CN101858945A - Laboratory icing simulating test method of optical power ground wires (OPGWs) - Google Patents

Abstract

The invention belongs to the technical field of power system communication, relating to a laboratory icing simulating test method of optical power ground wires (OPGWs), which can simulate and test the performance changes of running lines in various icing thicknesses states in a laboratory. The method carries out an experimental comparative study on the electrical properties, the communication and the mechanical properties of the OPGWs under an icing condition by utilizing a laboratory icing simulating test system, mainly carries out the experimental studies on lightning resistance, short-circuit current, attenuation, tensile strength, stress strain and the like on the OPGWs with different structures, types, technical parameters, materials and the like and then determines a comprehensive solution on resistance of the OPGWs on icing disasters through analyzing test data.

Description

Optical Fiber composite overhead Ground Wire (OPGW) laboratory icing simulating test method

Technical field

The invention belongs to the communication of power system technical field, be specifically related to the laboratory icing simulating test method of a kind of electric power special optical cable Optical Fiber composite overhead Ground Wire (OPGW).

Background technology

At the beginning of in January, 2008 to 2 month, the disastrous on a large scale ice and snow weather that continues has appearred in China south most of area in succession, this time sleet freezing weather process influence scope is wide, intensity big, longer duration, involve a wide range of knowledge, the extent of injury is big, a lot of areas surpass 50 years one chances, some areas surpass 100 years one chances, it is rare to belong to history, has brought for these regional traffic, electric power, communication and people's lives and has a strong impact on.This time freezing disaster has especially caused great harm to the electrical network of China southwest, Central China, East China, and wherein Hunan, Zhejiang, Jiangxi electrical network are impaired particularly serious.Because powerline ice-covering is serious, causes many iron tower of power transmission line, lead, insulator, optical cable, gold utensil etc. to suffer in various degree damage, and, also suffered heavy losses as the optical cable of the main transmission medium of China's communication of power system.The impaired of optical cable directly influenced communication of power system, and then influences the safe operation of electric system.

Though at present most of impaired circuit has obtained repairing,, still exist many problems to require study and solve for transformation circuit and newly-built circuit from now on.Changes of properties before and after Optical Fiber composite overhead Ground Wire (OPGW) icing (especially heavy icing), potential hidden danger and very big to the lightguide cable link influence on system operation, study in great detail at home and abroad and do not appear in the newspapers, especially Optical Fiber composite overhead Ground Wire (OPGW) in application on power system more and more widely, the properties of product of common regional OPGW detect and have comprised as physical dimension, transmission performance, mechanical property, environmental performance, all many-sides such as electric property, can grasp the fundamental characteristics of sample fully by these tests, can guarantee the product quality of OPGW, and the conventional quality test project of stipulating in the industry standard can not satisfy the requirement under the serious disaster situation (as icing etc.).Do not find both at home and abroad at present yet and can not set up corresponding experimental enviroment and method yet and carry out testing research, during in the face of nature icing disaster, be difficult to propose effective and feasible comprehensive solution for the technical indicator and the requirement of optical cable under the ice coating state of practical operation.Therefore, correlative study content and measuring technology need further perfect, so that instruct the engineering practical application.

Summary of the invention

The objective of the invention is to use the problem that exists in order to solve heavy ice-covering area optical cable project, proposed a kind of Optical Fiber composite overhead Ground Wire (OPGW) laboratory icing simulating test method, this method can be in the performance change of laboratory simulation test run circuit under various ice covering thickness states.This method is utilized laboratory icing simulation experiment system, to the comparative study that experimentizes of electric, communication, the mechanical property of OPGW under the icing condition, mainly the OPGW to different structure, different model (different technologies parameter), different materials etc. carries out an experimental study such as anti-thunderbolt, short-circuit current, decay, tensile property, ess-strain, determines that by the analytical test data OPGW resists the comprehensive solution of icing disaster again.

A kind of Optical Fiber composite overhead Ground Wire of the present invention (OPGW) laboratory icing simulating test method may further comprise the steps: the first step: according to the thickness of optical cable model and simulation icing, calculate the weight of icing:

W＝π(R ²-r ²)dl

Wherein:

The proportion of the radius d----ice of the OPGW radius r behind the R---icing---optical cable: 0.9 gram/cubic centimetre

The weight π----3.14 of l---cable length W---ice

Second step: the initial tension of optical cable with 16%RTS is fixed on the puller system, and cable length is greater than 100 meters, and the efficiency test length of optical cable sample is not less than 25 meters;

The 3rd step: at least 6 optical fiber serial connections with in the optical cable, make fiber lengths greater than 500 meters, be connected on then on the optical time domain reflectometer, monitoring is with the variation of the increase optical fiber attenuation of ice covering thickness;

The 4th step:, need to cover the weight and the value of thrust of simulation ice under the laboratory condition of actual span of conversion circuit and ice covering thickness correspondence according to the efficiency test length of described optical cable in the middle of the gold utensil stiff end of puller system two ends.Computation process is as follows:

Utilize catenary equation:

$y=a(\mathrm{ch}\frac{x}{a}-1)$

In the formula, a is the ratio of the deadweight W of optical cable Horizontal Tension H and unit for introducing parameter, and ch (x) is a hyperbolic cosine function;

Under the optical cable nature suspension status, make t=1/a, catenary equation must be about the relational expression of t:

$\mathrm{tl}=\ln (({\mathrm{ty}}_A+1)+\sqrt{{({\mathrm{ty}}_A+1)}^2-1})+\ln (({\mathrm{ty}}_B+1)+\sqrt{{({\mathrm{ty}}_B+1)}^2-1})$

In the formula, l is the horizontal range of adjacent two shaft towers, and unit is m; y _ABe the vertical range of optical cable left side hanging point A from minimum point, unit is m; y _BBe the vertical range of optical cable the right hanging point B from minimum point, unit is m, separates the above-mentioned relation formula with Newton method, draw parametric t, release parameter a, draw the former long Lo of optical cable again by the relational expression of parameter a and cable length and elongation, the starting condition that this former long Lo calculates as icing;

Behind the icing, the tension force of cable, elongation and suspension cable length overall all can change, and reach another balance again, suc as formula Lo=L ₂-e ₂, Lo is dangle the down former length of the suspension optical cable that obtains of nature, is known conditions, L ₂And e ₂Represent with the expression formula of containing parameter a ' that all the parameter a that changed for icing is caused of a ' wherein draws relational expression:

$\mathrm{Lo}=\sqrt{{(2a^{\′}\·\mathrm{sh}\frac{l}{2a^{\′}})}^2+h^2}-\frac{a^{\′}{\mathrm{\γ}}_3}{E}(\frac{l}{2}+\frac{h^2}{2a^{\′}}\·\coth \frac{l}{2a^{\′}}+\frac{a^{\′}}{2}\·\mathrm{sh}\frac{l}{a^{\′}})\·{10}^{-3}$

In the formula, γ ₃Be the icing load of optical cable, unit is N/mmm ²: γ ₃=γ ₁+ γ ₂

Wherein,

M is the optical cable deadweight in the formula, and unit is kg/km.S-optical cable sectional area, unit are mm ²

In the formula, b is an ice thickness, and unit is mm; D is a cable outer diameter, and unit is mm,

G-gravity constant, value are 9.8N/kg; S-optical cable sectional area, unit are mm ²

Following formula is solved parameter a ' with Newton method, a ' substitution relational expression:

$\left\{\begin{array}{c}{T}_{\max }=a^{\′}\·{\mathrm{\γ}}_3\·S\·\cosh (l_B/a^{\′})\·{10}^{-3}\\ T_{\max }=a^{\′}\·{\mathrm{\γ}}_3\·S\·\cosh (l_A/a^{\′})\·{10}^{-3}\end{array}\right.$

l _A---optical cable left side hanging point A is from the horizontal range of minimum point, and unit is m;

l _B---optical cable the right hanging point B is from the horizontal range of minimum point, and unit is m;

Thereby obtain parameters such as the suffered maximum tension value of optical cable;

The 5th step: repeatedly evenly overlay on the optical cable simulation ice weight fraction of covering that calculates, each 1 to 2 hour at interval, cover when weighing and consider that mainly the optical cable sag is not too big, in order to avoid run on the ground, add pulling force then to calculated value, finally make its emulation mode that reaches actual span length and actual ice covering thickness, optical fiber attenuation The performance test results before and after the record icing;

The 6th step: utilize optical cable behind this icing can continue to do every performance test behind the cable ice coatings of stipulating in Optical Fiber composite overhead Ground Wire (OPGW) industry standard such as tensile property, ess-strain, thunderbolt and short-circuit current.

Wherein, in described the 5th step simulation ice weight fraction of covering that calculates is evenly overlayed on the optical cable for 3-10 time.

Wherein, covering the simulation ice time in described the 5th step is more than 48 hours.

The principal feature of technical solution of the present invention is utilized the existing puller system in laboratory exactly, to cover and heavily be converted to value of thrust, make the optical cable sample promptly be subjected to covering longitudinally heavily, be subjected to horizontal pulling force again, need not set up longly, only need the laboratory of condition correspondences such as actual track span that correct calculation need simulate, ice covering thickness to cover heavy and value of thrust gets final product outdoor apart from shaft tower.

The invention has the beneficial effects as follows: method of the present invention is a scheme the simplest and the most direct under laboratory condition, do not need actual spray water mist and low temperature environment to form real icing, can reduce test space, equipment is simple, the time is easy to control, big span actual track situation be can simulate by converting, experimentation cost and test difficulty reduced greatly.And this scheme proves very effective through the overtesting contrast.

Description of drawings

The present invention is further described below in conjunction with accompanying drawing.

Fig. 1 is the OPGW structural representation of example among the present invention;

Fig. 2 is that 400 meters span 40mm ice covering thickness 96h optical fiber attenuations of optical cable simulation change broken line graph and 400 meters span 40mm ice covering thickness 96h optical fiber attenuations of optical cable simulation change broken line graph in time;

Fig. 3 is the strain curve synoptic diagram of 60%RTS stress-strain tester result behind the cable ice coating;

Fig. 4 is the process flow diagram according to method of the present invention.

Embodiment

At first utilize the icing laboratory to spray freezing mode, OPGW is carried out the icing test, simulation weighs up the ice tuple certificate under the nature icing different-thickness situation, and compares with Theoretical Calculation.

Icing calculated value and actual value verification:

(1) OPGW of icing is not weighed

To length is that the optical cable sample of 120cm is weighed, and weight is 795g.

(2) the OPGW weight of icing is weighed

To length is the optical cable of 120cm, and icing length is that 90cm weighs, and weight is 1580g.

(3) diameter of OPGW and the external diameter behind the icing are measured

By kind of calliper OPGW diameter is 15.2mm, and the external diameter behind the icing is 37mm.

(4) the ice weight of OPGW icing

It is that the cable ice coating length of 120cm is that the general assembly (TW) of 90cm deducts not that icing length is the OPGW weight of 120cm that the ice weight of OPGW icing equals length:

1580g-795g＝785g

(5) calculate the weight of icing

W＝π(R ²-r ²)dl

Sample radius r behind the R---icing--the radius of-OPGW

The proportion 0.9g/cm of d----ice ³L---icing length

W＝(1.85 ²-0.76 ²)*3.14*90*0.9＝724g

(6) proportion is 0.9g/cm ³Actual icing value is poor with calculating icing value:

785-724＝61g

Because actual track OPGW icing is for mixing the river in Jiangsu Province which flows into the Huangpu River of Shanghai, mixing river in Jiangsu Province which flows into the Huangpu River of Shanghai proportion is 0.6g/cm ³---0.9g/cm ³, the corresponding proportion of the heavy 785g of actual ice is 0.83g/cm ³, be more or less the same with calculated value, simultaneously, the ice coating state of optical cable should be examined or check in the laboratory under the strictest situation, so icing weight selects to calculate the icing value in the icing test.

Concrete implementation step is as follows:

The first step:, calculate the weight of icing according to the thickness of optical cable model and simulation icing:

W＝π(R ²-r ²)dl

The proportion 0.9 gram/cubic centimetre of the radius d----ice of the OPGW radius r behind the R---icing---optical cable

The weight π----3.14 of l---cable length W---ice

Second step: the initial tension of optical cable with 16%RTS is fixed on the puller system, 100 meters of cable lengths, sample efficiency test length is not less than 25 meters.

The 3rd step: at least 6 optical fiber serial connections with in the optical cable make fiber lengths greater than 500 meters.Be connected on then on the optical time domain reflectometer, monitoring is with the variation of the increase optical fiber attenuation of ice covering thickness.

The 4th step: according to efficiency test length in the middle of the gold utensil stiff end of puller system two ends, the laboratory condition of actual span of conversion circuit and ice covering thickness correspondence need cover the weight and the value of thrust of simulation ice down, and wherein the actual computation process is with reference to Chinese patent application 200910092540.6.

The 5th step: simulation ice weight fraction is covered in calculating evenly overlayed on the optical cable for 3 to 4 times, each 1 to 2 hour at interval, cover when weighing and consider that mainly the optical cable sag is not too big, in order to avoid run on the ground, add pulling force then to calculated value, finally make its emulation mode that reaches actual span length and actual ice covering thickness, cover the 96 hours ice time of simulation.Optical fiber attenuation The performance test results before and after the record icing.The 6th step: every performance test behind the cable ice coatings such as the tensile property of utilizing optical cable behind this icing can continue to do to stipulate in the OPGW industry standard, ess-strain, thunderbolt, short-circuit current.

Below with OPGW-24B1-89[74.2; 50.3] be example, provide the test of adopting the present invention to carry out under the 40mm ice covering thickness situation.The OPGW structure as shown in Figure 1, optic cable diameter 12.6mm, the center is the aluminum-clad steel wire of a 2.6mm diameter, ground floor is the stainless steel tube optical unit that the aluminum-clad steel wire of 5 2.5mm diameters adds a 2.5mm diameter, the second layer is the aluminum-clad steel wire of 12 2.5mm diameters, and its concrete technical parameter sees Table 1.

Table 1 OPGW technical parameter table

6 optical fiber serial connections with in 100 meters long optical cables are connected on the optical time domain reflectometer then, and monitoring optical fiber is with the variation of the increase decay of ice covering thickness.(span is 25 meters) is covered with certain simulation ice on puller system earlier, applies pulling force simultaneously, and making it reach span is 400 meters, and ice covering thickness is the emulation mode of 40mm, 96 hours icing time.

Concrete ice covering thickness counter stress value sees Table 2, under the actual 400 meters span 40mm ice covering thickness situations of test simulation, the 25 meters effective optical cable test lengths in corresponding laboratory equivalent ice covering thickness be 175mm, the counter stress value is 66.72kN (90%RTS), corresponding icing weight 92.83kN.

The optical fiber attenuation The performance test results sees Table 3 before and after the icing, has write down respectively that wavelength is the optical fiber attenuation performance of 1310nm and 1550nm under icing time and the corresponding state.

Optical fiber attenuation changes increase behind the icing, icing removed icing after 96 hours, optical fiber attenuation does not return to original state, compare with original state and to have increased approximately 30%, as shown in Figure 2, icing was compared with original state after 96 hours, under 1310mm and 1550mm wavelength, decay and all increased, therefore, this pattern optical cable performance under 400 meters span ice covering thickness 40mm situations is affected, and causes the transmission quality of optical fiber to descend simultaneously.In the stress-strain tester behind the icing optical fiber attenuation change greatly, Fig. 3 is stress-strain tester result behind the cable ice coating, among the figure, horizontal ordinate is the suffered value of thrust of optical cable (N of unit); Last figure ordinate is decay (dB of unit), and figure below ordinate is fibre strain (% of unit).Attenuation change exceeds standard-required greater than 0.08 as can be seen.Break test and satisfy the power industry standard requirement, tensile property does not reduce.

The corresponding parameter value of 400 meters span 40mm icing of table 2 simulation

	Ice covering thickness (mm)	Counter stress value (kN)	Corresponding icing weight
							(kg/m)
400 meters spans	40	66.72(90％RTS)	5.95
				25 meters spans	175	66.72(90％RTS)	92.83

OPGW fade performance test result (G.652) before and after table 3 icing

Invention has been described according to specific exemplary embodiment herein.It will be conspicuous carrying out suitable replacement to one skilled in the art or revise under not departing from the scope of the present invention.Exemplary embodiment only is illustrative, rather than to the restriction of scope of the present invention, scope of the present invention is by appended claim definition.

Claims (3)

1. an Optical Fiber composite overhead Ground Wire (OPGW) laboratory icing simulating test method may further comprise the steps: the first step: according to the thickness of optical cable model and simulation icing, calculate the weight of icing:

W＝π(R ²-r ²)dl

Wherein:

The proportion of the radius d----ice of the OPGW radius r behind the R---icing---optical cable: 0.9 gram/cubic centimetre

The weight π----3.14 of l---cable length W---ice

Second step: the initial tension of optical cable with 16%RTS is fixed on the puller system, and cable length is greater than 100 meters, and the efficiency test length of optical cable sample is not less than 25 meters;

The 3rd step: at least 6 optical fiber serial connections with in the optical cable, make fiber lengths greater than 500 meters, be connected on then on the optical time domain reflectometer, monitoring is with the variation of the increase optical fiber attenuation of ice covering thickness;

The 4th step:, need to cover the weight and the value of thrust of simulation ice under the laboratory condition of actual span of conversion circuit and ice covering thickness correspondence according to the efficiency test length of described optical cable in the middle of the gold utensil stiff end of puller system two ends.Computation process is as follows:

Utilize catenary equation:

$y=a(\mathrm{ch}\frac{x}{a}-1)$

In the formula, a is the ratio of the deadweight W of optical cable Horizontal Tension H and unit for introducing parameter, and ch (x) is a hyperbolic cosine function;

Under the optical cable nature suspension status, make t=1/a, catenary equation must be about the relational expression of t:

$\mathrm{tl}=\ln (({\mathrm{ty}}_A+1)+\sqrt{{({\mathrm{ty}}_A+1)}^2-1})+\ln (({\mathrm{ty}}_B+1)+\sqrt{{({\mathrm{ty}}_B+1)}^2-1})$

In the formula, l is the horizontal range of adjacent two shaft towers, and unit is m; y _ABe the vertical range of optical cable left side hanging point A from minimum point, unit is m; y _BBe the vertical range of optical cable the right hanging point B from minimum point, unit is m, separates the above-mentioned relation formula with Newton method, draw parametric t, release parameter a, draw the former long Lo of optical cable again by the relational expression of parameter a and cable length and elongation, the starting condition that this former long Lo calculates as icing;

Behind the icing, the tension force of cable, elongation and suspension cable length overall all can change, and reach another balance again, suc as formula Lo=L ₂-e ₂, Lo is dangle the down former length of the suspension optical cable that obtains of nature, is known conditions, L ₂And e ₂Represent with the expression formula of containing parameter a ' that all the parameter a that changed for icing is caused of a ' wherein draws relational expression:

$\mathrm{Lo}=\sqrt{{(2a^{\′}\·\mathrm{sh}\frac{l}{2a^{\′}})}^2+h^2}-\frac{a^{\′}{\mathrm{\γ}}_3}{E}(\frac{l}{2}+\frac{h^2}{2a^{\′}}\·\coth \frac{l}{2a^{\′}}+\frac{a^{\′}}{2}\·\mathrm{sh}\frac{l}{a^{\′}})\·{10}^{-3}$

In the formula, γ ₃Be the icing load of optical cable, unit is N/mmm ²: γ ₃=γ ₁+ γ ₂

Wherein, M is the optical cable deadweight in the formula, and unit is kg/km.S-optical cable sectional area, unit are mm ²

In the formula, b is an ice thickness, and unit is mm; D is a cable outer diameter, and unit is mm,

G-gravity constant, value are 9.8N/kg; S-optical cable sectional area, unit are mm ²Following formula is solved parameter a ' with Newton method, a ' substitution relational expression:

$\left\{\begin{array}{c}{T}_{\max }=a^{\′}\·{\mathrm{\γ}}_3\·S\·\cosh (l_B/a^{\′})\·{10}^{-3}\\ T_{\max }=a^{\′}\·{\mathrm{\γ}}_3\·S\·\cosh (l_A/a^{\′})\·{10}^{-3}\end{array}\right.$

l _A---optical cable left side hanging point A is from the horizontal range of minimum point, and unit is m;

l _B---optical cable the right hanging point B is from the horizontal range of minimum point, and unit is m; Thereby obtain parameters such as the suffered maximum tension value of optical cable;

The 5th step: repeatedly evenly overlay on the optical cable simulation ice weight fraction of covering that calculates, each 1 to 2 hour at interval, cover when weighing and consider that mainly the optical cable sag is not too big, in order to avoid run on the ground, add pulling force then to calculated value, finally make its emulation mode that reaches actual span length and actual ice covering thickness, optical fiber attenuation The performance test results before and after the record icing;

The 6th step: utilize optical cable behind this icing can continue to do every performance test behind the cable ice coatings of stipulating in Optical Fiber composite overhead Ground Wire (OPGW) industry standard such as tensile property, ess-strain, thunderbolt and short-circuit current.

2. the method for claim 1 is characterized in that in described the 5th step simulation ice weight fraction of covering that calculates evenly being overlayed on the optical cable for 3-10 time.

3. as the described method of claim 1-2, it is characterized in that covering the simulation ice time in described the 5th step is more than 48 hours.

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