CN101179188A - Second open circuit protector of current mutual inductor - Google Patents
Second open circuit protector of current mutual inductor Download PDFInfo
- Publication number
- CN101179188A CN101179188A CNA2007101129734A CN200710112973A CN101179188A CN 101179188 A CN101179188 A CN 101179188A CN A2007101129734 A CNA2007101129734 A CN A2007101129734A CN 200710112973 A CN200710112973 A CN 200710112973A CN 101179188 A CN101179188 A CN 101179188A
- Authority
- CN
- China
- Prior art keywords
- circuit
- relay
- mutual inductor
- open circuit
- current mutual
- 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.)
- Pending
Links
Images
Landscapes
- Emergency Protection Circuit Devices (AREA)
Abstract
The invention discloses a passive device for protecting a second open circuit of a current transformer which fully restrains overvoltage. The invention consists of a normally opening switch connected between secondary terminals of the current transformer and a control circuit, wherein, the control circuit includes a rectifying circuit, a relay and a filter capacitor; two input terminals of the rectifying circuit are respectively connected with the secondary terminals of the current transformer; two output terminals of the rectifying circuit are respectively connected with the relay and the filter capacitor which are connected in parallel. The invention provides effective protection for the current transformer, the secondary circuit and the accessed devices.
Description
(1) technical field
The present invention relates to a kind of second open circuit protector of current mutual inductor, particularly a kind of passive second open circuit protector of current mutual inductor that overvoltage is inhibited fully.
(2) background technology
At present, existing second open circuit protector, majority is two kinds of principles, be a kind of be to utilize to prevent that superpotential principle (employing has the devices such as metal oxide device, discharge tube and air gap of nonlinear resistance property) from constituting, prevent that the overvoltage that secondary coil open circuit back produces from damaging the Current Transformer Secondary coil; Another kind of then be the protective device that utilizes external power supply, be installed in by the equipment of electrical secondary system, with the equipment that moves in the protection secondary circuit.From performance, it is little that the former exists discharge capacity, can not be under the long-time condition that exists of protected instrument transformer second open circuit situation, still can move continuously and unlikely damage (and secondary circuit when open circuit of being in operation, could repair the inevitable long-time existence of open circuit phenomenon after exactly needing to investigate thoroughly the fault point); And when adopting gap protection,, may produce new higher overvoltage because the superpotential effect of secondary can make the two ends, gap produce intermittent electric arc, strengthen the probability of insulation damages; Another kind of device then needs external power supply; both more complicated; the reliability of protection is subjected to the influence of the power supply degree of reliability again; and the breaking point of the protective device of this principle when secondary circuit failure be in outside the instrument transformer secondary outlet terminal near during the position; just can only protect secondary device, and protective current instrument transformer itself reliably.
(3) summary of the invention
The objective of the invention is to overcome deficiency of the prior art, providing a kind of is Current Transformer Secondary protective device passive, that again the secondary overvoltage is inhibited fully, protects instrument transformer itself on the one hand, protects secondary circuit on the other hand again.
The present invention is achieved by the following technical solutions:
Second open circuit protector of current mutual inductor of the present invention is made up of normal open switch and a control circuit of being connected between the Current Transformer Secondary terminal; Described control circuit includes a commutating circuit, a relay and a filter capacitor, two inputs of described commutating circuit are connected with the secondary terminal of current transformer respectively, and two outputs of commutating circuit are connected with filter capacitor with the relay that is in parallel respectively; After described relay is triggered by secondary open-circuit over-voltage, the normal open switch closure.
Second open circuit protector of current mutual inductor of the present invention; for the rectifier bridge that makes this protective device can not exert an influence to the accuracy of instrument transformer; be connected with an amplitude limiter between the output of described commutating circuit and relay and the filter capacitor, described relay is parallel with an amplitude limiter.
Second open circuit protector of current mutual inductor of the present invention, described commutating circuit is chosen as the full-wave bridge rectifier loop.
Second open circuit protector of current mutual inductor of the present invention, described relay are latching relay.
Second open circuit protector of current mutual inductor of the present invention, described amplitude limiter is chosen as the discharge voltage-stabiliser tube.
The invention has the beneficial effects as follows:
(1) dispense with outer connecting power of the present invention is simple in structure;
(2) even the present invention still can possess effective protection to the equipment of current transformer and secondary circuit and access under the long-time condition that exists of instrument transformer second open circuit;
(3) the present invention is located at the inside of instrument transformer,, all can play a protective role unprotect dead band on the loop no matter transformer secondary circuit is opened a way in any position;
(4) description of drawings
Fig. 1 is a circuit theory schematic diagram of the present invention,
Parameter waveform figure when Fig. 2 tests for protective device of the present invention
Another kind of parameter waveform figure when Fig. 3 tests for protective device of the present invention.
Among the figure: 1, instrument transformer secondary terminal, 2, commutating circuit, 3, amplitude limiter a, 4, amplitude limiter b, 5, filter capacitor, 6, relay, 7, normal open switch
(5) embodiment
Below in conjunction with accompanying drawing the present invention is specified.
Fig. 1 is circuit theory diagrams of the present invention, and Current Transformer Secondary protective device of the present invention is made up of normal open switch 7 and a control circuit of being connected between the Current Transformer Secondary terminal 1; Described control circuit includes a commutating circuit 2, a relay 6 (latching relay) and a filter capacitor 5, and described commutating circuit 2 is the full-wave bridge rectifier loop.Two inputs of commutating circuit 2 are connected with the secondary terminal 1 of current transformer respectively; two outputs of commutating circuit 2 are connected with filter capacitor 5 with the relay 6 that is in parallel respectively; when second open circuit; the overvoltage (temporary overvoltage that comprise appearance) of rectifier bridge during with second open circuit is converted into direct voltage; inwardly establish filter capacitor 5 chargings; this direct voltage directly triggers the winding of subminiature relay 6 simultaneously; make its action; and with its (being connected the two ends of instrument transformer secondary winding outlet) normal open switch 7 closures; reach protected secondary winding in current transformer outlet short circuit; the voltage of secondary circuit is zero, fundamentally reaches to suppress superpotential purpose.
Current Transformer Secondary protective device of the present invention is connected with an amplitude limiter 3 between the output of described commutating circuit 2 and relay 6 and the filter capacitor 5, described relay 6 is parallel with another amplitude limiter 4, and amplitude limiter all adopts the discharge voltage-stabiliser tube.Be at secondary current under the condition of normal measuring range, discharge voltage-stabiliser tube voltage is lower, and the discharge voltage-stabiliser tube is not worked, and is equivalent to open-circuit condition, and input impedance be infinity, can not produce any influence for the measurement of secondary circuit; Produce overvoltage after secondary winding is opened a way, overvoltage value is considerably beyond discharge voltage-stabiliser tube rated voltage, and the voltage-stabiliser tube action of discharging this moment is discharged, make commutating circuit 1 conducting, rectifier bridge inserts secondary circuit, and reaching the rectification of secondary overvoltage is direct voltage, drives the purpose of relay 6 actions.Because the relay of selecting 6 can self-sustaining, therefore can be kept closed after the action of the contact of relay 6 always, up to the process maintenance, the cut-off point of secondary circuit is checked through and finishes dealing with, secondary circuit recovers loop circuit state, by manual operation relay 6 is returned to contact again and disconnect, device returns to standby condition once more.
Below experiment effect is described as follows.
Explanation; above-mentioned test is to carry out on the current transformer of 1000/1A; and secondary current is about to protective device and will insert protected instrument transformer only about 500A, artificially secondary circuit is disconnected; this moment, secondary produced the overvoltage of certain numerical value; utilize this superpotential energy, drive protective device, reach the protection action; secondary circuit makes secondary loop current recover normal value again by short circuit.Waveform when representing that as the dotted line among the following figure secondary current disconnects, the electric current in protective device loop utilizes waveform to represent for chain-dotted line, and the voltage waveform of secondary circuit is the solid line among the figure.Because secondary voltage moment may reach very high, therefore experimental circuit has also inserted one 40000/100 volt voltage divider, high voltage is reduced by 400 times be converted to the instrument that is input to wave recording after the low-voltage, the voltage ratio of this moment is 400/1, be that each voltage that lies prostrate on the secondary terminal of promptly representing instrument transformer of voltage that secondary records is 400 volts (scale figure three CH1 of the ordinate on the oscillogram are 1V/DIV, and every lattice are 400 volts).
Each parameter waveform figure that the protective device test is obtained is as follows: Fig. 2 abscissa is 10 milliseconds of every lattice, and the every lattice of abscissa are 2 milliseconds among Fig. 3.
Can find out all that from above-mentioned oscillogram be chopped to protective device action back secondary current from normal secondary current and recover normal, the time interval is extremely short, and is general all within 1 millisecond.And superpotential numerical value also can be controlled in 400 volts (being that 1 volt of scope is interior on the oscillogram).
Claims (5)
1. a second open circuit protector of current mutual inductor is characterized in that: be made up of normal open switch and a control circuit of being connected between the Current Transformer Secondary terminal; Described control circuit includes a commutating circuit, a relay and a filter capacitor, two inputs of described commutating circuit are connected with the secondary terminal of current transformer respectively, and two outputs of commutating circuit are connected with filter capacitor with the relay that is in parallel respectively; Described relay after the overvoltage of instrument transformer second open circuit triggers, the normal open switch closure.
2. second open circuit protector of current mutual inductor according to claim 1 is characterized in that: be connected with an amplitude limiter between the output of described commutating circuit and relay and the filter capacitor, described relay is parallel with an amplitude limiter.
3. second open circuit protector of current mutual inductor according to claim 1 and 2 is characterized in that: described commutating circuit is the full-wave bridge rectifier loop.
4. second open circuit protector of current mutual inductor according to claim 1 and 2 is characterized in that: described relay is a latching relay.
5. second open circuit protector of current mutual inductor according to claim 2 is characterized in that: described amplitude limiter is the discharge voltage-stabiliser tube.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007101129734A CN101179188A (en) | 2007-09-24 | 2007-09-24 | Second open circuit protector of current mutual inductor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007101129734A CN101179188A (en) | 2007-09-24 | 2007-09-24 | Second open circuit protector of current mutual inductor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101179188A true CN101179188A (en) | 2008-05-14 |
Family
ID=39405324
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2007101129734A Pending CN101179188A (en) | 2007-09-24 | 2007-09-24 | Second open circuit protector of current mutual inductor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101179188A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101989742A (en) * | 2009-08-04 | 2011-03-23 | 汤征宁 | No-load protection circuit for capacitor step-down |
| CN104614587A (en) * | 2013-11-05 | 2015-05-13 | 国家电网公司 | Harmonic measurement circuit and electric energy testing device |
| CN106371049A (en) * | 2016-08-31 | 2017-02-01 | 贵州电网有限责任公司贵阳供电局 | Current transformer secondary open circuit identification method |
| CN107315157A (en) * | 2017-08-04 | 2017-11-03 | 国网江苏省电力公司无锡供电公司 | A kind of current transformer circuit supervision fail alarm detector and current transformer device |
| CN107785869A (en) * | 2017-11-08 | 2018-03-09 | 河南森源电气股份有限公司 | A kind of current transformer and its secondary side protective arrangement for limiting output voltage |
| CN107785870A (en) * | 2017-11-11 | 2018-03-09 | 河南森源电气股份有限公司 | A kind of current transformer and its secondary side open-circuit protecting device |
| CN112636615A (en) * | 2020-12-10 | 2021-04-09 | 中国计量大学上虞高等研究院有限公司 | Ultra-wide voltage alternating current input AC-DC circuit and method |
-
2007
- 2007-09-24 CN CNA2007101129734A patent/CN101179188A/en active Pending
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101989742A (en) * | 2009-08-04 | 2011-03-23 | 汤征宁 | No-load protection circuit for capacitor step-down |
| CN104614587A (en) * | 2013-11-05 | 2015-05-13 | 国家电网公司 | Harmonic measurement circuit and electric energy testing device |
| CN104614587B (en) * | 2013-11-05 | 2017-11-14 | 国家电网公司 | Harmonic measure circuit and power test device |
| CN106371049A (en) * | 2016-08-31 | 2017-02-01 | 贵州电网有限责任公司贵阳供电局 | Current transformer secondary open circuit identification method |
| CN106371049B (en) * | 2016-08-31 | 2023-09-26 | 贵州电网有限责任公司贵阳供电局 | Current transformer secondary open circuit identification method |
| CN107315157A (en) * | 2017-08-04 | 2017-11-03 | 国网江苏省电力公司无锡供电公司 | A kind of current transformer circuit supervision fail alarm detector and current transformer device |
| CN107785869A (en) * | 2017-11-08 | 2018-03-09 | 河南森源电气股份有限公司 | A kind of current transformer and its secondary side protective arrangement for limiting output voltage |
| CN107785870A (en) * | 2017-11-11 | 2018-03-09 | 河南森源电气股份有限公司 | A kind of current transformer and its secondary side open-circuit protecting device |
| CN107785870B (en) * | 2017-11-11 | 2023-11-24 | 河南森源电气股份有限公司 | Current transformer and secondary side open circuit protection device thereof |
| CN112636615A (en) * | 2020-12-10 | 2021-04-09 | 中国计量大学上虞高等研究院有限公司 | Ultra-wide voltage alternating current input AC-DC circuit and method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US10211625B2 (en) | Mitigation of arc flash hazard in photovoltaic power plants | |
| US9219360B2 (en) | Safe quick disconnect leakage protector | |
| US9520713B2 (en) | Fast switch fault current limiter | |
| CN101179188A (en) | Second open circuit protector of current mutual inductor | |
| CN201656456U (en) | Supergrid short-circuit current limiting device | |
| CN104810793B (en) | A kind of transformer neutral point direct current blocking device | |
| Purgat et al. | On the protection of the power flow control converter in meshed low voltage DC networks | |
| WO2010149217A1 (en) | Method for protecting transformers, and a transformer | |
| CN201113393Y (en) | Current mutual inductor quadric open circuit protector | |
| CN204597457U (en) | Transformer neutral point direct current is every straight device | |
| CN113176470B (en) | Fast switching device for limiting short-circuit current direct-current component of power system and current limiting method | |
| Palone et al. | Temporary overvoltage mitigation in symmetrical monopole VSC-MMC HVDC links | |
| CN217282209U (en) | Open circuit protection device for current transformer | |
| CN206441677U (en) | The backup protection breaker of surge protector | |
| CN209148790U (en) | A kind of Surge Protector test device | |
| CN202840464U (en) | High-voltage reactive on-site compensation apparatus | |
| CN102486516A (en) | Nonperiodic trigger test method for direct current converter valve | |
| CN207184052U (en) | A kind of thunder-prevention switch cabinet with discharging gap | |
| Kaiser et al. | A Comprehensive Approach for Safety in DC-Microgrids | |
| CN202772820U (en) | Medium voltage motor soft start device of cold water set | |
| CN204154799U (en) | Based on the DC wave recording device of relay-set | |
| CN208548713U (en) | A kind of low appearance/low anti-flexible fling-cut system | |
| CN203103911U (en) | Protection device of indoor capacitor bank for smoke and arcing faults | |
| CN209329683U (en) | A kind of automatic short-circuiter for preventing Current Transformer Secondary side from opening a way | |
| CN207612057U (en) | A kind of novel fault current limiter |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |