CN101692402B - Method and device for drying large-scale power transformer - Google Patents
Method and device for drying large-scale power transformer Download PDFInfo
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- CN101692402B CN101692402B CN2009100755053A CN200910075505A CN101692402B CN 101692402 B CN101692402 B CN 101692402B CN 2009100755053 A CN2009100755053 A CN 2009100755053A CN 200910075505 A CN200910075505 A CN 200910075505A CN 101692402 B CN101692402 B CN 101692402B
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Abstract
The invention relates to a method for drying a large-scale power transformer, which is used for improving the drying effect and shortening the drying time of the large-scale power transformer. A vacuum tank, a heating tube array and a vacuum pump form a drying system. The temperature and the vacuum in the vacuum tank change according to the set curve through controlling the work state of the heating tube array and the vacuumizing speed of the vacuum pump. The large-scale power transformer in the vacuum tank is dried and the deep water in the large-scale power transformer is vaporized. The invention adopts an intermittent vacuumizing method to control the vacuum in the vacuum tank so that the temperature and the vacuum in the vacuum tank change according to the set curve, thus the vaporization of the deep water in the insulating layer can not be affected by the too rapid change of the vacuum, and the drying speed of the large-scale power transformer is accelerated. The invention can greatly shorten the drying time of the large-scale power transformer and obviously improve the drying effect of the large-scale power transformer and can meet the insulating requirement of the large-scale power transformer to the maximum extent.
Description
Technical field
The present invention relates to a kind of method of utilizing vacuum drying tank that large-scale power transformer coil or device body are dried, belong to the transformer technology field.
Background technology
Moisture in the transformer mainly accumulates in insulating paper (plate) and the transformer oil; It can make insulation resistance reduce; Dielectric loss increases; Office's discharge is pressed and breakdown strength also increases with the insulation system water content and rapid decline, and moisture constitutes bigger threat to the transformer security of operation, also can lead to the discharge breakdown accident when serious.In addition, moisture is also participated in the chemical degradation reaction of macromolecule mediums such as oil, paper cellulose directly, impels these material degradations aging, thereby quickens the reduction of insulation system dielectric strength and the deterioration of each top performance.Therefore, transformer must carry out dried in process of production.
The high voltage large capcity transformer has thicker insulating barrier, and traditional vacuum drying method is like electric heating boulton process, heat-wind circulate drying method etc.; Because can not implement accurately control to dry run, the vacuum tank internal pressure is very short from the pumpdown time that an atmospheric pressure drops to high vacuum, makes insulating paper (plate) top layer hair cell atrophy easily; Influence the evaporation of deep layer moisture; Cause the production cycle very long, and drying is not thorough, is difficult to satisfy the insulating requirements of transformer.
Summary of the invention
The objective of the invention is to overcome prior art deficiency, provide a kind of large-scale power transformer drying means that can make the deep layer water evaporates fast, up hill and dale, the present invention to give simultaneously to realize the employed device of this method.
Problem according to the invention realizes with following technical proposals:
A kind of large-scale power transformer drying means; It constitutes drying system with vacuum tank, heating calancria and vacuum pump; Through the operating state of control heating calancria and the vacuum pumping rate of vacuum pump; Temperature and vacuum degree in the vacuum tank are changed by setting curve, the transformer in the vacuum tank is carried out dried, concrete steps are following:
A. warm-up phase: utilize vacuum pump that vacuum tank is evacuated to jar interior gas vacuum degree to 40000 handkerchiefs, then stop to vacuumize, and utilize charge valve that vacuum tank is inflated; When treating that a jar internal pressure is increased to 80000 handkerchiefs, kept for 80000 handkerchief T1 times, the T1 time is by parameter setting; Numerical value is 20～30 minutes, accomplishes vacuum pumping for the first time, then; Repeat said operation 1～5 time, meanwhile, in the vacuum tank heating calancria, feed steam; Iron core is heated, make its temperature rise to 72 ℃, the temperature value scope is 70 ℃～80 ℃;
B. transition stage: continue iron core is heated; Simultaneously; Vacuum tank is continued to vacuumize, and making the pressure in the vacuum tank is that step reduces by linear rule gradually according to 60000 handkerchiefs, 40000 handkerchiefs, 20000 handkerchiefs and four numerical value of 10000 handkerchiefs, finally makes a jar interior vacuum reach 10000 handkerchiefs; When the pressure in the vacuum tank reaches the step value, keep this vacuum degree T2 time, no longer to the vacuum tank inflation, the T2 set point is 15～20 minutes during this at every turn;
C. dryer stage: continue iron core is heated, simultaneously, intermittent vacuum tank is vacuumized; Promptly vacuumized 10 minutes, and stopped 10 minutes, the vacuum degree in vacuum tank reaches set point; This value is by parameter setting; Numerical value is 500 handkerchiefs-200 handkerchiefs, and simultaneously, the iron core temperature reaches 85 ℃～90 ℃ scope;
D. whole drying stage: vacuumize continuously and make jar interior vacuum degree reach 200 handkerchiefs-150 handkerchief, make that vacuum degree kept this numerical value 4-6 hour in the vacuum tank; Then; The vacuum degree that vacuumizes continuously in vacuum tank reaches eventually below the dry pressure P m of end (Pm is the endpoint constant); Said Pm numerical value is difference with the transformer electric pressure; To its Pm value of 110KV electric pressure is the 10-15 handkerchief, and to the 220KV electric pressure, its Pm value is 1-1.5 handkerchief (electric pressure is higher than general unwrapping wire circle in the 220KV jar); Temperature is controlled at 105 ℃ in the vacuum tank;
E. in the endpoint stage, judge whether the degree of drying of transformer is qualified, if qualified, dried finishes, otherwise repeats above-mentioned dry run; Temperature is controlled at 105 ℃ in the vacuum tank.
Above-mentioned large-scale power transformer drying means, the dry whether qualified of said transformer carries out according to the following steps:
1. after whole drying stage finishes, shut down after continuing to take out the certain hour vacuum, and note the vacuum degree Pn of this moment, shuts down after 30 minutes, again record vacuum degree Pa at this moment;
2. the open vacuum pump vacuumizes the vacuum degree that makes in the vacuum tank and reaches Pn again, shut down then 30 minutes, and vacuum degree and Pb in record vacuum tank this moment;
3. the open vacuum pump vacuumizes the vacuum degree that makes in the vacuum tank and reaches Pn again, shut down then 30 minutes, and the vacuum degree Pc in record vacuum tank this moment;
Whether the degree of drying of 4. judging transformer is qualified: qualified if Pm＞Pa＞Pb＞Pc is, otherwise be defective.
A kind of large-scale power transformer drying device, it comprises vacuum tank, heating calancria, two lobe pumps, two sliding vane rotary pumps and control circuit, said heating calancria is positioned at the vacuum tank inner bottom part, is connected with vapor source through cap relief valve; The air inlet of first lobe pump is communicated with vacuum tank through main butterfly valve, and the gas outlet connects the air inlet of second lobe pump; The gas outlet of first sliding vane rotary pump and second sliding vane rotary pump and atmosphere, air inlet are connected with the gas outlet of second lobe pump with the second sliding vane rotary pump butterfly valve through the first sliding vane rotary pump butterfly valve respectively.
Above-mentioned large-scale power transformer drying device; Said control circuit is made up of switching signal input circuit, analog signal input circuit, PLC and executive circuit; Said switching signal input circuit comprises vacuum tank pressure switch, cooling water pressure switch, steam pressure switch and compressed air pressure switch; Said vacuum tank pressure switch is provided with six; Pressure values is respectively 80000 handkerchiefs, 40000 handkerchiefs, 20000 handkerchiefs, 10000 handkerchiefs, 4200 handkerchiefs and 2700 handkerchiefs, and the output of six vacuum tank pressure switches, cooling water pressure switch, steam pressure switch and compressed air pressure switches connects I0.0～I0.7 and the I1.0 end of PLC respectively; Said analog signal input circuit is made up of vacuum tank vacuum sensor and nine temperature sensors; Nine temperature sensors are respectively coil upper temperature sensor, coil middle part temperature sensor, coil temperature of lower transducer, iron core upper temperature sensor, iron core middle part temperature sensor, mandrel lower temperature sensor, space temperature transducer, steam temperature transducer and cooling-water temperature sensor, and vacuum tank vacuum sensor and nine temperature sensors connect the different input end of analog signal of PLC respectively; Said executive circuit is made up of ten relays and seven electromagnetically operated valves; The control coil of said ten relays connects Q0.0～Q0.7, Q1.0 and the Q1.1 end of PLC respectively, and their normally opened contact is controlled first lobe pump, second lobe pump, first sliding vane rotary pump, second sliding vane rotary pump, the first sliding vane rotary pump butterfly valve, the first sliding vane rotary pump charge valve, the second sliding vane rotary pump butterfly valve, the second sliding vane rotary pump charge valve, main butterfly valve, vacuum tank charge valve respectively; The MO of the control termination PLC of cap relief valve, IO end.
The method that the present invention adopts batch (-type) to vacuumize is controlled the vacuum degree in the vacuum tank; Vacuum degree and temperature in the vacuum tank are changed by setting curve; Prevent because of vacuum degree changes the too fast evaporation that waits cause influence insulating barrier deep layer moisture content, thereby accelerated the rate of drying of transformer.The present invention can shorten the transformer dry required time greatly; Through continuous 1 year test result; Shorten about 5 hours average drying time; And can significantly improve drying effect, the drying means more common through the water content that detects insulating part reduces about 20%, can satisfy the insulating requirements of transformer to greatest extent.
Description of drawings
Below in conjunction with accompanying drawing the present invention is described further.
Fig. 1 is vacuum degree of the present invention and temperature control curve;
Fig. 2 three-stage process endpoint schematic diagram;
Fig. 3 is the structural representation of drying device;
Fig. 4 is the electric theory diagram of control circuit;
Fig. 5 is the electrical schematic diagram of control circuit;
Fig. 6 is the electrical schematic diagram of major loop.
Each label is among the figure: 1, vacuum tank; 2, heating calancria; PLC, programmable controller; ZK, vacuum tank vacuum sensor; RT1～RT9, temperature sensor; XB1, first sliding vane rotary pump; XB2, second sliding vane rotary pump; LB1, first lobe pump; LB2, second lobe pump; V1, the first sliding vane rotary pump butterfly valve; V2, the first sliding vane rotary pump charge valve; V3, the second sliding vane rotary pump butterfly valve; V4, the second sliding vane rotary pump charge valve; V5, main butterfly valve; V6, vacuum tank charge valve; V7, cap relief valve; T1, warm-up phase are evacuated down to the retention time of 80000 handkerchiefs; T2, transition stage are in the retention time of 40000 handkerchiefs, 20000 handkerchiefs, 10000 handkerchiefs; The time that T3, dryer stage vacuumize; The time that T4, dryer stage stop to vacuumize; The time that T5, endpoint stage vacuumize; The time that T6, endpoint stage stop to vacuumize; The vacuum degree that P1, dryer stage finish; The vacuum degree that P2, whole drying stage finish; The vacuum degree of Pm, endpoint; Vacuumize the vacuum degree of T5 system after the time behind Pn, whole dry the end; Pa, the vacuum values of endpoint for the first time; Pb, the vacuum of endpoint for the second time; Pc, the vacuum difference of endpoint for the third time; SP1, (set point is) 80000 handkerchief pressure switches; SP2,40000 handkerchief pressure switches; SP3,20000 handkerchief pressure switches; SP4,10000 handkerchief pressure switches; SP5,4200 handkerchief pressure switches; SP6,2700 handkerchief pressure switches; SP7, cooling water pressure switch; SP8, steam pressure switch; SP9, compressed air pressure switch; J1, the first sliding vane rotary pump relay; The normally opened contact of J1-1, J1; J2, the second sliding vane rotary pump relay; The normally opened contact of J2-1, J2; J3, the first lobe pump relay; The normally opened contact of J3-1, J3; J4, the second lobe pump relay; The normally opened contact of J4-1, J4; J5, the first sliding vane rotary pump butterfly valve relay; The normally opened contact of J5-1, J5; J6, the first sliding vane rotary pump charge valve relay; The normally opened contact of J6-1, J6; J7, the second sliding vane rotary pump butterfly valve relay; The normally opened contact of J7-1, J7; J8, the second sliding vane rotary pump charge valve relay; The normally opened contact of J8-1, J8; J9, main butterfly valve relay; The normally opened contact of J9-1, J9; J10, vacuum tank charge valve relay; The normally opened contact of J10-1, J10;
Embodiment
Referring to Fig. 1, whole process flow of the present invention is divided into five stages: be respectively warm-up phase, transition stage, dryer stage, whole drying stage, endpoint stage.At warm-up phase, vacuum degree changes between 80000 handkerchiefs～40000 handkerchiefs in jar, and temperature unshakable in one's determination rises to 72 ℃, and such process that moves in circles makes a jar interior uniformity of temperature profile, can constantly the water evaporates in the deep layer insulating material be come out again; In transition stage, generally to finally make a jar interior vacuum reach 10000 handkerchiefs through the decline of 80000 handkerchiefs, 40000 handkerchiefs, 20000 handkerchiefs, four steps of 10000 handkerchiefs; In the dryer stage, vacuumize a period of time, close main valve a period of time, so move in circles, reach the value (being generally 500 handkerchiefs) of process stipulation up to vacuum degree; At whole drying stage, vacuumize continuously and finally reach below the Pm up to vacuum degree; In the endpoint stage, adopt three-stage process to judge whether drying is qualified.
Referring to Fig. 2, be the curve of endpoint.After whole drying stage finishes, take out regular hour T5 more continuously, T5 was generally 30 minutes; Record vacuum degree Pn (this numerical value can be chosen wantonly) this moment, the first step stops to vacuumize 30 minutes; Vacuum degree in jar can rise owing to the volatilization of moisture and the hot leakage of vacuum tank; Record this moment vacuum degree Pa, the hot leakage of moisture evaporation and vacuum tank causes the vacuum degree rising still in acceptable ranges if Pa＜Pm then shows, below twice judgement also be like this; In second step, the open vacuum pump up to the degree that is evacuated down to the vacuum degree Pn that initial record obtains, and then was shut down 30 minutes, then record vacuum degree Pb this moment; The 3rd step, the open vacuum pump, up to vacuumize write down at the beginning of reaching judgement the degree of vacuum degree Pn, and then shut down 30 minutes, then record vacuum degree Pc this moment.If the difference of judging for three times satisfies Pm＞Pa＞Pb＞Pc, then show and judge for three times all in acceptable ranges continuously, and three voltage rises descend continuously, promptly drying be judged as qualified, otherwise will be dry again and judge.
Referring to Fig. 3, heavy line is represented cooling water pipe among the figure, and dotted line is represented the pipeline that is connected with atmosphere, and the pipeline between sliding vane rotary pump and lobe pump and the vacuum tank is represented with fine line.During work, transformer places in the vacuum tank, and temperature sensor RT1～RT6 gathers the temperature of its coil upper, middle and lower portion and iron core upper, middle and lower portion respectively, and RT7～RT9 gathers space temperature, steam temperature and cooling water temperature respectively.Vacuum sensor ZK and vacuum tank pressure switch SP1～SP6 are loaded on the pipeline between the vacuum tank and the first lobe pump LB1; SP7～SP9 is respectively cooling water pressure switch, steam pressure switch (not shown) and compressed air pressure switch (not shown), and these three pressure switches are installed in the respective line respectively.
Referring to Fig. 5, Fig. 6; PLC is provided with six expansion modules, and an expansion module is EM235, connects vacuum sensor ZK and cap relief valve V7; All the other five expansion modules are EM231RTD, and each EM231RTD connects two or a temperature sensor (totally nine of TEMPs).PLC controls two lobe pump LB1, LB2, two sliding vane rotary pump XB1, XB2 and six electromagnetically operated valve V1～V6 respectively through normally opened contact J1-1～J10-1 of ten relay J 1～J10.
In the process of heating and vacuumizing, along with the reduction of vacuum degree, medium-air that moisture is able to volatilize more and more comes few more; If at whole drying stage,, be unfavorable for the evaporation of moisture on the contrary if vacuum degree decline is too fast; At whole drying stage, in the control of lobe pump, increase frequency converter, the pumping speed of control lobe pump; In the program of Programmable Logic Controller, increase a pid control circuit, with the output of frequency converter as controlled device; As feedback, jar interior vacuum degree is remained on about 170 handkerchiefs with vacuum degree in the jar, be beneficial to the evaporation of moisture.
Claims (2)
1. large-scale power transformer drying means; It is characterized in that; It constitutes drying system with vacuum tank, heating calancria and vacuum pump, through the operating state of control heating calancria and the vacuum pumping rate of vacuum pump, temperature and vacuum degree in the vacuum tank is changed by setting curve; Transformer in the vacuum tank is carried out dried, and concrete steps are following:
A. warm-up phase: utilize vacuum pump that vacuum tank is evacuated to jar interior gas vacuum degree to 40000 handkerchiefs, then stop to vacuumize, and utilize charge valve that vacuum tank is inflated; When treating that a jar internal pressure is increased to 80000 handkerchiefs, kept for 80000 handkerchief T1 times, the T1 time is by parameter setting; Numerical value is 20～30 minutes, accomplishes vacuum pumping for the first time, then; Repeat said operation 1～5 time, meanwhile, in the vacuum tank heating calancria, feed steam; Iron core is heated, its temperature is risen, the temperature value scope is 70 ℃～80 ℃;
B. transition stage: continue iron core is heated; Simultaneously; Vacuum tank is continued to vacuumize, and making the pressure in the vacuum tank is that step reduces by linear rule gradually according to 60000 handkerchiefs, 40000 handkerchiefs, 20000 handkerchiefs and four numerical value of 10000 handkerchiefs, finally makes a jar interior vacuum reach 10000 handkerchiefs; When the pressure in the vacuum tank reaches the step value, keep this vacuum degree T2 time, no longer to the vacuum tank inflation, the T2 set point is 15～20 minutes during this at every turn;
C. dryer stage: continue iron core is heated, simultaneously, intermittent vacuum tank is vacuumized; Promptly vacuumized 10 minutes, and stopped 10 minutes, the vacuum degree in vacuum tank reaches set point; This value is by parameter setting; Numerical value is 500 handkerchiefs-200 handkerchiefs, and simultaneously, the iron core temperature is controlled at 85 ℃～90 ℃ scope;
D. whole drying stage: vacuumize continuously and make jar interior vacuum degree reach 200 handkerchiefs-150 handkerchief, make that vacuum degree kept this numerical value 4-6 hour in the vacuum tank; Then; The vacuum degree that vacuumizes continuously in vacuum tank reaches below the dry eventually end pressure P m, and difference is the 10-15 handkerchief to its Pm value of 110KV electric pressure to said Pm numerical value with the transformer electric pressure; To the 220KV electric pressure, its Pm value is the 1-1.5 handkerchief; Temperature is controlled at 105 ℃ in the vacuum tank;
E. in the endpoint stage, judge whether the degree of drying of transformer is qualified, if qualified, dried finishes, otherwise repeats above-mentioned dry run; Temperature is controlled at 105 ℃ in the vacuum tank.
2. according to the said large-scale power transformer drying means of claim 1, it is characterized in that the dry whether qualified of said transformer carries out according to the following steps:
1. after whole drying stage finishes, shut down after continuing to take out the certain hour vacuum, and note the vacuum degree Pn of this moment, shuts down after 30 minutes, again record vacuum degree Pa at this moment;
2. the open vacuum pump vacuumizes the vacuum degree that makes in the vacuum tank and reaches Pn again, shut down then 30 minutes, and vacuum degree and Pb in record vacuum tank this moment;
3. the open vacuum pump vacuumizes the vacuum degree that makes in the vacuum tank and reaches Pn again, shut down then 30 minutes, and the vacuum degree Pc in record vacuum tank this moment;
Whether the degree of drying of 4. judging transformer is qualified: qualified if Pm＞Pa＞Pb＞Pc is, otherwise be defective.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009100755053A CN101692402B (en) | 2009-09-24 | 2009-09-24 | Method and device for drying large-scale power transformer |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009100755053A CN101692402B (en) | 2009-09-24 | 2009-09-24 | Method and device for drying large-scale power transformer |
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| Publication Number | Publication Date |
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| CN101692402A CN101692402A (en) | 2010-04-07 |
| CN101692402B true CN101692402B (en) | 2012-02-29 |
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| CN2009100755053A Expired - Fee Related CN101692402B (en) | 2009-09-24 | 2009-09-24 | Method and device for drying large-scale power transformer |
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Application publication date: 20100407 Assignee: Baoding Tianwei Zhuochuang Electric Equipment Technologies Co., Ltd. Assignor: Baoding Tianwei Group Co., Ltd. Contract record no.: 2014130000033 Denomination of invention: Method and device for drying large-scale power transformer Granted publication date: 20120229 License type: Exclusive License Record date: 20140326 |
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