CN103913221A - Method for measuring deicing jump damping coefficients of iced power transmission line - Google Patents

Abstract

The invention discloses a method for measuring deicing jump damping coefficients of an iced power transmission line. The method comprises the following steps that a time-displacement curve under the deicing jump of the test power transmission line is measured; simulation power transmission lines identical with the test power transmission line in initial state and deicing condition are calculated according to a formula (please see the formula in the specification), and time-displacement curves under the different damping coefficients are calculated; in the time-displacement curves of the simulation power transmission lines under the different damping coefficients, the time-displacement curve of the certain simulation power transmission line close to the time-displacement curve of the test power transmission line is selected, and the damping coefficient corresponding to the time-displacement curve of the certain simulation power transmission line is used as the damping coefficient of the test power transmission line under the initial state. The method can obtain the accurate damping coefficients of the test power transmission line.

Description

Icing power transmission line ice-shedding ratio of damping measuring method

[technical field]

The present invention relates to ultra-high-tension power transmission line design and test, relates in particular to icing power transmission line ice-shedding ratio of damping measuring method.

[background technology]

Overhead transmission line long-time running is subject to the interference of the impersonal force such as wind, icing factor in atmospheric environment.China is the most serious country of icing, and the probability that circuit Harm Accident occurs occupy prostatitis, the world.One of icing three large harm to the normal operation of transmission line of electricity are inhomogeneous icing or do not deice the Tension Difference of generation the same period, on electric, may cause phase fault tripping operation, flashover, mechanically insulator chain, shaft tower are formed to larger unbalanced tensile force damage insulator and even cause that shaft tower collapses, directly threaten the safe operation of electric system.In addition along with the unprecedented expansion of hydroelectric resources construction scale in development of the West Regions, over distance is super, UHV transmission will pass through high and cold, high humidity, re-cover ice and high altitude localities, powerline ice-covering disaster problem will be more outstanding, and wherein icing power transmission line ice-shedding problem is exactly one of the content that need to carry out in a deep going way research.Flourish along with China's extra-high voltage grid, sectional area of wire increases, and division number increases, the research that power transmission line ice-shedding problem need to be more deep.

In wire dynamics problem, the structure of damping matrix or the value of ratio of damping are comparatively complicated, are also the emphasis places of wire dynamic analysis.The value of lead wire damping parameter generally should be surveyed by test, but current test figure comparatively lacks, so both at home and abroad in the time of research wire dynamics problem, choosing generally of damping parameter chosen based on experience value, most of values do not have test basis.Damping parameter is very important in the calculating of power transmission line ice-shedding, the value of damping parameter directly affects the result of calculation of ice-shedding process, one accurately damping parameter be the prerequisite that obtains ice-shedding accurate result of calculation, so be necessary that in the time of research ice-shedding problem the ice-shedding that carries out true molded line road tests to obtain damping parameter accurately.

[summary of the invention]

In order to overcome the deficiencies in the prior art, the invention provides a kind of icing power transmission line ice-shedding ratio of damping measuring method, to measure the ratio of damping under icing power transmission line ice-shedding.

Icing power transmission line ice-shedding ratio of damping measuring method, comprises the steps:

Test power transmission line time-displacement curve measuring process, measures the time-displacement curve under test power transmission line ice-shedding;

Emulation power transmission line time-displacement curve calculation procedure, according to calculating has and the test identical original state of power transmission line and the identical emulation power transmission line that deices condition, the time-displacement curve under different ratio of damping, wherein,

$\stackrel{\·}{X}\left(t\right)=\frac{X(t+\mathrm{\Δt})-X(t-\mathrm{\Δt})}{2\mathrm{\Δt}},$

$\stackrel{\·\·}{X}\left(t\right)=\frac{X(t+\mathrm{\Δt})+X(t-\mathrm{\Δt})-2X\left(t\right)}{{\mathrm{\Δt}}^2},$

$K=\frac{E\×A+\frac{\sqrt{\mathrm{\Δ}{x}^2+\mathrm{\Δ}{y}^2+\mathrm{\Δ}{z}^2}}{\mathrm{\Δz}}T}{\sqrt{\mathrm{\Δ}{x}^2+\mathrm{\Δ}{y}^2+\mathrm{\Δ}{z}^2}}$

Wherein, the gross mass of described emulation power transmission line and the external force being subject to are distributed on each point of load discretely, and M is the mass matrix of the emulation power transmission line point of load, and P is the external force matrix that emulation power transmission line is subject to, and C is ratio of damping, for the acceleration matrix of the emulation power transmission line point of load, for the speed matrix of the emulation power transmission line point of load, the elastic modulus that E is power transmission line, the sectional area that A is power transmission line, the static tension force that T is power transmission line; The described identical condition that deices refers to: measure test power transmission line departs from certain quality icing in certain position, emulation power transmission line departs from the analog-quality of equal in quality on the point of load of identical position accordingly,

(t-Δ t) represents that the displacement of the t-Δ t moment i+1 point of load, X (t) represent the displacement of the i+1 point of load described in the t moment to X, and (t+ Δ t) represents the displacement of the i+1 point of load described in the t+ Δ t moment to X;

Δ x=x (i+1)-x (i), Δ y=y (i+1)-y (i), Δ z=z (i+1)-z (i), wherein x (i+1), y (i+1), z (i+1) is respectively the i+1 point of load at three coordinates in t+ Δ t moment, x (i), y (i), z (i) is respectively the i point of load adjacent with the i+1 point of load three coordinates in the t+ Δ t moment;

The ratio of damping determining step of test power transmission line, in the time-displacement curve of the emulation power transmission line under multiple different damping coefficients, choose the time-displacement curve of certain the emulation power transmission line comparatively approaching with the time-displacement curve of testing power transmission line, the ratio of damping using the ratio of damping corresponding time-displacement curve of described certain emulation power transmission line as described test power transmission line under described original state.

In one embodiment,

In the ratio of damping determining step of described test power transmission line: in the time-displacement curve of the emulation power transmission line under multiple different damping coefficients, choose maximum displacement with the maximum displacement of the time-displacement curve of test power transmission line at the time-displacement curve of setting certain the emulation power transmission line within displacement difference.

In one embodiment,

In the ratio of damping determining step of described test power transmission line: in the time-displacement curve of the emulation power transmission line under multiple different damping coefficients, choose the time-displacement curve of the rate of decay of curve crest and certain the emulation power transmission line of the corresponding curve crest rate of decay of the time-displacement curve of test power transmission line within setting speed difference.

In one embodiment,

Δ t≤2/ ω _n, wherein ω _nit is the high-order natural vibration frequency of power transmission line system.

In one embodiment,

The quality of each point of load of emulation power transmission line is m:

q＝ρπb(D+d)

m＝qL/N

Wherein, the quality of ice covering on transmission lines in q representation unit length, ρ represents the density of ice, and b represents transmission line icing thickness, and D represents the diameter of power transmission line, and L represents the length of power transmission line, N represents the number of the point of load.

Adopt technique scheme, can obtain test power transmission line ratio of damping comparatively accurately.

[accompanying drawing explanation]

Fig. 1 is the schematic diagram on the actual power transmission line of an embodiment of the present invention with icing;

Fig. 2 is the schematic diagram that the icing mass concentration of the emulation power transmission line of an embodiment of the present invention is distributed in multiple points of load;

Fig. 3 is the schematic diagram that the power transmission line of Fig. 1 of the present invention evenly deices;

Fig. 4 is the non-homogeneous schematic diagram deicing of the power transmission line of Fig. 1 of the present invention;

Fig. 5 is the schematic diagram evenly deicing of Fig. 2 emulation power transmission line;

Fig. 6 is the non-homogeneous schematic diagram deicing of Fig. 2 emulation power transmission line;

Fig. 7 is the time-displacement curve figure under 750kg that deices of a kind of embodiment;

Fig. 8 is the time-displacement curve figure under 1000kg that deices of a kind of embodiment;

Fig. 9 is the time-displacement curve figure under 1250kg that deices of a kind of embodiment;

Figure 10 be a kind of embodiment deice quality-displacement curve figure;

Figure 11 is the crest height decay schematic diagram corresponding with Fig. 7;

Figure 12 is the crest height decay schematic diagram corresponding with Fig. 8;

Figure 13 is the crest height decay schematic diagram corresponding with Fig. 9.

[embodiment]

Below the preferred embodiment of invention is described in further detail.

As shown in Figure 1, on actual power transmission line 1, there is icing 2, the span of power transmission line is L, and the diameter of power transmission line is D, and the density of ice is ρ, transmission line icing thickness is b, in unit length, the quality of ice covering on transmission lines is q, and the time-displacement curve for power transmission line is jumped at coating ice falling in the situation that carries out simulation calculation, as shown in Figure 2, suppose that the icing mass concentration on power transmission line is distributed on the point of load 3 that quantity is N, carries the weight 4 of respective quality on each point of load.In one embodiment, on each point of load 3, the weight 4 of carrying is identical in quality, is m:

$\left\{\begin{array}{c}q=\mathrm{\ρ\πb}(D+b)\\ m=\mathrm{qL}/N\end{array}\right..$

As shown in Figure 3, the icing 2 on actual power transmission line 1 comes off from power transmission line 1 equably, as shown in Figure 4, and icing 2 parts on power transmission line 1 and coming off from power transmission line 1 unevenly.As shown in Figure 5, in the calculating of emulation power transmission line, weight 4 evenly comes off from power transmission line 1, and as shown in Figure 6, and weight 4 that can emulation power transmission line anisotropically comes off from power transmission line 1.

Test power transmission line time-displacement curve measuring process:

As shown in Figures 3 and 4, if the icing 2 at certain position comes off on power transmission line 1, go out the time dependent numerical value of jump displacement of power transmission line by actual measurement, can obtain the time-displacement curve of power transmission line under ice-shedding.Can adopt the actual jump displacement deicing of camera record test power transmission line.Or, by carrying out the point of load as shown in Figure 2 with simulation ice-coating on identical power transmission line 1, then make the weight 4 of corresponding site depart from power transmission line 1, the jump displacement of recycling camera record test power transmission line, can obtain the time-displacement curve of identical or very approximate power transmission line under ice-shedding too.

Emulation power transmission line time-displacement curve calculation procedure:

The power transmission line of actual icing is modeled to the power transmission line of distributed mass on the discrete point of load as shown in Figure 2, power transmission line is divided into some transmission power line unit sections, the mass concentration of power transmission line is on the point of load of power transmission line, between the point of load, connect by the flexible member that there is no quality, connect with tension force, do not consider the rigidity of its bending and torsion, each point of load can space (X, Y, Z) interior translation (3DOF), the external force that power transmission line is subject to is evenly distributed on each point of load.And emulation power transmission line has the original state (comprise identical power transmission line length, icing quality, initial static tension force, initial displacement etc.) identical with test power transmission line and the identical condition that deices (in same area, the icing of equal in quality departs from power transmission line).

According to above-mentioned prerequisite, list when discrete and inscribe the displacement of power transmission line, the power transmission line kinetics equation of tension state is:

$M\stackrel{\·\·}{X}=P+F_c+T$

Wherein, $F_c=C\stackrel{\·}{X},T=\mathrm{KX};$

M is the mass matrix of the emulation power transmission line point of load, is diagonal matrix, is a known constant, and this mass matrix has represented the quality of each point of load; P is the external force matrix that emulation power transmission line is subject to, and is a known constant; c is ratio of damping; for the acceleration matrix of the emulation power transmission line point of load, it has represented the accekeration of each point of load; for the speed matrix of the emulation power transmission line point of load, it has represented the velocity amplitude of each point of load; E is the elastic modulus of power transmission line, is a constant; A is the sectional area of power transmission line, is a constant; K is stiffness matrix, is determined by the dynamic tension of adjacent two points of load and its deformation quantity, and deformation can be according to the calculative determination to wire displacement above, containing x, and y, tri-directions of z.

$\stackrel{\·}{X}\left(t\right)=\frac{X(t+\mathrm{\Δt})-X(t-\mathrm{\Δt})}{2\mathrm{\Δt}},$

$\stackrel{\·\·}{X}\left(t\right)=\frac{X(t+\mathrm{\Δt})+X(t-\mathrm{\Δt})-2X\left(t\right)}{{\mathrm{\Δt}}^2};$

$K=\frac{E\×A+\frac{\sqrt{\mathrm{\Δ}{x}^2+\mathrm{\Δ}{y}^2+\mathrm{\Δ}{z}^2}}{\mathrm{\Δz}}T}{\sqrt{\mathrm{\Δ}{x}^2+\mathrm{\Δ}{y}^2+\mathrm{\Δ}{z}^2}}$

(t-Δ t) represents that the displacement of the t-Δ t moment i+1 point of load, X (t) represent the displacement of the i+1 point of load described in the t moment to X, and (t+ Δ t) represents the displacement of the i+1 point of load described in the t+ Δ t moment to X;

Δ x=x (i+1)-x (i), Δ y=y (i+1)-y (i), Δ z=z (i+1)-z (i), wherein x (i+1), y (i+1), z (i+1) is respectively the i+1 point of load at three coordinates in t+ Δ t moment, x (i), y (i), z (i) is respectively the i point of load adjacent with the i+1 point of load three coordinates in the t+ Δ t moment;

Preferably, Δ t≤2/ ω _n, wherein ω _nit is the high-order natural vibration frequency of power transmission line system.

Comprehensive above-mentioned various known, in the case of the displacement of certain point of load that obtains continuous the first moment t-Δ t, the second moment t, can obtain the value of the displacement of the i+1 point of load of the 3rd continuous moment t+ Δ t, and the shift value of the i point of load adjacent with the i+1 point of load, thereby can be by continuous iteration, obtain the shift value of follow-up all these points of load of moment, and then under given ratio of damping C, obtain the time-displacement curve of this point of load.

The ratio of damping determining step of test power transmission line, in the time-displacement curve of the emulation power transmission line under multiple different damping coefficients, choose the time-displacement curve of certain the emulation power transmission line comparatively approaching with the time-displacement curve of testing power transmission line, the ratio of damping using the ratio of damping corresponding time-displacement curve of described certain emulation power transmission line as described test power transmission line under described original state.

As shown in Figure 7, that certain point of load of power transmission line deices time-displacement curve under certain quality (750kg) and (approaches or be zero situation in moment of face battle array, displacement approaches or equals jump height), curve S 1 represents the time-displacement curve of actual test power transmission line, and curve S 2, S3, S4 and S5 are to be respectively the time-displacement curve of the emulation power transmission line under 0.05,0.1,0.15 and 0.2 at ratio of damping, the most approaching with curve S 1 through observing curve S 3, thereby, can think that the ratio of damping of this test power transmission line is 0.1 under corresponding condition.

As shown in Figure 8, certain point of load that is power transmission line deices the time-displacement curve under another quality (1000kg), curve S 1 ' the represent time-displacement curve of actual test power transmission line, and curve S 2 ', S3 ', S4 ' and S5 ' be to be respectively the time-displacement curve of the emulation power transmission line under 0.05,0.1,0.15 and 0.2 at ratio of damping, through observation curve S 3 ' with curve S 1 ' the most approaching, thereby, can think that the ratio of damping of this test power transmission line is 0.1 under corresponding condition.

As shown in Figure 9, certain point of load that is power transmission line deices the time-displacement curve under another quality (1250kg), curve S 1 〞 represents the time-displacement curve of actual test power transmission line, and curve S 2 〞, S3 〞, S4 〞 and S5 〞 are to be respectively the time-displacement curve of the emulation power transmission line under 0.05,0.1,0.15 and 0.2 at ratio of damping, the most approaching through observing curve S 3 〞 and curve S 1 〞, thereby, can think that the ratio of damping of this test power transmission line is 0.1 under corresponding condition.

In the time selecting immediate emulation power transmission line displacement-curve, choose maximum displacement with the maximum displacement of the time-displacement curve of test power transmission line at the time-displacement curve of setting certain the emulation power transmission line within displacement difference, and choose the time-displacement curve of the rate of decay of curve crest and certain the emulation power transmission line of the corresponding curve crest rate of decay of the time-displacement curve of test power transmission line within setting speed difference.

As shown in figure 11, draw the altitude curve of the crest occurring successively in time-displacement curve, can more clearly find out that ratio of damping is in 0.1 situation, simulation result (being emulation power transmission line time-displacement curve S3) is more approaching with the crest variation tendency of test findings (testing power transmission line time-displacement curve S1).In like manner, in Figure 12, can find out that ratio of damping is in 0.1 situation, simulation result (being emulation power transmission line time-displacement curve S3 ') is more approaching with the crest variation tendency of test findings (testing power transmission line time-displacement curve S1 '); In Figure 13, can find out that ratio of damping is in 0.1 situation, simulation result (being emulation power transmission line time-displacement curve S3 〞) is more approaching with the crest variation tendency of test findings (testing power transmission line time-displacement curve S1 〞).

Above content is in conjunction with concrete preferred implementation further description made for the present invention, can not assert that specific embodiment of the invention is confined to these explanations.For general technical staff of the technical field of the invention, without departing from the inventive concept of the premise, can also make some simple deduction or replace, all should be considered as belonging to the present invention by the definite scope of patent protection of submitted to claims.

Claims (5)

1. icing power transmission line ice-shedding ratio of damping measuring method, is characterized in that, comprises the steps:

Test power transmission line time-displacement curve measuring process, measures the time-displacement curve under test power transmission line ice-shedding;

Emulation power transmission line time-displacement curve calculation procedure, according to calculating has and the test identical original state of power transmission line and the identical emulation power transmission line that deices condition, the time-displacement curve under different ratio of damping, wherein,

$\stackrel{\·}{X}\left(t\right)=\frac{X(t+\mathrm{\Δt})-X(t-\mathrm{\Δt})}{2\mathrm{\Δt}},$

$\stackrel{\·\·}{X}\left(t\right)=\frac{X(t+\mathrm{\Δt})+X(t-\mathrm{\Δt})-2X\left(t\right)}{{\mathrm{\Δt}}^2},$

$K=\frac{E\×A+\frac{\sqrt{\mathrm{\Δ}{x}^2+\mathrm{\Δ}{y}^2+\mathrm{\Δ}{z}^2}}{\mathrm{\Δz}}T}{\sqrt{\mathrm{\Δ}{x}^2+\mathrm{\Δ}{y}^2+\mathrm{\Δ}{z}^2}}$

Wherein, the gross mass of described emulation power transmission line and the external force being subject to are distributed on each point of load discretely, and M is the mass matrix of the emulation power transmission line point of load, and P is the external force matrix that emulation power transmission line is subject to, and C is ratio of damping, for the acceleration matrix of the emulation power transmission line point of load, for the speed matrix of the emulation power transmission line point of load, the elastic modulus that E is power transmission line, the sectional area that A is power transmission line, the static tension force that T is power transmission line; The described identical condition that deices refers to: measure test power transmission line departs from certain quality icing in certain position, emulation power transmission line departs from the analog-quality of equal in quality on the point of load of identical position accordingly,

(t-Δ t) represents that the displacement of the t-Δ t moment i+1 point of load, X (t) represent the displacement of the i+1 point of load described in the t moment to X, and (t+ Δ t) represents the displacement of the i+1 point of load described in the t+ Δ t moment to X;

Δ x=x (i+1)-x (i), Δ y=y (i+1)-y (i), Δ z=z (i+1)-z (i), wherein x (i+1), y (i+1), z (i+1) is respectively the i+1 point of load at three coordinates in t+ Δ t moment, x (i), y (i), z (i) is respectively the i point of load adjacent with the i+1 point of load three coordinates in the t+ Δ t moment;

The ratio of damping determining step of test power transmission line, in the time-displacement curve of the emulation power transmission line under multiple different damping coefficients, choose the time-displacement curve of certain the emulation power transmission line comparatively approaching with the time-displacement curve of testing power transmission line, the ratio of damping using the ratio of damping corresponding time-displacement curve of described certain emulation power transmission line as described test power transmission line under described original state.

2. icing power transmission line ice-shedding ratio of damping measuring method as claimed in claim 1, is characterized in that,

In the ratio of damping determining step of described test power transmission line: in the time-displacement curve of the emulation power transmission line under multiple different damping coefficients, choose maximum displacement with the maximum displacement of the time-displacement curve of test power transmission line at the time-displacement curve of setting certain the emulation power transmission line within displacement difference.

3. icing power transmission line ice-shedding ratio of damping measuring method as claimed in claim 1 or 2, is characterized in that,

In the ratio of damping determining step of described test power transmission line: in the time-displacement curve of the emulation power transmission line under multiple different damping coefficients, choose the time-displacement curve of the rate of decay of curve crest and certain the emulation power transmission line of the corresponding curve crest rate of decay of the time-displacement curve of test power transmission line within setting speed difference.

4. icing power transmission line ice-shedding ratio of damping measuring method as claimed in claim 1, is characterized in that,

Δ t≤2/ ω _n, wherein ω _nit is the high-order natural vibration frequency of power transmission line system.

5. icing power transmission line ice-shedding ratio of damping measuring method as claimed in claim 1, is characterized in that,

The quality of each point of load of emulation power transmission line is m:

q＝ρπb(D+d)

m＝qL/N

Wherein, the quality of ice covering on transmission lines in q representation unit length, ρ represents the density of ice, and b represents transmission line icing thickness, and D represents the diameter of power transmission line, and L represents the length of power transmission line, N represents the number of the point of load.