CN106644916A - Method for evaluating ageing life of cable insulation material for ship - Google Patents

Abstract

The invention discloses a method for evaluating the ageing life of a cable insulation material for a ship. The method comprises the following steps: carrying out accelerated thermal ageing experiments on the cable insulation material under the conditions of different ageing temperatures and ageing time so as to rapidly simulate the ageing process of a cable, acquiring an equation of the life of the cable based on elongation at break, calculating activation energy by using a time-temperature shift algorithm and deducing the extrapolation equation of the life; meanwhile, measuring the values of dielectric loss tangent of the insulation material within temperature and time nodes of the accelerated thermal ageing, selecting a curve located in a frequency range of 0.01 to 1 Hz for integration, acquiring an equation of the cable life based on the integral value of the dielectric loss tangent values, and correlating the life equation based on elongation at break with the life equation based on the integral value; and for a cable of a same kind, substituting the integral value of dielectric loss tangent values measured on site into the correlated equations so as to calculate the value of corresponding elongation at break, and then evaluating the life of the cable by using the extrapolation equation. The method provided by the invention can accurately and rapidly evaluate the cable life on site.

Description

Cable for ship insulating materials aging life-span appraisal procedure

Technical field

The present invention proposes a kind of cable for ship insulating materials aging life-span appraisal procedure, belongs to insulation of electrical installation diagnosis Technical field.The Patent classificating number H01B essential electronic elements being related to.

Background technology

Cable insulation material it is aging be cable failure major reason.The aging various degradations for making cable, finally Cause insulation breakdown or short circuit.Generally, low-voltage cable accessibility is good, it is little to change quantities, and cable life assessment can To use disruptive method, solve problem by cable is changed after pinpointing the problems in time.Therefore, the longevity of low-voltage cable quick nondestructive Life study on assessing method never obtains enough attention, lacks the technical data of correlation.In some special occasions, such as ship On, due to special use environment, such as high humility, high salt fog, high temperature, Long-term bend extruding makes cable and some other heavy Want the rubber-covered of cable easily aging, ultimately result in cable failure.Cable for ship is low-voltage cable (rated voltage power frequency Exchange 1kV and following), conventional insulating materials is EP rubbers material, due to lacking effectively lossless cable life assessment side Method, typically all regularly replaces at present to cable for ship.Ship main cable mostly is through pressure hull and the cable of pressure-bearing bulkhead, It is generally acknowledged that with the hull same life-span, when being keeped in repair, change cable be the huge and heavy operation of a quantities；Do not fill The replacing of point foundation must be changed and do not implemented, and necessarily cause the waste of manpower and materials, or even bring accident potential.

Existing document report shows that the aging main cause of low-pressure rubber-insulated cable is heat ageing, i.e., exist in oxygen Under heating condition, insulating materials slowly loses the process of service behaviour.For elastomeric material heat aging performance evaluation or Say that safe life is evaluated, internationally recognized method is that accelerating thermal aging test and Thermal life evaluation are tested, and is referred to as accelerated aging Test.Accelerated life test belongs to the test of single-factor temperature, and basic thought is to go extrapolation using the life characteristics under heavily stressed Life characteristics under normal stress level.It it is critical only that the relation set up between life characteristics and stress level, it is possible thereby to Realize the purpose of life characteristics under extrapolation normal stress level.Relation between this life characteristics and stress level is exactly to accelerate Model, or referred to as accelerate equation.In IEC IEC60216 and CNS GB/T20028-2005 The evaluation test carried out using the Arrhenius Equation is the experiment recognized by crowd and projectional technique.

Accelerate thermal life test to belong to disruptive method, or be referred to as the method for damaging.Current cable insulation state inspection In survey method, take it is mostly be offline, destructive experimental means, can be to the normal work of cable and follow-up work longevity Life causes certain impact, and experimental period is long, and either operating efficiency or reduces cost aspect all have much room for improvement.It is used to The conventional method of assessment cable insulation state cannot meet present detection demand, need to propose that one kind ensure that detection As a result accuracy, while meeting the new detection method of the aspects such as operability and efficiency requirement.

The content of the invention

It is an object of the invention to provide one kind can lossless, fast and effectively assess low-pressure rubber-insulated cable residual life Method, reach assessment the low-voltage cable life-span purpose, with following steps：

The first step：Acceleration thermal ageing test is carried out to cable insulation material under different aging temperatures and ageing time, soon The ageing process of fast dummycable insulating materials, obtains based on the life equation of elongation at break,

EAB=-Aexp (t/B)+C (1)

And the activation energy obtained by time-temperature translation algorithm derives life-span extrapolation equation：

In formula：EAB is elongation at break；T is the acceleration thermal aging time of insulating materials, is determined by experimental standard；A、B、C It is the coefficient relevant with material aging；t_TFor life-span at a temperature of extrapolation, i.e., required unknown quantity；T₁For heat ageing minimum temperature, i.e., 120℃；T is the operating temperature of extrapolation temperature, i.e. cable；α_TFor shift factor；E_aFor the activation energy of insulating materials；By Ah Lei Buddhist nun Black this equation is calculated with reference to shift factor；

Second step：In the temperature and time node for carrying out accelerating heat ageing, the dielectric loss of cable insulation material is measured Angle tangent value, obtains the dielectric loss angle tangent integrated value in 0.01Hz-1Hz frequency ranges, obtains based on integrated value Cable life equation：

Tan δ=Dexp (logt/E)+F (3)

In formula：Tan δ are the integrated value of dielectric loss angle tangent 0.01Hz-1Hz scopes, and to cut cable sample phase is carried out After with heat ageing process, its dielectric loss angle tangent is measured by the insulation diagnosis instrument IDAX300 of Mega Corp. of Sweden；T is The acceleration thermal aging time of insulating materials；Determined by experimental standard；D, E, F are the coefficient relevant with material aging；

3rd step：Two are drawn by the life equation of elongation at break and the life equation of dielectric loss angle tangent integrated value The incidence relation equation of person：

4th step：For same type cable, by in-site measurement its dielectric loss angle tangent in 0.01Hz-1Hz Integrated value, by incidence relation equation corresponding elongation at break values is obtained, and then by the life-span extrapolation equation of elongation at break Cable life is estimated.

Preferably, in the first step, 120 DEG C, 135 DEG C, the 150 DEG C and 165 DEG C acceleration for cable insulation material are chosen old Change temperature；Test period at a temperature of each accelerated ageing typically adopts arithmetic series, and last sample time should be close to End-of-life index.

Preferably, by gained elongation at break and dielectric loss under gained different temperatures, different ageing times in second step Angle tangent value curve moves to minimum aging temperature in 0.01Hz-1Hz integrated values, and the extension at break rate score after translation is entered Row curve matching, obtains based on elongation at break cable life equation (2) and dielectric loss angle tangent curve in 0.01Hz- The cable life equation (3) of 1Hz integrated values；Wherein, by the mistake of the Eigenvalue shift at 165 DEG C, 150 DEG C and 135 DEG C to 120 DEG C Corresponding ratio value is referred to as shift factor in journey.

Preferably, in the first step, the activation energy of cable is derived with reference to Arrhenius equation by shift factor, and then Obtain comprising the following steps that for cable life equation：

From Arrhenius equations, speed k and the exp (- E of reaction_a/ RT) be directly proportional, i.e.,：

In formula：K is reaction rate；A is pre-exponential factor；E_aFor activation energy, kJ/mol；R is gas molar constant, 8.314J/mol ﹒ k；T is absolute temperature, K.Reaction time t and k is inversely proportional to, and α_TIt is inversely proportional to t, therefore for different time points Transfer factor α_T1、α_T2

Assume α_T2=1, T₂=393K, substitutes into formula (6) and takes the logarithm and can obtain：

To ln α_TFigure is done with 1/393-1/T, slope is obtained for E_a/ R, so as to obtain activation energy numerical value；By calculated work Change energy numerical value brings formula (7) into can be obtained：

As life prediction equation.

Preferably, elongation at break EAB is obtained by accelerating thermal ageing test：From the ethylene propylene rubber insulated electricity of active service peculiar to vessel Cable makes dumb bell sample as experiment material；The process of experiment follows strictly GB/T2951.11-2008 and GB/T2951.12- The regulation of 2008 the insides is pruned sample operating, first and convex ridge or is polished so as to which thickness meets regulation and requires；Use slide measure The width and thickness of each sample are measured, rejecting does not meet the sample of requirement of experiment；Sample section is hung vertically in ageing oven The distance between middle part, sample section are set to 50mm, and the volume of baking oven should be not more than 2% shared by sample section；Each group of aging sample exists Reaching to be taken out after the ageing time of regulation needs to be placed at least 16h at a temperature of 23 ± 5 DEG C, it is to avoid sunlight direct irradiation；Then Mechanical stretching experiment is carried out with electronic tension tester, the elongation at break data of cable are obtained.

Preferably, material aging relevant coefficient A, B, C is obtained by Mathematical Fitting：When will be different aging under each temperature group Between corresponding elongation at break experimental data Input Software origin pro, select first order decay exponential function Mathematical Modeling, institute Select index Mathematical Modeling concrete form as follows：

EAB=-Aexp (t/B)+C (1)

Elongation at break data under each temperature group are moved into fiducial temperature according to shift factor, all data point roots are chosen The non-linear automatic Fitting of computer is carried out according to selected Mathematical Modeling, fitting coefficient is closer to 1, illustrates that degree of fitting is higher, its Accuracy is also higher.

Preferably, material aging relevant coefficient D, E, F is obtained by Mathematical Fitting：Will be different old under each aging temperature group The dielectric loss angle tangent that the change time measures Input Software origin pro after integral and calculating, select first order decay index Mathematical Modeling, selected index Mathematical Modeling concrete form is as follows：

Tan δ=Dexp (logt/E)+F (3)

Dielectric loss angle tangent integral and calculating result at each temperature is moved into fiducial temperature according to shift factor, is selected Take all data points carries out the non-linear automatic Fitting of computer according to selected Mathematical Modeling, and fitting coefficient is closer to 1, explanation Degree of fitting is higher, and its accuracy is also higher.

Preferably, shift factor α_TObtain by the following method：In order to eliminate the impact of measurement temperature ,-Wen Ping during utilization Data Extrapolation under high temperature accelerated ageing to lower temperature is built the elongation at break principal curve under different temperatures by shifting method, is entered And it is extrapolated to the Changing Pattern in Materials Fracture elongation and life-span under actual work temperature；Data level direction under high temperature is moved It is dynamic, each test temperature T_iUnder shift factor α_TiFor：

In formula, t_refiFor T_iMove to corresponding ageing time, t after fiducial temperature_TiFor T_iAgeing time before translation；

It is parameter to be optimized that each temperature group moves to the shift factor of fiducial temperature, in order to be able to more accurately intend curve Close, set up the non-linear naturalization equation of curve, the data under each aging temperature are translated to fiducial temperature, by comparing translation Degree of fitting afterwards is choosing optimum value；Optimal fitting degree is：

Wherein：

In formula, α_T1=1, α_Ti>1 (i=2 ..., m=4)；I is the serial number of each temperature group；J=1 ... .n_iFor i-th group Interior serial number；E_ijFor corresponding elongation at break, t under each group_ijFor the ageing time under each group；According to above step, to heat Degradation gained test data carries out principal curve construction and fitting, selects temperature on the basis of minimum aging temperature.

Beneficial effect：After using the present invention, during being estimated to cable insulation state and life-span, because of extension at break Rate is destructive test, and live direct measurement of getting along well is obtained, and dielectric loss angle tangent curve for it is lossless, live can be direct Measurement.Therefore, in analyzing at the scene can according to the dielectric loss angle tangent curve that obtains of measurement 0.01Hz-1Hz product Score value, using formula (4) and the life equation of formula (2), you can judge the state of insulation and life-span of cable.

Description of the drawings

Fig. 1 elongation at break matched curves.

Fig. 2 curve integrated value matched curves.

Specific embodiment

First, principle of the invention

Carry out acceleration thermal ageing test to cable insulation material sample, the ageing process of Fast simulation cable insulation material, Different ageing times and the elongation at break values under aging temperature are obtained, curve is translated by Time-temperature translation algorithms, And activation energy is obtained by shift factor.Using current internationally recognized elongation at break the 50% of initial value is reduced to as end in life-span Only index, obtains based on the cable life equation of elongation at break.

The equation of translation curve should have following form：

EAB=-Aexp (t/B)+C (1)

Life-span extrapolation equation should have following form：

In formula：EAB is elongation at break, and t is the acceleration thermal aging time of insulating materials；A, B, C are have with material aging The coefficient of pass, t_TFor life-span at a temperature of extrapolation, T₁For heat ageing minimum temperature, T is extrapolation temperature, α_TFor shift factor, E_aFor exhausted The activation energy of edge material.

Acceleration heat ageing is carried out to cut cable insulating materials under identical aging temperature and ageing time, and measures difference The dielectric loss angle tangent curve of insulating materials under aging temperature and ageing time.Choose and surveyed under each temperature spot and time point Data of the dielectric loss angle tangent curve for measuring in the frequency range of 0.01Hz-1Hz are integrated computing, obtain base In the cable life equation of cable insulation material dielectric loss angle tangent integrated value in the frequency range of 0.01Hz-1Hz, should Equation should have following form：

Tan δ=Dexp (logt/E)+F (3)

In formula：Tan δ are the integrated value of dielectric loss angle tangent 0.01Hz-1Hz scopes, and t adds speed heat for insulating materials Ageing time；D, E, F are the coefficient relevant with material aging.

Insulating materials to the cable of same specifications and models, using formula (1) and formula (3) time t is eliminated, and is derived The mathematical relationship of 0.01Hz-1Hz dielectric loss angle tangents integrated value and elongation at break, i.e.,：

The present invention follows following principle during cable life equation is obtained：

(1) 120 are chosen according to according to U.S.'s firepower power station cable testing specification and IEC60216 standards in experimentation DEG C, 135 DEG C, 150 DEG C and 165 DEG C for cable insulation material accelerated ageing temperature.Test at a temperature of each accelerated ageing Cycle typically adopts arithmetic series, and last sample time should close end-of-life index.

(2) by gained elongation at break and dielectric loss angle tangent curve under gained different temperatures, different ageing times Minimum aging temperature (120 DEG C) is moved in 0.01Hz-1Hz integrated values, and to the extension at break rate score march after translation Line is fitted, and obtains being accumulated in 0.01Hz-1Hz based on elongation at break cable life equation (2) and dielectric loss angle tangent curve The cable life equation (3) of score value.Wherein, the hardness retention rate value at 165 DEG C, 150 DEG C and 135 DEG C is moved into 120 DEG C During corresponding ratio value be referred to as shift factor.

(3) activation energy of cable is derived with reference to Arrhenius equation by shift factor, and then obtains cable life side Journey.

2nd, embodiment

(1) according to U.S.'s firepower power station cable testing specification and IEC60216 standards, 135 DEG C is aging essential temperature, its Remaining rank difference is 15 DEG C, and it is optimal to take 4 aging temperatures, chooses 120 DEG C, 135 DEG C, 150 DEG C and 165 DEG C as test cable The aging temperature of insulating materials.Sample after will be aging is placed in vacuum bag to place test its elongation at break after 16h, each temperature 5 sample values are measured under degree point and time point.In order to improve the accuracy of data, when processing data, average As actual measured value.Test data is as shown in table 1.

The elongation at break test data of table 1

Temperature (DEG C)	Ageing time t (h)	EAB (%)	Temperature (DEG C)	Ageing time t (h)	EAB (%)
						165	24	605.18	150	48	609.62
165	48	546.36	150	96	603.54
						165	72	489.45	150	144	523.64
165	96	423.19	150	192	481.19
						165	120	337.65	150	240	367.25
165	144	262.58	150	288	300.21
						165	168	157.25	150	336	281.54
165	192	108.54	150	384	242.36
						165	216	97.89	150	432	171.24
135	96	627.84	120	120	647.57
						135	144	616.32	120	192	627.24
135	192	588.21	120	264	615.32
						135	240	541.24	120	336	588.69
135	360	525.64	120	456	575.36
						135	456	497.68	120	648	525.25
135	648	427.31	120	868	465.21
						135	744	338.97	120	1108	393.68
135	984	293.61	120	1348	227.21

(2) data under high temperature are moved to 120 DEG C by temperature shifting method when utilizing to the test data of heat ageing, and carry out curve Fitting, can obtain curve as shown in Figure 1, wherein the elongation at break at 165 DEG C, 150 DEG C and 135 DEG C is moved into 120 DEG C During corresponding shift factor α_T=(12.99 5.1 1.6 1).

Elongation at break is that 120 DEG C of cable life equations of matched curves changed with ageing time are in aging temperature：

EAB=-48.107e^t/644.15+673.482 (5)

Wherein EAB is cable insulation material elongation at break at 120 DEG C, and t is acceleration thermal aging time (h).

(3) with reference to Arrhenius equations：

Can obtain for different time points shift factor α_T1、α_T2Can obtain：

Curve is transferred to 120 DEG C of lowest temperature, T by the present invention₂For kelvin rating, Gu T₂=120+273 DEG C=393 DEG C, put down Move factor-alpha_T2=1, can obtain：

To ln α_TDoing figure with 1/408-1/T can obtain slope of a curve for 1.2512 × 10^-4, trying to achieve activation energy is 104.03kJ/mol。

(4) can be based on the cable life extrapolation equation of elongation at break：

Wherein t is cable life (h) at temperature to be measured, and T is cable actual motion temperature (K).

(5) heat ageing is accelerated under same aging temperature and ageing time to cut cable sample, measures its dielectric loss angle Tangent value curve, chooses and the dielectric loss angle tangent curve for obtaining is measured under each temperature spot and time point in 0.01Hz-1Hz Frequency range in data be integrated computing, as a result as shown in table 2：

Tan δ integrated values in the range of the 0.01Hz-1Hz of table 2

(6) 66 data under high temperature are moved to 120 DEG C, and march by temperature shifting method when utilizing to the test data of heat ageing Line is fitted, and curve as shown in Figure 2 can be obtained, wherein the integrated value at 165 DEG C, 150 DEG C and 135 DEG C is moved into 120 DEG C During corresponding shift factor α_T=(10.6 4.1 1.3 1).

Dielectric loss angle tangent integrated value aging temperature be 120 DEG C with ageing time change matched curve it is aging Equation is：

(7) according to formula (5) and formula (9) can set up in the range of dielectric loss angle tangent 0.01Hz-1Hz integrated value with it is disconnected Split the contact between elongation：

(8) the unaged cut cable sample of experiment selection same size first carries out dielectric loss angle tangent measurement, its It is as shown in table 3 in the dielectric loss angle tangent of the measurement of 0.01Hz-1Hz frequency separations：

The field measurement data of table 3

Sampling frequency f (Hz)	Dielectric loss angle tangent
		0.01	0.01433
0.022	0.01017
		0.046	0.008248
0.1	0.006715
		0.22	0.0056073
0.46	0.004731
		1	0.003518

It is 0.004981 that it is obtained in the integrated value of 0.01Hz-1Hz, substitutes into formula (11) and obtains corresponding elongation at break For 618.1613%.The temperature range of EP rubbers cable long-term work peculiar to vessel according to used by experiment, by cable life prediction side Journey (9) obtains remaining life of the cable at a temperature of different operating such as table 4.

The life-span of cut cable sample under the different temperatures of table 4

After obtaining concrete surplus working life conclusion of the cable according to the calculating of dielectric loss angle tangent integrated value, this patent is used disconnected The result for splitting test of elongation rate verifies that dumb bell sample initial value is 658.04%, according to elongation at break to above-mentioned conclusion Calculating standard, the remaining life such as table 5 for obtaining cable at a temperature of different operating can be calculated by cable life predictive equation (9) It is shown.

The life-span of cable dumb bell sample under the different temperatures of table 5

Comparison sheet 4 and table 5 as can be seen that the cable that draws of two kinds of appraisal procedures different operating temperature the remaining work longevity Life conclusion is close, and the method for the present invention is effective.

The present invention is directed to cable for ship insulating materials, with reference to thermal life test is accelerated, is with elongation at break life characteristics Foundation, provides related law between dielectric loss angle tangent integration value tag and rubber material ages degree, sets up based on Jie The life equation of matter loss tangent, realizes quick nondestructive cable for ship life appraisal.The inventive method is different from existing side Method part is the life characteristics using dielectric loss angle tangent integrated value as its insulating materials, is a kind of new, quick Lossless low-voltage cable lifetime estimation method, both can provide assessment result to the insulation technology state of cable, again can be to electricity The residual life of cable is inferred.

Claims (8)

1. a kind of cable for ship insulating materials aging life-span appraisal procedure, it is characterised in that：

The first step：Acceleration thermal ageing test, Fast Modular are carried out to cable insulation material under different aging temperatures and ageing time Intend the ageing process of cable insulation material, obtain based on the life equation of elongation at break,

EAB=-Aexp (t/B)+C (1)

And the activation energy obtained by time-temperature translation algorithm derives life-span extrapolation equation：

${\mathrm{ln\α}}_T=\ln \frac{t}{t_T}=\frac{E_a}{8.314}(\frac{1}{T_1}-\frac{1}{T+273})---\left(2\right)$

In formula：EAB is elongation at break；T is the acceleration thermal aging time of insulating materials, is determined by experimental standard；A, B, C be with The relevant coefficient of material aging；t_TFor life-span at a temperature of extrapolation, i.e., required unknown quantity；T₁For heat ageing minimum temperature, i.e., 120 DEG C； T is the operating temperature of extrapolation temperature, i.e. cable；α_TFor shift factor；E_aFor the activation energy of insulating materials；By Arrhenius side Journey is calculated with reference to shift factor；

Second step：In the temperature and time node for carrying out accelerating heat ageing, the dielectric loss angle of cable insulation material is being measured just Value is cut, the dielectric loss angle tangent integrated value in 0.01Hz-1Hz frequency ranges is obtained, is obtained based on the cable of integrated value Life equation：

Tan δ=Dexp (logt/E)+F (3)

In formula：Tan δ are the integrated value of dielectric loss angle tangent 0.01Hz-1Hz scopes, and to cut cable sample identical heat is carried out After burin-in process, its dielectric loss angle tangent is measured by the insulation diagnosis instrument IDAX300 of Mega Corp. of Sweden；T is insulation The acceleration thermal aging time of material；Determined by experimental standard；D, E, F are the coefficient relevant with material aging；

3rd step：Draw both by the life equation of elongation at break and the life equation of dielectric loss angle tangent integrated value Incidence relation equation：

$tan\mathrm{\δ}=D\exp \left(\frac{\log Bln\frac{C-EAB}{A}}{E}\right)+F---\left(4\right);$

4th step：For same type cable, integrated in 0.01Hz-1Hz by its dielectric loss angle tangent of in-site measurement Value, by incidence relation equation corresponding elongation at break values is obtained, so by elongation at break life-span extrapolation equation to electricity The cable life-span is estimated.

2. a kind of cable for ship insulating materials aging life-span appraisal procedure according to claim 1, it is characterised in that In one step, 120 DEG C, 135 DEG C, the 150 DEG C and 165 DEG C accelerated ageing temperature for cable insulation material are chosen；Each accelerates old Test period at a temperature of change typically adopts arithmetic series, and last sample time should close end-of-life index.

3. a kind of cable for ship insulating materials aging life-span appraisal procedure according to claim 1, it is characterised in that second Gained elongation at break and dielectric loss angle tangent curve under gained different temperatures, different ageing times are existed in step 0.01Hz-1Hz integrated values move to minimum aging temperature, and the extension at break rate score after translation is carried out curve fitting, and obtain To based on elongation at break cable life equation (2) and dielectric loss angle tangent curve 0.01Hz-1Hz integrated values cable Life equation (3)；Wherein, by ratio corresponding during the Eigenvalue shift at 165 DEG C, 150 DEG C and 135 DEG C to 120 DEG C Example value is referred to as shift factor.

4. a kind of cable for ship insulating materials aging life-span appraisal procedure according to claim 1, it is characterised in that In one step, the activation energy of cable is derived with reference to Arrhenius equation by shift factor, and then obtain cable life equation Comprise the following steps that：

From Arrhenius equations, speed k and the exp (- E of reaction_a/ RT) be directly proportional, i.e.,：

$k=A\·\exp \left(\frac{-E_a}{RT}\right)---\left(5\right)$

In formula：K is reaction rate；A is pre-exponential factor；E_aFor activation energy, kJ/mol；R be gas molar constant, 8.314J/mol ﹒ k；T is absolute temperature, K.Reaction time t and k is inversely proportional to, and α_TIt is inversely proportional to t, therefore for different time points transfer factor α_T1、 α_T2

$\frac{{\mathrm{\α}}_{T1}}{{\mathrm{\α}}_{T2}}=\frac{A^{\′}\·\exp \left(\frac{-E_a}{{\mathrm{RT}}_1}\right)}{A^{\′}\·\exp \left(\frac{-E_a}{{\mathrm{RT}}_2}\right)}=\exp \left(\frac{E_a}{R}\right(\frac{1}{T_2}-\frac{1}{T_1}\left)\right)---\left(6\right)$

Assume α_T2=1, T₂=393K, substitutes into formula (6) and takes the logarithm and can obtain：

${\mathrm{ln\α}}_T=\frac{E_a}{R}(\frac{1}{393}-\frac{1}{T})---\left(7\right)$

To ln α_TFigure is done with 1/393-1/T, slope is obtained for E_a/ R, so as to obtain activation energy numerical value；By calculated activation energy Numerical value is brought formula (7) into and can be obtained：

${\mathrm{ln\α}}_T=\ln \frac{t}{t_T}=\frac{E_a}{8.314}(\frac{1}{T_1}-\frac{1}{T+273})---\left(8\right)$

As life prediction equation.

5. a kind of cable for ship insulating materials aging life-span appraisal procedure according to claim 1, it is characterised in that fracture Elongation EAB is obtained by accelerating thermal ageing test：From active service ethylene propylene rubber insulated cable peculiar to vessel as experiment material, make Dumb bell sample；The process of experiment follows strictly the regulation inside GB/T 2951.11-2008 and GB/T2951.12-2008 to grasp Make, sample is pruned convex ridge or polishes first so as to which thickness meets regulation and requires；The width of each sample is measured with slide measure Degree and thickness, rejecting does not meet the sample of requirement of experiment；Sample section is hung vertically in the distance between the middle part of ageing oven, sample section 50mm is set to, the volume of baking oven should be not more than 2% shared by sample section；Each group of aging sample is after the ageing time for reaching regulation Taking-up needs to be placed at least 16h at a temperature of 23 ± 5 DEG C, it is to avoid sunlight direct irradiation；Then carried out with electronic tension tester Mechanical stretching is tested, and obtains the elongation at break data of cable.

6. a kind of cable for ship insulating materials aging life-span appraisal procedure according to claim 1, it is characterised in that material Aging relevant coefficient A, B, C are obtained by Mathematical Fitting：By the corresponding elongation at break of different ageing times under each temperature group Experimental data Input Software origin pro, select first order decay exponential function Mathematical Modeling, and selected index Mathematical Modeling is concrete Form is as follows：

EAB=-Aexp (t/B)+C (1)

Elongation at break data under each temperature group are moved into fiducial temperature according to shift factor, all data points is chosen according to choosing Fixed Mathematical Modeling carries out the non-linear automatic Fitting of computer, and fitting coefficient is closer to 1, illustrates that degree of fitting is higher, and its is accurate Property is also higher.

7. a kind of cable for ship insulating materials aging life-span appraisal procedure according to claim 1, it is characterised in that material Aging relevant coefficient D, E, F are obtained by Mathematical Fitting：The medium that different ageing times under each aging temperature group are measured is damaged Consumption angle tangent value Input Software origin pro after integral and calculating, select first order decay index Mathematical Modeling, selected index Mathematical Modeling concrete form is as follows：

Tan δ=Dexp (logt/E)+F (3)

Dielectric loss angle tangent integral and calculating result at each temperature is moved into fiducial temperature according to shift factor, institute is chosen There is data point to carry out the non-linear automatic Fitting of computer according to selected Mathematical Modeling, fitting coefficient is closer to 1, illustrate fitting Degree is higher, and its accuracy is also higher.

8. a kind of cable for ship insulating materials aging life-span appraisal procedure according to claim 1, it is characterised in that translation Factor-alpha_TObtain by the following method：In order to eliminate the impact of measurement temperature, during utilization-warm shifting method is by under high temperature accelerated ageing Data Extrapolation to lower temperature, build the elongation at break principal curve under different temperatures, and then be extrapolated to actual work temperature Lower Materials Fracture elongation and the Changing Pattern in life-span；Data level direction under high temperature is moved, each test temperature T_iUnder Shift factor α_TiFor：

$a_{T_i}=\frac{t_{{\mathrm{ref}}_i}}{t_{T_i}}---(1-1)$

In formula, t_refiFor T_iMove to corresponding ageing time, t after fiducial temperature_TiFor T_iAgeing time before translation；

It is parameter to be optimized that each temperature group moves to the shift factor of fiducial temperature, in order to be able to more accurately be fitted to curve, Set up the non-linear naturalization equation of curve, by the data under each aging temperature to fiducial temperature translate, by compare translation after Degree of fitting choosing optimum value；Optimal fitting degree is：

$R^2=\frac{S_{xy}^2}{S_{xx}\·S_{yy}}---(1-2)$

Wherein：

$S_{xx}=\underset{i=1}{\overset{m}{\Σ}}\underset{j=1}{\overset{n_i}{\Σ}}{(a_{T_i}\·t_{ij})}^2-\frac{1}{\underset{i=1}{\overset{m}{\Σ}}{n}_i}{(\underset{i=1}{\overset{m}{\Σ}}\underset{j=1}{\overset{n_i}{\Σ}}{a}_{T_i}\·t_{ij})}^2---(1-3)$

$S_{yy}=\underset{i=1}{\overset{m}{\Σ}}\underset{j=1}{\overset{n_i}{\Σ}}{\left(E_{ij}\right)}^2-\frac{1}{\underset{i=1}{\overset{m}{\Σ}}{n}_i}{\left(\underset{i=1}{\overset{m}{\Σ}}\underset{j=1}{\overset{n_i}{\Σ}}{E}_{ij}\right)}^2---(1-4)$

$S_{xy}=\underset{i=1}{\overset{m}{\Σ}}\underset{j=1}{\overset{n_i}{\Σ}}{a}_{T_i}\·t_{ij}\·E_{ij}-\frac{1}{\underset{i=1}{\overset{m}{\Σ}}{n}_i}(\underset{i=1}{\overset{m}{\Σ}}\underset{j=1}{\overset{n_i}{\Σ}}{a}_{T_i}\·t_{ij})\·\left(\underset{i=1}{\overset{m}{\Σ}}\underset{j=1}{\overset{n_i}{\Σ}}{E}_{ij}\right)---(1-5)$

In formula, α_T1=1, α_Ti>1 (i=2 ..., m=4)；I is the serial number of each temperature group；J=1 ... .n_iFor in i-th group Serial number；E_ijFor corresponding elongation at break, t under each group_ijFor the ageing time under each group；According to above step, to heat ageing Test gained test data carries out principal curve construction and fitting, selects temperature on the basis of minimum aging temperature.