CN112881877A - Method and system for evaluating high-voltage insulation aging state - Google Patents
Method and system for evaluating high-voltage insulation aging state Download PDFInfo
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Abstract
The application discloses a method and a system for evaluating a high-voltage insulation aging state. Wherein, the method comprises the following steps: determining various input parameters of the high-voltage cable; determining the temperature of the cable conductor according to the current-carrying capacity, the average load current, the average ambient temperature and the rated working temperature of the cable conductor; determining the equivalent operation age of the cable under the accumulative temperature effect according to the temperature and service life of the cable conductor and the rated working temperature of the cable conductor, and determining the aging operation age of the cable according to the service life and the equivalent operation age; determining equivalent operation time of the cable according to family defect influence factors, historical fault influence factors, service life influence factors, load condition influence factor values, laying mode influence factors, operation environment influence factors and aging operation life of the cable; and evaluating the high-voltage insulation aging state of the cable through the equivalent running time of the cable.
Description
Technical Field
The present application relates to the field of power system technologies, and in particular, to a method and a system for evaluating a high-voltage insulation aging state.
Background
As power demands are increasing, the use of high voltage cables is also increasing year by year. However, due to multiple factors such as electricity, heat and environmental conditions, the insulation quality of the cable may gradually decrease during long-term operation until the insulation fails and a cable failure occurs. Once the cable is broken down, the cable needs to be maintained and repaired for a long time after power failure, and the cable brings serious influence to the normal production and life of residents and enterprises.
In China, the number of 110kV cables which run for more than 20 years is also large. Besides different service life, the cables come from different manufacturers, and the laying conditions and the operating conditions are different, so that the quality and the aging state of the in-service cables are different. How to accurately master the insulation aging state of the part of the cable so as to replace the old cable before the end of the cable life in time has very important significance for ensuring the safety and stability of a power grid and exerting the cable benefit to the maximum extent.
In order to improve the safe reliability of the operation of the cable in the last two decades, various methods for detecting the cable are formed. One of the most prominent detection methods is the periodic preventive testing of insulation, but these detection methods still have some limitations. First, preventive tests are typically performed in the event of a power outage; secondly, a preventive test is generally carried out on all cables, and the insulation of some originally good cables is more rapidly aged due to the fact that the cables are tested for many times under the condition that the rated voltage is higher; in addition, a set of maintenance teams is needed for manual power failure maintenance, labor cost and time schedule of maintenance are greatly increased, and particularly actual operation is difficult to realize under the condition that stock and newly-built cable line cardinality are continuously increased.
The insulation preventive tests existing in the prior art referred to above are generally carried out in the event of a power failure; the preventive test is generally carried out on all cables, and the insulation of some originally good cables is more rapidly aged due to the fact that the cables are tested for many times under the condition that the voltage is higher than the rated voltage; in addition, a set of maintenance teams is needed for manual power failure maintenance, labor cost and time schedule arrangement of maintenance are greatly increased, particularly, under the condition that stock and newly-built cable line cardinality are continuously increased, the technical problem that actual operation is difficult to achieve is solved, and an effective solution is not provided at present.
Disclosure of Invention
The embodiment of the disclosure provides a method and a system for evaluating a high-voltage insulation aging state, so as to at least solve the problem that an insulation preventive test in the prior art is generally carried out under the condition of power failure; the preventive test is generally carried out on all cables, and the insulation of some originally good cables is more rapidly aged due to the fact that the cables are tested for many times under the condition that the voltage is higher than the rated voltage; in addition, a set of maintenance teams is required for manual power failure maintenance, which greatly increases the labor cost and time schedule of maintenance, and particularly has the technical problem that the actual operation is more difficult to realize under the condition that the stock and the base number of newly-built cable lines are continuously increased.
According to an aspect of an embodiment of the present disclosure, there is provided a method for evaluating a high voltage insulation aging state, including: determining various input parameters of the high-voltage cable, wherein the input parameters comprise current-carrying capacity IMAverage load current IFAmbient average temperature θ0Service life t0Family defect influence factor KFHistorical fault influence factor KHAnd laying mode influence factor KMOperational environment influence factor KE(ii) a According to the ampacity IMThe average load current IFThe ambient average temperature theta0And rated working temperature theta of cable conductorMDetermining the temperature theta of the conductor of the cableF(ii) a According to the conductor temperature theta of the cableFThe service life t0And the rated working temperature of the cable conductor, determining the equivalent operating life t of the cable under the effect of the accumulated temperature1And according to the service life t0And the equivalent operating life t1Determining the aging operating age t of the cable2(ii) a According to the family defect influence factor KFThe historical fault influence factor KHThe service life influence factor KYThe value of the load condition influence factor KLThe laying mode influence factor KMOperational environment influence factor KEAnd age t of cable2Determining the equivalent operating time t of the cable; and evaluating the high-voltage insulation aging state of the cable through the equivalent running time of the cable.
According to another aspect of the disclosed embodiment, there is also provided a system for evaluating a high voltage insulation aging state. The method comprises the following steps: an input parameter determining module for determining various input parameters of the high-voltage cable, wherein the input parameters comprise current-carrying capacity IMAverage load current IFAmbient average temperature θ0Service life t0Family defect influence factor KFHistorical fault influence factor KHAnd laying mode influence factor KMOperational environment influence factor KE(ii) a A module for determining the temperature of the cable conductor according to the current-carrying capacity IMThe average load current IFThe ambient average temperature theta0And rated working temperature theta of cable conductorMDetermining the temperature theta of the conductor of the cableF(ii) a A module for determining the aging operation age of the cable according to the conductor temperature theta of the cableFThe service life t0And the rated working temperature of the cable conductor, determining the equivalent operating life t of the cable under the effect of the accumulated temperature1And according to the service life t0And the equivalent operating life t1Determining cable agingLine year t2(ii) a Determining a cable equivalent run time module for influencing factor K according to said family defectFThe historical fault influence factor KHThe service life influence factor KYThe value of the load condition influence factor KLThe laying mode influence factor KMOperational environment influence factor KEAnd age t of cable2Determining the equivalent operating time t of the cable; and the aging insulation state evaluation module is used for evaluating the high-voltage insulation aging state of the cable according to the equivalent running time of the cable.
In the invention, the high-voltage cable insulation aging state evaluation method based on the operation data analysis can carry out primary aging evaluation on the cable in service, thereby avoiding sampling detection on all cables, and greatly reducing the power failure loss caused by cable power failure maintenance and the labor cost and time arrangement of sampling detection.
Drawings
The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the disclosure and together with the description serve to explain the disclosure and not to limit the disclosure. In the drawings:
fig. 1 is a schematic flow chart of a method for evaluating a high voltage insulation aging state according to an embodiment of the present disclosure;
fig. 2 is a schematic flow chart of a method for evaluating insulation aging state of a high voltage cable based on operation data analysis according to an embodiment of the present disclosure;
fig. 3 is a schematic diagram of a system for evaluating a high voltage insulation aging state according to an embodiment of the disclosure.
Detailed Description
The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.
Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.
According to a first aspect of the present embodiment, a method 100 for evaluating a high voltage insulation aging state is provided. Referring to fig. 1, the method 100 includes:
s102, determining various input parameters of the high-voltage cable, wherein the input parameters comprise current-carrying capacity IMAverage load current IFAmbient average temperature θ0Service life t0Family defect influence factor KFHistorical fault influence factor KHAnd laying mode influence factor KMOperational environment influence factor KE；
S104, according to the current-carrying capacity IMThe average load current IFThe ambient average temperature theta0And rated working temperature theta of cable conductorMDetermining the temperature theta of the conductor of the cableF；
S106, according to the temperature theta of the cable conductorFThe service life t0And the rated working temperature of the cable conductor, determining the equivalent operating life t of the cable under the effect of the accumulated temperature1And according to the service life t0And the equivalent operating life t1Determining the aging operating age t of the cable2；
S108, according to the family defect influence factor KFThe historical fault influence factor KHThe service life influence factor KYThe value of the load condition influence factor KLThe laying mode influence factor KMOperational environment influence factor KEAnd aged operation of cableAge t2Determining the equivalent operating time t of the cable;
and S110, evaluating the high-voltage insulation aging state of the cable according to the equivalent running time of the cable.
Specifically, the conductor temperature is calculated through the cable operation data, the influence of the conductor temperature on the cable aging is considered, on the basis, the auxiliary influence factors such as cable family defects, historical fault conditions, service life, load conditions, laying modes, operation environments and the like are integrated, the corrected equivalent operation life of the cable is obtained, a preliminary aging evaluation is performed on the in-service cable according to the equivalent life value, and corresponding evaluation conclusions and recommended measures are given according to the evaluated operation state and aging degree of the cable.
(1) Cable conductor temperature estimation
The cable current and the cable conductor temperature are calculated as follows:
wherein: i is conductor current (A); θ is conductor temperature (. degree. C.); theta0Is the ambient temperature (deg.C) around the cable; wdLoss of insulating dielectric; r is conductor AC resistance; lambda [ alpha ]1Sheath and shield loss factor; lambda [ alpha ]2A metal armor loss factor; t is1The insulation thermal resistance (K.m/W) between the conductor and the metal sheath; t is2The thermal resistance (K.m/W) of the inner liner between the metal sheath and the armor layer; t is3Thermal resistance of the cable outer sheath (K.m/W); t is4Is the thermal resistance (K.m/W) between the cable surface and the surrounding medium.
Due to the loss W of the cable insulation mediumdRelative to conductor loss I2R is different by more than three orders of magnitude, so the latter has little influence on the calculation result, and therefore the relationship between the temperature rise of the cable conductor and the current can be approximated as follows:
θ-θ0≈I2R[T1+(1+λ1)T2+(1+λ1+λ2)(T3+T4)]formula 2
Assuming the ambient temperature θ of the cable run0At the actual operating current I of the cableFLower conductor temperature of thetaF(ii) a Cable conductor allowable long-term rated working temperature thetaM90 ℃ and a carrying capacity IM. Neglecting the effect of temperature changes on other parameters, the following relationship can be approximated:
at the current IFLower conductor temperature thetaFCan be approximately expressed as:
in the above formula, θMIs 90 deg.C, if the average ambient temperature is known to be θ0Current-carrying capacity of cable IMAnd the actual running current value I of the cableFThat is, the average temperature θ of the cable conductor can be estimated according to the above formulaF。
(2) Cable aging evaluation model
The design life of the XLPE power cable is 30 years at 90 ℃ operating conditions. Suppose that the service life of the cable is t0Year, cable conductor temperature thetaFAt t0Cumulative effect over the year and cable design operating temperature thetaMThe ratio of the cumulative effect over a design life of 30 years at 90 ℃ is:
in conjunction with equation 5, the equivalent operating life t1 of the cable under the effect of the accumulated temperature can be calculated as:
t1a 30 formula 6
The actual operation life of the cable is t0Equivalent operating life of t under cumulative effect of year and temperature1Year, cable aging operating age t2Synthesis ofThe two factors take the following values:
t2＝a0t0+a1t1formula 7
In the formula, a0And a1Is the actual operating life t of the cable0And equivalent operating life t under the effect of temperature accumulation1A balance coefficient of0+a1Because the conditions of the model are greatly simplified when the carrying capacity value and the temperature calculation of the cable are carried out, a is taken from the model0＝0.5，a1＝0.5。
In actual operation, most high-voltage cables are in a light-load state, the temperature of a cable conductor is probably far lower than the design temperature of a power cable by 90 ℃, the cables are probably not aged obviously, and if the service life of the cables can be prolonged, the waste of materials can be avoided, so that the economic effect of power in China is improved. However, in view of practical situations, if the power cable is aged to the extent that the power cable cannot be used continuously and the service life of the power cable is prolonged continuously, large-area power failure is caused, and great loss is brought to national economy.
The operating life of a cable is therefore measured only in terms of conductor temperature, which is clearly not in accordance with reality, and the aging of a high-voltage cable is not only related to its conductor temperature, but also to cable family defects, historical fault conditions, service life, load conditions, laying patterns and operating environment. The factors are collectively called accessory factors of the high-voltage cable aging state evaluation model.
1) Family defect influence factor
The family defect represents a common problem of some devices, which may come from a cable supplier or a production process. The aging problem of the cable with family defects is relatively serious, and conversely, the aging problem is relatively slight, and the family defect factor value K shown in the table 1 is obtained according to the existence or nonexistence of the family defectsF。
TABLE 1 family Defect Effect factor KF
2) Historical fault impact factor
The historical faults in the invention mainly refer to historical faults caused by non-external-damage reasons of the line, the cable aging problem with frequent historical faults is relatively serious, and otherwise, the cable aging problem is relatively light. In addition, each time the cable has a fault, certain impact may be caused to the insulation of the cable, so that the aging of the cable is accelerated, and a historical fault factor value KH shown in Table 2 is obtained according to the historical fault.
TABLE 2 historical Fault impact factor KH
3) Service life influence factor
The operation state degradation curve of the high-voltage cable substantially conforms to the equipment aging principle, and the change relation describing the equipment operation state along with the service life conforms to an exponential expression as shown in the following formula
KY＝A1exp(A2t0) Formula 8
In the formula: kYIs service life factor value; a. the1Is the amplitude coefficient; a. the2Is the aging factor; t is t0The service life of the cable. In the formula, A1＝0.9531，A2＝0.01917。
4) Factor of influence of load situation
Different loading conditions of the high-voltage cable have obvious influence on the aging of the cable. The cable with low load rate has unobvious line aging condition and the line with high load rate has serious aging condition, and the load factor value K shown in the table 3 is obtained according to the historical loadL. The average load rate of the line is calculated as follows:
TABLE 3 load situation influencing factor KL
5) Factor of laying mode
The way in which the cables are laid also has a significant effect on the operating conditions of the cables. The high-voltage cable is mainly laid in a tunnel, a cable trench, a direct burial mode and a calandria mode. Usually, the heat dissipation performance is 'tunnel' under the several laying modes>Cable trench>Direct burial>And the cable with the calandria' and poor heat dissipation performance is fast in aging. Laying mode influence factor value KMAs shown in table 4.
TABLE 4 laying mode influencing factor KM
6) Factor of operational environment
The operating environment of the cable also has a significant effect on the operating state of the cable. If the cable is in contact with soil, moisture and humidity for a long time, the insulating material is easy to corrode and penetrate, so that the insulation is not easy to age. Obtaining a laying environment factor value K shown in Table 5 according to the laying environmentE。
TABLE 5 operating Environment Effect factor KE
After family defects, the number of historical faults, a degradation curve of the insulation state of the high-voltage cable along with the service life, load conditions, a laying mode and cable operation environment influence factors are integrated, the equivalent operation time t of the cable is represented by the following expression:
t＝KF·KH·KY·KL·KM·KE·t2formula 10
(3) Evaluation standard of cable aging degree
From equation 10, the equivalent operating time t of the cable can be calculated, taking into account the various influencing factors, from which the operating state and the degree of ageing of the cable are divided into four classes.
The relationship between the equivalent operation time of the cable and the aging of the cable is shown in table 6, four grades of normal, attention, abnormal and dangerous are adopted for evaluation description, and the value range, the evaluation conclusion and the recommended measures of each grade are shown in table 6.
TABLE 6 evaluation criteria for cable aging degree
Fig. 2 is a flowchart of a high voltage cable insulation aging state evaluation method based on operational data analysis. According to the evaluation conclusion and the recommended measures given by the evaluation method, sampling tests can be reasonably arranged for the medium-aged and serious-aged cables, and the aging state of the cables can be further verified.
The principle is explained with reference to a specific example shown in fig. 2. For the sake of illustration, the current-carrying capacity, the load current and the ambient temperature are not considered in this example, and are taken as a fixed value, and in practical application, the values of these parameters may be variable with time.
(1) The input parameters of the high-voltage cable are assumed to be:
current carrying capacity IM：1766A
Average load current IF：1148A
Ambient average temperature θ0：23℃
Service life t0: 17 years old
Whether family defects exist or not: is free of
The historical failure frequency caused by non-outcropping reasons is as follows: 1 time of
Laying mode of tunnel
Whether in long-term contact with soil/moisture: whether or not
(2) Cable conductor temperature estimation
Current carrying capacity IM1766A, average load current IF1148A, ambient average temperature θ023 ℃ and the allowable long-term rated working temperature theta of the cable conductorMSubstituting 90 ℃ into equation 4, cable conductor temperature calculation
(3) The equivalent operating life t1 calculation of the cable under the effect of accumulated temperature
Temperature theta of cable conductorFThe service life t is 51.3 DEG C0Rated working temperature theta of cable conductor allowed for long time of 17 yearsMSubstituting formula 6 and formula 5, t at 90 ℃1Is calculated as
(4) Age t of cable2Computing
Setting the actual operation age of the cable as t017 years, and the equivalent operating life under the temperature accumulative effect is t19.69 times of formula 7, t2Is calculated as
t2＝0.5*t0+0.5*t1＝13.345
(5) Family defect influence factor KFComputing
Since the cable has no familial defect, according to table 1, the familial defect impact factor takes the value:
KF＝1
(6) history ofFactor of influence of failure KHComputing
The number of historical failures caused by the reason that the cable is not externally broken is 1, and according to the table 2, the historical failure factor KHThe values are as follows:
KH＝1
(7) service life influence factor KYComputing
Because the actual service life of the cable is 17 years, according to the formula 8, the service life influence factor calculation value is KY＝0.9531*exp(0.01917*17)＝1.32
(8) Factor of influence of load situation KLComputing
According to equation 9, the cable load factor is
According to Table 3, the load influence factor value KLIs composed of
KL＝1.2
(9) Factor of influence of laying mode KMComputing
Because the cable is laid in the tunnel, the influence factor value K of the laying modeMFrom table 4 it can be obtained:
KM＝1
(10) factor of operational environment KEComputing
Since the cable was not in contact with soil, moisture, and moisture for a long period of time, the laying environment factor value K was calculated as shown in table 5E：
KE＝1
(11) Cable equivalent run time tcomputation
By substituting the above calculation result into equation 10, the cable equivalent operating time t can be calculated and expressed by the following expression:
t＝KF·KH·KY·KL·KM·KE·t2＝1*1*1.32*1.2*1*1*13＝20.6
(12) outputting the evaluation result
The cable running state is abnormal; the degree of aging is moderate; the evaluation conclusion is that the comprehensive condition of the index performance is poor, the index value greatly exceeds the standard limit value, and the reliability performance is obviously reduced; the suggested measures are to suggest that the cable sampling is subjected to test analysis in the near term, and further verify the aging state of the cable.
Therefore, the high-voltage cable insulation aging state assessment method based on operation data analysis can perform primary aging assessment on the cables in service, can avoid sampling and detecting all the cables, and can greatly reduce power failure loss caused by cable power failure maintenance and labor cost and time arrangement of sampling and detecting.
Optionally, according to the current capacity IMThe average load current IFThe ambient average temperature theta0And rated working temperature theta of cable conductorMDetermining the temperature theta of the conductor of the cableFThe method comprises the following steps:
determining the cable conductor temperature θ according to the following formulaF：
Optionally, according to the cable conductor temperature θFThe service life t0And the rated working temperature of the cable conductor, determining the equivalent operating life t of the cable under the effect of the accumulated temperature1The method comprises the following steps:
determining the equivalent operating life t of the cable under the effect of the accumulated temperature according to the following formula1:
t1＝A*30
Wherein A is the temperature theta of the cable conductorFCumulative effect and cable design operating temperature theta in t0 yearsMThe ratio of the cumulative effect over a design life of 30 years at 90 c,
optionally, according to the service life t0And the equivalent operating life t1Determining the aging operating age t of the cable2The method comprises the following steps:
determining the aging operation age t of the cable according to the following formula2：
t2＝a0t0+a1t1
Wherein, a0And a1Service life t of all cables0And equivalent operating life t under the effect of temperature accumulation1A balance coefficient of0+a1Since the conditions of the model are simplified in the process of cable ampacity estimation and temperature estimation, the model takes a0 as 0.5 and a1 as 0.5.
Optionally, according to the family defect influence factor KFThe historical fault influence factor KHThe service life influence factor KYThe value of the load condition influence factor KLThe laying mode influence factor KMOperational environment influence factor KEAnd age t of cable2Determining the equivalent cable running time t, which comprises the following steps:
according to the service life t0Amplitude coefficient and aging coefficient, determining service life influence factor KY：
KY＝A1exp(A2t0)
Wherein, KYIs service life factor value; a. the1Is the amplitude coefficient; a. the2Is the aging factor; t is t0The service life of the cable;
according to the average load current IFAnd the ampacity IMDetermining the average load rate L of the line and determining the load condition influence factor value K according to the average load rateL：
Therefore, the high-voltage cable insulation aging state assessment method based on operation data analysis can perform primary aging assessment on the cables in service, can avoid sampling and detecting all the cables, and can greatly reduce power failure loss caused by cable power failure maintenance and labor cost and time arrangement of sampling and detecting.
According to another aspect of the present embodiment, there is also provided a system 300 for evaluating a high voltage insulation degradation condition. Referring to fig. 3, the system 300 further includes: determining input parameters module 310 for determining respective input parameters of the high voltage cable, the input parameters including ampacity IMAverage load current IFAmbient average temperature θ0Service life t0Family defect influence factor KFHistorical fault influence factor KHAnd laying mode influence factor KMOperational environment influence factor KE(ii) a A module 320 for determining the temperature of the cable conductor according to the current carrying capacity IMThe average load current IFThe ambient average temperature theta0And rated working temperature theta of cable conductorMDetermining the temperature theta of the conductor of the cableF(ii) a Determine cable aging operational age module 330 to determine a temperature θ of the cable conductorFThe service life t0And the rated working temperature of the cable conductor, determining the equivalent operating life t of the cable under the effect of the accumulated temperature1And according to the service life t0And the equivalent operating life t1Determining the aging operating age t of the cable2(ii) a A determine cable equivalent run time module 340 for determining the family defect impact factor KFThe historical fault influence factor KHThe service life influence factor KYThe value of the load condition influence factor KLThe laying mode influence factor KMOperational environment influence factor KEAnd age t of cable2Determining the equivalent operating time t of the cable; and an aging insulation state evaluation module 350 for evaluating the aging state of the high voltage insulation of the cable by the equivalent running time of the cable.
Optionally, the determine cable conductor temperature module 320 includes: submodule for determining the temperature of cable conductorsDetermining the conductor temperature theta of the cable according to the following formulaF：
Optionally, determining an aged operational life of the cable module 330 includes: a sub-module for determining the equivalent operation time of the cable, which is used for determining the equivalent operation age t of the cable under the effect of accumulated temperature according to the following formula1:
t1＝A*30
Wherein A is the temperature theta of the cable conductorFCumulative effect and cable design operating temperature theta in t0 yearsMThe ratio of the cumulative effect over a design life of 30 years at 90 c,
optionally, the determine cable aging operational age module 340 includes: the sub-module for determining the aging operation age of the cable is used for determining the aging operation age t of the cable according to the following formula2：
t2＝a0t0+a1t1
Wherein, a0And a1Service life t of all cables0And equivalent operating life t under the effect of temperature accumulation1A balance coefficient of0+a1Since the conditions of the model are simplified in the process of cable ampacity estimation and temperature estimation, the model takes a0 as 0.5 and a1 as 0.5.
Optionally, determining a cable equivalent runtime module 340 comprises: a submodule for determining service life influence factor according to the service life t0Amplitude coefficient and aging coefficient, determining service life influence factor KY：
KY＝A1exp(A2t0)
Wherein, KYIs service life factor value; a. the1Is the amplitude coefficient; a. the2Is the aging factor; t is t0The service life of the cable;
a submodule for determining the value of the load factor for determining the average load current IFAnd the ampacity IMDetermining the average load rate L of the line and determining the load condition influence factor value K according to the average load rateL：
The system 300 for evaluating a high voltage insulation aging state according to an embodiment of the present invention corresponds to the method 100 for evaluating a high voltage insulation aging state according to another embodiment of the present invention, and is not described herein again.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein. The scheme in the embodiment of the application can be implemented by adopting various computer languages, such as object-oriented programming language Java and transliterated scripting language JavaScript.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
While the preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all alterations and modifications as fall within the scope of the application.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.
Claims (10)
1. A method for assessing the aging state of a high voltage insulation, comprising:
determining various input parameters of the high-voltage cable, wherein the input parameters comprise current-carrying capacity IMAverage load current IFAmbient average temperature θ0Service life t0Family defect influence factor KFHistorical fault influence factor KHAnd laying mode influence factor KMOperational environment influence factor KE；
According to the ampacity IMThe average load current IFThe ambient average temperature theta0And rated working temperature theta of cable conductorMDetermining the temperature theta of the conductor of the cableF；
According to the conductor temperature theta of the cableFThe service life t0And the rated working temperature of the cable conductor, determining the equivalent operating life t of the cable under the effect of the accumulated temperature1And according to the service life t0And the equivalent operating life t1Determining the aging operating age t of the cable2；
According to the family defect influence factor KFThe historical fault influence factor KHThe service life influence factor KYThe value of the load condition influence factor KLThe laying mode influence factor KMOperational environment influence factor KEAnd age t of cable2Determining the equivalent operating time t of the cable;
and evaluating the high-voltage insulation aging state of the cable through the equivalent running time of the cable.
2. The method of claim 1, wherein the ampacity I is determined by the ampacity IMThe average load current IFThe ambient average temperature theta0And rated working temperature theta of cable conductorMDetermining the temperature theta of the conductor of the cableFThe method comprises the following steps:
determining the cable conductor temperature θ according to the following formulaF：
3. The method of claim 1, wherein the cable guide is based on the cable lengthBody temperature thetaFThe service life t0And the rated working temperature of the cable conductor, determining the equivalent operating life t of the cable under the effect of the accumulated temperature1The method comprises the following steps:
determining the equivalent operating life t of the cable under the effect of the accumulated temperature according to the following formula1：
t1＝A*30
Wherein A is the temperature theta of the cable conductorFCumulative effect and cable design operating temperature theta in t0 yearsMThe ratio of the cumulative effect over a design life of 30 years at 90 c,
4. method according to claim 1, characterised in that it is carried out according to the age of service t0And the equivalent operating life t1Determining the aging operating age t of the cable2The method comprises the following steps:
determining the aging operation age t of the cable according to the following formula2：
t2＝a0t0+a1t1
Wherein, a0And a1Service life t of all cables0And equivalent operating life t under the effect of temperature accumulation1A balance coefficient of0+a1Since the conditions of the model are simplified in the process of cable ampacity estimation and temperature estimation, the model takes a0 as 0.5 and a1 as 0.5.
5. The method of claim 1, wherein K is the family defect impact factorFThe historical fault influence factor KHThe service life influence factor KYThe value of the load condition influence factor KLThe laying mode influence factor KMOperational environment influence factor KEAnd age t of cable2Determining the cable, etcAn effective operation time t comprising:
according to the service life t0Amplitude coefficient and aging coefficient, determining service life influence factor KY：
KY＝A1exp(A2t0)
Wherein, KYIs service life factor value; a. the1Is the amplitude coefficient; a. the2Is the aging factor; t is t0The service life of the cable;
according to the average load current IFAnd the ampacity IMDetermining the average load rate L of the line and determining the load condition influence factor value K according to the average load rateL：
6. A system for assessing the state of aging of a high voltage insulation, comprising:
an input parameter determining module for determining various input parameters of the high-voltage cable, wherein the input parameters comprise current-carrying capacity IMAverage load current IFAmbient average temperature θ0Service life t0Family defect influence factor KFHistorical fault influence factor KHAnd laying mode influence factor KMOperational environment influence factor KE；
A module for determining the temperature of the cable conductor according to the current-carrying capacity IMThe average load current IFThe ambient average temperature theta0And rated working temperature theta of cable conductorMDetermining the temperature theta of the conductor of the cableF；
A module for determining the aging operation age of the cable according to the conductor temperature theta of the cableFThe service life t0And the rated working temperature of the cable conductor, determining the equivalent operating life t of the cable under the effect of the accumulated temperature1According toThe service life t0And the equivalent operating life t1Determining the aging operating age t of the cable2；
Determining a cable equivalent run time module for influencing factor K according to said family defectFThe historical fault influence factor KHThe service life influence factor KYThe value of the load condition influence factor KLThe laying mode influence factor KMOperational environment influence factor KEAnd age t of cable2Determining the equivalent operating time t of the cable;
and the aging insulation state evaluation module is used for evaluating the high-voltage insulation aging state of the cable according to the equivalent running time of the cable.
7. The system of claim 6, wherein the determine cable conductor temperature module comprises:
a determine cable conductor temperature submodule for determining a cable conductor temperature θ according to the following equationF：
8. The system of claim 6, wherein the determine cable age operational age module comprises:
a sub-module for determining the equivalent operation time of the cable, which is used for determining the equivalent operation age t of the cable under the effect of accumulated temperature according to the following formula1:
t1＝A*30
Wherein A is the temperature theta of the cable conductorFAt t0Cumulative effect over the year and cable design operating temperature thetaMThe ratio of the cumulative effect over a design life of 30 years at 90 c,
9. the system of claim 6, wherein the determine cable age operational age module comprises:
the sub-module for determining the aging operation age of the cable is used for determining the aging operation age t of the cable according to the following formula2：
t2＝a0t0+a1t1
Wherein, a0And a1Service life t of all cables0And equivalent operating life t under the effect of temperature accumulation1A balance coefficient of0+a1Because the conditions of the model are greatly simplified when the carrying capacity value and the temperature calculation of the cable are carried out, a is taken from the model0＝0.5，a1＝0.5。
10. The system of claim 6, wherein determining a cable equivalent runtime module comprises:
a submodule for determining service life influence factor according to the service life t0Amplitude coefficient and aging coefficient, determining service life influence factor KY：
KY＝A1exp(A2t0)
Wherein, KYIs service life factor value; a. the1Is the amplitude coefficient; a. the2Is the aging factor; t is t0The service life of the cable;
a submodule for determining the value of the load factor for determining the average load current IFAnd the ampacity IMDetermining the average load rate L of the line and determining the load condition influence factor value K according to the average load rateL：
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