CN110296885A - A kind of mechanical Fault Monitoring of HV method of photoelectric composite sea cable - Google Patents

A kind of mechanical Fault Monitoring of HV method of photoelectric composite sea cable Download PDF

Info

Publication number
CN110296885A
CN110296885A CN201910193537.7A CN201910193537A CN110296885A CN 110296885 A CN110296885 A CN 110296885A CN 201910193537 A CN201910193537 A CN 201910193537A CN 110296885 A CN110296885 A CN 110296885A
Authority
CN
China
Prior art keywords
strain
sea cable
cable
armouring
stress
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN201910193537.7A
Other languages
Chinese (zh)
Other versions
CN110296885B (en
Inventor
赵丽娟
徐志钮
胡志伟
李永倩
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
North China Electric Power University
Original Assignee
North China Electric Power University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by North China Electric Power University filed Critical North China Electric Power University
Priority to CN201910193537.7A priority Critical patent/CN110296885B/en
Publication of CN110296885A publication Critical patent/CN110296885A/en
Application granted granted Critical
Publication of CN110296885B publication Critical patent/CN110296885B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/26—Investigating twisting or coiling properties
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/30—Investigating strength properties of solid materials by application of mechanical stress by applying a single impulsive force, e.g. by falling weight
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/30—Circuit design
    • G06F30/36—Circuit design at the analogue level
    • G06F30/367—Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods

Abstract

The invention discloses a kind of mechanical Fault Monitoring of HV methods for the photoelectric composite sea cable for belonging to malfunction monitoring technical field.This method is with 110kV YJQ41 × 300mm2Type sea cable is research object, its Structural Dynamics finite element model is established based on the analysis of ANSYS/LS-DYNA Explicit Dynamics, sea cable is stretched, torsion, anchor pounds three kinds of typical fault situations and has carried out modeling and simulating, the corresponding relationship of the strain and stress and fibre strain of dependency structure in the Strain Distribution and sea cable along sea cable composite fiber during fault progression is obtained, establish stretching, cable core under twisting states, the functional relation of armouring strain and stress and fibre strain, and anchor pounds the evaluation index of sea cable faulted condition and fibre strain under state, the present invention can recognize the mechanical breakdown Status Type that sea cable is likely to be at, and the development degree of corresponding failure is tentatively judged in conjunction with established functional relation and damage evaluation index.

Description

A kind of mechanical Fault Monitoring of HV method of photoelectric composite sea cable
Technical field
The invention belongs to malfunction monitoring technical field, in particular to a kind of mechanical Fault Monitoring of HV side of photoelectric composite sea cable Method.
Background technique
Photoelectric composite sea cable cost is high, structure is complicated, running environment is severe, is monitored to its operating status and failure Diagnosis is the premise of consequent malfunction prevention and maintenance, particularly significant to the safe and stable operation for guaranteeing sea cable.Sea cable actual installation Very big threat can be caused to sea cable with the mechanical stress of multiplicity random in operation.The reason of causing mechanical breakdown mainly includes the mankind External force caused by fishing gear, ship anchor is destroyed in activity, is damaged caused by the damage and sea-floor relief environment in laid processes, external force Acting on lower sea cable will form bending while being also possible to generate local torsion and stretching, or even fracture.
Since sea cable working environment is special, the monitoring mode of many tradition overland cables is difficult to be applied directly to sea cable monitoring In.The development of Distributed Optical Fiber Sensing Techniques provides opportunity for the status monitoring of sea cable, sea cable is run and anchor is pounded, reversed, The variation of each structural strain of sea cable and stress can be presented as by the typical faults state such as stretching, if can further will it is above-mentioned mainly Strain and stress and in sea cable composite fiber strain foundation contact, according to fibre scattering signal characteristic quantity and strain existing for Corresponding relationship is expected to realize the monitoring of sea cable operating status.Up to the present, the sea cable state prison based on distributing optical fiber sensing Examining system substantially can the strain information to composite fiber effectively monitored, but since the diagnosis for lacking reflection sea cable state is special Sign amount and evaluation criteria, the problem of causing big data poor information.In order to establish the fault threshold information of sea cable, Nishimoto T and Tayama H et al. respectively in 66kV and 6.6kV sea cable using fibre optical sensor carried out artificial application mechanical presses, The detection of armouring abrasion, realizes localization of fault；Wang Guozhongs etc. are based on submarine cable mechanical test standard to model YJQF41-26/35 3×120mm2Three core composite cable samples carried out coiling, stretch, bending test, experimental study The structure change of sea cable is simultaneously tested optical fiber property；CNOOC Research Institute is carried out using the admiral anchor of different weight Optoelectronic composite cable falls anchor bump test, analyzes the deformation of electric unit and light unit in sea cable, proposes during anchor pounds Sea cable variation is the collective effect of local dent and integral sinking.Above-mentioned full-scale test is mainly limited to qualitative analysis, and maximum is asked Topic is to be difficult to extract strain relevant during test and stress data.In contrast, using numerical computation method Establishing and solve sea cable finite element model can effectively overcome that real experiment difficulty is big, at high cost, research case is few, information collection Difficult disadvantage, it is more and more common using modeling means research sea cable problem.Zhang Xu et al. constructs one using finite element software Armour photoelectric composite sea cable simulation model in the typical list of kind compares emulation and actual loading test as a result, demonstrating Modeling Research drawing Stretch the reliability of result；The stress of the deformation and armouring by FInite Element to submarine optical fiber cable during anchor evil such as Zhang Yanlong Variation has carried out simulation analysis, but is not directed to optical fiber therein；Knapp.R H using numerical simulation to nonuniform stretching and The armored cable of torsion mechanical property has carried out nonlinear analysis, and achieves and the good consistency of experimental result.To sum up institute It states, the existing research about sea cable modeling and simulating is mainly sea cable deformation and internal object under certain malfunction of independent analysis Reason amount lacks systematicness, not yet forms the identifying index of fault type, more answer without reference to certain class fault progression degree with optical fiber The quantitative study of change relationship and the foundation of diagnostic characteristic amount.
Our seminars have been successfully realized in 2013 based on BOTDR technology online to the sea cable in East China Sea somewhere Monitoring, obtains largely with sea cable position, the Brillouin shift data of time change, but also according to current present Research The sea cable based on measurement data cannot effectively be realized by the fault diagnosis under mechanical stress, prevent the effect of system is from abundant It plays.
Summary of the invention
The object of the present invention is to provide a kind of mechanical Fault Monitoring of HV methods of photoelectric composite sea cable, which is characterized in that with 110kV YJQ41×300mm2Type sea cable is research object, establishes its structure based on the analysis of ANSYS/LS-DYNA Explicit Dynamics Dynamics Finite Element Model pounds three kinds of typical fault situations and has carried out modeling and simulating, obtained sea to sea cable stretching, torsion, anchor Cable in the Strain Distribution and sea cable under above-mentioned fault condition along composite fiber the strain of associated structural component and stress with Corresponding relationship of fibre strain during fault progression, establish cable core under stretching, twisting states, armouring strain and stress with The functional relation and anchor of fibre strain pound the evaluation index of sea cable faulted condition and fibre strain under state, the sea cable machine The state monitoring method of tool failure includes:
1, sea cable structure and condition monitoring system
1.1, the sea cable condition monitoring systems based on BOTDR
With 110kV YJQ41 × 300mm2A certain two island sea area A, B in Eastern China of photoelectric composite sea cable connection, is used for it The real-time traffic information of electrical energy transportation and the operation of electric system tunneling traffic, transmission power network schedule automation；It builds thus The stereo synthesis of 110kV photoelectric composite sea cable monitors system, wherein the sea 110kV based on Brillouin light time domain scattering (BOTDR) Cable status monitoring subsystem uses the strain of distribution type fiber-optic measuring instrument real-time monitoring sea cable, Temperature Distribution；Sea cable status monitoring Subsystem has 6 channels, channel 1/2,3/4,5/6 be respectively applied to east, in, the monitoring of western three-phase sea cable；BOTDR test is set It is standby to be placed on the island B side, laser pulse is entered to inject in the compound single mode optical fiber of sea cable after connecting by general cable, laser passes in a fiber Defeated generation Brillouin scattering, Brillouin scattering reverse transfer reach transmitting terminal, utilize data acquisition unit in transmitting terminal (DAU) and data processing unit (DPU) detects the frequency displacement of Brillouin scattering optical signal and the strain of optical fiber, temperature can be obtained in intensity Spend information；
1.2, using the validity of Brillouin shift monitoring sea cable strain
There are linear relationships for frequency displacement, intensity and the temperature of Brillouin scattering and strain；For common single mode optical fiber, in cloth Deep frequency displacement νBIt is as follows with the expression formula of temperature T and strain stress
νB(T)=νB0+1.158×10-4ΔT (1)
νB(ε)=νB0+5.6ε (2)
In formula, νB0For initial temperature T0And Brillouin shift when without strain, unit GHz；Δ T=T-T0For relative to T0Temperature variation, unit be DEG C；
2, the finite element modeling of sea cable
2.1, sea cable Geometric Modeling
Influence three of each structure member to simulation result in a possibility that from quality, the initial breakthrough of mesh generation and sea cable A angle simplifies practical sea cable, and it is comparatively very thin and influence very little to model and leading that thickness in sea cable is omitted Interior serving is reduced to shell structure by body shielded layer, insulation screen, brass belt, and the sea cable model finally established includes copper Cable core, crosslinked polyetylene insulated layer, lead alloy sheath, high density polyethylene (HDPE) sheath, polyethylene terephthalate (PET) are filled out Item, light unit, interior serving, armor are filled, wherein light unit includes optical fiber, steel pipe, polypropylene cover.
In sea cable Geometric Modeling, armouring, PET packing, the modeling of three kinds of lay configuration components of light unit are the most key, essence True lay configuration model is most important to the structural mechanics characteristic of true representation sea cable, thus distinctive dependent on ANSYS APDL language constructs single intertwist body, then according to be twisted radical it is carried out under cylindrical coordinate duplication can be obtained it is twisted Layer；
2.2, the selection of unit material and mesh generation
Interior serving thin for structure in sea cable, contribution is small selects SHELL163 thin shell element to model it, adopts The Belytschko-Tsay algorithm of simple shell unit efficient stable is solved with default；The selection of sea cable other parts is explicit Body unit SOLID164, and it is solved using default single-point integral algorithm, in the feelings for effectively controlling hourglass mode Under condition, single-point integral is good for large deformation unit effect, can theoretically promote 8 times relative to full integral algorithm solution efficiency；
The material of each component of sea cable can be divided into two classes according to its physical characteristic: one kind is metal material, including cable Steel pipe in core, lead alloy sheath, armouring and light unit, metal material has typical elastoplasticity feature, using classics BKIN (Bilinear Kinematic Hardening) model as its material model, the model using piecewise linear function come Express the constitutive relation of material.The elasticity modulus of remaining nonmetal structure component materials is compared to wanting small for metal material It is more, elastic stage is in simulation process always, is studied using linear elastic model Isotropic, for ship anchor, due to The deformation that anchor pounds front and back anchor is negligible, therefore uses body material model Rigid to ship anchor；
The mode of mesh generation influences whether the convergence of the initial breakthrough of model, minimum cell size ratio and calculating Property, under the premise of having comprehensively considered mesh generation density and computational efficiency, individually to sea cable by the way of customized scan Each structure member carries out mesh generation；
2.3, contact definition can control with hourglass
Select automatically contact as modeling contact type, allow model any surface and other surfaces include it originally Body contact is highly suitable for the case where can not predicting contact surface when the modeling of sea cable mechanical breakdown, is connect using widely used single side Touching algorithm is this from contact or large deformation problem to handle；In conclusion sea cable modeling contact definition is automatic single-contact；
Hourglass mode is state that is a kind of mathematically stable, but physically cannot achieve, it is necessary to control simulation process The overall sandglass model of middle computation model is less than 10% of energy in overall, and simulation result is only effectively；From raising mesh generation matter It measures and hourglass control algorithm is applied to the biggish sea cable component of sandglass model to reduce their own sandglass model；By repeatedly tasting Examination, it should the sandglass model of overall process and the Ratio control of interior energy will be emulated below 2%；
3, the load of sea cable fault condition applies
3.1, stretching fault load applies
A Typical tensile load is chosen, is applied on sea cable model axial direction, the extensibility and tensile load of sea cable are made It is respectively 5 ‰ and 0.1s with the time, at the uniform velocity stretches；Fixed constraint is applied to all nodes on one end face of model, is intercepted another Hold the sea cable section of a bit of length as component, be arranged its material type be rigid body, by the component apply rigid body displacement-when Between load, and then stretch sea cable；
3.2, torque failure load applies
Similar with tensile load applying method, the realization of sea cable torsion is to apply fixed constraint to one end node, to group The rigid body portion of part applies rigid body rotation-time load, at the uniform velocity reverses, by the positive and negative and maximum value that rigid body spin load is arranged To control the direction and angle that sea cable is reversed, pass through the speed for changing the time control torsion that load applies.Torsional direction is not With being presented as that rigid body direction of rotation is identical and opposite as sea cable direction of lay.According to the practical winding method of sea cable, typical torsion is taken In the case of 0 °~20 ° of torsion angular region, reverse speed is respectively ± 4 °/s, ± 6 °/s and ± 8 °/s, and reverse speed is positive table Show that rigid body torsional direction is identical as sea cable direction of lay, is negative then contrary.
3.3, anchor pounds failure load application
Most representational 660kg Hall'sanchor work is chosen according to ship size above waters where sea cable and with anchor situation For modeling object, capable simplification is anchored into ship under the premise of guaranteeing anchor weight and constant proj ected bottom area；According to the whereabouts of ship anchor Speed calculation method acquires the maximum falling speed of ship anchor contact sea cable moment, and the falling speed of control ship anchor is less than or equal to maximum Speed is to tally with the actual situation, and when modeling, the collision area for controlling ship anchor and sea cable is located at the intermediate region of emulation section, to sea cable The node at both ends applies fixed constraint, only applies rigid body displacement-time load straight down to ship anchor section.Since anchor hawser is hit It is extremely short to hit process, it is believed that entire knockout process is at the uniform velocity.A typical anchor is taken to pound fault condition, anchor pounds depth 8cm, herein according to ship It is 0~0.036s that collision time, which is arranged, in anchor calculating speed, and in order to avoid structure Condition of Sudden Unloading causes model to restrain extremely, load is applied Slightly longer between added-time is 0.04s, and practical ship anchor stops the stable state after sinking in order to obtain, and the solution time is set as sufficiently long 10s, remaining time ship anchor are maintained at most deep impingement position；Due to having been added soil penetration resistance in the calculating of ship anchor kinetic energy Influence, comparatively wrap up the soft water saturation soil of sea cable to hit moment negligible to the resistance of anchor hawser；
4, FEM Numerical Simulation and analysis
4.1, stretch analysis of simulation result
The strain distributing disciplinarian of sea cable axial optical fiber in drawing process, the cylindrical body similar for other structures in sea cable, They are behaved like during axial tension, are analyzed using cable core component most important in sea cable as representative, drawing process The strain of middle cable core is axially distributed along sea cable, and the strain of the upper optical fiber of sea cable axial direction and cable core is with the increase of level of stretch And increase, cable core strain does not change with the variation of axial distance, and directly proportional to level of stretch, and optical fiber is in rigid body displacement along the line The main stretch zones dependent variable that load applies is maximum, and remoter apart from the main stretch zones of sea cable, fibre strain amount is smaller, then will This feature is in the criterion of tensional state as sea cable and carries out fault location；Axial 2~4.5m range the inner fiber of sea cable is taken to answer The relationship of cable core strain and fibre strain is established in the mean strain for changing the optical fiber and cable core in relatively obvious region；
It is therefore seen that cable core strain it is approximate with fibre strain linearly, meanwhile, for cable core in sea cable column structure with And the lay configuration of optical fiber, simultaneously as excess fiber length can gradually exhaust in actual use with accumulation strain, in modeling In the case where not considering excess fiber length, the initial strain of optical fiber and cable core is zero, is fitted cable core strain and fibre strain accordingly Approximate linear data, determine coefficients R2=0.9877, standard error RMSE=1.237 × 10-4, formula (3) can be obtained；
εc=1.204 εf (3)
In formula, εcIndicate cable core strain, εfIndicate fibre strain；It can determine whether the stretching of sea cable based on formula (3) and fibre strain Degree and state；
4.2, reverse analysis of simulation result
4.2.1, torsional direction is opposite with sea cable direction of lay
(1) optical fiber
The Strain Distribution of sea cable axial optical fiber in different torsion angles, increases, sea cable with the increase of sea cable torsion degree Load apply end and restrained end fibre strain influenced to be slightly above interlude by end effect, the strain of intermediate region is basic It is equal；Find out visible fibre strain and torsion angle at just from the relationship of emulation section intermediate region optical fiber mean strain and torsion angle Than；
(2) cable core
It is outermost that stress maximum suffered by outer layer of cable core unit when as torsion, the cable core strain and stress refer both to its Strain and stress；From cable core strain and stress and the relationship of fibre strain under sea cable twisting states it is found that cable core under twisting states Directly proportional to fibre strain always, fitting result such as formula (4) is strained, R is fitted2=0.9999, RMSE=1.04 × 10-5；
εc=4.16 εf (4)
Cable core material is changed into plastic deformation by elastic deformation with the increase of torsion angle, and in the elastic properties of materials stage, cable core is answered Power is directly proportional to fibre strain, is more than after yield point, cable core stress and fibre strain meet linear relationship, using piecewise linear function Number fitting result such as formula (5)；Fitting function first segment R2=1, RMSE=0.1171；Second segment R2=1, RMSE=0.5608, Reverse speed is on result without influence；
In formula, σcFor cable core stress, unit 0.1Mpa.
(3) armouring
Under different reverse speeds, from armouring strain known to armouring strain and stress and the relation curve of fibre strain and answer Power is approximate with fibre strain directly proportional, this is because when torsional direction is opposite with sea cable direction of lay, optical fiber in twist process It is in synchronization discrete state, fibre strain and the strain of armouring and stress with armouring lay configuration only to be generated by torsion, due to turning round Sea cable caused by turning, which stretches, can be ignored, therefore the strain of armouring and stress will not be mutated due to the superposition reversed and stretched, with Fibre strain is linear always；In 20 ° of turn-back angular regions of setting, armouring is in elastic stage always, bears Maximum stress is not up to material yield point, and reverse speed is on result substantially without influence；Shown in fitting result such as formula (6) and formula (7), Formula (6) is fitted R2=0.9993, RMSE=7.572 × 10-6；Formula (7) is fitted R2=0.9990, RMSE=20.53,
εt=1.15 εf (6)
σt=2.593 × 106εf 0≤εf≤8.28×10-4 (7)
In formula, εtFor armouring strain；σtFor armouring stress, unit 0.1Mpa.
4.2.2, torsional direction is identical as sea cable direction of lay,
Under this state, the stress of the cylindrical bodies such as cable core and strain are still only generated by torsion, unrelated with torsional direction；It is reversing The strain of the lay configurations such as degree hour, optical fiber and armouring and stress are mainly generated by torsion, the change of this period stress and strain Change little；As torsion degree is deepened, stress is started to be caused jointly by reversing and stretching by strain, and value significantly increases；
(1) optical fiber
According to the Strain Distribution of sea cable axial optical fiber when different torsion angles, it is seen that fibre strain with sea cable torsion degree increasing Add and increase, the fibre strain value in sea cable axial direction is of substantially equal, thus makees what mean strain along optical fiber changed with torsion angle Curve；It can be seen that when torsion degree is little, fibre strain is linear with torsion angle, with the intensification of torsion degree, optical fiber The rate that strain increases is accelerated, and eventually passes back to linearly increase, can be divided into three sections；
(2) cable core
According under different reverse speeds, the relationship of cable core strain and stress and fibre strain, for cylindrical body cable core structure, Its strain and stress it is unrelated with torsional direction with the changing rule of torsion angle, under twisting states cable core strain and stress respectively with torsion Corner is linear and piecewise linear function relationship；Cable core strain and stress and the relationship of fibre strain are fitted respectively, are fitted As a result as shown in formula (8) and formula (9), formula (8) is fitted R2Respectively 0.9999,0.9951 and 0.9996, RMSE are respectively 1.458×10-6、2.318×10-5With 1.185 × 10-5；Formula (9) is fitted R2Respectively 0.9999,0.9949 and 0.9997, RMSE difference 1.746,11.79 and 5.542；
(3) armouring
According to armouring strain and stress and the relationship of fibre strain under different reverse speeds it is found that armouring strain is answered with optical fiber Change can be divided into two stages in twist process, when torsion degree is little armouring strain it is directly proportional to fibre strain, strain only by Torsion generates；When torsion degree further increases, strain results from torsion and stretching, and armouring strains the increase with fibre strain It further increases；Armouring stress and the relationship of fibre strain are divided into three phases, the changing rule phase in the first two stage and strain Seemingly, armouring is in elastic stage at this time；When armouring stress further increases with the intensification of torsion degree the yield point of material Afterwards, armouring is plastically deformed, and the relationship of stress and fibre strain enters the phase III；Reverse speed is to result substantially without shadow It rings；Shown in the result such as formula (10) and formula (11) being fitted using piecewise function；Formula (10) is fitted R2Respectively 0.9994 He 0.9998, RMSE is respectively 4.434 × 10-7With 1.274 × 10-5；Formula (11) is fitted R2Respectively 0.9994,0.9994 and 0.9996, RMSE difference 4.496,23.39 and 25.03, the first segment function of formula (10) and (11) have higher linear fit Degree, this is consistent with the rule that formula (6) and (7) reflect,
It is interior when sea cable torsional direction is identical as its direction of lay in conjunction with the 4.2.1 result saved it is found that under identical torsion angle The strain of portion's optical fiber and armouring lay configuration and the variation degree of stress will be significantly greater than sea cable torsional direction and its direction of lay The case where when opposite；According to the relationship of cable core, armouring strain and stress and fibre strain under the sea cable twisting states of foundation, formula (4)~(11)) and BOTDR system actual measurement fibre strain, the strain and stress of cable core and armouring are predicted, and then sentences The torque failure degree of disconnected sea cable；
4.3, anchor pounds analysis of simulation result
(1) anchor pounds process aggregate analysis
Anchor is pounded failure early stage sea cable and is only locally deformed with, and overall deformation then just occurs, and whole process can be divided into armouring Layer local deformation stage, sea cable sink stage and sea cable rebound stage；The time interval of armouring local deformation only occurs in sea cable For 0~t1(t1=0.003s), the time interval for integral sinking occur is t1~t2(t2=0.0036s), then in t2~t3(t3 =0.004s) there is slight resilience, whole process sea cable sinking displacement amount is 7.3cm, and ship anchor displacement is 8cm, in sea cable Sinking stage, armouring are transitioned into surrender and strain from elastic stage, at this time the single armouring wire on anchor hawser contact surface from Figure becomes negligible, and as synchronous sinking occurs for the sinking of ship anchor, illustrate armouring to a certain extent to sea cable inside Structure has protective effect, but degree of protection is limited.
(2) optical fiber
Anchor is pounded under state, and sea cable axial optical fiber Strain Distribution changes with time rule, by main among sea cable emulation section The relationship that the average value of impingement region fibre strain and time and ship anchor position are moved is it is found that the strain of sea cable axial optical fiber is whole with anchor It pounds the increase of depth and increases and its distribution has symmetry, it is small that centre falls fibre strain at anchor, is falling near anchor point to two sides Develop fibre strain to increase, sea cable bending degree reduces after falling with a certain distance from anchor point, and fibre strain tends to decline；Fibre strain This feature of distribution, which can be used as, judges that the foundation that anchor pounds failure occurs for sea cable according to fibre strain.
(3) armouring
Plastic strain is the permanent strain generated in deformation process, as the mark of material damage, armouring in engineering Plastic strain largely reflect the faulted condition of sea cable, on the basis of falling anchor central point, extract central point and its two Armouring stress and plastic strain at side each 5cm, 10cm, 15cm, by armouring mean stress, plastic strain and fibre strain with The relationship of time is drawn in curve together and is compared；
According to the constitutive relation of elastic-plastic material in engineering, when state of armouring during entire anchor is pounded is divided into following Between section: OA period, armouring are in elastic stage, reach the elastic limit of material in A point, and there is one section of stress base at OA sections of middle parts This constant waving interval, this is because sea cable is by the local deformation step transition of armouring to the sinking stage in the section；AB Period, after A point, armouring stress is greater than the yield strength of material, and armouring plastic deformation occurs and enters yielding stage, the time Section armouring strain still in increase and stress does not increase, stress time curve present zigzag fluctuation, it appears that lose resistance The ability of deformation, AB sections of minimum point is known as yield point on stress curve；BC period, sea cable continue to sink with ship anchor, armouring It is transitioned into strain from yielding stage, stress first reduces increase afterwards at any time, and the size of the stage inner armor stress is always Less than the yield strength of its material, plastic strain is remained unchanged；The CD period, armouring is still in strain, and stress is at any time Between persistently increase, explanation to make armouring strain increase then must increasing stress, armouring restored the ability of resistance to deformation, this is also The main feature of strain, after C point, yield strength of the size of armouring stress again above material, plastic strain value Start again at increase；The DE period, due to the unloading of ship anchor rigid body displacement load, the sea cable sinking stage terminates to enter rebound rank Section, armouring still retain plastic strain but since a small amount of rebound lead to stress decrease；
(4) anchor pounds sea cable main feature moment analysis under failure
Above-mentioned sea cable anchor pounds three processes that are broadly divided into: process I is the local deformation stage of collision initial stage sea cable, time 0 ~0.003s；Process II is that sea cable is sunk the stage, time 0.003s~0.036s；Process III is the rebound stage of sea cable, time 0.036s~0.04s；Process II is subdivided into four-stage: the first stage is OA sections of second half section, from 0.003s~ Initial sinking occurs for 0.0045s, this stage sea cable, sinks since sea cable is just until A point, armouring are in elastic stage and do not go out Now be plastically deformed, there is birdcage shape deformation in armouring, and normal configuration is maintained inside sea cable, and second stage is AB sections, from 0.0045s~ 0.012s, armouring birdcage shape deformation further develop, and plastic strain occur into yielding stage, under the protection of armouring, sea cable Internal structure still keeps normal substantially；Phase III is BC sections, and from 0.012s~0.03s, this stage sea cable deflection is further Increase, for sea cable in sinking watching, armouring experienced a bit of process being gradually recovered from birdcage shape protrusion to deformation first, should Process armouring stress reduces, and subsequently enters strain stress and increases again, and plastic strain remains unchanged, and sea cable twists in the stage It closes layer to significantly increase the extruding of its internal structure, the protection of armouring has tended to the limit, this stage needs hig diligence as a result,；The Four stages were CD sections, and from 0.03s~0.036s, this stage armouring has been unable to maintain that normal lay configuration, has lost to sea The effective protection of cable internal structure, sea cable inside cable core cross-section deform, and jeopardize the normal use of sea cable, therefore, it is considered that this rank Section sea cable is damaged；Based on the analysis of summary front, then fault identification and feature extraction are able to carry out.
The beneficial effects of the invention are as follows the present invention with 110kV YJQ41 × 300mm2Type sea cable is research object, is based on Its Structural Dynamics finite element model is established in the analysis of ANSYS/LS-DYNA Explicit Dynamics, is stretched, is reversed to sea cable, anchor pounds three Kind typical fault situation has carried out modeling and simulating, has obtained Strain Distribution of the sea cable under above-mentioned fault condition along composite fiber And the corresponding relationship of the strain of associated structural component and stress and fibre strain during fault progression in sea cable, it establishes It stretches, the functional relation and anchor of cable core, armouring strain and stress and fibre strain are pounded sea cable under state and damaged under twisting states The evaluation index of state and fibre strain proposes the fibre strain distribution under sea cable difference mechanical breakdown based on above-mentioned analysis Feature mode and sea cable mechanical breakdown discrimination method based on fibre strain size and spatial distribution are the shape of sea cable mechanical breakdown State monitoring provides reference.
Detailed description of the invention
Fig. 1 is that sea cable routes compared with strain data.
Fig. 2 is sandglass model/interior energy-time graph.
Fig. 3 is drawing process optical fiber and cable core Strain Distribution, wherein fibre strain is distributed under (a) stretching fault, (b) is drawn Stretch cable core Strain Distribution under failure.
Fig. 4 is the relationship of cable core strain and fibre strain under sea cable tensional state.
Fig. 5 is the fibre strain under sea cable twisting states, wherein sea cable axial optical fiber answers variation when (a) difference torsion angle Cloth, (b) fibre strain-torsion angular curve.
Fig. 6 is the relationship of cable core strain/stress and fibre strain under sea cable twisting states, wherein (a) cable core strain-optical fiber Strain curve, (b) cable core stress-fibre strain curve.
Fig. 7 is the relationship of armouring strain/stress and fibre strain under sea cable twisting states, wherein (a) armouring strain-light Fine strain curve, (b) armouring stress-fibre strain curve.
Fig. 8 is the fibre strain under sea cable twisting states, wherein sea cable axial optical fiber answers variation when (a) difference torsion angle Cloth, (b) fibre strain-torsion angular curve.
Fig. 9 is the relationship of cable core strain/stress and fibre strain under sea cable twisting states, wherein (a) cable core strain-light Fine strain curve, (b) cable core stress-fibre strain curve.
Figure 10 is the relationship of armouring strain/stress and fibre strain under sea cable twisting states, wherein (a) armouring strain-light Fine strain curve, (b) armouring stress-fibre strain curve.
Figure 11 is that anchor pounds the shifting of the ship anchor position under failure and sea cable central point displacement-time curve.
Figure 12 is that sea cable anchor pounds the fibre strain under state, wherein (a) different moments sea cable axial optical fiber Strain Distribution, (b) fibre strain-time/ship anchor displacement curve.
Figure 13 is armouring stress/plastic strain-time/ship anchor displacement curve.
Specific embodiment
The present invention provides a kind of mechanical Fault Monitoring of HV method of photoelectric composite sea cable, in order to ensure the safety and stability of the sea cable Operation, we built in 2012 and complete with 110kV YJQ41 × 300mm2The Eastern China of photoelectric composite sea cable connection The real-time of power network schedule automation for its electrical energy transportation and the operation of electric system tunneling traffic, is transmitted in a certain two island sea area A, B Operation information；The present invention is with 110kV YJQ41 × 300mm2Type sea cable is research object, is explicitly moved based on ANSYS/LS-DYNA Its Structural Dynamics finite element model is established in mechanical analysis, is stretched, is reversed to sea cable, anchor is pounded three kinds of typical fault situations and carried out Modeling and simulating has obtained sea cable dependency structure portion in the Strain Distribution and sea cable under above-mentioned fault condition along composite fiber The corresponding relationship of the strain of part and stress and fibre strain during fault progression, establish cable core under stretching, twisting states, The functional relation and anchor of armouring strain and stress and fibre strain pound the assessment of sea cable faulted condition and fibre strain under state The state monitoring method of index, the sea cable mechanical breakdown includes:
1, sea cable structure and condition monitoring system
1.1, the sea cable condition monitoring systems based on BOTDR
110kV sea cable status monitoring subsystem based on Brillouin light time domain scattering (BOTDR) is surveyed using distribution type fiber-optic Measure strain, the Temperature Distribution of instrument real-time monitoring sea cable；Sea cable status monitoring subsystem has 6 channels, 1/2,3/4,5/6 point of channel Not Ying Yongyu east, in, the monitoring of western three-phase sea cable.BOTDR test equipment is placed on the island B side, by laser after being connected by general cable Pulse enters to inject in the compound single mode optical fiber of sea cable, and laser transmits in a fiber generates Brillouin scattering, and Brillouin scattering is anti- Transmitting terminal is reached to transmission, is dissipated in transmitting terminal using data acquisition unit (DAU) and data processing unit (DPU) detection Brillouin The strain of optical fiber, temperature information can be obtained in the frequency displacement and intensity for penetrating optical signal；Up to the present, which has had accumulated largely Sea cable strain data on the spot.
1.2, using the validity of Brillouin shift monitoring sea cable strain
There are linear relationships for frequency displacement, intensity and the temperature of Brillouin scattering and strain；For common single mode optical fiber, in cloth Deep frequency displacement νBIt is as follows with the expression formula of temperature T and strain stress
νB(T)=νB0+1.158×10-4ΔT (1)
νB(ε)=νB0+5.6ε (2)
In formula, νB0For initial temperature T0And Brillouin shift when without strain, unit GHz；Δ T=T-T0For relative to T0Temperature variation, unit be DEG C；
Presently the most reliable characteristic quantity is Brillouin shift, by treating the Brillouin shift under the identical conditions of survey line road It is continuously measured, standard curve is obtained after average, using the difference of subsequent measured curve and standard curve as route to be measured Experiment curv.Although can realize the combined measurement of temperature and strain accordingly, fiber optic temperature and strain can all lead to brillouin frequency Variation is moved, temperature and strain cannot be distinguished according only to it.In view of the temperature of sea cable mostly rises or falls in whole form, and It is mostly localized variation due to being influenced strain with position ups and downs by landform and localized external force, it can be with according to this characteristic Temperature and strain are distinguished to a certain extent.
Compound optical fiber is loose set in sea cable, this allows people whether can effectively reflect that sea cable strain produces bosom to fibre strain It doubts, illustrates this point below according to real data.It can according to strain sensitive coefficient 0.0482 ± 0.001MHz/ μ ε Brillouin shift To be converted to strain, as shown in Figure 1.As shown in realizing, sea cable routing is indicated the Strain Distribution of eastern phase sea cable by chain-dotted line.
Data are routed according to sea cable it is found that island A and B are very precipitous at inshore.As shown in Figure 1, island A and B are leaned on Strain value is larger at nearly debarkation point 100m, this should be since sea cable gravity causes.There is an abrupt slope at the 270m of the island A, at this Height above sea level quickly changes to -20m from -2m, accordingly also there is the peak value of a strain.There is a shoal at distance A island 1900m, it is corresponding Height above sea level be -10.2m, accordingly the strain at this have lesser valley.The reason is that shoal is smooth, the weight of sea cable is not easy Lead to biggish strain.However, the topography of shoal two sides is more precipitous, corresponding crustal strain is larger.According to the above analysis it is found that sea Cable routing is close with strain stress relation.The above result shows that although composite fiber is loose set in sea cable, according to the Brillouin of optical fiber Frequency displacement can effectively reflect the strained situation of sea cable.This provides support for the validity of subsequent modeling analysis result.
2, the finite element modeling of sea cable
2.1, sea cable Geometric Modeling
Geometric Modeling directly determines the quality of mesh generation, further influence solution efficiency and result it is accurate Property, structure is complicated for sea cable, to establish under the premise of making every effort to restore its real structure and be conducive to the several of finite element fission and calculating What model.Influence of each structure member to simulation result in a possibility that from quality, the initial breakthrough of mesh generation and sea cable, it is right Practical sea cable is simplified, be omitted thickness in sea cable it is comparatively very thin and on model influence very little conductor shield, Interior serving is reduced to shell structure by insulation screen, brass belt, and the sea cable model finally established includes copper cable core, crosslinking Polyethylene layer, lead alloy sheath, high density polyethylene (HDPE) sheath, polyethylene terephthalate (PET) packing, light list First, interior serving, armor, wherein light unit includes optical fiber, steel pipe, polypropylene cover.
In sea cable Geometric Modeling, armouring, PET packing, the modeling of three kinds of lay configuration components of light unit are the most key, essence True lay configuration model is most important to the structural mechanics characteristic of true representation sea cable, thus distinctive dependent on ANSYS APDL language constructs single intertwist body, then according to be twisted radical it is carried out under cylindrical coordinate duplication can be obtained it is twisted Layer.
2.2, the selection of unit material and mesh generation
Interior serving thin for structure in sea cable, contribution is small selects SHELL163 thin shell element to model it, adopts The Belytschko-Tsay algorithm of simple shell unit efficient stable is solved with default；The selection of sea cable other parts is explicit Body unit SOLID164, and it is solved using default single-point integral algorithm, in the feelings for effectively controlling hourglass mode Under condition, single-point integral is good for large deformation unit effect, can theoretically promote 8 times relative to full integral algorithm solution efficiency；
The material of each component of sea cable can be divided into two classes according to its physical characteristic: one kind is metal material, including cable Steel pipe in core, lead alloy sheath, armouring and light unit, metal material has typical elastoplasticity feature, using classics BKIN (Bilinear Kinematic Hardening) model as its material model, the model using piecewise linear function come Express the constitutive relation of material.The elasticity modulus of remaining nonmetal structure component materials is compared to wanting small for metal material It is more, elastic stage is in simulation process always, is studied using linear elastic model Isotropic, for ship anchor, due to The deformation that anchor pounds front and back anchor is negligible, therefore uses body material model Rigid to ship anchor；
The mode of mesh generation influences whether the convergence of the initial breakthrough of model, minimum cell size ratio and calculating Property, under the premise of having comprehensively considered mesh generation density and computational efficiency, individually to sea cable by the way of customized scan Each structure member carries out mesh generation；
2.3, contact definition can control with hourglass
Select automatically contact as modeling contact type, allow model any surface and other surfaces include it originally Body contact is highly suitable for the case where can not predicting contact surface when the modeling of sea cable mechanical breakdown, is connect using widely used single side Touching algorithm is this from contact or large deformation problem to handle；In conclusion sea cable modeling contact definition is automatic single-contact；
Hourglass mode is state that is a kind of mathematically stable, but physically cannot achieve, it is necessary to control simulation process The overall sandglass model of middle computation model is less than 10% of energy in overall, and simulation result is only effectively；From raising mesh generation matter It measures and hourglass control algorithm is applied to the biggish sea cable component of sandglass model to reduce their own sandglass model；By repeatedly tasting Examination, it should the sandglass model of overall process and the Ratio control of interior energy will be emulated below 2%；Fig. 2 is that sea cable anchor pounds process sandglass model With the relational graph of interior energy.For the angle of energy, the simulation result of mechanical modeling is reliable.
3, the load of sea cable fault condition applies
3.1, stretching fault load applies
A Typical tensile load is chosen, is applied on sea cable model axial direction, the extensibility and tensile load of sea cable are made It is respectively 5 ‰ and 0.1s with the time, at the uniform velocity stretches；Fixed constraint is applied to all nodes on one end face of model, is intercepted another The sea cable section for holding a bit of length is component, and it is rigid body that its material type, which is arranged, by applying rigid body displacement-time to the component Load, and then stretch sea cable；
3.2, torque failure load applies
Similar with tensile load applying method, the realization of sea cable torsion is to apply fixed constraint to one end node, to group The rigid body portion of part applies rigid body rotation-time load, at the uniform velocity reverses, by the positive and negative and maximum value that rigid body spin load is arranged To control the direction and angle that sea cable is reversed, pass through the speed for changing the time control torsion that load applies.Torsional direction is not With being presented as that rigid body direction of rotation is identical and opposite as sea cable direction of lay.According to the practical winding method of sea cable, typical torsion is taken In the case of 0 °~20 ° of torsion angular region, reverse speed is respectively ± 4 °/s, ± 6 °/s and ± 8 °/s, and reverse speed is positive table Show that rigid body torsional direction is identical as sea cable direction of lay, is negative then contrary.
3.3, anchor pounds failure load application
Most representational 660kg Hall'sanchor work is chosen according to ship size above waters where sea cable and with anchor situation For modeling object, capable simplification is anchored into ship under the premise of guaranteeing anchor weight and constant proj ected bottom area；According to the whereabouts of ship anchor Speed calculation method acquires the maximum falling speed of ship anchor contact sea cable moment, and the falling speed of control ship anchor is less than or equal to maximum Speed is to tally with the actual situation, and when modeling, the collision area for controlling ship anchor and sea cable is located at the intermediate region of emulation section, to sea cable The node at both ends applies fixed constraint, only applies rigid body displacement-time load straight down to ship anchor section.Since anchor hawser is hit It is extremely short to hit process, it is believed that entire knockout process is at the uniform velocity.A typical anchor is taken to pound fault condition, anchor pounds depth 8cm, herein according to ship It is 0~0.036s that collision time, which is arranged, in anchor calculating speed, and in order to avoid structure Condition of Sudden Unloading causes model to restrain extremely, load is applied Slightly longer between added-time is 0.04s, and practical ship anchor stops the stable state after sinking in order to obtain, and the solution time is set as sufficiently long 10s, remaining time ship anchor are maintained at most deep impingement position；Due to having been added soil penetration resistance in the calculating of ship anchor kinetic energy Influence, comparatively wrap up the soft water saturation soil of sea cable to hit moment negligible to the resistance of anchor hawser；
4, FEM Numerical Simulation and analysis
4.1, stretch analysis of simulation result
The strain distributing disciplinarian of sea cable axial optical fiber in drawing process, the cylinder similar for other structures in sea cable (ring) body, they are behaved like during axial tension, are analyzed using cable core component most important in sea cable as representative, are drawn The strain of cable core is axially distributed along sea cable during stretching, and the strain of the upper optical fiber of sea cable axial direction and cable core is with level of stretch Increase and increase, cable core strain does not change with the variation of axial distance, and directly proportional to level of stretch, optical fiber is rigid along the line The main stretch zones dependent variable that position transfer lotus applies is maximum, and remoter apart from the main stretch zones of sea cable, fibre strain amount is got over It is small, then this feature is in the criterion of tensional state as sea cable and carries out fault location；Take the axial 2~4.5m of sea cable in Fig. 3 Cable core strain and fibre strain are established in the mean strain of the optical fiber and cable core in the relatively obvious region of range inner fiber strain variation Relationship (as shown in Figure 4)；
As shown in Figure 4, it is therefore seen that cable core strain is approximate with fibre strain linear, this meets sea cable drawing force in document The theory analysis of characteristic is learned, meanwhile, the lay configuration of column structure and optical fiber for cable core in sea cable is tried in linear stretch It tests and has obtained the approximate directly proportional conclusion of the lay configuration being wrapped in outside cylindrical body and the cylinder strain in isometric deformation, this One conclusion further demonstrates the reliability of the cable core and fibre strain relationship obtained herein.Simultaneously as excess fiber length is in reality Border using when can gradually be exhausted with accumulation strain, in the case where not considering excess fiber length in modeling, optical fiber and cable core just Beginning to strain is zero, is fitted the data of cable core strain linear (as shown in Figure 4) approximate with fibre strain accordingly, determines coefficients R2 =0.9877, standard error RMSE=1.237 × 10-4, formula (3) can be obtained；
εc=1.204 εf (3)
In formula, εcIndicate cable core strain, εfIndicate fibre strain；It can determine whether the stretching of sea cable based on formula (3) and fibre strain Degree and state；
4.2, reverse analysis of simulation result
4.2.1, torsional direction is opposite with sea cable direction of lay
(1) optical fiber, the Strain Distribution (shown in such as Fig. 5 (a)) of sea cable axial optical fiber, reverses journey with sea cable when different torsion angles The increase of degree and increase, the fibre strain that the load of sea cable applies end and restrained end is influenced slightly above intermediate by end effect Section, the strain of intermediate region are of substantially equal；From relationship (such as Fig. 5 (b) of the emulation optical fiber mean strain of section intermediate region and torsion angle It is shown) find out that visible fibre strain is directly proportional to torsion angle；
(2) cable core
It is outermost that stress maximum suffered by outer layer of cable core unit when as torsion, the cable core strain and stress refer both to its Strain and stress；It, can from cable core strain and stress under sea cable twisting states and the relationship of fibre strain (shown in such as Fig. 6 (a)) Know, cable core strains directly proportional to fibre strain always, fitting result such as formula (4) under twisting states, is fitted R2=0.9999, RMSE =1.04 × 10-5；
εc=4.16 εf (4)
By Fig. 6 (b) it is found that cable core material is changed into plastic deformation by elastic deformation with the increase of torsion angle, in material bullet Sexual stage, cable core stress is directly proportional to fibre strain, is more than after yield point, and cable core stress and fibre strain meet linear relationship, Using piecewise linear function fitting result such as formula (5)；Fitting function first segment R2=1, RMSE=0.1171；Second segment R2=1, RMSE=0.5608, reverse speed is on result without influence (curve is matched curve in figure)；
In formula, σcFor cable core stress, unit 0.1Mpa.
(3) armouring
Under different reverse speeds, from armouring strain and stress and the relation curve of fibre strain (as shown in Figure 7) by scheming Armouring strain and stress are approximate with fibre strain directly proportional known to 7, this is because when torsional direction is opposite with sea cable direction of lay When, optical fiber and armouring lay configuration are in synchronization discrete state, fibre strain and the strain of armouring and stress only in twist process It is generated by torsion, since sea cable stretching caused by reversing is negligible, therefore the strain of armouring and stress will not be due to reversing and stretching Superposition be mutated, it is linear always with fibre strain；By Fig. 7 (b) it is further known that, at 20 ° of turn-back angles of setting In range, armouring is in elastic stage always, and the maximum stress born is not up to material yield point, and reverse speed is to result base This is without influence；Shown in fitting result such as formula (6) and formula (7), formula (6) is fitted R2=0.9993, RMSE=7.572 × 10-6；Formula (7) it is fitted R2=0.9990, RMSE=20.53.(curve is matched curve in figure)
εt=1.15 εf (6)
σt=2.593 × 106εf 0≤εf≤8.28×10-4 (7)
In formula, εtFor armouring strain；σtFor armouring stress, unit 0.1Mpa.
4.2.2, torsional direction is identical as sea cable direction of lay,
Under this state, the stress of the cylinders such as cable core (ring) body and strain are still only generated by torsion, unrelated with torsional direction；? The strain of the lay configurations such as torsion degree hour, optical fiber and armouring and stress are mainly generated by torsion, this period stress and strain Variation it is little；As torsion degree is deepened, stress is started to be caused jointly by reversing and stretching by strain, and value obviously increases Greatly；
(1) optical fiber
When different torsion angles shown in the Strain Distribution of sea cable axial optical fiber such as Fig. 8 (a), it is seen that fibre strain is reversed with sea cable The increase of degree and increase, fibre strain in sea cable axial direction value is of substantially equal.Make mean strain along optical fiber to become with torsion angle Shown in the curve of change such as Fig. 8 (b).It can be seen that when torsion degree is smaller, fibre strain is linear with torsion angle, with torsion The intensification of degree, the rate that fibre strain increases are accelerated, eventually pass back to linearly increase, can be divided into three sections.
(2) cable core
According under different reverse speeds, cable core strain and stress and the relationship of fibre strain (as shown in Figure 9).For cylinder Body cable core structure, strain and stress are unrelated with torsional direction with the changing rule of torsion angle, and Fig. 5 (b) shows to reverse with Fig. 6 Under state cable core strain and stress respectively with torsion angle is linear and piecewise linear function relationship；According to Fig. 8 (b) fibre strain with Three sections of relationships of torsion angle, can be used three piecewise functions to cable core strain in Fig. 9 and stress and the relationship of fibre strain respectively into Row fitting, shown in fitting result such as formula (8) and formula (9), formula (8) is fitted R2Respectively 0.9999,0.9951 and 0.9996, RMSE is respectively 1.458 × 10-6、2.318×10-5With 1.185 × 10-5；Formula (9) is fitted R2Respectively 0.9999,0.9949 and 0.9997, RMSE difference 1.746,11.79 and 5.542；
(3) armouring
(as shown in Figure 10 according to armouring strain and stress and the relationship of fibre strain under different reverse speeds.) by Figure 10 (a) it is found that armouring strain and fibre strain can be divided into two stages in twist process, when torsion degree is little armouring strain with Fibre strain is directly proportional, and strain is only generated by torsion；When torsion degree further increases, strain results from torsion and stretching, armour Dress strain is further increased with the increase of fibre strain；By Figure 10 (b) it is found that armouring stress and the relationship of fibre strain are divided into Three phases, the first two stage is similar to the changing rule of strain, and armouring is in elastic stage at this time；When armouring stress is with torsion After the intensification of carryover degree further increases the yield point of material, armouring is plastically deformed, the pass of stress and fibre strain System enters the phase III；Reverse speed is on result substantially without influence；As shown in Figure 10, the result being fitted using piecewise function As shown in formula (10) and formula (11)；Formula (10) is fitted R2Respectively 0.9994 and 0.9998, RMSE are respectively 4.434 × 10-7With 1.274×10-5；Formula (11) is fitted R2Respectively 0.9994,0.9994 and 0.9996, RMSE distinguish 4.496,23.39 and 25.03, (Figure 10 is shown in matched curve.) the first segment functions of formula (10) and (11) has higher Linear Quasi right, this and formula It is (6) consistent with the rule of (7) reflection,
It is interior when sea cable torsional direction is identical as its direction of lay in conjunction with the 4.2.1 result saved it is found that under identical torsion angle The strain of portion's optical fiber and armouring lay configuration and the variation degree of stress will be significantly greater than sea cable torsional direction and its direction of lay The case where when opposite；According to the relationship of cable core, armouring strain and stress and fibre strain under the sea cable twisting states of foundation, formula (4)~(11)) and BOTDR system actual measurement fibre strain, the strain and stress of cable core and armouring are predicted, and then sentences The torque failure degree of disconnected sea cable；
4.3, anchor pounds analysis of simulation result
(1) anchor pounds process aggregate analysis
Ship anchor position is moved during anchor as shown in figure 11 is pounded and the displacement of key strike region sea cable central point becomes at any time The curve of change.Anchor pounds failure early stage, and sea cable is only locally deformed with, and overall deformation then just occurs, whole process can be divided into armour Dress layer local deformation stage (sinking of sea cable is negligible during this), sea cable are sunk the stage and (are displaced with sea cable central point to weigh Amount) and the sea cable rebound stage；Optoelectronic composite cable has been carried out prior art describes admiral anchor to fall anchor bump test, has analyzed anchor The deformation process of sea cable armouring and cable core during pounding obtains sea cable deformation, while containing armouring local dent and sea cable is total Body sinking and bending deformation as a result, the present invention emulates resulting sea cable deformation and the analysis result of displacement is essentially identical, therefore this Invention is effectively verified.It it is further known that, is 0~t in the time interval that armouring local deformation only occurs for sea cable from Figure 111 (t1=0.003s), the time interval for integral sinking occur is t1~t2(t2=0.0036s), then in t2~t3(t3= 0.004s) there is slight resilience, whole process sea cable sinking displacement amount is 7.3cm, and ship anchor displacement is 8cm, under sea cable Heavy stage, armouring are transitioned into surrender and strain (see the analysis in the section of 4.3 (3)) from elastic stage, at this time anchor hawser contact surface On single armouring wire self-deformation it is negligible, and with the sinking of ship anchor occur it is synchronous sink, showed in Figure 11 It is substantially parallel with cable core central point displacement curve for the stage ship anchor displacement curve, to cable core after the armouring sinking arrival protection limit Occur to squeeze and leads to cable core deformation.This sea cable dissected after falling anchor impact test with document obtains the armour near anchor hawser contact area Dress deformation reaches unanimity with internal cable core deformation extent；Illustrate that armouring there is protection to make sea cable internal structure to a certain extent With, but degree of protection is limited.
(2) optical fiber
Anchor is pounded under state, and sea cable axial optical fiber Strain Distribution changes with time rule (shown in such as Figure 12 (a)) by sea Cable emulates the relationship of the average value that key strike area fiber strains among section and time and the shifting of ship anchor position (such as Figure 12 (b) institute Show).By Figure 12 (a)) it is found that the strain of sea cable axial optical fiber is whole as anchor pounds the increase of depth and increases and its distribution has pair Title property, it is small that centre falls fibre strain at anchor, develops fibre strain falling to two sides near anchor point and increases, from falling with a certain distance from anchor point Sea cable bending degree reduces afterwards, and fibre strain tends to decline；This feature of fibre strain distribution can be used as according to fibre strain Judge that the foundation that anchor pounds failure occurs for sea cable.
(3) armouring
Plastic strain is the permanent strain generated in deformation process, as the mark of material damage, armouring in engineering Plastic strain largely reflect the faulted condition of sea cable, on the basis of falling anchor central point, extract central point and its two Armouring stress and plastic strain at side each 5cm, 10cm, 15cm, by armouring mean stress, plastic strain and fibre strain with The relationship of time is drawn in curve together in Figure 13 and is compared；
As shown in figure 13, according to the constitutive relation of elastic-plastic material in engineering, by shape of armouring during entire anchor is pounded State is divided into the following period: OA period, and armouring is in elastic stage, reaches the elastic limit of material in A point, OA sections of middle parts have The waving interval that one section of stress is basically unchanged, this is because sea cable is by the local deformation step transition of armouring under in the section The heavy stage；The AB period, after A point, armouring stress is greater than the yield strength of material, and armouring plastic deformation occurs and enters surrender rank Section, the period armouring strain still in increase and stress does not increase, stress time curve present zigzag fluctuation, it appears that The ability for resisting deformation is lost, AB sections of minimum point is known as yield point on stress curve；BC period, sea cable continue with ship anchor Sink, armouring is transitioned into strain from yielding stage, and stress first reduces increase afterwards at any time, the stage inner armor stress Size is consistently less than the yield strength of its material, and plastic strain remains unchanged；The CD period, armouring still in strain, Stress persistently increases at any time, and explanation will make armouring strain increase, and then necessary increasing stress, armouring have restored the energy of resistance to deformation Power, this is also the main feature of strain, after C point, yield strength of the size of armouring stress again above material, and modeling Property strain value starts again at increase；The DE period, due to the unloading of ship anchor rigid body displacement load, the sea cable sinking stage terminates to enter Rebound stage, armouring still retain plastic strain but since a small amount of rebound lead to stress decrease；
(4) anchor pounds sea cable main feature moment analysis under failure
Above-mentioned sea cable anchor pounds three processes that are broadly divided into: process I is the local deformation stage of collision initial stage sea cable, time 0 ~0.003s；Process II is that sea cable is sunk the stage, time 0.003s~0.036s；Process III is the rebound stage of sea cable, time 0.036s~0.04s.(as shown in Figure 13) process II is subdivided into four-stage.First stage is OA sections of second half section, from Initial sinking occurs for 0.003s~0.0045s, this stage sea cable, sinks since sea cable is just until A point, armouring are in elasticity Stage is not plastically deformed, and birdcage shape deformation occurs in armouring, maintains normal configuration (such as II-1 stage institute in table 1 inside sea cable Show), as shown in I-stage in table 1, sea cable is in normal condition before this stage；Second stage be AB sections, from 0.0045s~ 0.012s, armouring birdcage shape deformation further develop, and plastic strain occur into yielding stage, under the protection of armouring, sea cable Internal structure still keeps normal substantially, is defined as slight attention stage (as shown in the II-2 stage in table 1).Phase III is BC sections, from 0.012s~0.03s, this stage sea cable deflection is further increased, and in sinking watching, armouring is undergone sea cable first The a bit of process being gradually recovered from birdcage shape protrusion to deformation, the process armouring stress reduce, and subsequently enter strain Stress increases again, and plastic strain remains unchanged, and sea cable twisted layer significantly increases the extruding of its internal structure in the stage, armour The protection of dress has tended to the limit, this stage needs hig diligence as a result, (as shown in the II-3 stage in table 1)；Fourth stage is CD sections, From 0.03s~0.036s, this stage armouring has been unable to maintain that normal lay configuration, and losing has sea cable internal structure Effect protection, sea cable inside cable core cross-section deform, and jeopardize the normal use of sea cable, herein therefore, it is considered that this stage sea cable occurs It damages (as shown in II-4, III stage in table 1).
(5) sea cable anchor pounds status monitoring index
It based on the analysis for pounding anchor process, establishes anchor and pounds the corresponding sea cable damage state assessment table of different phase, in table 1 The character pair moment for distinguishing sea cable difference faulted condition is respectively 0.0045s, 0.012s and 0.03s.
Table 1 is arranged anchor and pounds sea cable damage state assessment table under failure
The relationship of fibre strain and time during the anchor according to shown in Figure 12 (b) is pounded, when available anchor pounds main feature Carve corresponding fibre strain: when t=0.0045s, fibre strain is 4.25 × 10-3；When t=0.012s, fibre strain is 25.4×10-3；Fibre strain is 46.3 × 10 when t=0.03s-3.Thus it establishes the sea cable anchor based on fibre strain and pounds failure damage It is as shown in table 2 to hurt status assessment index.
Table 2 pounds damage state assessment index based on the sea cable anchor of fibre strain
4.4, fault identification and feature extraction
By previous analysis, it is found that sea cable occurs, mechanical breakdown type is different, the amplitude of internal optical fiber strain and space point Cloth can show different features.Sea cable stretches, torsion, anchor pounds sea cable deformation state under three kinds of typical faults and optical fiber is answered It is as shown in table 3 to become feature.
The feature identification of 3 submarine cable mechanical breakdown of table
Optical fiber Brillouin frequency-shift data based on actual measurement combines 1.3 section methods to can get fibre strain data, can in conjunction with table 4 The sea cable component strain/stress and fibre strain relational model further established by means of the present invention (formula (3)~11, scheme by table 4 13, table 3) can fault type to sea cable and development degree is further is judged, for discovery sea cable in time mechanical breakdown simultaneously It takes the necessary measures and foundation is provided.
5, conclusion
The present invention runs the stretching, torsion, anchor that can suffer to sea cable using the method for finite element modeling and pounds three kinds of typical cases Fault condition carried out simulation analysis, along system research the Strain Distribution of optical fiber and with cable core, armor piece strain/answer The correspondence variation relation of power.Main Conclusions is as follows:
Under (1) three kind of typical machine malfunction, the amplitude and spatial distribution of fibre strain have different spies along sea cable Sign, can accordingly recognize the fault type of sea cable.
(2) under sea cable tensional state, cable core strain is approximate with fibre strain directly proportional.Under twisting states, torsional direction with Bulge occurs for sea cable when direction of lay is opposite, and cable core strain is directly proportional to fibre strain, cable core stress and fibre strain satisfaction point Section linear functional relation；Armouring strain, stress are approximate with fibre strain directly proportional.Sea cable when torsional direction is identical as direction of lay It collects, cable core strain and the relationship of fibre strain can indicate that first section and latter end are linear, and interlude is full by three piecewise functions Sufficient quadratic polynomial relationship.It is directly proportional to fibre strain to reverse the strain of armouring early period, subsequent armouring strain is with fibre strain with two The form of order polynomial increases；Armouring stress and the relationship of fibre strain can indicate with three piecewise functions, first two sections with strain Regular consistent, third section armouring stress is approximate with fibre strain in a linear relationship.The foundation of above-mentioned relation function may be based on light The sea cable fault degree judgement of fibre strain provides reference.
(3) anchor of sea cable, which pounds faulted condition, can be divided into level Four, be based in conjunction with actual measurement fibre strain with established by the present invention The anchor of fibre strain pounds the evaluation index of degree of injury, can judge sea cable state.

Claims (1)

1. a kind of mechanical Fault Monitoring of HV method of photoelectric composite sea cable, which is characterized in that with 110kV YJQ41 × 300mm2Type sea Cable is research object, its Structural Dynamics finite element model is established based on the analysis of ANSYS/LS-DYNA Explicit Dynamics, to sea cable Stretching, torsion, anchor pound three kinds of typical fault situations and have carried out modeling and simulating, have obtained sea cable complex light under above-mentioned fault condition The strain of associated structural component and stress and fibre strain are during fault progression in Strain Distribution and sea cable along fibre Corresponding relationship, establish cable core under stretching, twisting states, armouring strain and stress and fibre strain functional relation, and Anchor pounds the evaluation index of sea cable faulted condition and fibre strain under state, the state monitoring method packet of the sea cable mechanical breakdown It includes:
1, sea cable structure and condition monitoring system
1.1, the sea cable condition monitoring systems based on BOTDR
With 110kV YJQ41 × 300mm2A certain two island sea area A, B in Eastern China of photoelectric composite sea cable connection, is used for its electric energy The real-time traffic information of conveying and the operation of electric system tunneling traffic, transmission power network schedule automation；110kV light has been built thus The stereo synthesis of electric composite sea cable monitors system, wherein the 110kV sea cable state prison based on Brillouin light time domain scattering (BOTDR) It surveys subsystem and uses the strain of distribution type fiber-optic measuring instrument real-time monitoring sea cable composite fiber, Temperature Distribution；Sea cable status monitoring Subsystem has 6 channels, channel 1/2,3/4,5/6 be respectively applied to east, in, the monitoring of western three-phase sea cable；BOTDR test equipment It is placed on the island B side, enters to inject in the compound single mode optical fiber of sea cable by laser pulse after connecting by general cable, laser transmits in a fiber Brillouin scattering is generated, Brillouin scattering reverse transfer reaches transmitting terminal, utilizes data acquisition unit (DAU) in transmitting terminal The strain of optical fiber, temperature letter can be obtained in frequency displacement and intensity with data processing unit (DPU) detection Brillouin scattering optical signal Breath；
1.2, using the validity of Brillouin shift monitoring sea cable strain
There are linear relationships for frequency displacement, intensity and the temperature of Brillouin scattering and strain；For common single mode optical fiber, brillouin frequency Move νBIt is as follows with the expression formula of temperature T and strain stress
νB(T)=νB0+1.158×10-4ΔT (1)
νB(ε)=νB0+5.6ε (2)
In formula, νB0For initial temperature T0And Brillouin shift when without strain, unit GHz；Δ T=T-T0For relative to T0's Temperature variation, unit are DEG C；
2, the finite element modeling of sea cable
2.1, sea cable Geometric Modeling
Three angles of influence of each structure member to simulation result in a possibility that from quality, the initial breakthrough of mesh generation and sea cable Degree, practical sea cable is simplified, be omitted thickness in sea cable it is comparatively very thin and on model influence very little conductor screen Cover layer, insulation screen, brass belt, interior serving be reduced to shell structure, the sea cable model finally established include copper cable core, Crosslinked polyetylene insulated layer, lead alloy sheath, high density polyethylene (HDPE) sheath, polyethylene terephthalate (PET) packing Layer, light unit, interior serving, armor, wherein light unit includes optical fiber, steel pipe, polypropylene cover；
In sea cable Geometric Modeling, armouring, PET packing, the modeling of three kinds of lay configuration components of light unit are the most key, accurately Lay configuration model is most important to the structural mechanics characteristic of true representation sea cable, thus depends on the distinctive APDL language of ANSYS Speech constructs single intertwist body, and then carrying out duplication to it under cylindrical coordinate according to twisted radical can be obtained twisted layer；
2.2, the selection of unit material and mesh generation
Interior serving thin for structure in sea cable, contribution is small selects SHELL163 thin shell element to model it, using silent Recognize and the Belytschko-Tsay algorithm of simple shell unit efficient stable is solved；Sea cable other parts select explicit body list First SOLID164, and it is solved using default single-point integral algorithm, in the case where effectively controlling hourglass mode, Single-point integral is good for large deformation unit effect, can theoretically promote 8 times relative to full integral algorithm solution efficiency；
The material of each component of sea cable can be divided into two classes according to its physical characteristic: one kind is metal material, including cable core, lead Steel pipe in alloy sleeve, armouring and light unit, metal material has typical elastoplasticity feature, using classical BKIN As its material model, which is expressed (Bilinear Kinematic Hardening) model using piecewise linear function The elasticity modulus of the constitutive relation of material, remaining nonmetal structure component materials is much smaller compared to for metal material, imitates Always it is in elastic stage during true, is studied using linear elastic model Isotropic, for ship anchor, before being pounded due to anchor The deformation of anchor is negligible afterwards, therefore uses body material model Rigid to ship anchor；
The mode of mesh generation influences whether the convergence of the initial breakthrough of model, minimum cell size ratio and calculating, Under the premise of having comprehensively considered mesh generation density and computational efficiency, individually to each knot of sea cable by the way of customized scan Structure component carries out mesh generation；
2.3, contact definition can control with hourglass
It selects to contact the contact type as modeling automatically, any surface of permission model includes that itself connects with other surfaces Touching is highly suitable for the case where can not predicting contact surface when the modeling of sea cable mechanical breakdown, is calculated using widely used single-contact Method is this from contact or large deformation problem to handle；In conclusion sea cable modeling contact definition is automatic single-contact；
Hourglass mode is state that is a kind of mathematically stable, but physically cannot achieve, it is necessary to control simulation process and fall into a trap The overall sandglass model for calculating model is less than 10% of energy in overall, and simulation result is only effectively；From improve mesh generation quality and Hourglass control algorithm is applied to the biggish sea cable component of sandglass model to reduce their own sandglass model；By repeatedly attempting, imitate The Ratio control of the sandglass model of true overall process and interior energy is below 2%；
3, the load of sea cable fault condition applies
3.1, stretching fault load applies
According to the sea cable mechanical test standard that the international bulk power grid committee proposes, chooses Typical tensile load and be applied to sea cable model On axial direction, the extensibility of sea cable and tensile load action time are respectively 5 ‰ and 0.1s, are at the uniform velocity stretched；To model one end All nodes on face apply fixed constraint, intercept the sea cable section of a bit of length of the other end as component, its material class is arranged Type is rigid body, by applying rigid body displacement-time load to the component, and then stretches sea cable；
3.2, torque failure load applies
Similar with tensile load applying method, the realization of sea cable torsion is to apply fixed constraint to one end node, to component Rigid body portion applies rigid body rotation-time load, at the uniform velocity reverses, and is controlled by the way that the positive and negative and maximum value of rigid body spin load is arranged The direction of sea cable processed torsion and angle, by changing the speed for the time control torsion that load applies, torsional direction it is not androgynous It is now identical with sea cable direction of lay and on the contrary, according to the practical winding method of sea cable for rigid body direction of rotation, take typical case to reverse situation Lower 0 °~20 ° of torsion angular region, reverse speed are respectively ± 4 °/s, ± 6 °/s and ± 8 °/s, and reverse speed, which is positive, indicates rigid Body torsional direction is identical as sea cable direction of lay, is negative then contrary；
3.3, anchor pounds failure load application
It is built according to ship size above waters where sea cable and with the most representational 660kg Hall'sanchor conduct of anchor situation selection Module object anchors into capable simplification to ship under the premise of guaranteeing anchor weight and constant proj ected bottom area；According to the falling speed of ship anchor Calculation method acquires the maximum falling speed of ship anchor contact sea cable moment, and the falling speed of control ship anchor is less than or equal to maximum speed To tally with the actual situation, when modeling, the collision area for controlling ship anchor and sea cable is located at the intermediate region of emulation section, to sea cable both ends Node apply fixed constraint, rigid body displacement-time load straight down only is applied to ship anchor section, since anchor hawser was hit Journey is extremely short, it is believed that entire knockout process is at the uniform velocity, to take a typical anchor to pound fault condition, anchor pounds depth 8cm, herein according to ship anchor meter Calculating speed setting collision time is 0~0.036s, in order to avoid structure Condition of Sudden Unloading causes model to restrain extremely, when load applies Between it is slightly longer be 0.04s, practical ship anchor stops the stable state after sinking in order to obtain, and the solution time is set as sufficiently long 10s, Remaining time ship anchor is maintained at most deep impingement position；Due to having been added the shadow of soil penetration resistance in the calculating of ship anchor kinetic energy It rings, the soft water saturation soil for comparatively wrapping up sea cable is negligible in resistance of the shock moment to anchor hawser, omits around sea cable The modeling of soil；
4, FEM Numerical Simulation and analysis
4.1, stretch analysis of simulation result
The cylindrical body similar for structure in sea cable, they are behaved like during axial tension, with most important in sea cable Cable core component is that representative is analyzed, and the strain of the upper optical fiber of sea cable axial direction and cable core is with the increasing of level of stretch in drawing process Increase greatly, cable core strain does not change with the variation of axial distance, and directly proportional to level of stretch, and optical fiber is in rigid body position along the line The main stretch zones dependent variable that transfer lotus applies is maximum, and remoter apart from the main stretch zones of sea cable, fibre strain amount is smaller, then This fibre strain distribution characteristics is in the criterion of tensional state as sea cable and carries out fault location；Take sea cable axial 2~ The mean strain of the optical fiber and cable core in the relatively obvious region of 4.5m range inner fiber strain variation is established cable core strain and is answered with optical fiber The relationship of change；It is approximate with fibre strain in a linear relationship that cable core strain can be obtained, simultaneously as excess fiber length is in actual use It can gradually be exhausted with accumulation strain, in the case where not considering excess fiber length in modeling, the initial strain of optical fiber and cable core is equal It is zero, is fitted cable core strain and fibre strain data accordingly, determines coefficients R2=0.9877, standard error RMSE=1.237 × 10-4, formula (3) can be obtained；
εc=1.204 εf (3)
In formula, εcIndicate cable core strain, εfIndicate fibre strain；It can determine whether the level of stretch of sea cable based on formula (3) and fibre strain And state；
4.2, reverse analysis of simulation result
4.2.1, torsional direction is opposite with sea cable direction of lay
(1) optical fiber
Sea cable axial optical fiber strain entirety increases with the increase of sea cable torsion degree, and fibre strain is distributed the shadow by end effect It rings and is slightly above interlude at load application end and restrained end, the strain of intermediate region is of substantially equal；From emulation section intermediate region light Fine mean strain is directlyed proportional to fibre strain known to the relationship of torsion angle to torsion angle；
(2) cable core
Stress suffered by outer layer of cable core unit is maximum when as torsion, and the cable core strain and stress refer both to its outermost strain And stress；By cable core strain and stress and the relationship of fibre strain under sea cable twisting states it is found that cable core strains under twisting states Always directly proportional to fibre strain, fitting result such as formula (4) is fitted R2=0.9999, RMSE=1.04 × 10-5；
εc=4.16 εf (4)
Cable core material is changed into plastic deformation by elastic deformation with the increase of torsion angle, in the elastic properties of materials stage, cable core stress with Fibre strain is directly proportional, is more than after yield point, and cable core stress and fibre strain meet linear relationship, quasi- using piecewise linear function Close result such as formula (5)；Fitting function first segment R2=1, RMSE=0.1171；Second segment R2=1, RMSE=0.5608, torsion speed Degree is on result without influence；
In formula, σcFor cable core stress, unit 0.1Mpa；
(3) armouring
By armouring strain and stress from the relation curve of fibre strain it is found that under different reverse speeds, armouring strain and stress and Fibre strain approximation is directly proportional, this is because when torsional direction is opposite with sea cable direction of lay, optical fiber and armour in twist process Dress lay configuration is in synchronization discrete state, fibre strain and the strain of armouring and stress and is only generated by torsion, since torsion is led The sea cable of cause, which stretches, can be ignored, therefore the strain of armouring and stress will not be mutated due to the superposition reversed and stretched, with optical fiber It strains linear always；In 20 ° of turn-back angular regions of setting, armouring is in elastic stage always, the maximum born Stress is not up to material yield point, and reverse speed is on result substantially without influence；Armouring strain and stress and fibre strain relationship Shown in fitting result such as formula (6) and formula (7), formula (6) is fitted R2=0.9993, RMSE=7.572 × 10-6；Formula (7) is fitted R2= 0.9990, RMSE=20.53,
εt=1.15 εf (6)
σt=2.593 × 106εf 0≤εf≤8.28×10-4 (7)
In formula, εtFor armouring strain；σtFor armouring stress, unit 0.1Mpa；
4.2.2, torsional direction is identical as sea cable direction of lay
Under this state, the stress of the cylindrical bodies such as cable core and strain are still only generated by torsion, unrelated with torsional direction；In torsion degree When little, the strain of the lay configurations such as optical fiber and armouring and stress are mainly generated by torsion, the variation of this period stress and strain Less；As torsion degree is deepened, strain and stress start to be caused jointly by reversing and stretching, and value significantly increases；
(1) optical fiber
According to the Strain Distribution of sea cable axial optical fiber when different torsion angles, it is known that fibre strain with the increase of sea cable torsion degree and Increasing, the fibre strain value in sea cable axial direction is of substantially equal, thus make the curve that mean strain changes with torsion angle along optical fiber, It can be seen that fibre strain is linear with torsion angle when torsion degree is little, with the intensification of torsion degree, fibre strain increases Big rate is accelerated, and eventually passes back to linearly increase, can be divided into three sections；
(2) cable core
For cylindrical body cable core structure, strain and stress are unrelated with torsional direction with the changing rule of torsion angle, distinguish always With torsion angle is linear and piecewise linear function relationship, by three sections of relationships of fibre strain and torsion angle, cable core strain and stress Three piecewise function fittings are carried out with the relationship of fibre strain, shown in fitting result such as formula (8) and formula (9), formula (8) is fitted R2Respectively It is 0.9999,0.9951 and 0.9996, RMSE is respectively 1.458 × 10-6、2.318×10-5With 1.185 × 10-5；Formula (9) is quasi- Close R2Respectively 0.9999,0.9949 and 0.9997, RMSE difference 1.746,11.79 and 5.542；
(3) armouring
According to armouring strain and stress and the relationship of fibre strain under different reverse speeds it is found that armouring strain and fibre strain exist Two stages can be divided into twist process, armouring strain is directly proportional to fibre strain when torsion degree is little, strains only by reversing It generates；When torsion degree further increases, strain results from torsion and stretching, and armouring strains the increase with fibre strain into one Step increases；Armouring stress and the relationship of fibre strain are divided into three phases, and the first two stage is similar to the changing rule of strain, this When armouring be in elastic stage；After armouring stress further increases the yield point of material with the intensification of torsion degree, armour Take on existing plastic deformation, the relationship of stress and fibre strain enters the phase III；Reverse speed is on result substantially without influence；Armour The result such as formula (10) and formula (11) institute that dress strain and stress use piecewise function to be fitted with the relationship of fibre strain respectively Show；Formula (10) is fitted R2Respectively 0.9994 and 0.9998, RMSE are respectively 4.434 × 10-7With 1.274 × 10-5；Formula (11) is quasi- Close R2Respectively 0.9994,0.9994 and 0.9996, RMSE difference 4.496,23.39 and 25.03, the first of formula (10) and (11) Section function has higher Linear Quasi right, this is consistent with the rule that formula (6) and (7) reflect；
In conjunction with the 4.2.1 result saved it is found that under identical torsion angle, when sea cable torsional direction is identical as its direction of lay, interior lights It is opposite with its direction of lay that the fine and strain of armouring lay configuration and the variation degree of stress will be significantly greater than sea cable torsional direction When the case where；According to cable core under the sea cable twisting states of foundation, armouring strain and stress and the relationship of fibre strain (formula (4)~ Formula (11)) and BOTDR system actual measurement fibre strain, can strain to cable core and armouring and stress predict, and then sentence The torque failure degree of disconnected sea cable；
4.3, anchor pounds analysis of simulation result
(1) anchor pounds process aggregate analysis
Anchor is pounded failure early stage sea cable and is only locally deformed with, and overall deformation then just occurs, and whole process can be divided into armor office Portion's deformation stage, sea cable are sunk stage and sea cable rebound stage；Sea cable only occur armouring local deformation time interval be 0~ t1(t1=0.003s), the time interval for integral sinking occur is t1~t2(t2=0.0036s), then in t2~t3(t3= 0.004s) there is slight resilience, whole process sea cable sinking displacement amount is 7.3cm, and ship anchor displacement is 8cm, under sea cable Heavy stage, armouring are transitioned into surrender and strain from elastic stage, at this time the single armouring wire itself on anchor hawser contact surface Deformation is negligible, and as synchronous sinking occurs for the sinking of ship anchor, armouring occurs cable core after sinking to reaching the protection limit Extruding leads to cable core deformation, illustrates that armouring has protective effect to sea cable internal structure to a certain extent, but degree of protection has Limit；
(2) optical fiber
Anchor is pounded under state, by sea cable axial optical fiber Strain Distribution and the relationship of time it is found that the strain of sea cable axial optical fiber it is whole with Anchor pound the increase of depth and increase and its distribution has symmetry, it is small that centre falls fibre strain at anchor, fall near anchor point to Two sides are developed fibre strain and are increased, and sea cable bending degree reduces after falling with a certain distance from anchor point, and fibre strain tends to decline；Optical fiber This feature of Strain Distribution, which can be used as, judges that the foundation that anchor pounds failure occurs for sea cable according to fibre strain；
(3) armouring
Plastic strain is the permanent strain generated in deformation process, as the mark of material damage, the modeling of armouring in engineering Property strain largely reflect the faulted condition of sea cable, on the basis of falling anchor central point, extract central point and its two sides be each Armouring stress and plastic strain at 5cm, 10cm, 15cm, by armouring mean stress, plastic strain and fibre strain and time Relationship be drawn in curve together and be compared；
According to the constitutive relation of elastic-plastic material in engineering, state of armouring during entire anchor is pounded is divided into the following time Section: OA period, armouring are in elastic stage, reach the elastic limit of material in A point, there is one section of stress at OA sections of middle parts substantially not The waving interval of change, this is because sea cable is by the local deformation step transition of armouring to the sinking stage in the section；The AB time Section, after A point, armouring stress is greater than the yield strength of material, and armouring plastic deformation occurs and enters yielding stage, the period armour Dress strain still in increase and stress does not increase, stress time curve present zigzag fluctuation, it appears that lose resistance deformation Ability, AB sections of minimum point is known as yield point on stress curve；BC period, sea cable continue to sink with ship anchor, armouring from bend Step transition is taken to strain, stress first reduces increase afterwards at any time, and the size of the stage inner armor stress is consistently less than The yield strength of its material, plastic strain remain unchanged；CD period, armouring are held at any time still in strain, stress Continuous to increase, explanation will make armouring strain increase, and then necessary increasing stress, armouring have restored the ability of resistance to deformation, this is also to strengthen The main feature in stage, after C point, the size of armouring stress is again above the yield strength of material, and plastic strain value is again Start to increase；The DE period, due to the unloading of ship anchor rigid body displacement load, the sea cable sinking stage terminates to enter rebound stage, armour Dress still retains plastic strain but since a small amount of rebound leads to stress decrease；
(4) anchor pounds sea cable main feature moment analysis under failure
Above-mentioned sea cable anchor pounds three processes that are broadly divided into: process I is the local deformation stage of collision initial stage sea cable, the time 0~ 0.003s；Process II is that sea cable is sunk the stage, time 0.003s~0.036s；Process III is the rebound stage of sea cable, time 0.036s~0.04s；Process II is subdivided into four-stage: the first stage is OA sections of second half section, from 0.003s~ Initial sinking occurs for 0.0045s, this stage sea cable, sinks since sea cable is just until A point, armouring are in elastic stage and do not go out Now be plastically deformed, there is birdcage shape deformation in armouring, and normal configuration is maintained inside sea cable, and second stage is AB sections, from 0.0045s~ 0.012s, armouring birdcage shape deformation further develop, and plastic strain occur into yielding stage, under the protection of armouring, sea cable Internal structure still keeps normal substantially；Phase III is BC sections, and from 0.012s~0.03s, this stage sea cable deflection is further Increase, for sea cable in sinking watching, armouring experienced a bit of process being gradually recovered from birdcage shape protrusion to deformation first, should Process armouring stress reduces, and subsequently enters strain stress and increases again, and plastic strain remains unchanged, and sea cable twists in the stage It closes layer to significantly increase the extruding of its internal structure, the protection of armouring has tended to the limit, this stage needs hig diligence as a result,；The Four stages were CD sections, and from 0.03s~0.036s, this stage armouring has been unable to maintain that normal lay configuration, has lost to sea The effective protection of cable internal structure, sea cable inside cable core cross-section deform, and jeopardize the normal use of sea cable, therefore, it is considered that this rank Section sea cable is damaged；Based on the analysis of summary front, then feature extraction and fault identification are able to carry out.
CN201910193537.7A 2019-03-14 2019-03-14 Mechanical fault monitoring method for photoelectric composite submarine cable Active CN110296885B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201910193537.7A CN110296885B (en) 2019-03-14 2019-03-14 Mechanical fault monitoring method for photoelectric composite submarine cable

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201910193537.7A CN110296885B (en) 2019-03-14 2019-03-14 Mechanical fault monitoring method for photoelectric composite submarine cable

Publications (2)

Publication Number Publication Date
CN110296885A true CN110296885A (en) 2019-10-01
CN110296885B CN110296885B (en) 2022-05-03

Family

ID=68026416

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201910193537.7A Active CN110296885B (en) 2019-03-14 2019-03-14 Mechanical fault monitoring method for photoelectric composite submarine cable

Country Status (1)

Country Link
CN (1) CN110296885B (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112133130A (en) * 2020-09-23 2020-12-25 苏州光格设备有限公司 Method for monitoring whole anchoring process of submarine cable
CN113219894A (en) * 2021-04-12 2021-08-06 成都飞机工业（集团）有限责任公司 Aircraft tool state real-time monitoring method based on three-dimensional force sensor
CN113959838A (en) * 2021-09-15 2022-01-21 深圳市比洋光通信科技股份有限公司 Stress monitoring method for optical fiber capillary tube
CN114389226A (en) * 2022-01-14 2022-04-22 宁波东方电缆股份有限公司 Attached type pipe cable system based on jacket platform and design method
CN115184193A (en) * 2022-09-06 2022-10-14 深圳永贵技术有限公司 Automatic testing method, device and equipment for cable and storage medium
CN116306084A (en) * 2023-01-06 2023-06-23 天津大学 Numerical method for simulating impact protection of seabed gas pipeline

Citations (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101266024A (en) * 2008-05-09 2008-09-17 于晋龙 Distributed optical fibre oil gas conveying pipeline early early-warning system based on polarization detection
CN101629852A (en) * 2009-08-19 2010-01-20 南昌航空大学 Method for eliminating temperature and stress backward influence effect in Brillouin optical-fiber sensing
CN101776441A (en) * 2010-02-09 2010-07-14 北京航空航天大学 Real-time online system for measuring space vehicle shell impact degree and impact position
CN101908930A (en) * 2010-07-28 2010-12-08 李淑英 Method and device capable of synchronously realizing brillouin distributed optical fiber sensing monitoring and data communication
WO2011103596A2 (en) * 2010-02-22 2011-08-25 Vello Systems, Inc. Subchannel security at the optical layer
CN102997949A (en) * 2012-12-18 2013-03-27 华北电力大学（保定） Method used for measuring temperature and strain simultaneously and based on brillouin scattering
CN103063325A (en) * 2013-01-16 2013-04-24 电子科技大学 Brillouin optical time domain analysis (BOTDA) temperature and strain simultaneous measurement method based on large effective area fiber (LEAF)
CN103274304A (en) * 2013-06-09 2013-09-04 广州市特种机电设备检测研究院 Method for dynamically adjusting monitoring and safety pre-warning threshold values of crane structure
US20130269423A1 (en) * 2010-02-12 2013-10-17 Dan Angelescu Passive Micro-vessel and Sensor
CN203688370U (en) * 2013-12-20 2014-07-02 中天科技海缆有限公司 Torsional rigidity testing device
CN103926061A (en) * 2009-05-27 2014-07-16 普睿司曼股份公司 Deformation monitoring method and system for measuring tensile strain of cable
US20140196953A1 (en) * 2001-08-19 2014-07-17 James E. Chitwood Drilling apparatus
CN104181193A (en) * 2014-08-23 2014-12-03 华北电力大学（保定） Method for calculating thermal resistance of packing layer in compound optical fiber of three-core submarine cable
CN106886645A (en) * 2017-02-21 2017-06-23 三峡大学 A kind of modeling method of cable flexing
CN106950138A (en) * 2017-04-06 2017-07-14 国网浙江省电力公司舟山供电公司 Optical fiber composite submarine cable wear test system and its method of work
CN107024183A (en) * 2017-06-01 2017-08-08 安徽理工大学 Exploring Loose Rock Country in Tunnels range test method and system
CN107402338A (en) * 2016-05-20 2017-11-28 国网天津市电力公司 Cable electrical failure analysis methods based on distributed optical fiber temperature measurement
CN107480875A (en) * 2017-08-02 2017-12-15 华北电力大学 A kind of marine frequency dividing cable transmission systems allocation plan choosing method
US20180060455A1 (en) * 2016-08-25 2018-03-01 Baker Hughes Incorporated Generating a script for performing a well operation job
CN207096517U (en) * 2017-06-08 2018-03-13 江苏亨通海洋光网系统有限公司 One kind feed deep-sea cable
CN108595898A (en) * 2018-06-13 2018-09-28 上汽大众汽车有限公司 Finite element modeling method based on vehicle collision simulation and system
CN108895974A (en) * 2018-05-08 2018-11-27 航天东方红卫星有限公司 A kind of malformation fiber-optic monitoring and reconstructing method and system
CN109033693A (en) * 2018-08-17 2018-12-18 北京道亨时代科技有限公司 A kind of method that power cable well parametric modeling and solid modelling blend
CN109324236A (en) * 2018-09-29 2019-02-12 国网山西省电力公司太原供电公司 A kind of assessment of fault method based on cable connector typical defect

Patent Citations (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140196953A1 (en) * 2001-08-19 2014-07-17 James E. Chitwood Drilling apparatus
CN101266024A (en) * 2008-05-09 2008-09-17 于晋龙 Distributed optical fibre oil gas conveying pipeline early early-warning system based on polarization detection
CN103926061A (en) * 2009-05-27 2014-07-16 普睿司曼股份公司 Deformation monitoring method and system for measuring tensile strain of cable
CN101629852A (en) * 2009-08-19 2010-01-20 南昌航空大学 Method for eliminating temperature and stress backward influence effect in Brillouin optical-fiber sensing
CN101776441A (en) * 2010-02-09 2010-07-14 北京航空航天大学 Real-time online system for measuring space vehicle shell impact degree and impact position
US20130269423A1 (en) * 2010-02-12 2013-10-17 Dan Angelescu Passive Micro-vessel and Sensor
WO2011103596A2 (en) * 2010-02-22 2011-08-25 Vello Systems, Inc. Subchannel security at the optical layer
CN101908930A (en) * 2010-07-28 2010-12-08 李淑英 Method and device capable of synchronously realizing brillouin distributed optical fiber sensing monitoring and data communication
CN102997949A (en) * 2012-12-18 2013-03-27 华北电力大学（保定） Method used for measuring temperature and strain simultaneously and based on brillouin scattering
CN103063325A (en) * 2013-01-16 2013-04-24 电子科技大学 Brillouin optical time domain analysis (BOTDA) temperature and strain simultaneous measurement method based on large effective area fiber (LEAF)
CN103274304A (en) * 2013-06-09 2013-09-04 广州市特种机电设备检测研究院 Method for dynamically adjusting monitoring and safety pre-warning threshold values of crane structure
CN203688370U (en) * 2013-12-20 2014-07-02 中天科技海缆有限公司 Torsional rigidity testing device
CN104181193A (en) * 2014-08-23 2014-12-03 华北电力大学（保定） Method for calculating thermal resistance of packing layer in compound optical fiber of three-core submarine cable
CN107402338A (en) * 2016-05-20 2017-11-28 国网天津市电力公司 Cable electrical failure analysis methods based on distributed optical fiber temperature measurement
US20180060455A1 (en) * 2016-08-25 2018-03-01 Baker Hughes Incorporated Generating a script for performing a well operation job
CN106886645A (en) * 2017-02-21 2017-06-23 三峡大学 A kind of modeling method of cable flexing
CN106950138A (en) * 2017-04-06 2017-07-14 国网浙江省电力公司舟山供电公司 Optical fiber composite submarine cable wear test system and its method of work
CN107024183A (en) * 2017-06-01 2017-08-08 安徽理工大学 Exploring Loose Rock Country in Tunnels range test method and system
CN207096517U (en) * 2017-06-08 2018-03-13 江苏亨通海洋光网系统有限公司 One kind feed deep-sea cable
CN107480875A (en) * 2017-08-02 2017-12-15 华北电力大学 A kind of marine frequency dividing cable transmission systems allocation plan choosing method
CN108895974A (en) * 2018-05-08 2018-11-27 航天东方红卫星有限公司 A kind of malformation fiber-optic monitoring and reconstructing method and system
CN108595898A (en) * 2018-06-13 2018-09-28 上汽大众汽车有限公司 Finite element modeling method based on vehicle collision simulation and system
CN109033693A (en) * 2018-08-17 2018-12-18 北京道亨时代科技有限公司 A kind of method that power cable well parametric modeling and solid modelling blend
CN109324236A (en) * 2018-09-29 2019-02-12 国网山西省电力公司太原供电公司 A kind of assessment of fault method based on cable connector typical defect

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
ZHINIU,XU: "Application of temperature field modeling in monitoring of optic-electric composite submarine calbe with insulation degradation", 《MEASUREMENT》 *
徐志钮: "光电复合海缆温度场建模分析及在在线监测中的应用", 《红外与激光工程》 *
胡玉娇: "光纤复合海底电缆机械行为的有限元模型研究", 《中国优秀硕士学位论文全文数据库工程科技II辑》 *

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112133130A (en) * 2020-09-23 2020-12-25 苏州光格设备有限公司 Method for monitoring whole anchoring process of submarine cable
CN112133130B (en) * 2020-09-23 2021-12-17 苏州光格科技股份有限公司 Method for monitoring whole anchoring process of submarine cable
CN113219894A (en) * 2021-04-12 2021-08-06 成都飞机工业（集团）有限责任公司 Aircraft tool state real-time monitoring method based on three-dimensional force sensor
CN113219894B (en) * 2021-04-12 2022-12-13 成都飞机工业（集团）有限责任公司 Aircraft tool state real-time monitoring method based on three-dimensional force sensor
CN113959838A (en) * 2021-09-15 2022-01-21 深圳市比洋光通信科技股份有限公司 Stress monitoring method for optical fiber capillary tube
CN113959838B (en) * 2021-09-15 2024-03-29 深圳市比洋光通信科技股份有限公司 Method for monitoring stress of optical fiber capillary tube
CN114389226A (en) * 2022-01-14 2022-04-22 宁波东方电缆股份有限公司 Attached type pipe cable system based on jacket platform and design method
CN115184193A (en) * 2022-09-06 2022-10-14 深圳永贵技术有限公司 Automatic testing method, device and equipment for cable and storage medium
CN116306084A (en) * 2023-01-06 2023-06-23 天津大学 Numerical method for simulating impact protection of seabed gas pipeline
CN116306084B (en) * 2023-01-06 2023-10-27 天津大学 Numerical method for simulating impact protection of seabed gas pipeline

Also Published As

Publication number Publication date
CN110296885B (en) 2022-05-03

Similar Documents

Publication Publication Date Title
CN110296885A (en) A kind of mechanical Fault Monitoring of HV method of photoelectric composite sea cable
CN103942417B (en) Ice coating wire ice-shedding emulation test method
CN102288125A (en) Metal-based cable distributed optical fiber sensor
CN102095449A (en) Method for alarming dancing of overhead transmission circuit
Ambühl et al. Extrapolation of extreme response for different mooring line systems of floating wave energy converters
CN107887065A (en) A kind of high-strength corrosion-resisting cable
Raoof Axial fatigue of multilayered strands
CN101858945A (en) Laboratory icing simulating test method of optical power ground wires (OPGWs)
Zhang et al. Analysis of three-core composite submarine cable damage due to ship anchor
Zheng et al. Structural monitoring techniques for the largest excavation section subsea tunnel: Xiamen Xiang’an Subsea Tunnel
CN105895244B (en) Remote monitoring early warning Through ground wire
JP4628188B2 (en) Landslide detection device
CN108061522A (en) Distribution type fiber-optic Bragg grating MISSILE LAUNCHING case strain monitoring system
CN105093450B (en) A kind of intelligent submarine optical fiber cable being embedded in sensing element in cable core insulating layer
CN205003327U (en) Intelligent submarine fiber cable at core insulation layer embedding sensing part
CN104535220B (en) A kind of electric aerial optical cable distributed on line monitoring device
CN111609807B (en) Power transmission line dynamic deformation reconstruction method based on OPGW (optical fiber composite overhead ground wire) multi-core stress sensing
CN115877120A (en) Optical cable security evaluation method and device, terminal equipment and storage medium
Zheng et al. Normal stress between steel wires in the stay-cable
CN107144387B (en) A kind of parallel steel wire bridge intelligence suspension cable
CN111856674A (en) Variable-diameter fixed-point structure strain sensing optical cable and manufacturing method thereof
Alani et al. Effect of mean axial load on axial fatigue life of spiral strands
Yue et al. Buckling behavior of Nb3Sn strand caused by electromagnetic force and thermal mismatch in ITER cable-in-conduit conductor
CN102880742B (en) Analysis method for judging mechanical failure of armored optic/electric composite cables through adopting optical fibers
CN217504701U (en) Hydropower station pressure pipeline monitoring system based on large-scale grating strain

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant