CN111289804B - Method for evaluating correlation between transformer oil paper insulation dielectric response and paraffin content - Google Patents

Method for evaluating correlation between transformer oil paper insulation dielectric response and paraffin content Download PDF

Info

Publication number
CN111289804B
CN111289804B CN202010137921.8A CN202010137921A CN111289804B CN 111289804 B CN111289804 B CN 111289804B CN 202010137921 A CN202010137921 A CN 202010137921A CN 111289804 B CN111289804 B CN 111289804B
Authority
CN
China
Prior art keywords
temperature
test
paraffin content
tanδ
formula
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202010137921.8A
Other languages
Chinese (zh)
Other versions
CN111289804A (en
Inventor
郭蕾
张传辉
代禄喻
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Southwest Jiaotong University
Original Assignee
Southwest Jiaotong University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Southwest Jiaotong University filed Critical Southwest Jiaotong University
Priority to CN202010137921.8A priority Critical patent/CN111289804B/en
Publication of CN111289804A publication Critical patent/CN111289804A/en
Application granted granted Critical
Publication of CN111289804B publication Critical patent/CN111289804B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
    • G01R27/2617—Measuring dielectric properties, e.g. constants
    • G01R27/2623—Measuring-systems or electronic circuits
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance
    • G01N27/221—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance by investigating the dielectric properties
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
    • G01R27/2688—Measuring quality factor or dielectric loss, e.g. loss angle, or power factor
    • G01R27/2694—Measuring dielectric loss, e.g. loss angle, loss factor or power factor
    • 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
    • G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
    • G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
    • G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation

Landscapes

  • General Physics & Mathematics (AREA)
  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Electrochemistry (AREA)
  • Power Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Measurement Of Resistance Or Impedance (AREA)

Abstract

The invention discloses a method for evaluating the correlation between dielectric response and paraffin content of oil paper insulation of a transformer. The method comprises the steps of testing the frequency domain dielectric spectrum of the oil-immersed transformer on site under the severe cold condition, recording the environmental temperature, obtaining a corresponding test curve, combining a mathematical model obtained by a laboratory, extracting a site paraffin content evaluation index, and comparing the site paraffin content evaluation index with a paraffin content evaluation index expert library, so that the paraffin content of the oil-immersed transformer under the severe cold condition can be effectively evaluated, and a guidance method is provided for accurately evaluating the insulation state of the oil paper and removing faults in the actual engineering.

Description

Method for evaluating correlation between transformer oil paper insulation dielectric response and paraffin content
Technical Field
The invention belongs to the field of insulation assessment and diagnosis of oil-immersed transformers, and particularly relates to a method for evaluating correlation between oil paper insulation dielectric response and paraffin content of a transformer.
Background
With the gradual maturity of the ultra-high voltage transmission technology, a plurality of ultra-high voltage projects are built on the ground in the northeast, inner Mongolia and Xinjiang cold areas. In addition, with the proposal of the concept of global energy Internet, the electric power of clean energy bases such as 'one-pole-one-way' and the like is possible to be transmitted by the ultra-high voltage transmission technology, and the historical lowest temperature of the north pole reaches-68 ℃. The large oil-immersed power transformer is a core part of a power system, whether a power grid can safely run is determined by the quality of the insulation state of the large oil-immersed power transformer, and paraffin precipitation of the oil-immersed power transformer is mostly found in Xinjiang, Jilin, Harbin and the like in severe cold weather, and is often accompanied with gas action, so that the transformer cannot be normally switched on; meanwhile, the paraffin is separated out, so that the insulation and heat dissipation are uneven, and the internal insulation of the transformer is damaged. Under the severe cold condition, paraffin becomes an important factor threatening the safe operation of the oil-immersed transformer.
At present, the frequency domain dielectric spectroscopy is widely applied to field insulation state evaluation and diagnosis due to the advantages of nondestructive testing, rich carried insulation information and strong anti-interference performance. However, when the dielectric spectrum curve of the oil-immersed transformer is tested on site under the severe cold condition, the relation between the spectrogram and the paraffin content is not established, a paraffin content evaluation method in the oil-immersed transformer under the severe cold condition is not available, and the accurate evaluation of the insulation state of the oil-immersed transformer cannot be realized. Therefore, an evaluation method for correlation between the insulation dielectric response of the oil paper of the transformer and the paraffin content is urgently needed to realize accurate evaluation of the insulation state of the oil-immersed transformer.
Disclosure of Invention
In order to effectively evaluate the paraffin content of the oil-immersed transformer under the high and cold conditions, the invention provides a method for evaluating the correlation between the insulation dielectric response of oil paper of the transformer and the paraffin content, which comprises the following steps:
the first step is as follows: dielectric spectrum testing platform for paraffin content frequency domain of built low-temperature oil-immersed transformer
The method comprises the following steps of constructing a low-temperature oil-immersed transformer paraffin content frequency domain dielectric spectrum test platform which mainly comprises a temperature control system and a frequency domain dielectric spectrum test system, wherein the temperature control box (1), a heating loop (7), a refrigerating loop (8), a first temperature sensor (9), a second temperature sensor (17), a temperature sensor loop (10), a temperature control box test control unit (11) and a first power supply lead (18) jointly form the temperature control system; the frequency domain dielectric spectrum testing system comprises a three-electrode outer wall (2), a high-voltage electrode (3), a test sample (4), insulating oil (19), a low-voltage electrode (5), a protective electrode (6), a grounding wire (16), a dielectric response testing loop (15), a dielectric response tester (14), a notebook computer (12), a testing data transmission line (20) and a second power supply lead (13); the temperature control box test control unit (11) sets a test temperature, the heating loop (7) or the refrigerating loop (8) acts, the first temperature sensor (9) and the second temperature sensor (17) feed the temperature in the temperature control box (1) back to the temperature control box test control unit (11), when the set temperature is reached, the heating loop (7) or the refrigerating loop (8) is controlled to be disconnected, and the frequency domain dielectric spectrum test system starts to test; the first temperature sensor (9) is fixed at the bottom of the inner layer of the temperature control box (1), and the second temperature sensor (17) is fixed outside the outer wall (2) of the three electrodes; the first power supply lead (18) supplies power to the low-temperature oil-immersed transformer paraffin content frequency domain dielectric spectrum test platform, and the second power supply lead (13) supplies power to the dielectric response tester (14);
the second step is that: preparing oil-immersed transformer XY model samples with different paraffin content and different voltage levels
The method comprises the following steps of preparing XY model samples of the oil-immersed transformer with the voltage grades of 110kV, 220kV and 500kV according to the volume ratio of 1:10, 1:50 and 1:100, wherein the paraffin content of the XY model samples under all the voltage grades is 0-5%, and the paraffin content gradient increment in the XY model samples is 0.01% of the total mass of the XY model samples;
the third step: testing the dielectric response frequency domain spectrum from 0.001Hz to 1kHz under the set low-temperature environment
The testing temperature is-60 ℃ to-20 ℃, the low-temperature testing temperature is set, the temperature control box testing control unit (11) is switched on, the refrigeration loop (8) is switched on, the temperature control box (1) starts to refrigerate, the first temperature sensor (9) and the second temperature sensor (17) jointly monitor the temperature in the temperature control box (1), the temperature is transmitted to the temperature control box testing control unit (11) in real time, when the temperature in the temperature control box (1) is consistent with a set value, the refrigeration loop (8) is switched off, the dielectric response tester (14) is started, the dielectric loss factor tan delta of 0.001Hz to 1kH under the set temperature is tested, wherein the testing characteristic frequency points are 0.001Hz, 0.00215Hz, 0.00464Hz, 0.01Hz, 0.0215Hz, 0.0464Hz, 0.1Hz, 0.215Hz, 0.464Hz, 1Hz, 2.15Hz, 4.64Hz, 10Hz, 20Hz, 40Hz, 70Hz, 110, 222.22Hz, 446.68Hz and 1000Hz, obtaining a frequency domain dielectric spectrum at a set temperature;
when testing the frequency domain dielectric spectrum at a temperature higher than the initial set value, the temperature control box test control unit (11) is connected with the heating loop (7) to heat the temperature control box (1), meanwhile, the first temperature sensor (9) and the second temperature sensor (17) jointly monitor the temperature in the temperature control box (1), the temperature is transmitted to the temperature control box test control unit (11) in real time, when the temperature in the temperature control box (1) is consistent with the set value, the heating loop (7) is disconnected, the dielectric response tester (14) is started, the dielectric loss factor tan delta of 0.001Hz to 1kH at the set temperature is tested, the frequency domain dielectric spectrum at the newly set temperature is obtained, and the fourth step is executed after the test is finished;
the fourth step: mathematical model establishment and paraffin content evaluation index extraction
Firstly, selecting a characteristic frequency point f from a frequency domain dielectric spectrum graph under a test set temperatureiCorresponding dielectric loss factor tan deltaiIn sequence of (f)1,tanδ1)、(f2,tanδ2)、(f3,tanδ3)、(f4,tanδ4)、(f5,tanδ5)……(f19,tanδ19)、(f20,tanδ20)，f20Is the highest characteristic frequency point, f1For the lowest characteristic frequency point, the relationship between the frequency f and the dielectric loss tangent tan delta at the set temperature is constructed by combining the formula (1):
Figure GDA0002815364140000021
wherein i is 1,2,3, …, n, k is 1,2,3, …, n, n is 20, i and k cannot be equal at the same time;
the characteristic frequency of the nearest point at the inflection point of a certain test curve from high frequency to low frequency is fiTake fi、fi-1And fi-2The slope tan delta' (f) of the curvei)、tanδ′(fi-1) And tan δ' (f)i-2) Recording the test temperature T, constructing the frequency average value at the 'turning point' by the formula (2), and constructing the upper limit W of the evaluation index by the formula (3)maxThe lower limit W of the structural evaluation index of formula (4)min：
Figure GDA0002815364140000031
Figure GDA0002815364140000032
Figure GDA0002815364140000033
Wherein, i is 1,2,3, …, n, n is 20; lambda is an XY model sample differentiation coefficient, and lambda is 1-3;
the fifth step: establishing an expert database for paraffin content evaluation indexes
Respectively carrying out low-temperature dielectric response tests on XY model samples of oil-immersed transformers with different voltage levels, wherein the test temperature is-60 ℃ to-20 ℃, the initial temperature is-60 ℃, and the temperature gradient is 2 ℃, wherein the paraffin content in the XY model samples under each voltage level is 0-5%, and the paraffin content gradient increment is 0.01% of the total mass of the XY model samples;
calculating a paraffin content evaluation index according to test curves of different contents, different test samples and different temperatures by combining the formula (1), the formula (2), the formula (3) and the formula (4), wherein the paraffin content evaluation index obtained by each test is WminAnd WmaxForming a section, wherein a plurality of groups of sample determination and evaluation sections form an expert database of paraffin content evaluation indexes at different voltage levels and different temperatures;
and a sixth step: evaluation of paraffin content in field test oil-immersed transformer
When the oil-immersed transformer is tested on site under the severe cold condition, the testing frequency, the testing temperature and the testing data are recorded, and (f) is sequentially carried out according to the testing result in the frequency domain dielectric spectrum graph under the site testing temperaturecs1,tanδcs1)、(fcs2,tanδcs2)、(fcs3,tanδcs3)、(fcs4,tanδcs4)、(fcs5,tanδcs5)……(fcs19,tanδcs19)、(fcs20,tanδcs20)，fcs20To the highest test eigenfrequencyPoint, fcs1For the lowest test characteristic frequency point, combining the formula (1) to construct the frequency f and the dielectric loss factor tan delta in the field testcsSatisfies the formula (5):
Figure GDA0002815364140000034
wherein i is 1,2,3, …, n, k is 1,2,3, …, n, n is 20, i and k cannot be equal at the same time;
taking the characteristic frequency of the inflection point closest to the high frequency of the test curve to the low frequency as fcsiTake fcsi、fcsi-1And fcsi-2The slope tan delta of the curvec′s(fcsi)、tanδc′s(fcsi-1) And tan deltac′s(fcsi-2) Recording the test temperature TcsThe formula (6) constructs the frequency average value at the 'turning point', and the formula (7) constructs the upper limit W of the field test evaluation indexcsmaxThe lower limit W of the evaluation index of the field test of the structure of formula (8)csmin：
Figure GDA0002815364140000041
Figure GDA0002815364140000042
Figure GDA0002815364140000043
Wherein, i is 1,2,3, …, n, n is 20; lambda is an XY model sample differentiation coefficient, and lambda is 1-3;
according to field test data, combining a formula (5), a formula (6), a formula (7) and a formula (8), drawing a curve, calculating upper and lower limit parameters of a paraffin content evaluation index, comparing the calculated value of the paraffin content evaluation index with a paraffin content evaluation index expert library, determining that the field test paraffin falls into an interval of the paraffin content evaluation index expert library, finding a corresponding paraffin content range, namely completing paraffin content evaluation in the oil-immersed transformer, and bringing the field test data of each time into the paraffin content evaluation index expert library.
The method can effectively realize the evaluation of the paraffin content of the oil-immersed transformer under the high and cold conditions, and provides a method for accurately evaluating the insulation performance and fault elimination of the field transformer in the actual engineering.
Drawings
FIG. 1 is a method for evaluating the correlation between the dielectric response of the oil paper insulation of a transformer and the content of paraffin.
Fig. 2 shows a paraffin-containing test curve of an oil-immersed transformer.
FIG. 3 is a schematic diagram of a testing platform of a method for evaluating the correlation between the dielectric response of the oil paper insulation of the transformer and the paraffin content.
Detailed Description
The invention will be further described with reference to the accompanying drawings in which:
the method provided by the invention comprises the following steps:
the first step is as follows: dielectric spectrum testing platform for paraffin content frequency domain of built low-temperature oil-immersed transformer
The method comprises the following steps of constructing a low-temperature oil-immersed transformer paraffin content frequency domain dielectric spectrum test platform which mainly comprises a temperature control system and a frequency domain dielectric spectrum test system, wherein the temperature control box (1), a heating loop (7), a refrigerating loop (8), a first temperature sensor (9), a second temperature sensor (17), a temperature sensor loop (10), a temperature control box test control unit (11) and a first power supply lead (18) jointly form the temperature control system; the frequency domain dielectric spectrum testing system comprises a three-electrode outer wall (2), a high-voltage electrode (3), a test sample (4), insulating oil (19), a low-voltage electrode (5), a protective electrode (6), a grounding wire (16), a dielectric response testing loop (15), a dielectric response tester (14), a notebook computer (12), a testing data transmission line (20) and a second power supply lead (13); the temperature control box test control unit (11) sets a test temperature, the heating loop (7) or the refrigerating loop (8) acts, the first temperature sensor (9) and the second temperature sensor (17) feed the temperature in the temperature control box (1) back to the temperature control box test control unit (11), when the set temperature is reached, the heating loop (7) or the refrigerating loop (8) is controlled to be disconnected, and the frequency domain dielectric spectrum test system starts to test; the first temperature sensor (9) is fixed at the bottom of the inner layer of the temperature control box (1), and the second temperature sensor (17) is fixed outside the outer wall (2) of the three electrodes; the first power supply lead (18) supplies power to the low-temperature oil-immersed transformer paraffin content frequency domain dielectric spectrum test platform, and the second power supply lead (13) supplies power to the dielectric response tester (14);
the second step is that: preparing oil-immersed transformer XY model samples with different paraffin content and different voltage levels
The method comprises the following steps of preparing XY model samples of the oil-immersed transformer with the voltage grades of 110kV, 220kV and 500kV according to the volume ratio of 1:10, 1:50 and 1:100, wherein the paraffin content of the XY model samples under all the voltage grades is 0-5%, and the paraffin content gradient increment in the XY model samples is 0.01% of the total mass of the XY model samples;
the third step: testing the dielectric response frequency domain spectrum from 0.001Hz to 1kHz under the set low-temperature environment
The testing temperature is-60 ℃ to-20 ℃, the low-temperature testing temperature is set, the temperature control box testing control unit (11) is switched on, the refrigeration loop (8) is switched on, the temperature control box (1) starts to refrigerate, the first temperature sensor (9) and the second temperature sensor (17) jointly monitor the temperature in the temperature control box (1), the temperature is transmitted to the temperature control box testing control unit (11) in real time, when the temperature in the temperature control box (1) is consistent with a set value, the refrigeration loop (8) is switched off, the dielectric response tester (14) is started, the dielectric loss factor tan delta of 0.001Hz to 1kH under the set temperature is tested, wherein the testing characteristic frequency points are 0.001Hz, 0.00215Hz, 0.00464Hz, 0.01Hz, 0.0215Hz, 0.0464Hz, 0.1Hz, 0.215Hz, 0.464Hz, 1Hz, 2.15Hz, 4.64Hz, 10Hz, 20Hz, 40Hz, 70Hz, 110, 222.22Hz, 446.68Hz and 1000Hz, obtaining a frequency domain dielectric spectrum at a set temperature;
when testing the frequency domain dielectric spectrum at a temperature higher than the initial set value, the temperature control box test control unit (11) is connected with the heating loop (7) to heat the temperature control box (1), meanwhile, the first temperature sensor (9) and the second temperature sensor (17) jointly monitor the temperature in the temperature control box (1), the temperature is transmitted to the temperature control box test control unit (11) in real time, when the temperature in the temperature control box (1) is consistent with the set value, the heating loop (7) is disconnected, the dielectric response tester (14) is started, the dielectric loss factor tan delta of 0.001Hz to 1kH at the set temperature is tested, the frequency domain dielectric spectrum at the newly set temperature is obtained, and the fourth step is executed after the test is finished;
the fourth step: mathematical model establishment and paraffin content evaluation index extraction
Firstly, selecting a characteristic frequency point f from a frequency domain dielectric spectrum graph under a test set temperatureiCorresponding dielectric loss factor tan deltaiIn sequence of (f)1,tanδ1)、(f2,tanδ2)、(f3,tanδ3)、(f4,tanδ4)、(f5,tanδ5)……(f19,tanδ19)、(f20,tanδ20)，f20Is the highest characteristic frequency point, f1For the lowest characteristic frequency point, the relationship between the frequency f and the dielectric loss tangent tan delta at the set temperature is constructed by combining the formula (1):
Figure GDA0002815364140000051
wherein i is 1,2,3, …, n, k is 1,2,3, …, n, n is 20, i and k cannot be equal at the same time;
the characteristic frequency of the nearest point at the inflection point of a certain test curve from high frequency to low frequency is fiTake fi、fi-1And fi-2The slope tan delta' (f) of the curvei)、tanδ′(fi-1) And tan δ' (f)i-2) Recording the test temperature T, constructing the frequency average value at the 'turning point' by the formula (2), and constructing the upper limit W of the evaluation index by the formula (3)maxThe lower limit W of the structural evaluation index of formula (4)min：
Figure GDA0002815364140000061
Figure GDA0002815364140000062
Figure GDA0002815364140000063
Wherein, i is 1,2,3, …, n, n is 20; lambda is an XY model sample differentiation coefficient, and lambda is 1-3;
the fifth step: establishing an expert database for paraffin content evaluation indexes
Respectively carrying out low-temperature dielectric response tests on XY model samples of oil-immersed transformers with different voltage levels, wherein the test temperature is-60 ℃ to-20 ℃, the initial temperature is-60 ℃, and the temperature gradient is 2 ℃, wherein the paraffin content in the XY model samples under each voltage level is 0-5%, and the paraffin content gradient increment is 0.01% of the total mass of the XY model samples;
calculating a paraffin content evaluation index according to test curves of different contents, different test samples and different temperatures by combining the formula (1), the formula (2), the formula (3) and the formula (4), wherein the paraffin content evaluation index obtained by each test is WminAnd WmaxForming a section, wherein a plurality of groups of sample determination and evaluation sections form an expert database of paraffin content evaluation indexes at different voltage levels and different temperatures;
and a sixth step: evaluation of paraffin content in field test oil-immersed transformer
When the oil-immersed transformer is tested on site under the severe cold condition, the testing frequency, the testing temperature and the testing data are recorded, and (f) is sequentially carried out according to the testing result in the frequency domain dielectric spectrum graph under the site testing temperaturecs1,tanδcs1)、(fcs2,tanδcs2)、(fcs3,tanδcs3)、(fcs4,tanδcs4)、(fcs5,tanδcs5)……(fcs19,tanδcs19)、(fcs20,tanδcs20)，fcs20Is the highest test characteristic frequency point, fcs1For the lowest test characteristic frequency point, combining the formula (1) to construct the frequency f and the dielectric loss factor tan delta in the field testcsSatisfies the formula (5):
Figure GDA0002815364140000064
wherein i is 1,2,3, …, n, k is 1,2,3, …, n, n is 20, i and k cannot be equal at the same time;
taking the characteristic frequency of the inflection point closest to the high frequency of the test curve to the low frequency as fcsiTake fcsi、fcsi-1And fcsi-2The slope tan delta of the curvec′s(fcsi)、tanδc′s(fcsi-1) And tan deltac′s(fcsi-2) Recording the test temperature TcsThe formula (6) constructs the frequency average value at the 'turning point', and the formula (7) constructs the upper limit W of the field test evaluation indexcsmaxThe lower limit W of the evaluation index of the field test of the structure of formula (8)csmin：
Figure GDA0002815364140000071
Figure GDA0002815364140000072
Figure GDA0002815364140000073
Wherein, i is 1,2,3, …, n, n is 20; lambda is an XY model sample differentiation coefficient, and lambda is 1-3;
according to field test data, combining a formula (5), a formula (6), a formula (7) and a formula (8), drawing a curve, calculating upper and lower limit parameters of a paraffin content evaluation index, comparing the calculated value of the paraffin content evaluation index with a paraffin content evaluation index expert library, determining that the field test paraffin falls into an interval of the paraffin content evaluation index expert library, finding a corresponding paraffin content range, namely completing paraffin content evaluation in the oil-immersed transformer, and bringing the field test data of each time into the paraffin content evaluation index expert library.

Claims (1)

1. The method for evaluating the relevance between the insulation dielectric response and the paraffin content of the transformer oil paper is characterized by comprising the following steps of:
the first step is as follows: dielectric spectrum testing platform for paraffin content frequency domain of built low-temperature oil-immersed transformer
The method comprises the following steps of constructing a low-temperature oil-immersed transformer paraffin content frequency domain dielectric spectrum test platform which mainly comprises a temperature control system and a frequency domain dielectric spectrum test system, wherein the temperature control box (1), a heating loop (7), a refrigerating loop (8), a first temperature sensor (9), a second temperature sensor (17), a temperature sensor loop (10), a temperature control box test control unit (11) and a first power supply lead (18) jointly form the temperature control system; the frequency domain dielectric spectrum testing system comprises a three-electrode outer wall (2), a high-voltage electrode (3), a test sample (4), insulating oil (19), a low-voltage electrode (5), a protective electrode (6), a grounding wire (16), a dielectric response testing loop (15), a dielectric response tester (14), a notebook computer (12), a testing data transmission line (20) and a second power supply lead (13); the temperature control box test control unit (11) sets a test temperature, the heating loop (7) or the refrigerating loop (8) acts, the first temperature sensor (9) and the second temperature sensor (17) feed the temperature in the temperature control box (1) back to the temperature control box test control unit (11), when the set temperature is reached, the heating loop (7) or the refrigerating loop (8) is controlled to be disconnected, and the frequency domain dielectric spectrum test system starts to test; the first temperature sensor (9) is fixed at the bottom of the inner layer of the temperature control box (1), and the second temperature sensor (17) is fixed outside the outer wall (2) of the three electrodes; the first power supply lead (18) supplies power to the low-temperature oil-immersed transformer paraffin content frequency domain dielectric spectrum test platform, and the second power supply lead (13) supplies power to the dielectric response tester (14);
the second step is that: preparing oil-immersed transformer XY model samples with different paraffin content and different voltage levels
The method comprises the following steps of preparing XY model samples of the oil-immersed transformer with the voltage grades of 110kV, 220kV and 500kV according to the volume ratio of 1:10, 1:50 and 1:100, wherein the paraffin content of the XY model samples under all the voltage grades is 0-5%, and the paraffin content gradient increment in the XY model samples is 0.01% of the total mass of the XY model samples;
the third step: testing the dielectric response frequency domain spectrum from 0.001Hz to 1kHz under the set low-temperature environment
The testing temperature is-60 ℃ to-20 ℃, the low-temperature testing temperature is set, the temperature control box testing control unit (11) is switched on, the refrigeration loop (8) is switched on, the temperature control box (1) starts to refrigerate, the first temperature sensor (9) and the second temperature sensor (17) jointly monitor the temperature in the temperature control box (1), the temperature is transmitted to the temperature control box testing control unit (11) in real time, when the temperature in the temperature control box (1) is consistent with a set value, the refrigeration loop (8) is switched off, the dielectric response tester (14) is started, the dielectric loss factor tan delta of 0.001Hz to 1kH under the set temperature is tested, wherein the testing characteristic frequency points are 0.001Hz, 0.00215Hz, 0.00464Hz, 0.01Hz, 0.0215Hz, 0.0464Hz, 0.1Hz, 0.215Hz, 0.464Hz, 1Hz, 2.15Hz, 4.64Hz, 10Hz, 20Hz, 40Hz, 70Hz, 110, 222.22Hz, 446.68Hz and 1000Hz, obtaining a frequency domain dielectric spectrum at a set temperature;
when testing the frequency domain dielectric spectrum at a temperature higher than the initial set value, the temperature control box test control unit (11) is connected with the heating loop (7) to heat the temperature control box (1), meanwhile, the first temperature sensor (9) and the second temperature sensor (17) jointly monitor the temperature in the temperature control box (1), the temperature is transmitted to the temperature control box test control unit (11) in real time, when the temperature in the temperature control box (1) is consistent with the set value, the heating loop (7) is disconnected, the dielectric response tester (14) is started, the dielectric loss factor tan delta of 0.001Hz to 1kH at the set temperature is tested, the frequency domain dielectric spectrum at the newly set temperature is obtained, and the fourth step is executed after the test is finished;
the fourth step: mathematical model establishment and paraffin content evaluation index extraction
Firstly, selecting a characteristic frequency point f from a frequency domain dielectric spectrum graph under a test set temperatureiCorresponding dielectric loss factor tan deltaiIn sequence of (f)1,tanδ1)、(f2,tanδ2)、(f3,tanδ3)、(f4,tanδ4)、(f5,tanδ5)……(f19,tanδ19)、(f20,tanδ20)，f20Is the highest characteristic frequency point, f1For the lowest characteristic frequency point, the relationship between the frequency f and the dielectric loss tangent tan delta at the set temperature is constructed by combining the formula (1):
Figure FDA0002815364130000021
wherein i is 1,2,3, …, n, k is 1,2,3, …, n, n is 20, i and k cannot be equal at the same time;
the characteristic frequency of the nearest point at the inflection point of a certain test curve from high frequency to low frequency is fiTake fi、fi-1And fi-2The slope tan delta' (f) of the curvei)、tanδ′(fi-1) And tan δ' (f)i-2) Recording the test temperature T, constructing the frequency average value at the 'turning point' by the formula (2), and constructing the upper limit W of the evaluation index by the formula (3)maxThe lower limit W of the structural evaluation index of formula (4)min：
Figure FDA0002815364130000022
Figure FDA0002815364130000023
Figure FDA0002815364130000024
Wherein, i is 1,2,3, …, n, n is 20; lambda is an XY model sample differentiation coefficient, and lambda is 1-3;
the fifth step: establishing an expert database for paraffin content evaluation indexes
Respectively carrying out low-temperature dielectric response tests on XY model samples of oil-immersed transformers with different voltage levels, wherein the test temperature is-60 ℃ to-20 ℃, the initial temperature is-60 ℃, and the temperature gradient is 2 ℃, wherein the paraffin content in the XY model samples under each voltage level is 0-5%, and the paraffin content gradient increment is 0.01% of the total mass of the XY model samples;
calculating a paraffin content evaluation index according to test curves of different contents, different test samples and different temperatures by combining the formula (1), the formula (2), the formula (3) and the formula (4), wherein the paraffin content evaluation index obtained by each test is WminAnd WmaxForming a section, wherein a plurality of groups of sample determination and evaluation sections form an expert database of paraffin content evaluation indexes at different voltage levels and different temperatures;
and a sixth step: evaluation of paraffin content in field test oil-immersed transformer
When the oil-immersed transformer is tested on site under the severe cold condition, the testing frequency, the testing temperature and the testing data are recorded, and (f) is sequentially carried out according to the testing result in the frequency domain dielectric spectrum graph under the site testing temperaturecs1,tanδcs1)、(fcs2,tanδcs2)、(fcs3,tanδcs3)、(fcs4,tanδcs4)、(fcs5,tanδcs5)……(fcs19,tanδcs19)、(fcs20,tanδcs20)，fcs20Is the highest test characteristic frequency point, fcs1For the lowest test characteristic frequency point, combining the formula (1) to construct the frequency f and the dielectric loss factor tan delta in the field testcsSatisfies the formula (5):
Figure FDA0002815364130000031
wherein i is 1,2,3, …, n, k is 1,2,3, …, n, n is 20, i and k cannot be equal at the same time;
taking the characteristic frequency of the inflection point closest to the high frequency of the test curve to the low frequency as fcsiTake fcsi、fcsi-1And fcsi-2The slope tan delta of the curve'cs(fcsi)、tanδ′cs(fcsi-1) And tan delta'cs(fcsi-2) Recording the test temperature TcsThe formula (6) is used for constructing the frequency average value at the turning point, and the formula (7) is used for constructing the upper part of the field test evaluation indexLimit of WcsmaxThe lower limit W of the evaluation index of the field test of the structure of formula (8)csmin：
Figure FDA0002815364130000032
Figure FDA0002815364130000033
Figure FDA0002815364130000034
Wherein, i is 1,2,3, …, n, n is 20; lambda is an XY model sample differentiation coefficient, and lambda is 1-3;
according to field test data, combining a formula (5), a formula (6), a formula (7) and a formula (8), drawing a curve, calculating upper and lower limit parameters of a paraffin content evaluation index, comparing the calculated value of the paraffin content evaluation index with a paraffin content evaluation index expert library, determining that the field test paraffin falls into an interval of the paraffin content evaluation index expert library, finding a corresponding paraffin content range, namely completing paraffin content evaluation in the oil-immersed transformer, and bringing the field test data of each time into the paraffin content evaluation index expert library.
CN202010137921.8A 2020-03-03 2020-03-03 Method for evaluating correlation between transformer oil paper insulation dielectric response and paraffin content Active CN111289804B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010137921.8A CN111289804B (en) 2020-03-03 2020-03-03 Method for evaluating correlation between transformer oil paper insulation dielectric response and paraffin content

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010137921.8A CN111289804B (en) 2020-03-03 2020-03-03 Method for evaluating correlation between transformer oil paper insulation dielectric response and paraffin content

Publications (2)

Publication Number Publication Date
CN111289804A CN111289804A (en) 2020-06-16
CN111289804B true CN111289804B (en) 2021-02-19

Family

ID=71025784

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010137921.8A Active CN111289804B (en) 2020-03-03 2020-03-03 Method for evaluating correlation between transformer oil paper insulation dielectric response and paraffin content

Country Status (1)

Country Link
CN (1) CN111289804B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113447537B (en) * 2021-06-25 2023-05-05 海南电网有限责任公司电力科学研究院 Method and device for measuring dielectric spectrum of oilpaper insulating frequency domain, storage medium and terminal
CN115508674A (en) * 2022-09-19 2022-12-23 国网山西省电力公司电力科学研究院 A Dielectric Spectrum Test and Diagnosis Method for High-Voltage Cable Whole Cable

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH506226A (en) * 1968-05-11 1971-04-15 Gaiser Kurt Flat electrical heating device, in particular for floor, wall and ceiling heating
JPS5297200A (en) * 1976-02-12 1977-08-15 Nippon Oil Co Ltd Electric insulating oil composition
SU572698A1 (en) * 1976-04-08 1977-09-15 Институт Тепло И Массообмена Им. А.В.Лыкова Ан Белорусской Сср Method of measuring humidity of fluent dielectric materials
CN101329376A (en) * 2008-07-29 2008-12-24 中国科学院物理研究所 Device and method for measuring dielectric constant and dielectric loss of samples under high temperature and high pressure
CN101451949A (en) * 2007-12-07 2009-06-10 上海宝钢工业检测公司 Method for detecting and diagnosing inner inlet for open type transformer by dissolving gas by utilizing insulating oil
CN102485846A (en) * 2010-12-03 2012-06-06 中国石油天然气股份有限公司 Preparation method of transformer oil base oil
CN103399043A (en) * 2013-08-23 2013-11-20 哈尔滨理工大学 Method for studying inorganic particles and dielectric properties of LDPE (low-density polyethylene) composite materials based on zeta potential
CN105137349A (en) * 2015-07-22 2015-12-09 广东电网有限责任公司电力科学研究院 Large-scale generator stator winding major insulation aging state test method based on frequency domain spectroscopy
CN106128710A (en) * 2016-08-19 2016-11-16 国家电网公司 A kind of heat insulation power equipment being exclusively used in open air
CN106932651A (en) * 2017-03-23 2017-07-07 武汉理工大学 Irregular shape is gathered materials the detection method of dielectric constant
CN107342157A (en) * 2017-08-08 2017-11-10 徐州鑫贝克电力设备有限公司 A kind of power transformer based on nano material

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020115198A1 (en) * 2000-09-20 2002-08-22 Nerenberg Michael I. Microfabricated ultrasound array for use as resonant sensors

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH506226A (en) * 1968-05-11 1971-04-15 Gaiser Kurt Flat electrical heating device, in particular for floor, wall and ceiling heating
JPS5297200A (en) * 1976-02-12 1977-08-15 Nippon Oil Co Ltd Electric insulating oil composition
SU572698A1 (en) * 1976-04-08 1977-09-15 Институт Тепло И Массообмена Им. А.В.Лыкова Ан Белорусской Сср Method of measuring humidity of fluent dielectric materials
CN101451949A (en) * 2007-12-07 2009-06-10 上海宝钢工业检测公司 Method for detecting and diagnosing inner inlet for open type transformer by dissolving gas by utilizing insulating oil
CN101329376A (en) * 2008-07-29 2008-12-24 中国科学院物理研究所 Device and method for measuring dielectric constant and dielectric loss of samples under high temperature and high pressure
CN102485846A (en) * 2010-12-03 2012-06-06 中国石油天然气股份有限公司 Preparation method of transformer oil base oil
CN103399043A (en) * 2013-08-23 2013-11-20 哈尔滨理工大学 Method for studying inorganic particles and dielectric properties of LDPE (low-density polyethylene) composite materials based on zeta potential
CN105137349A (en) * 2015-07-22 2015-12-09 广东电网有限责任公司电力科学研究院 Large-scale generator stator winding major insulation aging state test method based on frequency domain spectroscopy
CN106128710A (en) * 2016-08-19 2016-11-16 国家电网公司 A kind of heat insulation power equipment being exclusively used in open air
CN106932651A (en) * 2017-03-23 2017-07-07 武汉理工大学 Irregular shape is gathered materials the detection method of dielectric constant
CN107342157A (en) * 2017-08-08 2017-11-10 徐州鑫贝克电力设备有限公司 A kind of power transformer based on nano material

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
变压器检修后油介损异常原因分析及处理;黎自用 等;《广西电力》;20170430(第2期);全文 *

Also Published As

Publication number Publication date
CN111289804A (en) 2020-06-16

Similar Documents

Publication Publication Date Title
CN109239546B (en) Transformer insulation life prediction and reliability test method
CN103149452B (en) Method for evaluating ageing state of paper oil insulation
CN108680613B (en) Method for evaluating moisture content in insulating paper by using initial slope of complex dielectric constant
CN108872820B (en) Method and system for evaluating insulation aging state of oil impregnated paper in high-voltage current transformer
CN111289804B (en) Method for evaluating correlation between transformer oil paper insulation dielectric response and paraffin content
Zhang et al. Aging state assessment of transformer cellulosic paper insulation using multivariate chemical indicators
CN107860894B (en) Method for predicting furfural content in transformer insulating oil based on frequency domain complex dielectric constant initial slope
CN109670138B (en) Fractional Zener model-based vegetable oil paper insulation state evaluation method
CN112179852B (en) Method and device for predicting residual life of composite insulator
CN104215669B (en) Moisture Content Measurement Method of Transformer Insulation System
CN110045243B (en) A method for evaluating the thermal aging state of transformer bushings
Yew et al. Effects of moisture and temperature on the frequency domain spectroscopy analysis of power transformer insulation
CN110045245B (en) Method for evaluating X wax content of oil-immersed transformer bushing
CN116306012A (en) Oilpaper insulation equivalent circuit model based on weighting function and parameter identification method
CN113203918B (en) Power cable residual life prediction method based on aging factor and unequal-interval GM (1,1) model
CN111337797A (en) XLPE power cable main insulation non-uniform thermal aging state evaluation method based on modified Debye model
CN114543896A (en) Capacitive equipment medium water content and aging evaluation method based on temperature drift electrical parameters
Fan et al. Moisture evaluation of oil-immersed insulation in bushing based on frequency domain spectroscopy and grey relational analysis
CN114895151B (en) Monitoring method of superconducting cable reheating process based on dielectric spectrum
Zheng et al. Investigation on hot spot temperature of resin-impregnated paper high-voltage bushing based upon dielectric loss
Zhang et al. Analysis of transformer oil-paper insulation state using fractional Poynting–Thomson model
CN111047210A (en) Method for evaluating aging state of insulating oil of traction transformer
CN116859189A (en) Method for judging relevance of water content of sleeve and frequency domain dielectric spectrum characteristics
CN111308286B (en) Method for estimating service life of traction transformer under multi-parameter empowerment combination
CN108593714B (en) Transformer internal moisture measurement system based on dielectric response characteristics of transformer built-in oiled paper insulation sample

Legal Events

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