Special high-tension current inductor transient characteristics tester
Affiliated technical field
The present invention relates to the test unit of current transformer transient characterisitics, particularly special high-tension current inductor transient characteristics tester, it belongs to the field category of extra-high voltage electric power equipment.
Background technology
Usually, the working voltage of extra-high voltage grid surpasses 1000kV, when electrical network has an accident, can produce the short-circuit current bigger than supergrid, for example reaches more than the 100kA.So just require to be installed in the in the past bigger fault current of current transformer energy response ratio that extra-high voltage grid is used to protect.According to the knowledge of the applicant, the test unit of existing current transformer transient characterisitics is not undergoing technological transformation or is taking under the condition of ancillary technique means, with regard to the technical level of existing test unit, it is very difficult that such current transformer is carried out the transient characterisitics test.Though present dynamic and thermal stability test unit can provide this other alternating current of level, can not satisfy closing-minute and close-minute-close-time constant of minute circulation requirement.This is that loop resistance is little because during the alternate or relative ground circuit of electrical network, and power factor is low, and time constant generally surpasses 100ms, for example reaches 120ms; And because the electric current of dynamic and thermal stability test loop passes through transformer conversion generation, and the resistance string of Transformer Winding is connected in the loop, thus loop resistance is significantly increased, be directed at the power factor height, time constant is difficult to surpass 50ms.Up to the present, the transient characterisitics test unit of great current mutual inductor has only and uses surge generator or directly grid short circuit.Because the extra-high voltage current transformer requires that bigger transient state test current is arranged, existing these two kinds of test units only carry out could using behind the capacity upgrade, and this is an engineering that investment is huge.
Summary of the invention
The objective of the invention is, the problem that is difficult to carry out the special high-tension current inductor transient characteristics test at existing testing equipment is carried out technological improvement, special high-tension current inductor transient characteristics tester is proposed, so, just can under less input situation, satisfy the needs of special high-tension current inductor transient characteristics test.
The technical scheme that the present invention solves its technical matters employing is, by the transient current generating means, transient current bus and measuring and controlling are formed, it is characterized in that: the transient current generating means comprises alternating current generating means and pulse direct current generating means, the transient current bus comprises that interchange waits ampere-turn buses such as ampere-turn bus and pulse direct current, they are on the toroid winding of transient current transformer, constitute interchange and wait ampere-turn bus windings such as ampere-turn bus winding and pulse direct current, interchange waits ampere-turn bus winding to be connected and to form ampere-turn loops such as interchange with the alternating current generating means, ampere-turn bus windings such as direct current are through switch, reactor and resistor are connected and form ampere-turn loops such as direct current with one or two pulse direct current generating meanss, and the sequential of discharge is operated by measuring and controlling.
It is characterized in that: interchange waits the equal turn numbers of ampere-turn bus windings such as ampere-turn bus winding and pulse direct current, and uses common decoupling impedance.
The present invention uses alternating current generating means and pulse direct current generating means and forms the transient current generating means by ampere-turn bus windings such as ampere-turn bus winding and pulse direct current such as exchanging, the present invention adopts the transient current bus to be wound with ampere-turn bus windings such as ampere-turn bus windings such as interchange and pulse direct current respectively by the even distribution mode of circumference on the toroid winding of transient current transformer, the equal turn numbers of two windings, two windings use common decoupling impedance, interchange waits ampere-turn bus winding to be connected and to form ampere-turn loops such as interchange through switch with a high capacity step-down transformer output terminal, and ampere-turn bus windings such as direct current are through switch, reactor and resistor are filled with high-tension capacitor and are connected and form ampere-turn loops such as direct current with one or two.The sequential of discharge is operated by measuring and controlling, and two loops can obtain the transient state test current of needs on the annular core of tested transient current transformer when uniting discharge.
Principle of work of the present invention is, the extra-high voltage transient current transformer is a bus type current transformer, the ampere-turn bus such as can use to carry out equivalent test, wherein interchange waits ampere-turn buses such as ampere-turn bus and pulse direct current to be wound with multiturn with even distribution mode on the toroid winding circumference of transient current transformer, constitute interchange respectively and wait ampere-turn bus windings such as ampere-turn bus winding and pulse direct current, by waiting ampere-turn synthesis mode to reach transient current amplitude and the enlarged areas multiple that needs.Interchange waits the electric current in ampere-turn loop to use the high capacity step-down transformer to produce, and the electric current in ampere-turn loops such as direct current uses and is filled with high-tension capacitor through reactor and resistor discharge generation.During test, the Secondary Winding of transient current transformer inserts the secondary load of regulation, promptly wait on the ampere-turn bus after the alternating current switch closes a floodgate and produce the alternating current that direct current offset is arranged in interchange, when alternating current when reaching maximal value, being filled with high-tension capacitor set discharge switch closes a floodgate, produce pulse current on ampere-turn buses such as pulse direct current, pulse current is wavefront time 20ms~30ms, two exponential waves of hemiwave time 100ms~150ms.The phase place of closing a floodgate is controlled with phase-selecting switch, so that produce the big dc offset of trying one's best.Use two capacitor alternating discharges can close transient current transformer-minute-close-minute cyclic test, two capacitors discharge simultaneously and then can carry out single and close-separating tests.No matter close-minute the circulation or close-minute-close-minute the circulation, the whole test time all is no more than 1s, has taken into full account current transformer dynamic and thermal stability time restriction.In order to offset the induced potential that alternating current loop and pulse direct current loop produce by tested transient current transformer iron core, make two to wait the ampere-turn loop to have the equal number of turn, two circuit connect by the decoupling impedance simultaneously, the size of decoupling impedance equals the resistance value that tested transient current transformer secondary circuit resulting impedance such as converts at the ampere-turn loop, and the coupling coefficient in two loops is close to zero.
Advantage of the present invention is, and is novel, reasonable in design, simple in structure, easy to use.One of beneficial effect is to have avoided building the huge input of high capacity surge generator more and avoid electrical network is produced damaging long-time short-circuit current rush; reduced the experimentation cost of extra-high voltage transient current transformer; two of beneficial effect is strategic materials and land resources such as a large amount of copper iron of saving; three of beneficial effect is the operation time to economize electric energy and lower the electromagnetic pollution of test current to environment greatly, and is favourable to environmental protection.
Description of drawings
Fig. 1, be ampere-turn synthetic test loop synoptic diagram such as of the present invention.
Fig. 2, be capacitor discharge circuit theory circuit diagram.
Fig. 3, be the embodiments of the invention synoptic diagram.
Among the figure: 1. alternating current generating means, 2. pulse direct current generating means, 3. transient current bus, 4. transient current transformer, 5. high current load case, 6. decoupling impedance, 7. AC transformer, 8. alternating current switch, 9. interchange waits the ampere-turn bus, 10. ampere-turn bus such as pulse direct current, 11. resistor, 12. reactor, 13. electric capacity A organize discharge switch, and 14. capacitor A organize charge switch, 15. electric capacity A group, 16. capacitor A organizes tungar, 17. rectifier transformers, and 18. capacitor B organize discharge switch, 19. capacitor B organizes charge switch, 20. capacitor B group, 21. capacitor B organize tungar, 22.. measuring and controlling.
Embodiment
Below, describe embodiments of the invention with reference to the accompanying drawings in detail.
As Fig. 1, Fig. 2, shown in Figure 3, the present invention is made up of transient current generating means, transient current bus 3 and measuring and controlling.The transient current generating means comprises alternating current generating means 1 and pulse direct current generating means 2, alternating current generating means 1 is made up of AC transformer 7 and switch 8, transient current bus 3 comprises that interchange waits ampere-turn buses 10 such as ampere-turn bus 9 and pulse direct current, they are on the toroid winding of transient current transformer 4, constitute interchange and wait ampere-turn bus windings such as ampere-turn bus winding and pulse direct current, interchange waits ampere-turn bus winding to be connected and to form ampere-turn loops such as interchange with the alternating current generating means, ampere-turn bus windings such as direct current process switch is (among Fig. 1, the switch that adopts is electric capacity A group discharge switch 13, the switch that adopts among Fig. 3 comprises electric capacity A group discharge switch 13 and electric capacity B group discharge switch 18), reactor 12 and resistor 11 are connected and form ampere-turn loops such as direct current with one or two pulse direct current generating meanss 2, the alternating current generating means 1 and 2 electric coupling of pulse direct current generating means of measuring and controlling 22 and transient current generating means, interchange waits the sequential of ampere-turn loop discharge, the sequential of ampere-turn loops such as direct current discharge is by measuring and controlling 22 operations.Interchange waits the 10 shared decoupling impedances 6 of ampere-turn buses such as ampere-turn bus 9 and pulse direct current to form transient current bus 3.Alternating current generating means 1 and pulse direct current generating means 2 respectively by ampere-turn bus winding such as ampere-turn buses 10 such as ampere-turn bus 9 such as exchanging of transient current bus 3 and pulse direct current exchanging on the toroid winding of transient current transformer 4 and and the toroid winding electric coupling of ampere-turn bus winding such as pulse direct current and transient current transformer 4, high current load case 5 and transient current transformer 4 connect.
Shown in Figure 1 waiting in the ampere-turn synthetic test loop, adopting has alternating current generating means 1, pulse direct current generating means 2, transient current bus 3, transient current transformer 4, high current load case 5.Alternating current generating means 1 is made up of AC transformer 7 and alternating current switch 8, and the pulse direct current generating means is by resistor 11, reactor 12, electric capacity A group discharge switch 13. capacitor A group 15, capacitor A organizes charge switch 14, and capacitor A organizes tungar 16. rectifier transformer 17 is formed.The transient current bus waits ampere-turn bus 9 by interchange, ampere-turn buses 10 such as pulse direct current, and decoupling impedance 6 is formed.The present invention has adopted and has waited the ampere-turn synthetic test loop that transient current transformer 4 is carried out the transient characterisitics equivalent test, the secondary side of transient current transformer inserts high current load case 5 during test, comprise two current returns that wait ampere-turn buses 10 such as ampere-turn bus 9 and pulse direct current to form respectively by interchange Deng the ampere-turn synthetic test loop, respectively by alternating current generating means 1 and 2 power supplies of pulse direct current generating means, two shared decoupling impedances 6 of current return, two current returns produce pressure drop in decoupling impedance 6, offset two loops owing to wait the induced potential of ampere-turn winding by the iron core generation magnetic coupling generation of transient current transformer 4.Be wound on the transient current transformer iron core with the even distribution mode of circumference Deng ampere-turn alternating current bus and bus such as pulse direct current such as ampere-turn such as grade.
In the discharge circuit of capacitor shown in Figure 2, the capacitor C that is filled with electromotive force E by K switch to pulse direct current bus discharge with resistance R and inductance L, note τ
1=RC, τ
2=L/R is satisfying τ
1>>τ
2Condition under, will produce the dash current of two exponential waves.The wavefront time is about 3 τ
1, hemiwave time is about τ
2Peak point current is near E/R.
In the embodiment synoptic diagram that Fig. 3 provides, the rated current of transient current transformer 4 is 6kA, transient current 100kA, transient state area coefficient 10.The output-current rating 5kA of AC transformer 7, impedance voltage 12%.Interchange wait ampere-turn bus 9 on the toroid winding circumference of transient current transformer 4 all around 20 circles.Interchange waits the ampere-turn impedance loop and the ratio of transformer internal impedance to be controlled at below 4, and the secondary no-load voltage of AC transformer 7 is pressed short-circuit current 25kA design.After alternating current switch 8 closes a floodgate, wait the alternating current that produces 5kA band direct current offset in the ampere-turn bus 9 in interchange.The pulse direct current electric current is by electric capacity 0.5F's. capacitor A group 15 and capacitor B group 20 be respectively by electric capacity A group discharge switch 13 and electric capacity B group discharge switch 18 discharge generation, ampere-turn buses 10 such as pulse direct current on the toroid winding circumference of transient current transformer 4 all around 20 circles.The inductance value of reactor 12 and pulse direct current etc. ampere-turn loop inductance amount with about 2mH, resistor 11 and this loop resistance and about 0.2 Ω, capacitor maximum charging voltage 3kV.Rectifier transformer 17 by commutator tube 16 and 21 and capacitor A group charge switch 14 and capacitor B group charge switch 19 respectively to capacitor A group 15 and 20 chargings of capacitor B group.The value of decoupling impedance 6 equals the value that transient current transformer 4 secondary circuit resulting impedances (equaling high current load case 5, secondary lead, Secondary Winding resistance and leakage reactance sum) such as convert at the ampere-turn winding, is about 0.15m Ω in the present embodiment.Only use capacitor A to organize, τ at 15 o'clock
1=RC ≈ 100ms, τ
2=L/R ≈ 10ms, the transient state area multiple of testing behind the capacitor discharge 100ms is about τ
1/ T, wherein T is the power current cycle, equals 20ms, like this τ
1The value of/T is substantially equal to 5.Measuring and controlling 22 drops into capacitor B group 20 at the appropriate time according to the reclosing testing requirements, can satisfy closing by two group capacitor alternating discharges-minute-close-testing requirements of minute circulation transient state enlarged areas multiple 10.The circuit of Fig. 3 also can carry out single and close-separating tests, if capacitor A group 15 and capacitor B group 20 discharge simultaneously, timeconstant
1To increase to, the transient state area of test is increased near original 2 times near original 2 times.