CN204290260U - Anti-harmonic wave interference type aftercurrent action protecting equipment - Google Patents
Anti-harmonic wave interference type aftercurrent action protecting equipment Download PDFInfo
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- CN204290260U CN204290260U CN201420761732.8U CN201420761732U CN204290260U CN 204290260 U CN204290260 U CN 204290260U CN 201420761732 U CN201420761732 U CN 201420761732U CN 204290260 U CN204290260 U CN 204290260U
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Abstract
A kind of anti-harmonic wave interference type aftercurrent action protecting equipment, comprising: current signal detecting unit obtains the residual current in supply line; Electric current pretreatment unit carries out filtering to the harmonic wave of residual current, and carries out preliminary treatment to residual current signal, makes residual current signal amplitude reach the treatable level range of residual current detection unit; Residual current detection unit carries out current amplitude and harmonic wave content analysis to pretreated residual current, and produces deciliter control signal; Deciliter control unit, based on a deciliter control signal, is connected or disjunction supply line; Wherein, when pretreated residual current current value exceedes current threshold, and pretreated harmonic content exceedes setting threshold values, and described residual current detection unit controls deciliter control unit can not perform breaking operation.
Description
Technical field
The utility model relates to aftercurrent action protecting technical field, particularly relates to a kind of anti-harmonic wave interference type aftercurrent action protecting equipment.
Background technology
At present general aftercurrent action protecting equipment be all the size of the residual electricity flow valuve detected as criterion, as long as detect that the residual current size in circuit exceedes the threshold values preset, namely this protective device performs protection act.Along with the growth in the living standard of users and the application of clean energy resource, the application capacity of frequency conversion equipment is in quick growth, the installed capacity of photovoltaic generation is also in raising at full speed, and the extensive application of these non-linear equipments, also significantly improves the harmonic pollution of voltage Grid.The significantly increase of harmonic content in low voltage electric network, directly has influence on the normal operation of the aftercurrent action protecting equipment of extensive use in low voltage electric network.Because humorous wave frequency is higher, there is intrinsic distributed capacitance in the supply line of low voltage electric network, for the first-harmonic of 50Hz, the leakage residual current that this intrinsic distributed capacitance causes is less, but for harmonic wave, the intrinsic distribution capacitive reactance in circuit can reduce along with the increase of frequency, thus causes the leakage residual current in circuit to increase, especially 3n subharmonic, increases with the amplitude of 3 times for the leakage residual current in these 3n subharmonic circuits.This will significantly increase the misoperation probability of the aftercurrent action protecting equipment applied in low voltage electric network, thus have influence on the power supply reliability of voltage Grid.
Based on the harmonic analysis of residual current in above-mentioned low voltage electric network; now stricter requirement is proposed for aftercurrent action protecting equipment; require that aftercurrent action protecting equipment has anti-harmonic wave interference function; make RCD not by the humorous wave interference in electrical network, effectively can ensure the normal operation of low voltage electric network.
Utility model content
The problem that the utility model solves is to provide a kind of anti-harmonic wave interference type aftercurrent action protecting equipment; harmonic management and analysis can be carried out to the residual current detected in circuit; calculate the total harmonic distortion detected in residual current; the action assistant criteria that transfinites using this total harmonic distortion as aftercurrent action protecting equipment, improves the anti-misoperation ability of aftercurrent action protecting equipment.
For solving the problem, the utility model embodiment provides a kind of anti-harmonic wave interference type aftercurrent action protecting equipment, comprising: current signal detecting unit, electric current pretreatment unit, residual current detection unit and deciliter control unit;
Described current signal detecting unit is for obtaining the residual current in supply line;
Described electric current pretreatment unit, carries out filtering to the harmonic wave of residual current, and carries out preliminary treatment to residual current signal and make residual current signal amplitude reach the treatable level range of residual current detection unit;
Described residual current detection unit carries out residual current amplitude and harmonic analysis to pretreated residual current, and produces deciliter control signal;
Described deciliter control unit, based on a deciliter control signal, is connected or disjunction supply line;
Wherein, when pretreated residual current amplitude exceedes residual current acting threshold value, and pretreated harmonic content exceedes setting harmonic content threshold values, and described residual current detection unit controls deciliter control unit can not perform breaking operation.
Optionally, described electric current pretreatment unit comprises signal amplifier, harmonic filter and level translator.
Optionally, described harmonic filter comprises: the first electric capacity, second electric capacity, first load resistance, second resistance, 3rd resistance, first limiter diode, second limiter diode and operational amplifier, described first electric capacity is electric capacity of uncoupling, described first electric capacity, first load resistance, first limiter diode, second limiter diode is with the parallel connection of current signal detecting unit and the direction of described first limiter diode and the second limiter diode is contrary, described second electric capacity, second resistance, 3rd resistance and operational amplifier form low-pass filter amplifier, wherein the second electric capacity, 3rd resistance composition RC resonant tank.
Optionally, described current signal detecting unit is zero sequence current mutual inductor.
Optionally, described residual current detection unit comprises A/D change-over circuit, current value testing circuit, harmonic content testing circuit and comparison circuit, pretreated residual current is changed through A/D, utilize current amplitude calculate and harmonic wave content analysis acquisition residual current amplitude and residual current in harmonic content, the residual current amplitude recorded and residual current acting threshold value are compared, the harmonic content recorded and setting harmonic content threshold values are compared, judge, the need of connection or disjunction power supply circuits, to produce corresponding deciliter control signal.
Optionally, described residual current detection unit is integrated in MCU.
Optionally, described MCU is the concrete model that ST Microelectronics produces is the M3 core ARM high-performance microcontroller of STM32F103RBT6.
Optionally, also comprise alarm signal output unit, when pretreated residual current current value exceedes current threshold, and pretreated harmonic content exceedes setting threshold values, utilizes alarm signal output unit to send alarm signal.
Compared with prior art, the technical program has the following advantages:
The utility model first carries out harmonic to residual current and carries out preliminary treatment; then harmonic management and analysis are carried out to the residual current detected in circuit; calculate the total harmonic distortion detected in residual current; the action assistant criteria that transfinites using this total harmonic distortion as aftercurrent action protecting equipment, improves the anti-misoperation ability of aftercurrent action protecting equipment.
Accompanying drawing explanation
Fig. 1 is the structural representation of the anti-harmonic wave interference type aftercurrent action protecting equipment of the utility model embodiment;
Fig. 2 is the harmonic filter of the utility model embodiment and the structural representation of level switch module;
Fig. 3 is the structural representation of the reference level generation module of the utility model embodiment;
Fig. 4 is the structural representation of the synchronizing signal generation module of the utility model embodiment.
Embodiment
Below in conjunction with accompanying drawing, by specific embodiment, clear, complete description is carried out to the technical solution of the utility model.
Please refer to Fig. 1, Fig. 1 is the anti-harmonic wave interference type aftercurrent action protecting equipment of the utility model embodiment, comprising: current signal detecting unit 10, electric current pretreatment unit 20, residual current detection unit 30 and deciliter control unit 40;
Described current signal detecting unit 10 is for obtaining the residual current in supply line;
Described electric current pretreatment unit 20, carries out filtering to the harmonic wave of residual current, and carries out preliminary treatment to residual current signal and make residual current signal amplitude reach the treatable level range of residual current detection unit;
Described residual current detection unit 30 carries out current amplitude and harmonic wave content analysis to pretreated residual current, and produces deciliter control signal;
Described deciliter control unit 40, based on a deciliter control signal, is connected or disjunction supply line;
Display unit 50, for showing detection and control result.
Wherein, when pretreated residual current current value exceedes current threshold, and pretreated harmonic content exceedes setting threshold values, and described residual current detection unit controls deciliter control unit can not perform breaking operation.
In the present embodiment, described current signal detecting unit 10 is zero sequence current mutual inductor, utilize zero sequence current mutual inductor as signal detection component, all leakage currents in low-voltage circuit are all induced by this precision transformer, and deliver to signal processing circuit and process.The minimum induced current of the zero sequence current mutual inductor of the present embodiment should be less than 5mA, ensures that faint small area analysis signal can detect accurately.
Obtain the residual current in supply line when current signal detecting unit 10 after, residual current signal is sent to pretreatment unit 20 and carries out preliminary treatment.Described electric current pretreatment unit 20 comprises the level switch module, reference level generation module, synchronizing signal generation module etc. of harmonic filter and necessity.The residual current signal that described current signal pretreatment unit 20 will detect in zero sequence current mutual inductor, is undertaken amplifying by harmonic filter, the process such as filtering, and corresponding level conversion of carrying out, reach the treatable level range of microcontroller.
There is intrinsic distributed capacitance in the supply line due to existing low voltage electric network, for the first-harmonic of 50Hz, the leakage residual current that this intrinsic distributed capacitance causes is less, but for harmonic wave, intrinsic distribution capacitive reactance in circuit can reduce along with the increase of frequency, thus causes the leakage residual current in circuit to increase, especially 3n subharmonic, leakage residual current in these 3n subharmonic circuits is increased with the amplitude of 3 times, residual current can be caused to increase.When utilizing existing aftercurrent action protecting equipment to protect, as long as detect that residual current exceedes current threshold, all can perform breaking operation, supply line is disconnected.The leakage residual current caused due to intrinsic distributed capacitance is less; even if the residual current detected exceedes current threshold; also little on the impact of power supply circuits; this does not need to disconnect supply line; adopt existing aftercurrent action protecting equipment will significantly increase the misoperation probability of the aftercurrent action protecting equipment applied in low voltage electric network, thus have influence on the power supply reliability of voltage Grid.
And in the present embodiment; first filtering is carried out to the harmonic wave of residual current; the filtering content of the harmonic wave of residual current is significantly reduced; when residual current detection unit inspection goes out harmonic content still higher than setting threshold; even if the residual electricity flow valuve surveyed has exceeded the predetermined current threshold of protector; but because harmonic content exceeds standard, protector only does the operation of harmonic wave overload alarm, and no longer performs the sub-switching operation that transfinites.Can not make RCD misoperation not occur to greatest extent like this, improve power supply reliability.
Please refer to Fig. 2, for the harmonic filter of electric current pretreatment unit and the structural representation of level switch module of the present embodiment, described harmonic filter comprises: the first electric capacity C1, second electric capacity C2, first load resistance R1, second resistance R2, 3rd resistance R3, first limiter diode D1, second limiter diode D2 and operational amplifier IC1, described first electric capacity C1 is electric capacity of uncoupling, the capacitive reactance Rc=1/2 π fc of the first electric capacity C1, for the power frequency component of 50Hz, its capacitive reactance is about 32k Ω, but for 3k time, and more high order harmonic component, its capacitive reactance will significantly reduce, thus the decay of this kind of signal is also significantly increased.Described first electric capacity C1, first load resistance R1, first limiter diode D1, second limiter diode D2 is with zero sequence current mutual inductor parallel connection and the direction of described first limiter diode D1 and the second limiter diode D2 is contrary, described second electric capacity C2, second resistance R2, 3rd resistance R3 and operational amplifier IC1 forms low-pass filter amplifier, wherein the second electric capacity C2, 3rd resistance R3 forms RC resonant tank, resonance frequency design is at 100Hz, like this, for the signal being less than 100Hz, this amplifier can normally amplify, but for being greater than the signal of 100Hz, along with the increase of frequency, the decay of signal is also along with increase, therefore, this circuit is for high order harmonic component signal, 3n subharmonic is particularly inhibited, namely the function that the current signal simultaneously achieving normal frequency amplifies and decays to harmonic wave.
In the present embodiment, described level switch module can realize automatic range switching function, because the amplitude range of residual current signal is comparatively large, from several milliamperes to tens amperes, realize the linear measurement in whole current range, the level shifting circuit that certainly will range will be adopted to switch.
Please refer to Fig. 3, is the structural representation of the reference level generation module of the present embodiment, and the A/D conversion that described reference level generation module is MCU provides reference, carries out level deviation simultaneously, make this signal adaptation MCU carry out signal transacting to AC signal.
Please refer to Fig. 4, be the structural representation of the synchronizing signal generation module of the present embodiment, described synchronizing signal generation module is carried out synchronously, for ensureing the accuracy of input to AC power frequency signal.
In the present embodiment, described residual current detection unit 30 is integrated in MCU, and described MCU is the concrete model that ST Microelectronics produces is the M3 core ARM high-performance microcontroller of STM32F103RBT6.This microcontroller cost performance is higher, complicated scientific calculation can be carried out, the various signals of input are processed, comprise residual current signal, key operation signal and deciliter control signal etc. that control is necessary, the information of necessity is shown by the man-machine interface such as charactron or liquid crystal simultaneously.
In the present embodiment, described residual current detection unit 30 comprises A/D change-over circuit, current value testing circuit, harmonic content testing circuit and comparison circuit, pretreated residual current is changed through A/D, utilize current amplitude calculate and harmonic wave content analysis acquisition residual current amplitude and residual current in 3n subharmonic content, the residual current current amplitude recorded and residual current acting threshold value are compared, the 3n subharmonic content recorded and setting harmonic content threshold values are compared, judge the need of connection or disjunction power supply circuits, produce corresponding deciliter control signal.Wherein, harmonic content obtains after the fft analysis by carrying out A/D conversion the data obtained to the residual current signal detected; if 3 subharmonic and more higher harmonic content exceed setting threshold values; even if the residual current amplitude surveyed has exceeded the predetermined threshold values of protector; but because harmonic content exceeds standard; protector only does the operation of harmonic wave overload alarm, and no longer performs the sub-switching operation that transfinites.And when residual electricity flow valuve has exceeded the predetermined threshold values of protector, and harmonic content does not exceed standard, and just performs the operation of disjunction power supply circuits.Only in this way can not make RCD generation misoperation to greatest extent, improve power supply reliability.
In the present embodiment, also comprise display unit 50, be charactron or liquid crystal display screen etc., described display unit is connected with MCU, for showing detection and control result.Described display unit can also as alarm signal output unit, and when pretreated residual current current value exceedes current threshold, and pretreated harmonic content exceedes setting threshold values, utilizes alarm signal output unit to send alarm signal.
Described deciliter control unit 40 is actuators of residual current operated protective device, and this mechanism performs all control commands of MCU, and under line fault conditions, disjunction major loop, connects major loop under normal condition.Even if the residual electricity flow valuve surveyed has exceeded the predetermined threshold values of protector, when harmonic content exceeds standard, protector only does the operation of harmonic wave overload alarm, and no longer performs the sub-switching operation that transfinites.And when residual electricity flow valuve has exceeded the predetermined threshold values of protector, and harmonic content does not exceed standard, and just performs the operation of disjunction power supply circuits.
Although the utility model with preferred embodiment openly as above; but it is not for limiting the utility model; any those skilled in the art are not departing from spirit and scope of the present utility model; the Method and Technology content of above-mentioned announcement can be utilized to make possible variation and amendment to technical solutions of the utility model; therefore; every content not departing from technical solutions of the utility model; the any simple modification done above embodiment according to technical spirit of the present utility model, equivalent variations and modification, all belong to the protection range of technical solutions of the utility model.
Claims (10)
1. an anti-harmonic wave interference type aftercurrent action protecting equipment, is characterized in that, comprising: current signal detecting unit, electric current pretreatment unit, residual current detection unit and deciliter control unit;
Described current signal detecting unit is for obtaining the residual current in supply line;
Described electric current pretreatment unit, carries out filtering to the harmonic wave of residual current, and carries out preliminary treatment to residual current and make residual current reach the treatable level range of residual current detection unit;
Described residual current detection unit carries out current value and harmonic analysis to pretreated residual current, and produces deciliter control signal;
Described deciliter control unit, based on a deciliter control signal, is connected or disjunction supply line;
Wherein, when pretreated residual current current value exceedes current threshold, and pretreated harmonic content exceedes setting threshold values, and a described residual current detection unit controls deciliter control unit does not perform breaking operation.
2. anti-harmonic wave interference type aftercurrent action protecting equipment as claimed in claim 1, it is characterized in that, described electric current pretreatment unit comprises signal amplifier, harmonic filter and/or level translator.
3. anti-harmonic wave interference type aftercurrent action protecting equipment as claimed in claim 1, it is characterized in that, described harmonic filter comprises: the first electric capacity, second electric capacity, first load resistance, second resistance, 3rd resistance, first limiter diode, second limiter diode and operational amplifier, described first electric capacity is electric capacity of uncoupling, described first electric capacity, first load resistance, first limiter diode, second limiter diode is with the parallel connection of current signal detecting unit and the direction of described first limiter diode and the second limiter diode is contrary, described second electric capacity, second resistance, 3rd resistance and operational amplifier form low-pass filter amplifier, wherein the second electric capacity, 3rd resistance composition RC resonant tank.
4. anti-harmonic wave interference type aftercurrent action protecting equipment as claimed in claim 1, it is characterized in that, described current signal detecting unit is zero sequence current mutual inductor.
5. anti-harmonic wave interference type aftercurrent action protecting equipment as claimed in claim 1, it is characterized in that, described residual current detection unit comprises A/D change-over circuit, current value testing circuit, harmonic content testing circuit and comparison circuit, pretreated residual current is changed through A/D, current value testing circuit and harmonic wave content detection circuit is utilized to obtain harmonic content in residual electricity flow valuve and residual current, the residual current current value recorded and current threshold are compared, the harmonic content recorded and setting threshold values are compared, judge the need of connection or disjunction power supply circuits, produce corresponding deciliter control signal.
6. the anti-harmonic wave interference type aftercurrent action protecting equipment as described in claim 1 or 4, it is characterized in that, described harmonic wave is 3n subharmonic.
7. anti-harmonic wave interference type aftercurrent action protecting equipment as claimed in claim 1, it is characterized in that, described residual current detection unit is integrated in MCU.
8. anti-harmonic wave interference type aftercurrent action protecting equipment as claimed in claim 7, it is characterized in that, also comprise display unit, described display unit is connected with MCU, for showing detection and control result.
9. anti-harmonic wave interference type aftercurrent action protecting equipment as claimed in claim 1, is characterized in that, described MCU is the concrete model that ST Microelectronics produces is the 3 core ARM high-performance microcontrollers of STM32F103RBT6M.
10. anti-harmonic wave interference type aftercurrent action protecting equipment as claimed in claim 1; it is characterized in that; also comprise alarm signal output unit; when pretreated residual current current value exceedes current threshold; and pretreated harmonic content exceedes setting threshold values, alarm signal output unit is utilized to send alarm signal.
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| CN201420761732.8U CN204290260U (en) | 2014-12-05 | 2014-12-05 | Anti-harmonic wave interference type aftercurrent action protecting equipment |
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| CN201420761732.8U CN204290260U (en) | 2014-12-05 | 2014-12-05 | Anti-harmonic wave interference type aftercurrent action protecting equipment |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111693800A (en) * | 2020-05-09 | 2020-09-22 | 国网湖南省电力有限公司 | Action characteristic test method and circuit of leakage protection action device |
| CN116845822A (en) * | 2023-07-11 | 2023-10-03 | 北京达三江电器设备厂 | Anti-interference intelligent residual current action protector system |
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2014
- 2014-12-05 CN CN201420761732.8U patent/CN204290260U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111693800A (en) * | 2020-05-09 | 2020-09-22 | 国网湖南省电力有限公司 | Action characteristic test method and circuit of leakage protection action device |
| CN116845822A (en) * | 2023-07-11 | 2023-10-03 | 北京达三江电器设备厂 | Anti-interference intelligent residual current action protector system |
| CN116845822B (en) * | 2023-07-11 | 2024-01-26 | 北京达三江电器设备厂 | Anti-interference intelligent residual current action protector system |
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