CN102095449B - A galloping early warning method for overhead transmission lines - Google Patents

Abstract

The invention discloses a method for alarming the dancing of an overhead transmission circuit. The method comprises the following steps of: (S1) monitoring the dynamic load change condition of an iced lead and measuring the data of a vertical load and a horizontal load in at least one period; (S2) estimating a lead dancing amplitude A according to the change of the horizontal dynamic load; (S3) calculating a maximum dynamic load and a minimum electric gap according to the dynamic load measurement of lead dancing in the step (S1) and the lead dancing amplitude A estimated in the step (2); (S4) calculating the design load and calculating a design electric gap according to the design parameters of an overhang insulator strings, fittings, overhead transmission line leads and a linear tower; and (S5) comparing the maximum dynamic load calculated in the step (S3) with the design load calculated in the step (S4) or comparing the minimum electric gap calculated in the (S3) with the design electric gap calculated in the step (S4) for judging alarm and returning to the step (S1). The invention has the advantages of good line safety and high accuracy.

Description

A galloping early warning method for overhead transmission lines

technical field

The invention relates to the field of online monitoring of overhead transmission lines in the field of electric power, in particular to a galloping early warning method for overhead transmission lines.

Background technique

Overhead transmission line galloping is a self-excited vibration with low frequency (0.1-3Hz) and large amplitude (5-300 times the diameter of the wire) generated by ice-coated wires. Its formation mainly depends on three aspects: ice coating, wind speed and wind direction , line structure and parameters.

The hazards of conductor galloping can be divided into two categories: one is phase-to-phase flashover or discharge accidents relative to overhead ground wires caused by large conductor galloping amplitude; the other is the large dynamic load generated by conductor galloping on insulators, fittings, conductors And towers cause impact damage, leading to local damage and even serious grid accidents such as tower collapse.

At present, there are two main methods for monitoring and early warning of galloping in transmission lines: one is to analyze the galloping trajectory by using the images captured by the camera during galloping, and judge the galloping amplitude qualitatively; the other is to arrange multiple sensors along the line to collect galloping parameters and fit the conductor galloping trajectory , calculate the galloping amplitude, frequency and half-wave number, and warn the conductor galloping from the aspect of amplitude (ie height). Apparently, the prior art lacks a method for early warning of wire galloping from this aspect of regularly changing force.

Although tension sensors (such as fiber grating strain sensors) have been used to monitor the increase of loads such as icing on transmission lines, their acquisition methods are fixed regardless of galloping or not. Related, the monitoring results cannot fully reflect the dynamic load change of the wire galloping, and there is no specific way to realize the fault warning for the monitored dynamic force, and there is no realization method to calculate the galloping amplitude based on the change of the dynamic force, so it is currently impossible to accurately analyze the galloping process. The stress situation of transmission lines and towers, let alone the comprehensive analysis of galloping parameters to achieve the purpose of early warning of galloping accidents of the above two types of transmission lines.

Contents of the invention

The purpose of the present invention is to overcome above-mentioned deficiency, provide a kind of galloping early warning method of overhead transmission line, it has solved current early warning method and only monitors amplitude aspect and does not have transmission line dynamic load change monitoring, and lacks through integrated amplitude and dynamic load change monitoring Results The early warning wire galloping, which may cause damage to the wires, insulators, fittings and towers, etc., can effectively avoid galloping accidents, and has the advantages of good safety and high accuracy.

The purpose of the present invention is achieved through the following technical solutions: a galloping early warning method for overhead transmission lines, comprising the following steps:

S1. Monitor the dynamic load change of the ice-coated conductor, and measure the vertical load and horizontal load data in at least one cycle;

S2. Estimate the wire galloping amplitude A according to the change of the horizontal dynamic load;

S3, according to the dynamic load measurement of the wire galloping in the step S1 and the wire galloping amplitude A in the step S2, carry out the calculation of the maximum dynamic load and the minimum electrical clearance;

S4. Carry out design load calculation and design electrical clearance calculation according to the design parameters of suspension insulator strings and fittings, overhead transmission line conductors and straight towers;

S5. Compare the maximum dynamic load in step S3 with the design load in step S4, or compare the minimum electrical clearance in step S3 with the design electrical clearance in step S4, make an early warning judgment, and return to step S1.

For better realization of the present invention, said step S1 specifically refers to:

When the line equivalent ice thickness h>0, the wire vibration sensor is fixed on the wire, and the wire galloping frequency v is measured by the wire vibration sensor, then the galloping cycle time T=1/v;

Fix the wire tension sensor on the surface of the wire, and continuously measure the change data of the line horizontal load F _h (t) in at least one cycle T through the wire tension sensor;

The insulator string tension sensor is installed on the upper end of the insulator string, and the change data of the line vertical load F _v (t) in at least one period T is continuously measured by the insulator string tension sensor.

Preferably, the wire tension sensor and the insulator string tension sensor are resistance strain sensors or optical fiber grating strain sensors.

Preferably, said S2 specifically includes the following steps:

S2.1 Calculate the static line length S _s of the ice-coated conductor:

Calculate the static displacement f _s (x) of the ice-covered conductor before galloping as follows:

f _s (x)＝xtanβ-γx(lx)/(2F ₀ cosβ)

In the formula, γ is the load per unit length of the ice-coated conductor, β is the height difference angle, l is the span, and F ₀ is the static horizontal load of the ice-coated conductor;

Find F ₀ by the following formula:

${\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="3"\; label="l"\; filenames="HSA00000326827900011.png,HSA00000326827900012.png"\; state="\{\{state\}\}">l</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 3</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&beta;</span>}}{\mathrm{<span\; class="notranslate">\; twenty\; four</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&beta;</span>}<span\; class="notranslate">\; )</span>}}$

In the formula, S _s is the static line length of the ice-coated conductor, and S _s is calculated by the following formula:

${\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; \&Integral;</span>}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="l"\; filenames="HSA00000326827900011.png,HSA00000326827900012.png"\; state="\{\{state\}\}">l</figure-callout></span>}}\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; [</span>\frac{{\mathrm{<span\; class="notranslate">\; df</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; dx</span>}}{<span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}\mathrm{<span\; class="notranslate">\; dx</span>}$

S2.2 Calculation of wire galloping length S _g :

Conductor galloping displacement f _g (x, t) is calculated by the following formula:

f _g (x, t) = A sin (nπx/l) sinwt

In the formula, A is the galloping amplitude of the conductor, n is the galloping half-wave number, w is the galloping angular frequency, w=2πv;

Then the displacement f(x, t) of the dancing wire is

f(x, t) = f _s (x) + f _g (x, t)

The wire galloping length S _g is

${\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; g</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; \&Integral;</span>}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="l"\; filenames="HSA00000326827900011.png,HSA00000326827900012.png"\; state="\{\{state\}\}">l</figure-callout></span>}}\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; [</span>\frac{{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; g</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>}{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}\mathrm{<span\; class="notranslate">\; dx</span>}$

S2.3 Calculate the maximum galloping amplitude A _max :

During galloping, the horizontal load F _h (t) measured by the wire tension sensor fixed on the surface of the wire and the static horizontal load F ₀ of the ice-coated wire satisfy Hooke’s law

F _h (t)-F ₀ =ΔF=kΔS/S _s =k(S _g -S _s )/S _s

In the formula, k=EA _r , E is the comprehensive elastic modulus of the wire, _Ar is the cross-sectional area of the wire;

Substituting the line length calculation formula into the above formula, we get:

①When n is an even number, F _h (t)-F ₀ ≈n ² π ² kA ² sin ² wt/(4l)

②When n is an odd number, F _h (t)-F ₀ ≈n ² π ² kA ² sin ² wt/(4l)-2γklAsinwt/(nπF ₀ cosβ)

＝n ² π ² kA ² sin ² wt/(4l)-16dkAsinwt/(nπl)

In the formula, d is the line sag;

The conductor galloping amplitude A is calculated by the maximum value of the horizontal load of the conductor

F _max = max(F _h (t))

In the formula, A is related to the value of the half-wave number n. Generally, when n exceeds 5, the galloping amplitude does not pose a threat, so the galloping amplitudes with n being 1 to 4 are calculated; since the measured galloping amplitude does not exceed 12 meters, if the maximum If the galloping amplitude is greater than 12 meters, the maximum galloping amplitude is 12 meters, and if the maximum galloping amplitude is less than 12 meters, the maximum value is directly taken as the maximum galloping amplitude A _max .

Preferably, the step S3 calculates the maximum dynamic load and the minimum electrical clearance, specifically referring to:

The maximum dynamic load includes a maximum vertical load F _vmax and a maximum horizontal load F _max , wherein,

F _vmax = max(F _v (t))

F _max = max(F _h (t))

The minimum electrical clearance includes the minimum electrical clearance relative to the phase and the minimum electrical clearance relative to the ground wire. Among them, the minimum electrical clearance D _p-pmin relative to the phase and the minimum electrical clearance D _p-gmin relative to the ground wire are respectively obtained by the following formula:

D _p-pmin = D _pp -2A _max

Dp _-gmin = _Dpg - _Amax

In the formula, D _pp is the vertical phase-to-phase distance, and D _pg is the vertical relative ground distance.

Preferably, the design parameters of the suspension insulator string and fittings, overhead transmission line conductors and straight towers in the step S4 include the electromechanical failure load F _I of the insulator and its safety factor S _fI , the mechanical strength F _H of the fittings and its safety factor S _fH , the calculated breaking force F _C of the conductor and its safety factor S _fC , the self-weight of the conductor m, the designed ice thickness of the conductor h _m and the vertical span of the tower l _V ;

The design load calculation carried out in the step S4 includes design vertical load calculation and design horizontal load calculation; wherein, the design vertical load calculation is

F _v0 = min(F _T0 , F _I0 , F _H0 )

F _T0 ＝n ₁ γ _m l _V

F _I0 ＝F _I /S _fI

F _H0 ＝F _H /S _fH

In the formula, n ₁ is the splitting number of the conductor, γ _m is the load per unit length of the conductor under the design ice thickness, and γ _m is calculated by using m and h _m ;

The design horizontal load is calculated as

F _h0 ＝F _C /S _fC

The design electrical clearance includes the minimum design electrical clearance relative to the phase and the minimum design electrical clearance relative to the ground _wire . Gap refers to the minimum air gap d _pg relative to ground where no discharge occurs.

Preferably, in the step S5, the maximum dynamic load in the step S3 is compared with the design load in the step S4, or the minimum electrical clearance in the step S3 is compared with the design electrical clearance in the step S4, and an early warning judgment is performed, specifically refer to:

a. When the maximum vertical load exceeds or is equal to the design vertical load, or the maximum horizontal load exceeds or is equal to the design horizontal load, a galloping overload warning signal is issued;

b. When the minimum electrical clearance of the relative phase is less than or equal to the minimum design electrical clearance of the relative phase, or the minimum electrical clearance of the relative ground wire is less than or equal to the minimum design electrical clearance of the relative ground wire, an early warning signal of galloping amplitude exceeding the standard is issued.

Preferably, the type of the wire is aluminum steel cored wire or aluminum alloy steel cored wire.

Preferably, the hardware is a wire clamp.

Compared with the prior art, the present invention has the following beneficial effects:

First, a reasonable dynamic load collection method is provided: the present invention proposes to collect dynamic load data according to the galloping frequency, which meets the requirement of low energy consumption of the online monitoring system, and solves the problem of high energy consumption of unfounded and long-term collection methods The problem.

Second, improve accuracy, effectively avoid accidents, and improve line safety: a galloping early warning method for overhead transmission lines provided by the present invention proposes an implementation method for estimating the galloping amplitude of conductors based on conductor galloping load changes, and proposes specific mechanics and The implementation method of early warning of wire galloping faults in electrical aspects ensures the safety of transmission lines.

Description of drawings

Fig. 1 is the dynamic load measurement schematic diagram of wire galloping in embodiment 1;

Fig. 2 is the dynamic load measurement schematic diagram of wire galloping in embodiment 2;

Fig. 3 is a working flow chart of the galloping early warning method of the overhead transmission line in Embodiments 1 and 2.

Detailed ways

The present invention will be described in further detail below in conjunction with the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

Example 1

Referring to FIG. 1 , embodiment 1 of the present invention includes a conductor vibration sensor 1 , a conductor tension sensor 2 , an insulator string tension sensor 3 , a hanging insulator string and fittings 4 , an overhead transmission line conductor 5 , and a straight tower 6 . The hardware is a wire clip.

A galloping early warning method for overhead transmission lines in this embodiment includes the following steps:

Step S1, monitoring the dynamic load change of the ice-coated conductor:

When the line equivalent ice thickness h>0, use the wire vibration sensor 1 to measure the wire galloping frequency v, galloping cycle time T=1/v, and use the wire tension sensor 2 and the insulator string tension sensor 3 to continuously measure at least one cycle T The data of horizontal load F _h (t) and vertical load F _v (t) in .

Wherein the line equivalent icing thickness h can be calculated by the existing monitoring technology, the wire vibration sensor 1 is fixed on the wire, the wire tension sensor 2 and the insulator string tension sensor 3 can be resistance strain sensors or optical fiber grating strain sensors; 2 is fixed on the surface of the wire to measure the change data of the horizontal load F _h (t) of the line; the tension sensor 3 of the insulator string is installed on the upper end of the insulator string to measure the change data of the vertical load F _v (t) of the line.

Step S2, estimate the conductor galloping amplitude A according to the change of the horizontal dynamic load:

The static displacement f _s (x) of the ice-coated conductor before galloping is

f _s (x)＝xtanβ-γx(lx)/(2F ₀ cosβ)

In the formula, γ is the load per unit length of the ice-coated conductor, β is the height difference angle, l is the span, and F ₀ is the static horizontal load of the ice-coated conductor, that is, the horizontal tension.

F ₀ is obtained by the following formula:

${\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="3"\; label="l"\; filenames="HSA00000326827900011.png,HSA00000326827900012.png"\; state="\{\{state\}\}">l</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 3</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&beta;</span>}}{\mathrm{<span\; class="notranslate">\; twenty\; four</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&beta;</span>}<span\; class="notranslate">\; )</span>}}$

In the formula, S _s is the static line length of the ice-coated conductor, and S _s is calculated by the following formula:

${\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; \&Integral;</span>}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="l"\; filenames="HSA00000326827900011.png,HSA00000326827900012.png"\; state="\{\{state\}\}">l</figure-callout></span>}}\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; [</span>\frac{{\mathrm{<span\; class="notranslate">\; df</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; dx</span>}}{<span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}\mathrm{<span\; class="notranslate">\; dx</span>}$

The stable wire galloping shape is approximately a simple harmonic, then the wire galloping displacement f _g (x, t) is

f _g (x, t) = A sin (nπx/l) sinwt

In the formula, A is the galloping amplitude of the conductor, n is the galloping half-wave number, w is the galloping angular frequency, w=2πv;

Then the displacement f(x, t) of the dancing wire is

f(x, t) = f _s (x) + f _g (x, t)

The wire galloping length S _g is

${\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; g</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; \&Integral;</span>}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="l"\; filenames="HSA00000326827900011.png,HSA00000326827900012.png"\; state="\{\{state\}\}">l</figure-callout></span>}}\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; [</span>\frac{{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; g</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>}{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}\mathrm{<span\; class="notranslate">\; dx</span>}$

When galloping, the horizontal load F _h (t) measured by the wire tension sensor 2 fixed on the surface of the wire and the static horizontal load F ₀ of the ice-coated wire satisfy Hooke’s law

F _h (t)-F ₀ =ΔF=kΔS/S _s =k(S _g -S _s )/S _s

In the formula, k=EA _r , E is the comprehensive elastic modulus of the wire, and _Ar is the cross-sectional area of the wire.

Substituting the line length calculation formula into the above formula, we get

①When n is an even number, F _h (t)-F ₀ ≈n ² π ² kA ² sin ² wt/(4l)

②When n is an odd number, F _h (t)-F ₀ ≈n ² π ² kA ² sin ² wt/(4l)-2γklAsinwt/(nπF ₀ cosβ)

＝n ² π ² kA ² sin ² wt/(4l)-16dkAsinwt/(nπl)

In the formula, d is the line sag.

Obviously, in the above two formulas, the maximum horizontal load of the conductor is related to the galloping amplitude A and the half-wave number n. At this time, the galloping amplitude A of the conductor can be calculated by the maximum value F _{max of} the horizontal load of the conductor

F _max = max(F _h (t))

In the formula, A is related to the value of the half-wave number n. Generally, when n exceeds 5, the galloping amplitude does not pose a threat. Therefore, the galloping amplitude with n being 1 to 4 is calculated. Since the measured galloping amplitude does not exceed 12 meters, if the maximum galloping amplitude is greater than 12 meters, take the maximum galloping amplitude as 12 meters, and if it is smaller, directly take the maximum value as the maximum galloping amplitude A _max .

Step S3, carry out galloping warning of transmission line, as shown in Fig. 3, according to the design parameters of hanging insulator string and fittings 4, overhead transmission line conductor 5 and straight tower 6, carry out design load calculation and design electrical clearance calculation; Load measurement and amplitude estimation data are used to calculate the maximum dynamic load and minimum electrical clearance; when the maximum dynamic load exceeds the design load or the minimum electrical clearance is smaller than the design electrical clearance, an early warning message is issued.

Described step S3 comprises the following steps:

S3.1 Calculate the maximum dynamic load and minimum electrical clearance:

The maximum dynamic load in the step S3 includes a maximum vertical load F _vmax and a maximum horizontal load F _max , wherein,

F _vmax = max(F _v (t))

F _max = max(F _h (t))

The minimum electrical clearance includes the minimum electrical clearance relative to the phase and the minimum electrical clearance relative to the ground wire, where the minimum electrical clearance D _p-pmin relative to the phase and the minimum electrical clearance D _p-gmin relative to the ground wire are respectively

D _p-pmin = D _pp -2A _max

Dp _-gmin = _Dpg - _Amax

In the formula, D _pp is the vertical phase-to-phase distance, and D _pg is the vertical relative ground distance.

S3.1 Perform design load calculation and design electrical clearance calculation:

The design parameters of the suspension insulator string and fittings 4, overhead transmission line conductors 5 and straight towers 6 in the step S3 specifically include the electromechanical failure load F _I of the insulator and its safety factor S _fI , the mechanical strength F _H of the fittings and its safety. Factor S _fH , the calculated breaking force F _C of the conductor and its safety factor S _fC , the self-weight of the conductor m, the design ice thickness of the conductor h _m and the vertical span of the tower l _V .

The design load calculations carried out include design vertical load calculations and design horizontal load calculations; where the design vertical load calculations are

F _v0 = min(F _T0 , F _I0 , F _H0 )

F _T0 ＝n ₁ γ _m l _V

F _I0 ＝F _I /S _fI

F _H0 ＝F _H /S _fH

In the formula, n ₁ is the splitting number of the conductor, γ _m is the load per unit length of the conductor under the design ice thickness, and γ _m is calculated by using m and h _m ;

The design horizontal load is calculated as

F _h0 ＝F _C /S _fC

The design electrical clearance includes the minimum design electrical clearance relative to the phase and the minimum design electrical clearance relative to the ground _wire . Gap refers to the minimum air gap d _pg relative to the ground where no discharge occurs;

S3.3 Early warning judgment based on maximum dynamic load or minimum electrical clearance:

When F _vmax ≥ F _v0 , or F _max ≥ _{F h0} , a galloping overload warning signal is issued;

When D _p-pmin ≤ d _pp , or D _p-gmin ≤ d _pg , an early warning signal of excessive galloping amplitude is issued.

Example 2

The present invention can be implemented by installing tension sensors on the straight line tower and the tension tower in the same file. Referring to FIG. 2 , embodiment 2 of the present invention includes a wire vibration sensor 1, a wire tension sensor 2, an insulator string tension sensor 3, an insulator string and fittings. 4. Overhead transmission lines 5, straight towers 6, and tension towers 13.

Adopt embodiment 2 a kind of galloping early warning method of overhead transmission line, comprise the following steps:

Step S1, monitoring the dynamic load change of the ice-coated conductor:

When the line equivalent ice thickness h>0, use the wire vibration sensor 1 to measure the wire galloping frequency v, galloping cycle time T=1/v, and use the wire tension sensor 2 and the insulator string tension sensor 3 to continuously measure at least one cycle T The data of horizontal load F _h (t) and vertical load F _v (t) in .

Wherein the line equivalent ice thickness h can be calculated by the existing monitoring technology, the wire vibration sensor 1 is fixed on the wire, the wire tension sensor 2 and the insulator string tension sensor 3 can be resistance strain sensors or optical fiber grating strain sensors, wire tension sensors 2 is fixed on the surface of the wire to measure the change data of the horizontal load F _h (t) of the line; the tension sensor 3 of the insulator string is installed on the upper end of the insulator string to measure the change data of the vertical load F _v (t) of the line.

Step S2, estimate the wire galloping amplitude A according to the change of the horizontal dynamic load:

The static displacement f _s (x) of the ice-coated conductor before galloping is

f _s (x)＝xtanβ-γx(lx)/(2F ₀ cosβ)

In the formula, γ is the load per unit length of the ice-coated conductor, β is the height difference angle, l is the span, and F ₀ is the static horizontal load of the ice-coated conductor, that is, the horizontal tension.

F ₀ is obtained by the following formula:

${\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="3"\; label="l"\; filenames="HSA00000326827900011.png,HSA00000326827900012.png"\; state="\{\{state\}\}">l</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 3</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&beta;</span>}}{\mathrm{<span\; class="notranslate">\; twenty\; four</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&beta;</span>}<span\; class="notranslate">\; )</span>}}$

In the formula, S _s is the static line length of the ice-coated conductor, and S _s is calculated by the following formula:

${\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; \&Integral;</span>}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="l"\; filenames="HSA00000326827900011.png,HSA00000326827900012.png"\; state="\{\{state\}\}">l</figure-callout></span>}}\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; [</span>\frac{{\mathrm{<span\; class="notranslate">\; df</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; dx</span>}}{<span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}\mathrm{<span\; class="notranslate">\; dx</span>}$

The stable wire galloping shape is approximately a simple harmonic, then the wire galloping displacement f _g (x, t) is

f _g (x, t) = Asin(nπx/l) sinwt

In the formula, A is the galloping amplitude of the conductor, n is the galloping half-wave number, w is the galloping angular frequency, w=2πv;

Then the displacement f(x, t) of the dancing wire is

f(x, t) = f _s (x) + f _g (x, t)

The wire galloping length S _g is

${\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; g</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; \&Integral;</span>}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="l"\; filenames="HSA00000326827900011.png,HSA00000326827900012.png"\; state="\{\{state\}\}">l</figure-callout></span>}}\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; [</span>\frac{{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; g</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>}{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}\mathrm{<span\; class="notranslate">\; dx</span>}$

When galloping, the horizontal load F _h (t) measured by the wire tension sensor 2 fixed on the surface of the wire and the static horizontal load F ₀ of the ice-coated wire satisfy Hooke’s law

F _h (t)-F ₀ =ΔF=kΔS/S _s =k(S _g -S _s )/S _s

In the formula, k=EA _r , E is the comprehensive elastic modulus of the wire, and _Ar is the cross-sectional area of the wire.

Substituting the line length calculation formula into the above formula, we get

①When n is an even number, F _h (t)-F ₀ ≈n ² π ² kA ² sin ² wt/(4l)

②When n is an odd number, F _h (t)-F ₀ ≈n ² π ² kA ² sin ² wt/(4l)-2γklAsinwt/(nπF ₀ cosβ)

＝n ² π ² kA ² sin ² wt/(4l)-16dkAsinwt/(nπl)

In the formula, d is the line sag.

Obviously, in the above two formulas, the maximum horizontal load of the conductor is related to the galloping amplitude A and the half-wave number n. At this time, the galloping amplitude A of the conductor can be calculated by the maximum horizontal load of the conductor

F _max = max(F _h (t))

In the formula, A is related to the value of the half-wave number n. Generally, when n exceeds 5, the galloping amplitude does not pose a threat. Therefore, the galloping amplitude with n being 1 to 4 is calculated. Since the measured galloping amplitude does not exceed 12 meters, if the maximum galloping amplitude is greater than 12 meters, take the maximum galloping amplitude as 12 meters, and if it is smaller, directly take the maximum value as the maximum galloping amplitude A _max .

Step S3, carry out galloping warning of transmission line, as shown in Fig. 3, according to the design parameters of hanging insulator string and fittings 4, overhead transmission line conductor 5 and straight tower 6, carry out design load calculation and design electrical clearance calculation; Load measurement and amplitude estimation data are used to calculate the maximum dynamic load and minimum electrical clearance; when the maximum dynamic load exceeds the design load or the minimum electrical clearance is smaller than the design electrical clearance, an early warning message is issued.

Described step S3 specifically comprises:

S3.1 Calculate the maximum dynamic load and minimum electrical clearance:

The maximum dynamic load includes a maximum vertical load F _vmax and a maximum horizontal load F _max . in,

F _vmax = max(F _v (t))

F _max = max(F _h (t))

The minimum electrical clearance includes the phase-to-phase minimum electrical clearance and the phase-to-ground minimum electrical clearance, where the phase-to-phase minimum electrical clearance Dp _-pmin and the phase-to-ground minimum electrical clearance Dp _-gmin are respectively

D _p-pmin = D _pp -2A _max

Dp _-gmin = _Dpg - _Amax

In the formula, D _pp is the vertical phase-to-phase distance, and D _pg is the vertical relative ground distance.

S3.2 Perform design load calculation and design electrical clearance calculation:

The design parameters of the suspension insulator string and fittings 4, overhead transmission line conductors 5 and straight towers 6 in the step S3 specifically include the electromechanical failure load F _I of the insulator and its safety factor S _fI , the mechanical strength F _H of the fittings and its safety. Factor S _fH , the calculated breaking force F _C of the conductor and its safety factor S _fC , the self-weight of the conductor m, the design ice thickness of the conductor h _m and the vertical span of the tower l _V .

The design load calculations carried out include design vertical load calculations and design horizontal load calculations; where the design vertical load calculations are

F _v0 = min(F _T0 , F _I0 , F _H0 )

F _T0 ＝n ₁ γ _m l _V

F _I0 ＝F _I /S _fI

F _H0 ＝F _H /S _fH

In the formula, n ₁ is the splitting number of the conductor, γ _m is the load per unit length of the conductor under the design ice thickness, and γ _m is calculated by using m and h _m ;

The design horizontal load is

F _h0 = min(F _C0 , F _I0 , F _H0 )

F _C0 ＝F _C /S _fC

The design electrical clearance includes the minimum design electrical clearance relative to the phase and the minimum design electrical clearance relative to the ground _wire . Gap refers to the minimum air gap d _pg relative to the ground where no discharge occurs;

S3.3 Early warning judgment based on maximum dynamic load or minimum electrical clearance:

In the step S3, when F _vmax ≥ F _v0 , or F _max ≥ _{F h0} , a galloping overload warning signal is issued;

When D _p-pmin ≤ d _pp , or D _p-gmin ≤ d _pg , an early warning signal of excessive galloping amplitude is issued.

Apparently, those skilled in the art should understand that each step or each module of the present invention described above can be realized by a general-purpose computing device, and they can be concentrated on a single computing device or distributed on a network formed by multiple computing devices. Therefore, they can be stored in a storage device to be executed by a computing device, or they can be fabricated into individual integrated circuit modules, or multiple steps or modules can be implemented in a single integrated circuit module. Thus, the present invention is not limited to any specific combination of hardware and software.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the embodiment, and any other changes, modifications, substitutions and combinations made without departing from the spirit and principle of the present invention , simplification, all should be equivalent replacement methods, and are all included in the protection scope of the present invention.

Claims (6)

1. The early warning method for the galloping of the overhead transmission line is characterized by comprising the following steps of:

s1, monitoring the dynamic load change condition of the ice-coated conductor, and measuring the data of vertical load and horizontal load in at least one period, wherein the data specifically comprises the following steps:

when the equivalent ice coating thickness h of the line is larger than 0, fixing a lead vibration sensor on the lead, and measuring the lead galloping frequency v through the lead vibration sensor, wherein the galloping period time T is 1/v;

fixing the wire tension sensor on the surface of the wire byThe wire tension sensor continuously measures the horizontal load F of the line in at least one period T_h(t) change data;

installing an insulator string tension sensor at the upper end of an insulator string, and continuously measuring the vertical load F of the line in at least one period T by the insulator string tension sensor_v(t) change data;

s2, estimating the wire galloping amplitude A according to the horizontal dynamic load change, which comprises the following steps:

s2.1 calculating the static line length S of the ice-coated wire_s：

The static displacement f of the ice-coated conductor before the waving is obtained by_s(x)：

f_s(x)＝xtanβ-γx(l-x)/(2F₀cosβ)

Wherein gamma is the load of the ice-coated wire per unit length, beta is the height difference angle, l is the span, F₀Static horizontal load of the ice-coated wire;

f was determined by the following equation₀：

<math> <mrow> <msub> <mi>F</mi> <mn>0</mn> </msub> <msqrt> <mfrac> <mrow> <msup> <mi>&gamma;</mi> <mn>2</mn> </msup> <msup> <mi>l</mi> <mn>3</mn> </msup> <mi>cos</mi> <mi>&beta;</mi> </mrow> <mrow> <mn>24</mn> <mrow> <mo>(</mo> <msub> <mi>S</mi> <mi>s</mi> </msub> <mo>-</mo> <mi>l</mi> <mo>/</mo> <mi>cos</mi> <mi>&beta;</mi> <mo>)</mo> </mrow> </mrow> </mfrac> </msqrt> </mrow> </math>

In the formula, S_sFor icing the static wire length, S_sCalculated by the following formula:

<math> <mrow> <msub> <mi>S</mi> <mi>s</mi> </msub> <mo>=</mo> <msubsup> <mo>&Integral;</mo> <mn>0</mn> <mi>l</mi> </msubsup> <msqrt> <mn>1</mn> <mo>+</mo> <msup> <mrow> <mo>[</mo> <mfrac> <mrow> <msub> <mi>df</mi> <mi>s</mi> </msub> <mrow> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> </mrow> <mi>dx</mi> </mfrac> <mo>]</mo> </mrow> <mn>2</mn> </msup> </msqrt> <mi>dx</mi> </mrow> </math>

s2.2 calculating the wire galloping length S_g：

Conductor galloping displacement f_g(x, t) is determined by the following equation:

f_g(x，t)＝Asin(nπx/l)sinwt

in the formula, A is a wire galloping amplitude, n is a galloping half wave number, w is a galloping angular frequency, and w is 2 pi v;

the displacement f (x, t) of the dancing wire is

f(x，t)＝f_s(x)+f_g(x，t)

Conductor galloping line length S_gIs composed of

<math> <mrow> <msub> <mi>S</mi> <mi>g</mi> </msub> <mo>=</mo> <msubsup> <mo>&Integral;</mo> <mn>0</mn> <mi>l</mi> </msubsup> <msqrt> <mn>1</mn> <mo>+</mo> <msup> <mrow> <mo>[</mo> <mfrac> <mrow> <msub> <mrow> <mo>&PartialD;</mo> <mi>f</mi> </mrow> <mi>g</mi> </msub> <mrow> <mo>(</mo> <mi>x</mi> <mo>,</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> <mrow> <mo>&PartialD;</mo> <mi>x</mi> </mrow> </mfrac> <mo>]</mo> </mrow> <mn>2</mn> </msup> </msqrt> <mi>dx</mi> </mrow> </math>

S2.3 obtaining the maximum waving amplitude A_max：

During waving, the horizontal load F measured by the wire tension sensor fixed on the surface of the wire_h(t) and static horizontal load of iced conductor F₀Satisfy Hooke's law

F_h(t)-F₀＝ΔF＝kΔS/S_s＝k(S_g-S_s)/S_s

Wherein k is EA_rE is the overall modulus of elasticity of the wire, A_rIs the cross-sectional area of the wire;

substituting the line length calculation formula into the formula to obtain:

when n is even number, F_h(t)-F₀≈n²π²kA²sin²wt/(4l)

F when n is odd number_h(t)-F₀≈n²π²kA²sin²wt/(4l)-2γklAsinwt/(nπF₀cosβ)

＝n²π²kA²sin²wt/(4l)-16dkAsinwt/(nπl)

In the formula, d is a circuit sag;

calculating the wire galloping amplitude A through the maximum value of the horizontal load of the wire

In the formula, calculating the galloping amplitude A of which n is 1 to 4 respectively, and if the maximum galloping amplitude is larger than 12 m, taking the maximum galloping amplitude A_maxIs 12 meters, and if the maximum galloping amplitude is less than 12 meters, the maximum value is directly taken as the maximum galloping amplitude A_max；

S3 dynamic load measurement according to conductor galloping in step S1And the wire galloping amplitude A in the step S2, and calculating the maximum dynamic load and the minimum electric gap, wherein the maximum dynamic load comprises the maximum vertical load F_vmaxAnd maximum horizontal load F_maxWherein

F_vmax＝max(F_v(t))

F_max＝max(F_h(t))

the minimum electrical gap comprises a relative phase minimum electrical gap and a relative ground line minimum electrical gap, wherein the relative phase minimum electrical gap D_p-pminAnd minimum electrical clearance to earth wire D_p-gminThe following equations were respectively obtained:

D_p-pmin＝D_p-p-2A_max

D_p-gmin＝D_p-g-A_max

in the formula, D_p-pIs a vertical spacing distance, D_p-gIs the vertical relative ground distance;

s4, calculating design load and electric clearance according to design parameters of the suspension insulator string, hardware fittings, overhead transmission line conductors and tangent towers;

and S5, comparing the maximum dynamic load in the step S3 with the designed load in the step S4, or comparing the minimum electric clearance in the step S3 with the designed electric clearance in the step S4, carrying out early warning judgment, and returning to the step S1.

2. The overhead transmission line galloping early warning method of claim 1, wherein the lead tension sensor and the insulator string tension sensor are resistance strain type sensors or fiber grating strain sensors.

3. The overhead transmission line galloping early warning method of claim 1, wherein the design parameters of the suspended insulator string and hardware, the overhead transmission line conductor and the tangent tower in the step S4 comprise electromechanical damage load F of the insulator_IAnd its safety factor S_fIMechanical strength F of hardware_HAnd its safety factor S_fHCalculated breaking force F of wire_CAnd its safety factor S_fCThe dead weight m of the lead, the designed ice coating thickness h of the lead_mAnd tower vertical span l_V；

The design load calculation performed in the step S4 includes design vertical load calculation and design horizontal load calculation; wherein the design vertical load is calculated as

F_v0＝min(F_T0，F_I0，F_H0)

F_T0＝n_lγ_ml_V

F_I0＝F_I/S_fI

F_H0＝F_H/S_fH

In the formula, n_lNumber of split conductors, gamma_mFor designing the load of the conductor under ice thickness per unit length, gamma_mCalculating by using m and hm;

the design horizontal load is calculated as

F_h0＝F_C/S_fC

The designed electrical gap comprises a relative phase minimum designed electrical gap and a relative ground wire minimum designed electrical gap, wherein the relative phase minimum designed electrical gap is specifically a minimum air gap d of an interphase conductor without discharge_p-p’The minimum designed electrical gap with respect to the ground wire is the minimum air gap d of the ground wire without discharge_p-g。

4. The method according to claim 3, wherein in step S5, the maximum dynamic load in step S3 is compared with the design load in step S4, or the minimum electrical gap in step S3 is compared with the design electrical gap in step S4, and an early warning judgment is performed, specifically:

a. when the maximum vertical load exceeds or equals to the design vertical load or the maximum horizontal load exceeds or equals to the design horizontal load, a galloping overload early warning signal is sent out;

b. and when the minimum electrical clearance of the relative phase is smaller than or equal to the minimum designed electrical clearance of the relative phase, or the minimum electrical clearance of the relative ground wire is smaller than or equal to the minimum designed electrical clearance of the relative ground wire, sending out a warning signal that the galloping amplitude exceeds the standard.

5. The overhead transmission line galloping early warning method of claim 1, wherein the type of the wire is a steel-cored aluminum strand or a steel-cored aluminum alloy strand.

6. The early warning method for galloping of the overhead transmission line according to claim 1, wherein the hardware is a wire clamp.

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