] Specifically, during the actual operation of the conductor, the conductor tension is generally 25% of the rated breaking force of the conductor, that is, the above tension can be obtained by the following formula:

[0098] T=0.25T p

[0099] Where T represents tension.

[0100] According to the tension, the line density and the span length, the first-order vibration wavelength and the second-order vibration wavelength of the conductor 4 to be tested are calculated;

[0101] Specifically, the wave velocity of the vibration mechanical wave of the conductor 4 to be tested can be calculated by the following formula:

[0102]

[0103] Where u represents the wave velocity and ρ represents the linear density, and the unit is kg / m.

[0104] Specifically, after the wave velocity is obtained, the theoretical value of the vibration natural frequency of the conductor 4 to be tested can be calculated according to the following formula:

[0105]

[0106] In the formula, f n It represents the theoretical value of the nth order vibration natural frequency, and l represents the gear spacing.

[0107] Specifically, the wavelengths of the vibrations of the conductor 4 to be tested are calculated according to the following formula:

[0108]

[0109] In the formula, λ n represents the nth order vibration wavelength.

[0110] According to the first-order vibration wavelength and the second-order vibration wavelength, the maximum amplitude position of the conductor 4 to be tested is determined.

[0111] Specifically, since the wire vibration is mainly affected by the first two order modes, according to the calculation of the wavelengths of each order vibration of the wire, the wavelengths of the first two order vibrations are 1 and 1 / 2 respectively. Figure 3As shown, the suspension clamp 8 is equivalent to a fixed point, and the antinodes of the first two modes are located at 1 / 2 and 1 / 4 respectively. In order to suppress the vibration of the 1st and 2nd order modes at the same time, it should be installed at the maximum amplitude of the superimposed vibration. In order to isolate the vibration of the wire to the greatest extent, the first shock absorbing fixture 9 and the second shock absorbing fixture 10 are installed at a quarter of the distance from the left and right sides of the suspension clamp 8.

[0112] In this preferred embodiment, the maximum amplitude region is determined by calculating the wavelength of each order of vibration of the wire.

[0113] In another preferred embodiment, after calculating the tension of the conductor 4 to be tested according to the rated breaking force, the method further includes:

[0114] According to the tension, the maximum bearing capacity of the first pole tower 1 and the second pole tower 2 is determined; wherein the maximum bearing capacity is higher than the tension;

[0115] According to the above maximum bearing capacity and the preset conductor installation height, the maximum bearing capacity bending moment of the above first pole tower 1 and the above second pole tower 2 is calculated;

[0116] Schematically, the first pole tower 1 and the second pole tower 2 can be equivalent to a cantilever beam module with one end fixed under the tension of the conductor. The force analysis of the pole tower is as follows: Figure 4 shown. Figure 4 Here, a represents the preset conductor installation height, d represents the pole tower diameter, and F represents the conductor tension on the pole tower.

[0117] Specifically, the maximum bearing capacity bending moment is calculated according to the following formula:

[0118]

[0119] In the formula, Mu max Indicates the maximum bearing capacity bending moment.

[0120] The models of the first pole tower 1 and the second pole tower 2 are determined according to the maximum bearing capacity bending moment.

[0121] Preferably, a tower with a maximum bearing capacity and bending moment of 90.2 kN·m is finally selected.

[0122] Preferably, to ensure safety, the maximum bearing capacity of the first tower 1 and the second tower 2 should be slightly higher than the tension. To meet the tension conditions of all types of conductors required for the test, the preset conductor installation height should be less than 0.9m. To ensure safety and facilitate testing, the conductor installation height is finally set to 0.5m.

[0123] In this preferred embodiment, the models of the first pole tower 1 and the second pole tower 2 are determined according to the tension and the preset conductor installation height.

[0124] In another preferred embodiment, it further comprises: a first metal support frame 11 and a second metal support frame 12;

[0125] One end of the first metal support frame 11 is fixed on the ground, and the other end of the first metal support frame 11 is fixed on the first shock-absorbing fixture 9;

[0126] One end of the second metal support frame 12 is fixed on the ground, and the other end of the second metal support frame 12 is fixed on the second shock-absorbing fixture 10 .

[0127] Indicative, such as Figure 1 As shown, the distance between the first metal support frame 11 and the second metal support frame 12 is 6m.

[0128] Specifically, the wire 4 to be tested is installed to a preset wire installation height by the first metal support frame 11 and the second metal support frame 12 , and the first shock absorbing fixture 9 and the second shock absorbing fixture 10 are made more stable.

[0129] In this preferred embodiment, the first metal support frame 11 and the second metal support frame 12 enable the wire 4 to be installed at a preset wire installation height.

[0130] In another preferred embodiment, the vibration modal analysis result of the conductor 4 to be tested is calculated according to the vibration acceleration and the preset impact excitation, including:

[0131] Preprocessing the vibration acceleration to obtain a target vibration acceleration set, and performing Fourier transform on the target vibration acceleration set to obtain frequency domain vibration acceleration;

[0132] Specifically, since the acquired target vibration acceleration set is a discrete signal, discrete Fourier transform is used to perform frequency domain transformation on the target vibration acceleration set. Specifically, the frequency domain vibration acceleration is obtained by the following formula:

[0133]

[0134] In the formula, G out (k) represents the frequency domain vibration acceleration, n represents the number of acceleration data in the target vibration acceleration set after preprocessing, G out (n) represents the target vibration acceleration set, k represents the kth target vibration acceleration in the target vibration acceleration set, and W N represents the Fourier transform integration operator.

[0135] Perform Fourier transform on the above impact excitation to obtain frequency domain impact excitation;

[0136] Specifically, the impact force of the impact hammer is set to F p , the vibration excitation is applied at time 0, and the time domain expression of the impact excitation can be described by the following formula:

[0137] G in (t) = F p δ(t)

[0138] In the formula, G in (t) represents the preset impulse excitation, F p represents the impact force, and δ(t) represents the vibration excitation applied at time 0.

[0139] Specifically, the frequency domain impulse excitation is calculated by the following formula:

[0140]

[0141] In the formula, G in (ω) represents the above-mentioned frequency domain impulse excitation, F represents the Fourier operator, Represents the frequency domain impact force after Fourier transformation.

[0142] The vibration frequency response function of the conductor 4 to be tested is calculated based on the quotient of the frequency domain vibration acceleration and the frequency domain impact excitation;

[0143] Specifically, the vibration frequency response function is calculated according to the following formula:

[0144]

[0145] Where H(k) represents the vibration frequency response function.

[0146] According to the vibration frequency response function, the vibration modal analysis result of the conductor 4 to be tested is determined.

[0147] In this preferred embodiment, the vibration modal analysis result of the conductor 4 to be tested is obtained through vibration acceleration and preset impact excitation.

[0148] In another preferred embodiment, the above vibration acceleration is preprocessed to obtain a target vibration acceleration set, including:

[0149] Calculating an average value of the vibration acceleration, and calculating a standard deviation of the vibration acceleration based on the vibration acceleration and the average value;

[0150] Specifically, the standard deviation is calculated according to the following formula:

[0151]

[0152] In the formula, σ represents the standard deviation, N represents the total number of vibration accelerations, and Rj represents the jth vibration acceleration, Indicates the average value.

[0153] Calculate the difference between each vibration acceleration and the above standard deviation;

[0154] The vibration accelerations whose differences are not greater than a preset threshold are retained to obtain a first vibration acceleration set;

[0155] Specifically, the preset threshold is 3 times the standard deviation.

[0156] Deduplication is performed on the first vibration acceleration set to obtain a deduplication-free second vibration acceleration set;

[0157] The second vibration acceleration set is complemented by a linear interpolation method to obtain the target vibration acceleration set.

[0158] Specifically, it is completed by the following formula:

[0159]

[0160] Where D i+n represents the n+ith vibration acceleration in the second vibration acceleration set, D i represents the i-th vibration acceleration in the second vibration acceleration set, and k represents the number of missing vibration accelerations between adjacent vibration accelerations in the second vibration acceleration set.

[0161] Preferably, considering that the vibration acceleration data collected by the acceleration sensor 7 has duplicate items, abnormal items and data missing, it is necessary to pre-process the vibration acceleration data, and the processing process includes deleting abnormal data and duplicate data, and repairing missing data.

[0162] In this preferred embodiment, the vibration acceleration is preprocessed to obtain a target vibration acceleration set.

[0163] In another preferred embodiment, the vibration modal analysis result of the conductor 4 to be tested is determined according to the vibration frequency response function, including:

[0164] According to the vibration frequency response function, the vibration amplitude-frequency curve of the conductor 4 to be tested is obtained;

[0165] Specifically, according to the vibration frequency response function, a vibration amplitude-frequency curve is drawn. Schematically, the vibration amplitude-frequency curve is as follows Figure 5 shown.

[0166] The frequency corresponding to the peak point of the vibration amplitude-frequency curve is taken as the natural frequency of the conductor 4 to be tested;

[0167] Specifically, the peak value in the vibration amplitude-frequency curve corresponds to the natural frequency of the conductor 4 to be tested, and a phase jump occurs at these frequency points. The natural frequency of the vibration of the conductor 4 to be tested can be obtained by extracting the peak value of the vibration amplitude-frequency curve.

[0168] According to the half power spectrum method and the vibration amplitude-frequency curve, the damping ratios of each order of the above-mentioned conductor 4 to be tested are calculated;

[0169] Specifically, at 0.707 times the peak value in the vibration amplitude-frequency curve, a straight line parallel to the horizontal axis is drawn and intersects the i-th peak value of the vibration amplitude-frequency curve at A. i , B i Points, these two points have a horizontal coordinate of Therefore, the modal damping ratios of the conductor 4 to be tested can be calculated according to the following formula:

[0170]

[0171] In the formula, ξ i represents the i-th order mode damping ratio.

[0172] According to the above natural frequency and the above modal damping ratios of each order, the vibration modal analysis result of the above-mentioned conductor 4 to be tested is obtained.

[0173] In this preferred embodiment, the natural frequency of the conductor 4 to be tested and the damping ratios of each modal order are calculated according to the vibration frequency response function, and then the vibration modal analysis result of the conductor 4 to be tested is obtained.

[0174] By implementing the above-mentioned embodiments of the present invention, the vibration mode of the conductor at the suspension clamp 8 can be tested and analyzed.

[0175] The above are preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also regarded as protection of the present invention.

Claims

1. A conductor vibration modal test system, characterized in that: include: Cross arm, acceleration sensor, suspension wire clamp, tension sensor, winch, first tower, second tower and host computer; One end of the cross arm is connected to the first pole tower, and the other end of the cross arm is connected to the second pole tower; The hanging bracket of the suspension clamp is connected to the cross arm through an insulating component, and the pressure strip of the suspension clamp is clamped on the wire to be tested; the acceleration sensor is arranged on the wire area at the outlet of the suspension clamp; The hoist is fixed on the first pole tower, one end of the tension sensor is connected to the hoist, the other end of the tension sensor is connected to the first end of the wire to be measured, and the second end of the wire to be measured is connected to the second pole tower; The hoist is used to pull the wire to be tested until the readings of the acceleration sensor and the tension sensor are stable; The host computer is used to obtain the vibration acceleration of the conductor to be measured by the acceleration sensor, and calculate the vibration modal analysis result of the conductor to be measured according to the vibration acceleration and the preset impact excitation; wherein, after the readings of the acceleration sensor and the tension sensor are stable, the conductor to be measured is struck according to the preset impact excitation at a preset distance from the acceleration sensor, so that the acceleration sensor measures the vibration acceleration of the conductor to be measured.

2. A conductor vibration modal test system according to claim 1, characterized in that: The insulating component is a suspension insulator; One end of the suspension insulator is connected to the cross arm through a hanging ring, and the other end of the suspension insulator is connected to the hanging bracket of the suspension wire clamp through a hanging ring.

3. A conductor vibration modal test system according to claim 2, characterized in that: Also includes: A first tension clamp and a second tension clamp; The conductor to be tested is connected to the tension sensor via the first tension clamp; The conductor to be tested is connected to the second tower via the second tension clamp.

4. A conductor vibration modal test system according to claim 3, characterized in that: Also included: a first shock absorbing fixture and a second shock absorbing fixture; The conductor to be tested is provided with a first damping area and a second damping area; the first damping area is the right side of the suspension clamp, and is the area with the maximum amplitude of the superimposed vibration of the conductor to be tested; the second damping area is the left side of the suspension clamp, and is the area with the maximum amplitude of the superimposed vibration of the conductor to be tested; The first shock absorbing fixture is clamped on the first shock absorbing area of ​​the conductor to be tested, and the second shock absorbing fixture is clamped on the second shock absorbing area of ​​the conductor to be tested.

5. A conductor vibration modal test system according to claim 4, characterized in that: The determination of the maximum amplitude region includes: Obtain the maximum tension of the conductor to be tested at the lowest point of the sag, the conductor design safety factor, the line density of the conductor to be tested, and the span length; Calculate the rated breaking force of the conductor to be tested according to the product of the maximum tension and the conductor design safety factor; Calculating the tension of the conductor to be tested according to the rated breaking force; Calculating the first-order vibration wavelength and the second-order vibration wavelength of the conductor to be tested according to the tension, the line density and the span length; The maximum amplitude position of the conductor to be measured is determined according to the first-order vibration wavelength and the second-order vibration wavelength.

6. A conductor vibration modal test system according to claim 5, characterized in that: After calculating the tension of the conductor to be tested according to the rated breaking force, the method further includes: Determine the maximum bearing capacity of the first pole tower and the second pole tower according to the tension; wherein the maximum bearing capacity is higher than the tension; According to the maximum bearing capacity and the preset conductor installation height, the maximum bearing capacity bending moment of the first pole tower and the second pole tower is calculated; The models of the first pole tower and the second pole tower are determined according to the maximum bearing capacity bending moment.

7. A conductor vibration modal test system according to claim 6, characterized in that: Also includes: A first metal support frame and a second metal support frame; One end of the first metal support frame is fixed on the ground, and the other end of the first metal support frame is fixed on the first shock-absorbing fixture; One end of the second metal support frame is fixed on the ground, and the other end of the second metal support frame is fixed on the second shock-absorbing fixture.

8. A conductor vibration modal test system according to claim 7, characterized in that: The step of calculating the vibration modal analysis result of the conductor to be tested according to the vibration acceleration and the preset impact excitation includes: Preprocessing the vibration acceleration to obtain a target vibration acceleration set, and performing Fourier transform on the target vibration acceleration set to obtain frequency domain vibration acceleration; Performing Fourier transform on the impact excitation to obtain frequency domain impact excitation; Calculating the vibration frequency response function of the conductor to be tested according to the quotient of the frequency domain vibration acceleration and the frequency domain impact excitation; A vibration modal analysis result of the conductor to be tested is determined according to the vibration frequency response function.

9. A conductor vibration modal test system according to claim 8, characterized in that: The vibration acceleration is preprocessed to obtain a target vibration acceleration set, including: Calculating an average value of the vibration acceleration, and calculating a standard deviation of the vibration acceleration based on the vibration acceleration and the average value; Calculating the difference between each vibration acceleration and the standard deviation; Retain the vibration accelerations whose differences are not greater than a preset threshold to obtain a first vibration acceleration set; Deduplicating the first vibration acceleration set to obtain a deduplicated second vibration acceleration set; The second vibration acceleration set is complemented by a linear interpolation method to obtain the target vibration acceleration set.

10. A conductor vibration modal test system according to claim 9, characterized in that: Determining the vibration modal analysis result of the conductor to be tested according to the vibration frequency response function includes: Obtaining a vibration amplitude-frequency curve of the conductor to be tested according to the vibration frequency response function; The frequency corresponding to the peak point of the vibration amplitude-frequency curve is used as the natural frequency of the conductor to be tested; According to the half power spectrum method and the vibration amplitude-frequency curve, the modal damping ratios of each order of the conductor to be tested are calculated; The vibration modal analysis result of the conductor to be tested is obtained according to the natural frequency and the modal damping ratios of each order.

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