CN103558533B - Based on insulation ag(e)ing diagnostic system and the method for 10kV XLPE cable - Google Patents
Based on insulation ag(e)ing diagnostic system and the method for 10kV XLPE cable Download PDFInfo
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- CN103558533B CN103558533B CN201310585942.6A CN201310585942A CN103558533B CN 103558533 B CN103558533 B CN 103558533B CN 201310585942 A CN201310585942 A CN 201310585942A CN 103558533 B CN103558533 B CN 103558533B
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- 238000000034 method Methods 0.000 title claims abstract description 47
- 238000009413 insulation Methods 0.000 title claims abstract description 20
- 239000004703 cross-linked polyethylene Substances 0.000 title abstract description 17
- 229920003020 cross-linked polyethylene Polymers 0.000 title abstract description 17
- 230000032683 aging Effects 0.000 claims description 9
- 230000000694 effects Effects 0.000 claims description 4
- 238000005259 measurement Methods 0.000 claims description 3
- 238000001514 detection method Methods 0.000 abstract 1
- 240000005572 Syzygium cordatum Species 0.000 description 9
- 235000006650 Syzygium cordatum Nutrition 0.000 description 9
- 238000005516 engineering process Methods 0.000 description 5
- 230000015556 catabolic process Effects 0.000 description 3
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 238000002405 diagnostic procedure Methods 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000003745 diagnosis Methods 0.000 description 1
- 238000012631 diagnostic technique Methods 0.000 description 1
- 230000004069 differentiation Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Abstract
The present invention relates to a kind of based on 10kV? the insulation ag(e)ing diagnostic system of XLPE cable and method, does this system comprise moisture tree 10kV? XLPE cable, direct supply, high-voltage pulse power source and data acquisition process unit; Does the method comprising the steps of have: (1) is to moisture tree 10kV? XLPE cable applies negative dc voltage V
dc; (2) by the high-pressure side ground connection of cable, trapped charge becomes residual charge in ground connection discharge process; (3) to moisture tree 10kV? XLPE cable applies high-voltage pulse, and gather the voltage DC component signal on resistance R by data acquisition process unit, line time integral operation of going forward side by side, obtains residual charge amount simultaneously; (4) the water-treeing degree of cable is judged according to residual charge amount.The present invention can detect water-treeing degree preferably, and Detection results is obvious, effectively can prevent the generation of insulation fault.
Description
Technical field
The invention belongs to crosslinking polyethylene-insulated cable insulation aging analysis and diagnostic techniques field, particularly a kind of insulation ag(e)ing diagnostic system based on 10kVXLPE cable and method.
Background technology
Urban Electric Network Cabling degree weighs the important symbol of urban distribution network technical merit, is also to promote that urban civilization process strides forward rapidly, improves the necessary means of urban life environment.The most in the last thirty years, the every technology of domestic and international power cable develops rapidly, particularly three-layer co-extruded production technology manufactures the development of XLPE cable technology, make XLPE cable compared with oil-filled cable, have the premium properties such as do not need that oil servicing facitities, fire protecting performance are good, installation and maintenance are simple and mechanical electric performance is good, adopt by increasing country.The cable that current many big cities are laid is nearly all XLPE cable.Domestic electrical network 10kVXLPE cable use amount in 2007 reaches 40000km, calculate that every profession and trade use amount reaches 120000km, in high-tension cable, only Beijing area has 220kV cable line 64 road 164.1km, 110kV cable line 565 road 647.4km, external for Japan, in 22kV grade and above cable, XLPE cable accounts for more than 70% of cable laying total amount, and has the trend increased year by year.In addition, the price of High Voltage XLPE Power Cable is very expensive, and one-time investment expense is larger, and cable line not easily changes and branch.
In recent years, along with the development of urban modernization, the continuous increase of unit capacity, power cable shared share in the net power supply of city increases the weight of, and progressively replaces overhead transmission line with cabling in the urban district in some cities; Increasing and the prolongation of working time simultaneously along with number of cables, the degradation failure of the XLPE cable of laying in the past is frequent, causes dielectric breakdown accident, even causes part grid power blackout, bring interruption and inconvenience to production and people's lives, cause great economic loss.According to statistics, by the aging dielectric breakdown accident causing XLPE cable of water tree in ascendant trend year by year, water tree has become the major hidden danger of power cable safe operation.In state's inner city net 10 ~ 35kV system, the common XLPE cable that underground uses, generally grows large water gaging tree for 8 to 12 years in operation, and cause a large amount of XLPE cable to occur because water tree punctures the accident caused, the life-span is short, affects the safe operation of electrical network.At present, water-treeing for XLPE cable detects, propose multiple method both at home and abroad, mainly contained: DC component method, DC superposition method, AC superimposition method, low frequency method of superposition, dielectric loss method and online shelf depreciation method etc., and develop corresponding pick-up unit.In these methods, various method respectively has relative merits, all can not reflect the water-treeing state of cable insulation well.In recent years water tree is had ac-excited formula residual charge method as the off-line diagnostic method of Ageing Diagnosis object, but its major defect to be residual charge release rate slow, characteristic quantity is not obvious.
Summary of the invention
The object of the invention is for the deficiencies in the prior art, and propose a kind of insulation ag(e)ing diagnostic system based on 10kVXLPE cable and method.
The present invention solves its technical matters and takes following technical scheme to realize:
A kind of insulation ag(e)ing diagnostic system based on 10kVXLPE cable, this system includes: moisture tree 10kVXLPE cable, direct supply, high-voltage pulse power source and data acquisition process unit, one end of moisture tree 10kVXLPE cable core is by wire connecting valve S1 respectively, one end of switch S 2 and switch S 3, the other end of switch S 1 connects direct supply, the other end ground connection of switch S 2, the other end of switch S 3 connects high-voltage pulse power source, contact resistance R outside the moisture tree 10kVXLPE cable insulation near this end and between ground, at the two ends connection data acquisition process unit of resistance R, near away from connecting valve S4 outside the moisture tree 10kVXLPE cable insulation of the other end of this end and between ground.
And, described data acquisition process unit comprises conventional high-speed data acquisition card, adopt conventional numerical integration method process to carry out time integral computing by computing machine after high-speed data acquisition card gathers voltage DC component signal, the residual charge amount that voltage DC component signal is corresponding can be obtained.
Based on a method for the insulation ag(e)ing diagnostic system of 10kVXLPE cable, it is characterized in that the method comprises the steps:
(1) negative dc voltage V is applied to moisture tree 10kVXLPE cable
dc; Close by switch S 1 and switch S 4, switch S 2 and switch S 3 disconnect, and apply negative dc voltage V to moisture tree 10kVXLPE cable
dc;
(2) by the high-pressure side ground connection of cable; Disconnect by switch S 1 and switch S 3, switch S 2 and switch S 4 close, and trapped charge becomes residual charge in ground connection discharge process;
(3) high-voltage pulse is applied to moisture tree 10kVXLPE cable, namely when switch S 1, switch S 2 and switch S 4 disconnect, when switch S 3 closes, apply high-voltage pulse, gather the voltage DC component signal on resistance R by data acquisition process unit simultaneously, and time integral computing is carried out to voltage DC component, obtain residual charge amount
(4) the water-treeing degree of moisture tree 10kVXLPE cable is judged according to residual charge amount.
And, negative dc voltage V in described step (1)
dcsize and being set to of application time: when for the time of putting into operation, the 10kV power cable in 1-5 detects, negative dc voltage V
dccan-5kV be set to, application time 5min, for the 10kV power cable of working time more than 5 years, negative dc voltage V
dccan be set to-3.5kV, application time is 2min.
And, the high-voltage pulse value applied in described step (3), when detecting the 10kV power cable put into operation in time 1-5, high-voltage pulse value can be set to 8kV, repetition frequency 30Hz-50Hz, application time 30s, pulse train interval 10s, pulse train applies number of times and is no more than 5 times; When detecting the 10kV power cable of more than the 5 years time of putting into operation, high-voltage pulse value can be set as 5kV, repetition frequency 10Hz-20Hz, application time 15s, pulse train interval 10s, and pulse train applies number of times 5-8 time.
And, described step (4) judges that according to residual charge amount the concrete grammar of the water-treeing degree of moisture tree 10kVXLPE cable is: when after the first group pulse group effect, if discharge more than 1/2 of the total residual quantity of electric charge at the end of the quantity of electric charge accounts for measurement, can think that water-treeing degree is serious; If between 1/3 ~ 1/2, mittlere alterung can be thought; If be less than 1/3, think that degree of aging is lighter.
Advantage of the present invention and good effect are
1, the present invention substitutes existing ac-excited technology by applying pulse train, and residual charge is discharged easier, the ratio acting on rear release electric charge according to the first group pulse group judges as characteristic quantity, and the differentiation of degree of aging is more obvious.
2, pulsed residual charge method of the present invention can differentiate the water tree degree of aging of XLPE cable preferably, the method can be applicable to the ageing management of cable, belong to a kind of nondestructive test, water-treeing degree can be detected preferably, and can provide alert according to residual charge rate of release, the generation of prevention insulation fault.
Accompanying drawing explanation
Fig. 1 is the experimental circuit that the inventive method uses.
Embodiment
Be further described the invention process below in conjunction with accompanying drawing, following examples are descriptive, are not determinate, can not limit protection scope of the present invention with this.
A kind of insulation ag(e)ing diagnostic system based on 10kVXLPE cable and method, this system includes: moisture tree 10kVXLPE cable, direct supply, high-voltage pulse power source and data acquisition process unit, as shown in Figure 1, one end of moisture tree 10kVXLPE cable core is by wire connecting valve S1 respectively, one end of switch S 2 and switch S 3, the other end of switch S 1 connects direct supply, the other end ground connection of switch S 2, the other end of switch S 3 connects high-voltage pulse power source, contact resistance R outside the moisture tree 10kVXLPE cable insulation near this end and between ground, at the two ends connection data acquisition process unit of resistance R, near away from connecting valve S4 outside the moisture tree 10kVXLPE cable insulation of the other end of this end and between ground, the step of this insulation ag(e)ing diagnostic method comprises:
(1) negative dc voltage V is applied to moisture tree 10kVXLPE cable
dc; Switch S 1 and switch S 4 are closed, switch S 2 and switch S 3 disconnect, and apply negative dc voltage V to moisture tree 10kVXLPE cable
dc, negative dc voltage V
dcsize and application time all according to user require arrange, as when for the time of putting into operation, shorter 10kV power cable in 1-5 detects, negative dc voltage V
dccan-5kV be set to, application time 5min, as longer 10kV power cable more than 5 years working time, negative dc voltage V
dccan be set to-3.5kV, application time is 2min.
(2) by the high-pressure side ground connection of cable; Disconnect by switch S 1 and switch S 3, switch S 2 and switch S 4 close, electric charge in the equivalent capacity of cable, polarization charge and part ion type electric charge can discharge, and in water tree part, especially still can there is electric charge in water tree tip, and this part electric charge is trapped charge, can not discharge in ground connection discharge process, can exist for a long time in water tree part, i.e. residual charge;
(3) high-voltage pulse is applied to moisture tree 10kVXLPE cable, namely when switch S 1, switch S 2 and switch S 4 disconnect, when switch S 3 closes, apply high-voltage pulse, the residual charge of water tree part is discharged, and residual charge can superpose out DC component in the loop on pulse current, the voltage DC component signal on resistance R is gathered by data acquisition process unit, and time integral computing is carried out to voltage DC component, obtain residual charge amount
(4) the water-treeing degree of moisture tree 10kVXLPE cable is judged according to residual charge amount.
In specific embodiment of the invention, described data acquisition process unit adopts conventional high-speed data acquisition card, adopts conventional numerical integration method process to carry out time integral computing can obtain residual charge amount after instrument gathers voltage DC component signal by computing machine.
In specific embodiment of the invention, the high-voltage pulse value of described applying, when detecting the 10kV power cable in the time of putting into operation shorter 1-5, high-voltage pulse value can be set to 8kV, repetition frequency 30Hz-50Hz, application time 30s, pulse train interval 10s, pulse train applies number of times and is no more than 5 times; When 10kV power cable at longer more than 5 years to the time of putting into operation detects, high-voltage pulse value can be set as 5kV, repetition frequency 10Hz-20Hz, application time 15s, pulse train interval 10s, and pulse train applies number of times 5-8 time.
In specific embodiment of the invention, the water-treeing degree of 10kVXLPE cable can be judged according to the fractional release of residual charge amount, when after the first group pulse group effect, if discharge more than 1/2 of the total residual quantity of electric charge at the end of the quantity of electric charge accounts for measurement, can think that water-treeing degree is serious; If between 1/3 ~ 1/2, mittlere alterung can be thought; If be less than 1/3, think that degree of aging is lighter.
Claims (1)
1. the method based on the insulation ag(e)ing diagnostic system of 10kVXLPE cable, this system includes: moisture tree 10kVXLPE cable, direct supply, high-voltage pulse power source and data acquisition process unit, one end of moisture tree 10kVXLPE cable core is by wire connecting valve S1 respectively, one end of switch S 2 and switch S 3, the other end of switch S 1 connects direct supply, the other end ground connection of switch S 2, the other end of switch S 3 connects high-voltage pulse power source, contact resistance R outside the moisture tree 10kVXLPE cable insulation near this end and between ground, at the two ends connection data acquisition process unit of resistance R, near away from connecting valve S4 outside the moisture tree 10kVXLPE cable insulation of the other end of this end and between ground, it is characterized in that the method comprises the steps:
(1) negative dc voltage V is applied to moisture tree 10kVXLPE cable
dc; Close by switch S 1 and switch S 4, switch S 2 and switch S 3 disconnect, and apply negative dc voltage V to moisture tree 10kVXLPE cable
dc, wherein, negative dc voltage V
dcsize and being set to of application time: when for the time of putting into operation, the 10kV power cable in 1-5 detects, negative dc voltage V
dccan-5kV be set to, application time 5min, for the 10kV power cable of working time more than 5 years, negative dc voltage V
dccan be set to-3.5kV, application time is 2min;
(2) by the high-pressure side ground connection of cable; Disconnect by switch S 1 and switch S 3, switch S 2 and switch S 4 close, and trapped charge becomes residual charge in ground connection discharge process;
(3) high-voltage pulse is applied to moisture tree 10kVXLPE cable, namely when switch S 1, switch S 2 and switch S 4 disconnect, when switch S 3 closes, apply high-voltage pulse, gather the voltage DC component signal on resistance R by data acquisition process unit simultaneously, and time integral computing is carried out to voltage DC component, obtain residual charge amount, wherein, the high-voltage pulse value applied, when detecting the 10kV power cable put into operation in time 1-5, high-voltage pulse value can be set to 8kV, repetition frequency 30Hz-50Hz, application time 30s, pulse train interval 10s, pulse train applies number of times and is no more than 5 times, when detecting the 10kV power cable of more than the 5 years time of putting into operation, high-voltage pulse value can be set as 5kV, repetition frequency 10Hz-20Hz, application time 15s, pulse train interval 10s, and pulse train applies number of times 5-8 time,
(4) the water-treeing degree of moisture tree 10kVXLPE cable is judged according to residual charge amount, wherein, judge that according to residual charge amount the concrete grammar of the water-treeing degree of moisture tree 10kVXLPE cable is: when after the first group pulse group effect, if discharge more than 1/2 of the total residual quantity of electric charge at the end of the quantity of electric charge accounts for measurement, can think that water-treeing degree is serious; If between 1/3 ~ 1/2, mittlere alterung can be thought; If be less than 1/3, think that degree of aging is lighter.
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