CN203826975U - Zero-sequence current converter and zero-sequence current converting device - Google Patents
Zero-sequence current converter and zero-sequence current converting device Download PDFInfo
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- CN203826975U CN203826975U CN201420219235.5U CN201420219235U CN203826975U CN 203826975 U CN203826975 U CN 203826975U CN 201420219235 U CN201420219235 U CN 201420219235U CN 203826975 U CN203826975 U CN 203826975U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/50—Arrangements for eliminating or reducing asymmetry in polyphase networks
Abstract
The utility model discloses a zero-sequence current converter and a zero-sequence current converting device. The converter comprises three primary windings and three secondary windings, wherein the number of turns of the primary windings is the same as the number of turns of the secondary windings, the input ends of the three primary windings are connected with an N-phase line at the output side of a low-voltage distribution transformer, and the output ends of the primary windings are in cross connection with the input ends of the secondary windings. The converting device comprises a first circuit breaker, the converter, a second circuit breaker, a protection control circuit, a surge protector, a phase failure protector, an air switch used for protecting the phase failure protector, a current transformer used for acquiring a current value of an N-phase line at the input end of the zero-sequence current converter, an ammeter used for displaying the current value acquired by the current transformer, and a time relay. The zero-sequence current converter and the zero-sequence current converting device can enable the proportion of zero-sequence current, which is generated by a three-phase load imbalance phenomenon in a low-voltage distribution network, flowing back to the distribution transformer to be reduced, and can also effectively reduce the three-phase current imbalance degree, thereby reducing damages imposed on the transformer by the zero-sequence current.
Description
Technical field
The utility model relates to the solution that zero-sequence current that three-phase load energy imbalance in low-voltage distribution network produces works the mischief to transformer.
Background technology
In the traditional three-phase four-wire system distribution transformer wiring system of China, because low pressure single-phase load can not be by manually dividing equally completely, the not equal a variety of causes of the load in-service factor of distribution, just inevitably causes three-phase load energy imbalance.Transformer under three-phase load unbalanced operation, will inevitably produce zero-sequence current, and the existence of the inner zero-sequence current of transformer can produce zero sequence magnetic flux in iron core, and these zero sequence magnetic fluxs will form loop in the oil tank wall of transformer or other hardwares.But do not consider that these hardwares are magnetic conductive part during distribution transformer design, the magnetic hysteresis causing thus and eddy current loss make these parts heatings, cause the local metalwork temperature anomaly of transformer to raise, when serious, will cause transformer interruption of service.
For above-mentioned technical problem, in prior art, there is no effective solution.In prior art, have for idle or harmonic wave and compensate, reduce the size of zero-sequence current, but the zero-sequence current producing for meritorious imbalance does not still have method that it is reduced.Someone may carry out switchable load and adjust zero-sequence current, but the uncertainty of residential electricity consumption, more how to adjust load and all can produce zero-sequence current.Therefore the problem that the zero-sequence current that, in low-voltage distribution network, three-phase load energy imbalance produces works the mischief to transformer is urgently to be resolved hurrily.
Summary of the invention
The utility model is for deficiency of the prior art, the ratio that provides a kind of zero-sequence current that can make three-phase load energy imbalance in low-voltage distribution network produce to be back to distribution transforming transformer reduces, and can effectively reduce three-phase current unbalance degree, thereby can reduce zero-sequence current transducer and conversion equipment that zero-sequence current works the mischief to transformer.
In order to address the above problem, the utility model is solved by following technical proposals:
Zero-sequence current transducer, comprise three armature winding A2, B2, C2 and three secondary winding A1, B1, C1, armature winding is identical with the secondary winding number of turn, three armature winding A2, B2, the input of C2 is the terminals for zero-sequence current input that are connected with low-voltage distribution transformer transformer outlet side N phase line, the output of armature winding A2 is connected with the input of secondary winding C1, the output of armature winding B2 is connected with the input of secondary winding A1, the output of armature winding C2 is connected with the input of secondary winding B1, secondary winding A1, B1, the output of C1 is the A of described transducer, B, C three-phase output end.
Above-mentioned zero-sequence current transducer is the transformer that a kind of three phase windings are formed by connecting through particular form.Elementary, secondary umber of turn is identical, and it is exactly identical making like this induced current amplitude of primary and secondary.So obtain: IA1 (t)=IB1 (t)=IC1 (t).The electric current current amplitude on the former limit of inflow transformer equates, so transducer is the path that resistance value is very low to zero-sequence current.When zero-sequence current transducer is linked into the outlet side of distribution transforming transformer, can make zero-sequence current through zero-sequence current transducer and no longer by the distribution transforming transformer neutral line.The mutual interconnection of each phase winding of zero-sequence current transducer, by the magnetic flux of mutual conversion iron core, makes each phase winding form high impedance and residual voltage is formed to Low ESR positive sequence, negative sequence voltage.In this characteristic theory, make zero-sequence current mainly by this transformer, form loop, after zero-sequence current is compensated to three-phase circuit, make in three-phase circuit, the phase side electric current of current value maximum reduces, the phase side electric current of current value minimum increases, and another phase side current value is according to the difference of above-mentioned biphase current phase place and size, or increase or minimizing, the effect that finally realizes the difference minimizing of maximum phase current and minimum circuitry phase, has reduced again the zero-sequence current on neutral line distribution transforming transformer simultaneously.
Zero-sequence current conversion equipment, comprise for controlling the first circuit breaker of described conversion equipment break-make, above-mentioned zero-sequence current transducer, for controlling the second circuit breaker of zero-sequence current transducer, for controlling the protection control circuit of the second circuit breaker, for limiting the too high Surge Protector to described conversion equipment infringement of input voltage, for preventing input phase failure and the phase sequence mistake open phase protector to described conversion equipment infringement, air switch for the protection of open phase protector, for gathering the current transformer of zero-sequence current transducer input N phase line current value, for showing that current transformer gathers the ammeter of current value, for gathering the voltmeter of the first circuit breaker input three-phase voltage value and the time relay of restarting after disconnecting because of overcurrent for controlling the second circuit breaker, the N phase input of described zero-sequence current transducer is connected with the N phase line of low-voltage distribution transformer transformer outlet side, the A of described zero-sequence current transducer, B, C three-phase output end are connected with A, B, the C three-phase input end of the second circuit breaker, the A of the second circuit breaker, B, C three-phase output end are connected with A, B, the C three-phase input end of the first circuit breaker, and the A of the first circuit breaker, B, C three-phase output end are connected with A, B, the C phase line of low-voltage distribution transformer transformer outlet side.
Said apparatus is used the outlet side at low-voltage distribution transformer transformer, and the zero-sequence current that three-phase imbalance is produced is changed, and balanced being assigned in three-phase gone; Can be by zero-sequence current filtering more than 80%; The output current of energy balance distribution transforming transformer, the zero-sequence current that device absorbs is on average converted to each phase current; Energy balance output voltage, prevents that low-voltage distribution transformer transformer neutral current is excessive, the neutral point drifting causing; Can improve capacity utilance and the power output of low-voltage distribution transformer transformer, the conversion efficiency that improves transformer reduces loss, improves the useful life of transformer.Above-mentioned conversion equipment has accessed after civil power, to self having surge protection, open-phase protection, overcurrent protection function.Both guaranteed that zero-sequence current transducer can normally work, and can guarantee again to occur phase shortage when circuit, and when overcurrent or voltage are very big, can cut off rapidly circuit, to protect the safety of all appliance components.Described three-phase voltage meter is for the convenient voltage of observing of when energising is installed.
As preferably, the A of described Surge Protector, B, C three-phase input end are connected with A, B, the C three-phase input end of the first circuit breaker, the output head grounding of Surge Protector; The input operating range of described Surge Protector is 440V, and when A, the B of Surge Protector, C triple line input voltage are during higher than 440V, Surge Protector earth connection is communicated with.Surge Protector earth connection is communicated with, the infringement of restriction high pressure to described device internal circuit.The surge protection response time is 0.02S, and maximum discharge current is 15KA, can protect to greatest extent the fail safe of whole line system.
As preferably, described protection control circuit comprise AC220V power supply group, for receive open phase protector output signal often open control group, for change and the overcurrent sample circuit of the current value of amplified current instrument transformer secondary side collection, for exporting, control the second circuit breaker make-and-break signal control group, for the time relay of control time relay, often open group, time relay power supply group.
As preferably, A, the B of the described air switch for the protection of open phase protector, C three-phase input end are connected with A, B, the C three-phase input end of the first circuit breaker, the A of described air switch, B, C three-phase output end are connected with A, B, the C three-phase input end of open phase protector, and the two-phase signal output part of described phase-lacking protective unit is connected with the control group of often opening of protection control circuit; When phase shortage and phase sequence mistake appear in A, B, the C three-phase input end of the air switch for the protection of open phase protector, the described control group of protection control circuit is to the second circuit breaker output break signal.Protect the phase-lacking protective unit of open phase protector and air switch composition fully to guarantee when phase shortage appears in circuit, system can be out of service in time, the safety of protection single unit system.
As preferably, the current signal that described Current Transformer Secondary side output gathers is also connected with described overcurrent sample circuit, voltage signal after current conversion is amplified of overcurrent sample circuit output is also connected with described control group, when the voltage signal that described control group monitors described output is greater than reference voltage, exports break signal and is connected with the second circuit breaker; After the second circuit breaker opens circuit, described control group output time relay timing signal is also connected with the time relay, arrives after gate time time relay output channel signal, described control group is to the second circuit breaker output channel signal, and the second circuit breaker is communicated with again.
The secondary side of overcurrent sample circuit by instrument transformer collects current value and converts magnitude of voltage to, through the amplification of signal, processes, and exports a voltage signal; The voltage signal of output and the reference voltage in control protection electric circuit compare, after the zero-sequence current of changing is excessive, the voltage signal of output will be greater than reference voltage, control protection voltage and directly send a control signal to breaker control circuit, breaker control circuit is directly turn-offed circuit breaker; When circuit breaker closes, have no progeny, time counting circuit is started working it is arrived after gate time, sends a control signal to breaker control circuit, makes circuit breaker open normal work.Overcurrent protection scope is 150～160A, and protected mode is for cutting off being connected of zero-sequence current transducer and A, B, C three-phase, and after 10～30 minutes, oneself is dynamically connected.Described reference voltage is that circuit provides, and sets in advance.
The technical solution of the utility model, the ratio that the zero-sequence current that can make three-phase load energy imbalance in low-voltage distribution network produce is back to distribution transforming transformer reduces, and can effectively reduce three-phase current unbalance degree, thereby can reduce zero-sequence current, transformer be worked the mischief.When the utility model can be grown, band carries; and there is overload protection function; can be by low-voltage distribution transformer because the zero-sequence current that three-phase imbalance produces is changed more than 80%; effectively reduce the impact of zero-sequence current on transformer, electric equipment and power consumption equipment; thereby greatly improve the useful life of various device, reduce circuit, the various losses of transformer etc.
accompanying drawing explanation:
Fig. 1 is the schematic diagram of zero-sequence current transducer in the utility model embodiment.
Fig. 2 is the schematic diagram of zero-sequence current conversion equipment in the utility model embodiment.
Fig. 3 is the schematic diagram of protecting the AC220V power supply group of control circuit in the utility model embodiment.
Fig. 4 be in the utility model embodiment, protect control circuit for receiving the schematic diagram of often opening control group of open phase protector output signal.
Fig. 5 be in the utility model embodiment, protect control circuit for changing the overcurrent sample circuit of the current value gathering with amplified current instrument transformer secondary side.
Fig. 6 be in the utility model embodiment, protect control circuit for exporting the control group of controlling the second circuit breaker make-and-break signal.
Fig. 7 protects the time relay for control time relay of control circuit often to open group and time relay power supply group in the utility model embodiment.
Fig. 8 is the schematic diagram after conversion equipment access low-voltage distribution transformer transformer outlet side in the utility model embodiment 1.
embodiment:
Below in conjunction with accompanying drawing, the utility model is described in further detail.
Embodiment
Zero-sequence current transducer, comprise three armature winding A2, B2, C2 and three secondary winding A1, B1, C1, armature winding is identical with the secondary winding number of turn, three armature winding A2, B2, the input of C2 is the terminals for zero-sequence current input that are connected with low-voltage distribution transformer transformer outlet side N phase line, the output of armature winding A2 is connected with the input of secondary winding C1, the output of armature winding B2 is connected with the input of secondary winding A1, the output of armature winding C2 is connected with the input of secondary winding B1, secondary winding A1, B1, the output of C1 is the A of described transducer, B, C three-phase output end.
Zero-sequence current conversion equipment, comprise for controlling the first circuit breaker of described conversion equipment break-make, above-mentioned zero-sequence current transducer, for controlling the second circuit breaker of zero-sequence current transducer, for controlling the protection control circuit of the second circuit breaker, for limiting the too high Surge Protector to described conversion equipment infringement of input voltage, for preventing input phase failure and the phase sequence mistake open phase protector to described conversion equipment infringement, air switch for the protection of open phase protector, for gathering the current transformer of zero-sequence current transducer input N phase line current value, for showing that current transformer gathers the ammeter of current value, for gathering the voltmeter of the first circuit breaker input three-phase voltage value and the time relay of restarting after disconnecting because of overcurrent for controlling the second circuit breaker, the N phase input of described zero-sequence current transducer is connected with the N phase line of low-voltage distribution transformer transformer outlet side, the A of described zero-sequence current transducer, B, C three-phase output end are connected with A, B, the C three-phase input end of the second circuit breaker, the A of the second circuit breaker, B, C three-phase output end are connected with A, B, the C three-phase input end of the first circuit breaker, and the A of the first circuit breaker, B, C three-phase output end are connected with A, B, the C phase line of low-voltage distribution transformer transformer outlet side.
The A of described Surge Protector, B, C three-phase input end are connected with A, B, the C three-phase input end of the first circuit breaker, the output head grounding of Surge Protector; The input operating range of described Surge Protector is 440V, and when A, the B of Surge Protector, C triple line input voltage are during higher than 440V, Surge Protector earth connection is communicated with.Surge Protector earth connection is communicated with, the infringement of restriction high pressure to described device internal circuit.The surge protection response time is 0.02S, and maximum discharge current is 15KA, can protect to greatest extent the fail safe of whole line system.
Described protection control circuit comprise AC220V power supply group, for receive open phase protector output signal often open control group, for change and the overcurrent sample circuit of the current value of amplified current instrument transformer secondary side collection, for exporting, control the second circuit breaker make-and-break signal control group, for the time relay of control time relay, often open group, time relay power supply group.
A, the B of the described air switch for the protection of open phase protector, C three-phase input end are connected with A, B, the C three-phase input end of the first circuit breaker, the A of described air switch, B, C three-phase output end are connected with A, B, the C three-phase input end of open phase protector, and the two-phase signal output part of described phase-lacking protective unit is connected with the control group of often opening of protection control circuit; When phase shortage and phase sequence mistake appear in A, B, the C three-phase input end of the air switch for the protection of open phase protector, the described control group of protection control circuit is to the second circuit breaker output break signal.Protect the phase-lacking protective unit of open phase protector and air switch composition fully to guarantee when phase shortage appears in circuit, system can be out of service in time, the safety of protection single unit system.
The current signal that described Current Transformer Secondary side output gathers is also connected with described overcurrent sample circuit, voltage signal after current conversion is amplified of overcurrent sample circuit output is also connected with described control group, when the voltage signal that described control group monitors described output is greater than reference voltage, exports break signal and is connected with the second circuit breaker; After the second circuit breaker opens circuit, described control group output time relay timing signal is also connected with the time relay, arrives after gate time time relay output channel signal, described control group is to the second circuit breaker output channel signal, and the second circuit breaker is communicated with again.
As preferably; described the first circuit breaker is SIN125R125 circuit breaker; described the second circuit breaker is A110-30-11 circuit breaker; described Surge Protector is OVR BT2 3-40-440P TS Surge Protector; described ammeter is PA750AA-5X1 intelligent digital table; described air switch is SH203-C6 air switch, and described open phase protector is XJ3-G open phase protector, and described voltmeter is PZ750AV-AX4 three-phase intelligent digital display meter.
By above-mentioned conversion equipment access low-voltage distribution transformer transformer outlet side, measure the zero-sequence current of input unit, and transformer outlet side N line back flow current and A, B, C three-phase current, concrete data are as following table one.
Table one
Visible according to upper table one, after zero-sequence current conversion equipment access low-voltage distribution transformer transformer outlet side, can make N line back flow current obviously reduce.
When single-phase active power load 65A, the data of surveying as following table two.
If the conversion equipment of transformer impact is installed near load-side by reducing zero-sequence current, can almost all zero sequence circuit all be changed, the effect that test data is seen is exactly all very little of the zero-sequence current that refluxes, this is because the connecting line of zero sequence has impedance, and this impedance is larger.Above-mentioned test is by reducing zero-sequence current, the conversion equipment of transformer impact to be installed near the outlet side of transformer, now there is no described impedance, only has the zero sequence impedance of transformer inside.After the transformer installation testing of different capabilities repeatedly, find, zero-sequence current conversion ratio minimum reaches 80%.
As can be seen here, the technical solution of the utility model, can make the poor and N line back flow current of three-phase maximum current obviously reduce, and reduces the transformer additional iron losses that neutral line current brings; The winding copper loss bringing while reducing three-phase imbalance; The variation bringing while reducing three-phase imbalance; Prevent that the overheated transformer center line that causes of the neutral line from burning, guarantee transformer safe operation, and then improve the useful life of transformer.
In a word, the foregoing is only preferred embodiment of the present utility model, all equalizations of doing according to the utility model claim change and modify, and all should belong to the covering scope of the utility model patent.
Claims (6)
1. zero-sequence current transducer, it is characterized in that: comprise three armature winding A2, B2, C2 and three secondary winding A1, B1, C1, armature winding is identical with the secondary winding number of turn, three armature winding A2, B2, the input of C2 is the terminals for zero-sequence current input that are connected with low-voltage distribution transformer transformer outlet side N phase line, the output of armature winding A2 is connected with the input of secondary winding C1, the output of armature winding B2 is connected with the input of secondary winding A1, the output of armature winding C2 is connected with the input of secondary winding B1, secondary winding A1, B1, the output of C1 is the A of described transducer, B, C three-phase output end.
2. zero-sequence current conversion equipment, it is characterized in that: comprise for controlling the first circuit breaker of described conversion equipment break-make, zero-sequence current transducer claimed in claim 1, for controlling the second circuit breaker of zero-sequence current transducer, for controlling the protection control circuit of the second circuit breaker, for limiting the too high Surge Protector to described conversion equipment infringement of input voltage, for preventing input phase failure and the phase sequence mistake open phase protector to described conversion equipment infringement, air switch for the protection of open phase protector, for gathering the current transformer of zero-sequence current transducer input N phase line current value, for showing that current transformer gathers the ammeter of current value, for gathering the voltmeter of the first circuit breaker input three-phase voltage value and the time relay of restarting after disconnecting because of overcurrent for controlling the second circuit breaker, the N phase input of described zero-sequence current transducer is connected with the N phase line of low-voltage distribution transformer transformer outlet side, the A of described zero-sequence current transducer, B, C three-phase output end are connected with A, B, the C three-phase input end of the second circuit breaker, the A of the second circuit breaker, B, C three-phase output end are connected with A, B, the C three-phase input end of the first circuit breaker, and the A of the first circuit breaker, B, C three-phase output end are connected with A, B, the C phase line of low-voltage distribution transformer transformer outlet side.
3. zero-sequence current conversion equipment according to claim 2, is characterized in that: the A of described Surge Protector, B, C three-phase input end are connected with A, B, the C three-phase input end of the first circuit breaker, the output head grounding of Surge Protector; The input operating range of described Surge Protector is 440V, and when A, the B of Surge Protector, C triple line input voltage are during higher than 440V, Surge Protector earth connection is communicated with.
4. zero-sequence current conversion equipment according to claim 2, is characterized in that: described protection control circuit comprise AC220V power supply group, for receive open phase protector output signal often open control group, for change and the overcurrent sample circuit of the current value of amplified current instrument transformer secondary side collection, for exporting, control the second circuit breaker make-and-break signal control group, for the time relay of control time relay, often open group, time relay power supply group.
5. zero-sequence current conversion equipment according to claim 4, it is characterized in that: A, the B of the described air switch for the protection of open phase protector, C three-phase input end are connected with A, B, the C three-phase input end of the first circuit breaker, the A of described air switch, B, C three-phase output end are connected with A, B, the C three-phase input end of open phase protector, and the two-phase signal output part of described phase-lacking protective unit is connected with the control group of often opening of protection control circuit; When phase shortage and phase sequence mistake appear in A, B, the C three-phase input end of the air switch for the protection of open phase protector, the described control group of protection control circuit is to the second circuit breaker output break signal.
6. zero-sequence current conversion equipment according to claim 4, it is characterized in that: the current signal that described Current Transformer Secondary side output gathers is also connected with described overcurrent sample circuit, voltage signal after current conversion is amplified of overcurrent sample circuit output is also connected with described control group, and described control group monitors when voltage signal that overcurrent sample circuit exports is greater than reference voltage and exports break signal and be connected with the second circuit breaker; After the second circuit breaker opens circuit, described control group output time relay timing signal is also connected with the time relay, arrives after gate time time relay output channel signal, described control group is to the second circuit breaker output channel signal, and the second circuit breaker is communicated with again.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420219235.5U CN203826975U (en) | 2014-04-30 | 2014-04-30 | Zero-sequence current converter and zero-sequence current converting device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420219235.5U CN203826975U (en) | 2014-04-30 | 2014-04-30 | Zero-sequence current converter and zero-sequence current converting device |
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| CN203826975U true CN203826975U (en) | 2014-09-10 |
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| CN201420219235.5U Expired - Fee Related CN203826975U (en) | 2014-04-30 | 2014-04-30 | Zero-sequence current converter and zero-sequence current converting device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103928936A (en) * | 2014-04-30 | 2014-07-16 | 杭州千目电力科技有限公司 | Converter and converting device for reducing effect of zero-sequence current on transformer |
| CN106645930A (en) * | 2016-11-23 | 2017-05-10 | 浙江恩鸿电子有限公司 | Three-phase four-wire electric energy metering device having null line missing detection function |
-
2014
- 2014-04-30 CN CN201420219235.5U patent/CN203826975U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103928936A (en) * | 2014-04-30 | 2014-07-16 | 杭州千目电力科技有限公司 | Converter and converting device for reducing effect of zero-sequence current on transformer |
| CN103928936B (en) * | 2014-04-30 | 2016-08-17 | 杭州千目电力科技有限公司 | For reducing converter and the conversion equipment that transformer is affected by zero-sequence current |
| CN106645930A (en) * | 2016-11-23 | 2017-05-10 | 浙江恩鸿电子有限公司 | Three-phase four-wire electric energy metering device having null line missing detection function |
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