CN116227171B - Method and device for evaluating residual life of oil immersed transformer - Google Patents
Method and device for evaluating residual life of oil immersed transformer Download PDFInfo
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- CN116227171B CN116227171B CN202310085225.0A CN202310085225A CN116227171B CN 116227171 B CN116227171 B CN 116227171B CN 202310085225 A CN202310085225 A CN 202310085225A CN 116227171 B CN116227171 B CN 116227171B
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- 238000000034 method Methods 0.000 title claims abstract description 16
- 230000032683 aging Effects 0.000 claims abstract description 101
- 238000009413 insulation Methods 0.000 claims abstract description 49
- 238000004458 analytical method Methods 0.000 claims abstract description 32
- 238000011156 evaluation Methods 0.000 claims abstract description 17
- 238000004364 calculation method Methods 0.000 claims description 34
- 238000012937 correction Methods 0.000 claims description 32
- 239000000835 fiber Substances 0.000 claims description 7
- 238000007405 data analysis Methods 0.000 claims description 6
- 230000035939 shock Effects 0.000 claims description 6
- 239000003921 oil Substances 0.000 description 47
- 238000010438 heat treatment Methods 0.000 description 21
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 6
- 239000004020 conductor Substances 0.000 description 6
- 229910052802 copper Inorganic materials 0.000 description 6
- 239000010949 copper Substances 0.000 description 6
- 238000010219 correlation analysis Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 6
- 238000002474 experimental method Methods 0.000 description 6
- 230000033228 biological regulation Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 238000005314 correlation function Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000002431 foraging effect Effects 0.000 description 1
- 239000012774 insulation material Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000002480 mineral oil Substances 0.000 description 1
- 235000010446 mineral oil Nutrition 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
- G01K11/32—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/003—Environmental or reliability tests
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- G—PHYSICS
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- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
- G06F17/10—Complex mathematical operations
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
- G06F2119/04—Ageing analysis or optimisation against ageing
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
- G06F2119/08—Thermal analysis or thermal optimisation
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
Abstract
The invention discloses a method and a device for evaluating the residual life of an oil immersed transformer, wherein the evaluating method comprises the following steps: acquiring voltage data and working temperature data of a transformer in a power distribution network system, and calculating a working temperature change coefficient of the transformer according to the voltage data and the working temperature data; analyzing the working temperature change data of the transformer according to the working temperature change coefficient; analyzing and calculating the insulation aging constant of the transformer according to the working temperature change data; analyzing and calculating a hot spot temperature value of the transformer according to the voltage data; and evaluating the residual working life of the transformer by combining the insulation aging constant and the hot spot temperature value. According to the evaluation method, the correlation between the voltage data and the working temperature data in the historical working data of the power distribution network system is analyzed, the working temperature change data of the transformer is obtained, the ageing constant and the hot spot temperature of the transformer are calculated, and the accuracy of the working life analysis of the transformer is improved.
Description
Technical Field
The invention mainly relates to the technical field of distribution networks, in particular to a method and a device for evaluating the residual life of an oil-immersed transformer.
Background
The oil immersed transformer is used as one of important equipment in a power distribution network system, the service life of the transformer is generally used as a basis for transformer decommissioning at present, and the service life of the transformer is estimated by analyzing the aging degree of an insulation system of the transformer, so that the service state of the transformer is obtained. The aging constant of the transformer insulation system needs to be calculated in the analysis of the aging degree, the aging experiments of different time and temperature are usually carried out for different insulation materials, but the working temperature of the transformer is not fixed, the voltage fluctuation often occurs in the working process of the power distribution network system, the voltage is regulated through the voltage regulating function of the power distribution network system, the working temperature of the transformer generates certain fluctuation along with the voltage change, and therefore the insulation system of the transformer is placed in a stable temperature environment for aging treatment, the aging condition of the transformer cannot be truly reflected, and the accuracy of the analysis of the working life of the transformer is affected.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, and provides a method and a device for evaluating the residual life of an oil immersed transformer.
The invention provides an evaluation method for residual life of an oil-immersed transformer, which comprises the following steps:
acquiring voltage data and working temperature data of a transformer in a power distribution network system, and calculating a working temperature change coefficient of the transformer according to the voltage data and the working temperature data;
analyzing the working temperature change data of the transformer according to the working temperature change coefficient;
analyzing and calculating the insulation aging constant of the transformer according to the working temperature change data;
analyzing and calculating a hot spot temperature value of the transformer according to the voltage data;
and evaluating the residual working life of the transformer by combining the insulation aging constant and the hot spot temperature value.
Further, the obtaining the voltage data and the transformer working temperature data in the power distribution network system includes:
and extracting voltage data and transformer working temperature data of the power distribution network system from the historical working data of the power distribution network system.
Further, the calculating the transformer operating temperature change coefficient according to the voltage data and the operating temperature data includes:
calculating and analyzing linear correlation coefficients of the voltage data and the working temperature data;
performing correction coefficient analysis and calculation on the voltage data and the working temperature data to obtain a correction coefficient;
and calculating the working temperature change coefficient of the transformer by combining the linear correlation coefficient and the correction coefficient.
Further, the calculating and analyzing the linear correlation coefficient of the voltage data and the operating temperature data includes:
dividing the voltage data into a plurality of voltage sample data according to a preset time interval, and extracting corresponding working temperature sample data from the working temperature data according to the plurality of voltage sample data;
and analyzing the voltage sample data and the working temperature sample data by a correlation coefficient analysis method to obtain a linear correlation coefficient.
Further, the performing correction coefficient analysis calculation on the voltage data and the working temperature data to obtain a correction coefficient includes:
extracting data samples of data abrupt changes in the voltage data and the working temperature data to obtain abrupt change data samples;
and analyzing the correlation between the voltage data abrupt change and the working temperature data abrupt change to obtain the correction coefficients of the voltage data and the working temperature data.
Further, the calculation formula of the working temperature change coefficient of the transformer is as follows:
wherein: τ 3 For the working temperature change coefficient, M is the total number of samples, X i For the ith voltage data sample, X 0 As the average value of the voltage data, Y i For the ith operating temperature data sample, Y 0 For the average value of the working temperature data, J is the number of abrupt data samples, X 1j For the jth voltage shock data sample, Y 1j For the jth operating temperature dip data sample, λ is the probability of dip data occurrence.
Further, the analyzing and calculating the insulation aging constant of the transformer according to the working temperature change data comprises:
and fitting an aging curve of the insulating oil and the insulating paper of the transformer under the environment of time change and working temperature change through double-temperature calculation and analysis to obtain the aging constant of the transformer.
Further, the calculating the hot spot temperature value of the transformer according to the voltage data analysis includes:
and acquiring hot spot position temperature, oil top position temperature and oil bottom position temperature data of the transformer by arranging the fiber bragg grating sensor in the transformer, and fitting the hot spot position temperature, the oil top position temperature and the oil bottom position temperature data to form a hot spot temperature change curve.
Further, the evaluation calculation formula of the residual life of the transformer is as follows:
wherein V is the ageing rate of the transformer, theta h The hot spot temperature, k is the aging constant of the transformer, 110 is the insulation heat-resistant temperature of the transformer, 273 is the absolute temperature of the environment, L is the life loss of the transformer, and V n For the relative ageing rate of the nth time interval, t n The ordinal number of the nth time interval, N, is the total number of time intervals in the considered period.
The invention also provides an evaluation device for the residual life of the oil-immersed transformer, which comprises:
and a data acquisition module: acquiring voltage data and working temperature data of a transformer in a power distribution network system, and calculating a working temperature change coefficient of the transformer according to the voltage data and the working temperature data;
and a data analysis module: analyzing the working temperature change data of the transformer according to the working temperature change coefficient;
and an aging calculation module: analyzing and calculating the insulation aging constant of the transformer according to the working temperature change data;
and a hot spot temperature calculation module: analyzing and calculating a hot spot temperature value of the transformer according to the voltage data;
and an evaluation module: and evaluating the residual working life of the transformer by combining the insulation aging constant and the hot spot temperature value.
The invention provides an evaluation method and device for the residual life of an oil immersed transformer, wherein the evaluation method is used for obtaining the working temperature change data of the transformer along with the voltage change through linear correlation analysis by extracting the voltage data and the working temperature data in the historical working data of a power distribution network system, so that the transformer aging constant analysis and the hot spot temperature calculation are carried out according to the temperature change data, the residual life of the transformer is obtained through analysis by calculating the aging degree of the transformer in the service period, and the accuracy of the residual life analysis of the transformer is effectively improved.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings which are required in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic flow chart of a method for evaluating the residual service life of an oil immersed transformer according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a calculation flow of a temperature change coefficient of a transformer according to an embodiment of the present invention;
fig. 3 is a schematic diagram of an apparatus for evaluating remaining service life of an oil immersed transformer according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Fig. 1 shows a schematic flow chart of a method for evaluating the residual service life of an oil immersed transformer according to an embodiment of the present invention, where the method includes:
s11: and acquiring voltage data and working temperature data of a transformer in the power distribution network system, and calculating a working temperature change coefficient of the transformer according to the voltage data and the working temperature data.
Specifically, in the historical working data of the power distribution network system, the voltage data of the power distribution network system in one year is extracted, and in order to ensure the working stability of the power distribution network system during the working period of the power distribution network system according to the historical data record of the power distribution network work, the power distribution network system needs to be subjected to voltage regulation and voltage stabilization through a transformer, namely the transformer needs to be subjected to voltage regulation work under different voltage states of the power distribution network system during the working period.
Further, in the historical working data of the power distribution network system, working temperature data of a transformer in the power distribution network system are extracted, the voltage data are divided into a plurality of voltage sample data according to preset time intervals, corresponding working temperature sample data are extracted from the working temperature data according to the plurality of voltage sample data, and the plurality of voltage sample data and the working temperature sample data are analyzed to obtain working temperature change coefficients of the transformer.
Specifically, fig. 2 shows a schematic diagram of a calculation flow of a change coefficient of a working temperature of a transformer according to an embodiment of the present invention, where the calculation flow includes:
s111: and calculating and analyzing the linear correlation coefficient of the voltage data and the working temperature data.
Specifically, the analyzing the voltage sample data and the working temperature sample data to obtain linear correlation coefficients of the voltage data and the working temperature data, analyzing the voltage sample data and the working temperature sample data by a correlation coefficient analysis method, namely drawing the voltage sample data and the working temperature sample data into a scatter diagram, observing the relation between the voltage sample data and the working temperature sample data by the scatter diagram, selecting a proper correlation function, and analyzing and calculating to obtain the correlation coefficients between the voltage sample data and the working temperature sample data.
Further, in order to facilitate analysis and calculation, when linear correlation coefficient calculation is performed on the voltage data and the operating temperature data, data samples of data abrupt changes in the voltage data and the operating temperature data are removed, so that a linear relationship between the voltage data and the operating temperature data is analyzed conveniently.
Specifically, the calculation formula of the linear correlation coefficient of the voltage data and the working temperature data is as follows:
wherein: τ 1 Is a linear correlation coefficient, M is the total number of samples, X i For the ith voltage data sample, X 0 As the average value of the voltage data, Y i For the ith operating temperature data sample, Y 0 Is the average value of the working temperature data.
S112: and carrying out correction coefficient analysis and calculation on the voltage data and the working temperature data to obtain a correction coefficient.
Specifically, calculating the working temperature change coefficient of the transformer according to the voltage data and the working temperature data further comprises performing correction coefficient analysis calculation on the voltage data and the working temperature data, and calculating the working temperature change coefficient of the transformer by combining the correction coefficient and the linear correlation coefficient.
Specifically, the data samples of the data bursts in the voltage data and the working temperature data are extracted to obtain the data samples of the bursts, analysis and calculation are performed according to time sequence, and according to the change amplitude, the change duration and the change data of the working temperature after each data burst, the correlation between the voltage data bursts and the working temperature data bursts is analyzed to obtain the correction coefficients of the voltage data and the working temperature data.
The calculation formula of the correction coefficient is as follows:
wherein τ 2 For correction factor, J is the number of samples of the abrupt data, X 1j For the jth voltage shock data sample, Y 1j For the jth operating temperature dip data sample.
S113: and calculating the working temperature change coefficient of the transformer by combining the linear correlation coefficient and the correction coefficient.
Specifically, correction analysis is performed on the voltage data and the working temperature data according to the correlation of the data abrupt change, the correlation coefficient and the correction coefficient are combined to obtain a working temperature change coefficient, and the expression of the working temperature change coefficient is as follows:
wherein: τ 3 For the working temperature change coefficient, M is the total number of samples, X i For the ith voltage data sample, X 0 As the average value of the voltage data, Y i For the ith operating temperature data sample, Y 0 For the average value of the working temperature data, J is the number of abrupt data samples, X 1j For the jth voltage shock data sample, Y 1j For the jth operating temperature dip data sample, λ is the probability of dip data occurrence.
S12: and analyzing the working temperature change data of the transformer according to the working temperature change coefficient.
Specifically, according to the working temperature change coefficient of the transformer, a working temperature change curve of the transformer in one year is fitted, so that working temperature change data of the transformer are obtained, the change condition of the actual working environment temperature of the transformer can be determined through the working temperature change data of the transformer, and the accuracy of the residual life estimation of the transformer is improved.
Furthermore, according to the working condition of the power distribution network system, the working temperature change curve is mainly divided into a high heating stage in a peak power utilization period and a low heating stage in a valley power utilization period, and the working temperatures of the transformers are periodically distributed, namely, the working temperatures of the transformers pass through the low heating stage and the high heating stage in sequence.
S13: analyzing and calculating the insulation aging constant of the transformer according to the working temperature change data;
specifically, the insulation aging constant of the transformer is analyzed through double-temperature calculation, a plurality of insulation oil and insulation paper are set to serve as analysis samples, each sample is independently placed in a corresponding aging tank to conduct aging experiments, the temperature in the aging tank is adjusted according to the working temperature change data, the temperature change in the aging tank is close to the working temperature change of the transformer, aging degrees of the insulation oil and the insulation paper under different time are recorded, and aging curves of the insulation oil and the insulation paper under the working temperature change environment are fitted, so that the aging constant of the transformer is obtained.
Furthermore, according to the insulating oil and the insulating paper with different materials, the aging constant curves of the transformers are different, so that analysis is required according to the materials of the insulating oil and the insulating paper of the actual transformer to obtain the corresponding transformer aging constant.
Specifically, in this embodiment, an average value of the working temperature in the voltage-stabilizing state during the low-heating stage of the transformer is taken as an initial ambient temperature of the aging tank, a high-temperature region and a low-temperature region are set in the aging tank, the heating temperature of the low-temperature region is kept at the working temperature of the voltage-stabilizing stage of the transformer, and the heating temperature of the high-temperature region is set to be the highest working temperature of the transformer in a corresponding time period.
Furthermore, the high temperature area and the low temperature area are isolated by arranging a copper conductor heating device, and the high temperature area is subjected to heating treatment, so that the temperature of the high temperature area can be kept at the highest working temperature of the transformer.
Further, the copper conductor heating device is arranged above the low-temperature area, the heating part of the copper conductor heating device acts in the high-temperature area, the part, close to the copper conductor heating device, in the low-temperature area is affected by the copper conductor heating device, so that the temperature in the low-temperature area changes, the temperature in the aging tank gradually rises from the low-temperature area to the high-temperature area, and the actual working temperature of the transformer is attached to the temperature change, so that the accuracy of the aging experiment is improved.
Specifically, a heating device is arranged in the low-temperature area of the aging tank, the liquid in the aging tank is heated through the heating device, the output power of the heating device is adjusted according to the temperature change data, so that the temperature change in the aging tank is attached to the temperature change data of the transformer, the working environment of the transformer in a voltage stabilizing state is simulated in the aging tank, and the accuracy of an aging test of the transformer insulation system is improved.
Specifically, in this embodiment, mineral oil is used as insulating oil of a transformer, a wood board is used as an insulating plate of the transformer, and an insulation aging curve of the transformer is obtained by performing an insulation system aging experiment on the transformer, and the insulation aging constant of the transformer is 15000 according to analysis of the insulation aging curve.
S14: and analyzing and calculating a hot spot temperature value of the transformer according to the voltage data.
Specifically, according to IEC 60076-7, part 7 of the power transformer, namely the loading guide of the oil immersed power transformer, the proposed hot spot temperature of the transformer is equal to the sum of the ambient temperature, the temperature rise of the top oil level of the oil tank relative to the ambient temperature and the temperature rise of the hot spot position relative to the top oil level of the oil tank under the condition of variable load, namely the temperature of the top oil level of the oil tank of the transformer and the temperature of the hot spot position of the transformer during working need to be determined, and in the embodiment, the temperature of the top oil level of the oil tank and the temperature of the hot spot position of the transformer are measured by arranging a fiber grating sensor.
Specifically, the fiber bragg grating sensor is arranged in the transformer, a plurality of hot spot position temperature, oil top position temperature and oil bottom position temperature data are extracted in different working time periods, hot spot temperature change curves of the transformer are calculated and fitted by combining the hot spot position temperature, the oil top position temperature and the oil bottom position temperature data, voltage change curves of the transformer are formed according to voltage data fitting of the transformer, and correction fitting is carried out on the hot spot temperature change curves through the voltage change curves, so that hot spot temperature correction curves are obtained.
S15: and calculating the residual working life of the transformer by combining the insulation aging constant and the hot spot temperature value.
Specifically, the residual service life of the transformer is obtained by calculating the service life loss of the insulation system of the transformer in the service period and analyzing the residual service life condition of the transformer according to the service life loss of the insulation system of the transformer.
Specifically, the hot spot temperature correction curve is used for acquiring hot spot temperature data of the transformer according to the service condition of the transformer, and the aging rate of the transformer, namely the aging condition of the transformer insulation system, is obtained by analyzing and calculating according to the aging constant of the transformer insulation system and combining the hot spot temperature data of the transformer.
Specifically, the aging rate calculation formula of the transformer is as follows:
wherein V is the ageing rate of the transformer, theta h The hot spot temperature, k is the transformer aging constant, 110 is the transformer insulation heat resistance temperature, 273 is the ambient absolute temperature.
The life loss of the transformer in a certain period is as follows:
specifically, L is the life loss of the transformer, V n For the relative ageing rate of the nth time interval, t n The ordinal number of the nth time interval, N, is the total number of time intervals in the considered period.
Specifically, during the service period of the transformer, the aging rate of the transformer, namely the aging degree of the transformer insulation system, is calculated, and the service life loss condition of the transformer after a period of working is obtained through analysis, so that the residual working life of the transformer is obtained.
Furthermore, according to the life loss of the transformer, namely the aging degree of the transformer insulation system, the aging condition of the transformer can be evaluated in combination with the aging rate of the transformer, when the aging degree of the transformer reaches 80%, the transformer can not meet the operation requirement of the power distribution network system, and the residual working life of the transformer can be obtained through analysis according to the aging degree of the transformer.
The embodiment of the invention provides an evaluation method of the residual life of an oil immersed transformer, which is characterized in that voltage data and working temperature data in historical working data of a power distribution network system are extracted, and the working temperature change data of the transformer along with the voltage change is obtained through linear correlation analysis and correction processing, so that the ageing constant analysis and the hot spot temperature calculation of the transformer are carried out according to the temperature change data, and the residual life of the transformer is obtained through analysis by calculating the ageing degree of the transformer in the service period, and the accuracy of analyzing the residual life of the transformer can be effectively improved.
Embodiment two:
fig. 3 shows a schematic diagram of an apparatus for evaluating residual life of an oil immersed transformer according to an embodiment of the present invention, the apparatus includes:
the data acquisition module 10: and acquiring voltage data and working temperature data of a transformer in the power distribution network system, and calculating a working temperature change coefficient of the transformer according to the voltage data and the working temperature data.
Specifically, voltage data and transformer working temperature data of the power distribution network system are extracted from historical working data of the power distribution network, and voltage data and transformer working temperature data of the power distribution network system are extracted from annual working data of the power distribution network system.
Specifically, the voltage data and the working temperature data are divided into a plurality of sample data according to a time sequence, and correlation coefficients of the voltage data and the working temperature data are analyzed through a linear correlation method.
Further, when the sample data are divided, the data with abrupt changes of voltage values and temperature values in the voltage data and the working temperature data are removed from the plurality of sample data, so that correlation analysis can be conducted.
Specifically, independent correlation analysis is performed on the removed abrupt change data, and the correlation analysis of the voltage data and the working temperature data is corrected by combining the occurrence probability of the abrupt change data, so as to obtain the working temperature change coefficient of the transformer.
Furthermore, according to the condition that voltage shock and temperature shock occur in the working process of the power distribution network system, the voltage data and the working temperature data are corrected, so that the condition that the working temperature of the transformer changes along with the voltage change can be truly reflected.
Data analysis module 20: and analyzing the working temperature change data of the transformer according to the working temperature change coefficient.
Specifically, according to the working temperature change coefficient of the transformer, a working temperature change curve of the transformer in one year is fitted, so that working temperature change data of the transformer are obtained, the change condition of the actual working environment temperature of the transformer can be determined through the working temperature change data of the transformer, and the accuracy of the residual life estimation of the transformer is improved.
The aging calculation module 30: and analyzing and calculating the insulation aging constant of the transformer according to the working temperature change data.
Specifically, according to the setting parameters of the ageing tank adjusted according to the working temperature change data, an ageing experiment is carried out according to an insulation system of the transformer, a high-temperature area and a low-temperature area are arranged in the ageing tank, the output power of the heating device is adjusted according to the working temperature change data by arranging a heating device on the low-temperature area, so that the working temperature of the low-temperature area in the ageing tank is in a temperature change state in a voltage stabilizing state of the transformer, a copper conductor heating device is arranged on the high-temperature area, the working temperature in the high-temperature area is heated, the temperature in the high-temperature area is kept at the maximum value of the working temperature of the transformer, and the insulation ageing curve of the transformer is obtained through a double-temperature ageing experiment, so that the ageing constant of the transformer is obtained.
Further, in the temperature setting of the high temperature area, corresponding temperature values are adopted in different time periods according to the working temperature change data, for example, in a peak working time period of the transformer, the temperature of the high temperature area is set to be the highest temperature value in a high heating stage, so that the temperature in the aging tank is attached to the working environment of the transformer, and an insulation aging constant capable of reflecting the actual aging condition of the transformer is obtained.
Hot spot temperature calculation module 40: and analyzing and calculating a hot spot temperature value of the transformer according to the voltage data.
Specifically, according to IEC 60076-7, part 7 of the power transformer, namely the loading guide of the oil immersed power transformer, the proposed hot spot temperature of the transformer is equal to the sum of the ambient temperature, the temperature rise of the top oil level of the oil tank relative to the ambient temperature and the temperature rise of the hot spot position relative to the top oil level of the oil tank under the condition of variable load, namely the temperature of the top oil level of the oil tank of the transformer and the temperature of the hot spot position of the transformer during working need to be determined, and in the embodiment, the temperature of the top oil level of the oil tank and the temperature of the hot spot position of the transformer are measured by arranging a fiber grating sensor.
Specifically, the fiber bragg grating sensor is arranged in the transformer, a plurality of hot spot position temperature, oil top position temperature and oil bottom position temperature data are extracted in different working time periods, hot spot temperature change curves of the transformer are calculated and fitted by combining the hot spot position temperature, the oil top position temperature and the oil bottom position temperature data, voltage change curves of the transformer are formed according to voltage data fitting of the transformer, and correction fitting is carried out on the hot spot temperature change curves through the voltage change curves, so that hot spot temperature correction curves are obtained.
Further, according to the hot spot temperature correction curve, the hot spot temperature of the transformer working in a certain time can be estimated.
The evaluation module 50: and evaluating the residual working life of the transformer by combining the insulation aging constant and the hot spot temperature value.
Specifically, the aging rate calculation formula of the transformer is as follows:
wherein V is the ageing rate of the transformer, theta h The hot spot temperature, k is the transformer aging constant, 110 is the transformer insulation heat resistance temperature, 273 is the ambient absolute temperature.
The life loss of the transformer in a certain period is as follows:
wherein: l is the life loss of the transformer, V n For the relative ageing rate of the nth time interval, t n The ordinal number of the nth time interval, N, is the total number of time intervals in the considered period.
Specifically, the aging speed of the transformer insulation system is analyzed and calculated by analyzing and calculating the insulation aging condition of the transformer after the transformer is in service for a certain time, so that the residual service life of the transformer is obtained by analysis, and when the aging degree of the transformer insulation system reaches 80%, the transformer is considered to be incapable of meeting the operation requirement of the power distribution network system, and the transformer needs to be replaced.
Specifically, the embodiment of the invention provides an evaluation device for the residual life of an oil immersed transformer, the evaluation device obtains the working temperature change data of the transformer along with the voltage change through linear correlation analysis and correction processing by extracting voltage data and working temperature data in historical working data of a power distribution network system, so that the transformer aging constant analysis and hot spot temperature calculation are carried out according to the temperature change data, the residual life of the transformer is obtained through analysis by calculating the aging degree of the transformer in the service period, and the accuracy of the residual life analysis of the transformer can be effectively improved.
In addition, the foregoing has outlined rather broadly the more detailed description of embodiments of the invention in order that the detailed description of the principles and embodiments of the invention may be implemented in conjunction with the present examples, the above examples being provided to facilitate the understanding of the method and core concepts of the invention; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present invention, the present description should not be construed as limiting the present invention in view of the above.
Claims (5)
1. An evaluation method for residual life of an oil immersed transformer, which is characterized by comprising the following steps:
acquiring voltage data and working temperature data of a transformer in a power distribution network system, and calculating a working temperature change coefficient of the transformer according to the voltage data and the working temperature data;
the calculating the transformer operating temperature change coefficient according to the voltage data and the operating temperature data comprises:
calculating and analyzing linear correlation coefficients of the voltage data and the working temperature data;
performing correction coefficient analysis and calculation on the voltage data and the working temperature data to obtain a correction coefficient;
extracting data samples of data abrupt changes in the voltage data and the working temperature data to obtain abrupt change data samples;
analyzing the correlation between the voltage data abrupt change and the working temperature data abrupt change to obtain the correction coefficients of the voltage data and the working temperature data;
calculating to obtain a transformer working temperature change coefficient by combining the linear correlation coefficient and the correction coefficient; analyzing the working temperature change data of the transformer according to the working temperature change coefficient;
analyzing and calculating the insulation aging constant of the transformer according to the working temperature change data;
the step of analyzing and calculating the insulation aging constant of the transformer according to the working temperature change data comprises the following steps:
fitting an aging curve of the insulating oil and the insulating paper of the transformer under the working temperature change environment along with the time change through double-temperature calculation and analysis to obtain an aging constant of the transformer;
analyzing and calculating a hot spot temperature value of the transformer according to the voltage data;
the calculating the hot spot temperature value of the transformer according to the voltage data analysis comprises:
acquiring hot spot position temperature, oil top position temperature and oil bottom position temperature data of the transformer by arranging a fiber bragg grating sensor in the transformer, and fitting the hot spot position temperature, the oil top position temperature and the oil bottom position temperature data to form a hot spot temperature change curve;
evaluating the remaining working life of the transformer by combining the insulation aging constant and the hot spot temperature value;
the evaluation calculation formula of the residual life of the transformer is as follows:
wherein V is the ageing rate of the transformer, theta h The hot spot temperature, k is the aging constant of the transformer, 110 is the insulation heat-resistant temperature of the transformer, 273 is the absolute temperature of the environment, L is the life loss of the transformer, and V n For the relative ageing rate of the nth time interval, t n The ordinal number of the nth time interval, N, is the total number of time intervals in the considered period.
2. The method for evaluating the remaining life of an oil immersed transformer according to claim 1, wherein the step of acquiring voltage data and transformer operating temperature data in a power distribution network system comprises:
and extracting voltage data and transformer working temperature data of the power distribution network system from the historical working data of the power distribution network system.
3. The method of evaluating remaining life of an oil-immersed transformer according to claim 1, wherein said calculating and analyzing linear correlation coefficients of said voltage data and operating temperature data comprises:
dividing the voltage data into a plurality of voltage sample data according to a preset time interval, and extracting corresponding working temperature sample data from the working temperature data according to the plurality of voltage sample data;
and analyzing the voltage sample data and the working temperature sample data by a correlation coefficient analysis method to obtain a linear correlation coefficient.
4. The method for evaluating the residual life of an oil-immersed transformer according to claim 1, wherein the calculation formula of the working temperature change coefficient of the transformer is:
wherein: τ 3 For the working temperature change coefficient, M is the total number of samples, X i For the ith voltage data sample, X 0 Is the voltage data levelMean value, Y i For the ith operating temperature data sample, Y 0 For the average value of the working temperature data, J is the number of abrupt data samples, X 1j For the jth voltage shock data sample, Y 1j For the jth operating temperature dip data sample, λ is the probability of dip data occurrence.
5. An evaluation device for remaining life of an oil immersed transformer, characterized in that the evaluation device comprises:
and a data acquisition module: acquiring voltage data and working temperature data of a transformer in a power distribution network system, and calculating a working temperature change coefficient of the transformer according to the voltage data and the working temperature data;
the calculating the transformer operating temperature change coefficient according to the voltage data and the operating temperature data comprises:
calculating and analyzing linear correlation coefficients of the voltage data and the working temperature data;
performing correction coefficient analysis and calculation on the voltage data and the working temperature data to obtain a correction coefficient;
extracting data samples of data abrupt changes in the voltage data and the working temperature data to obtain abrupt change data samples;
analyzing the correlation between the voltage data abrupt change and the working temperature data abrupt change to obtain the correction coefficients of the voltage data and the working temperature data;
calculating to obtain a transformer working temperature change coefficient by combining the linear correlation coefficient and the correction coefficient;
and a data analysis module: analyzing the working temperature change data of the transformer according to the working temperature change coefficient;
and an aging calculation module: analyzing and calculating the insulation aging constant of the transformer according to the working temperature change data;
the step of analyzing and calculating the insulation aging constant of the transformer according to the working temperature change data comprises the following steps:
fitting an aging curve of the insulating oil and the insulating paper of the transformer under the working temperature change environment along with the time change through double-temperature calculation and analysis to obtain an aging constant of the transformer;
and a hot spot temperature calculation module: analyzing and calculating a hot spot temperature value of the transformer according to the voltage data;
the calculating the hot spot temperature value of the transformer according to the voltage data analysis comprises:
acquiring hot spot position temperature, oil top position temperature and oil bottom position temperature data of the transformer by arranging a fiber bragg grating sensor in the transformer, and fitting the hot spot position temperature, the oil top position temperature and the oil bottom position temperature data to form a hot spot temperature change curve;
and an evaluation module: evaluating the remaining working life of the transformer by combining the insulation aging constant and the hot spot temperature value;
the evaluation calculation formula of the residual life of the transformer is as follows:
wherein V is the ageing rate of the transformer, theta h The hot spot temperature, k is the aging constant of the transformer, 110 is the insulation heat-resistant temperature of the transformer, 273 is the absolute temperature of the environment, L is the life loss of the transformer, and V n For the relative ageing rate of the nth time interval, t n The ordinal number of the nth time interval, N, is the total number of time intervals in the considered period.
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