CN108054726A - A kind of circuit overcurrent control device - Google Patents
A kind of circuit overcurrent control device Download PDFInfo
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- CN108054726A CN108054726A CN201810095632.9A CN201810095632A CN108054726A CN 108054726 A CN108054726 A CN 108054726A CN 201810095632 A CN201810095632 A CN 201810095632A CN 108054726 A CN108054726 A CN 108054726A
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/50—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to the appearance of abnormal wave forms, e.g. ac in dc installations
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
- G01R19/16566—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533
- G01R19/16571—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533 comparing AC or DC current with one threshold, e.g. load current, over-current, surge current or fault current
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
The present invention relates to a kind of circuit overcurrent control devices, including housing, nameplate explanation are equipped with above the positive boss of housing and toggle switch, the toggle switch are connected with enclosure interior circuit board by conducting wire, installing plate is equipped in the upper and lower ends of housing.The circuit overcurrent control device can be in running order in breaker closing or power grid, and when having exciting current formation on circuit, detection line current and delayed releasing control prevent excitation from generating breaker malfunction and threading off.Using microcontroller technology, when electric current is more than setting multiple setting current, Cutoff current property and fast tripping protection is carried out immediately, can also carry out delay duration as needed adjusts.
Description
Technical field
The present invention relates to defeated, distribution technique field, a kind of more particularly to circuit overcurrent with high-voltage circuitbreaker cooperation controls
Device.
Background technology
In order to realize long-term uninterrupted power supply, it is necessary to constantly improve electric system and promote the power supply quality of electric system
And efficiency.Meanwhile when running into failure, the higher electric power system of intelligence degree can identify failure and take corresponding guarantor as early as possible
Shield measure, so as to further be protected to equipment.Protection equipment in this electric power system avoids failure and is triggered more
Big loss all to best direction goes work efficiency and maintenance cost to develop.Nowadays the development of electronic industrial technology such as fire
Such as the bitter edible plant.Much type ultra-voltage transformers are managed to be developed and put into production.However formed comparison, transformer are being protected
Protect this development and its slowly, it some times happens that the situation of tripping.
Compared with All other routes, the distribution line of 10kV is to apply most, quantity species more by electric system of today
It is more, while its dielectric level is than relatively low.The situation of relatively conventional obstruction normal operation mainly has following three kinds：It is alternate short
Road, circuit overcurrent and single-line to ground fault.If circuit occur above-mentioned first two failure, from system with it is shortest when
Between cut off circuit be very necessary.
Excitation surge current endangers less the safe operation of transformer, however it can generate relay protection more serious shadow
It rings.Because there is the requirement of super-pressure and long distance power transmission, high-power transformer becomes more and more popular.When power transformer quilt
When idle-loaded switching-on puts into power grid, transformer can generate larger excitation surge current.When Removal of external faults, voltage recover
It waits, transformer equally can also generate excitation surge current, make waveform largely lopsided, while may also cause protection misoperation.
Transformer excitation surge current under the situation of stable state is very small, is about 1% rated current size.If but go out
Existing above-mentioned two kinds of situations being previously mentioned, the increase of excitation surge current moment, the transient process of one about several cycle duration of generation, this
When excitation surge current it is related to short circuit current flow little.Simultaneously when operation, the situation of transformer short-time overload lotus and overvoltage
It happens occasionally.These multiple minor failures and substantial amounts of transient process can increase the damage probability of transformer.
And existing inrush current control fills pavilion in method frequently with following two principles, wherein secondary harmonic brake principle
There is problems with：1st, brake percentage is difficult to；2nd, possible None- identified symmetrically shoves；3rd, modern transformer magnetic raises the variation of characteristic, makes
Secondary harmonic component reduces when must shove, and protects easily malfunction.
Some problems can equally be faced to differentiate with interrupted angle principle：1st, higher sample rate is needed, thus will to hardware
Ask higher；2nd, need to take certain measure and satisfied the interval angle after closing with measuring CT.
The content of the invention
In view of the above-mentioned problems, the present invention in the case where overcoming the shortage of prior art, provides a kind of circuit overcurrent control dress
It puts, using the housing formed by high density SMC composite material pressure injections, special material makes it adapt to a variety of evils when running outdoors
Bad condition, can not only anticorrosive and good insulation preformance, fracture toughness is strong.
The present invention adopts the following technical scheme that：A kind of circuit overcurrent control device, including housing, circuit board, installing plate, shell
Circuit board is equipped in vivo, and installing plate is connected with housing；Housing is equipped with toggle switch, and toggle switch is connected with circuit board.
The housing is the square casing of SMC composite materials.
Toggle switch is installed on the front boss of the housing.
The housing is equipped with nameplate explanation.
The installing plate is connected with housing by frock hole.
The circuit board includes the current signal sampling module, microcontroller, output switch parameter and the tripping coil that are linked in sequence
Driving circuit and the switching value input circuit being connected with microcontroller；The switching value input circuit includes toggle switch, described
Toggle switch is connected with microcontroller.
The current signal sampling module includes the current signal sample circuit being linked in sequence, filtering and signal condition electricity
Road；The current signal sample circuit accesses electric current, and filtering and signal conditioning circuit are connected with microcontroller.
Circuit overcurrent control method, comprises the following steps：
1) current signal sampling module acquisition A, C phase current of circuit board；
2) discrete fourier decomposition is carried out respectively to A, C biphase current of the current effective value more than setting valve, every phase is obtained
The Half-cycle Fourier Algorithmfor of electric current and the difference current fundamental wave value of full wave Fourier algorithm sampled value and every phase current pass through all-wave fourier
The ratio for the difference current fundamental wave value that algorithm is calculated；
If any one ratio in biphase current is more than the threshold value of excitation surge current, then it is assumed that is shoved in circuit；It is no
Then, it is believed that occur overcurrent, short-circuit conditions in circuit；
3) when in the time of setting any phase current continuously occur shoving or overcurrent, short circuit, then send separating brake at this time and refer to
Order, the output of driving switch amount and tripping coil driving circuit complete protection act.
The difference current fundamental wave value of the Half-cycle Fourier Algorithmfor and full wave Fourier algorithm sampled value is obtained by following formula：
The ratio of difference current fundamental wave value：
In formula, N be per power frequency period sampling number, ik、ik+N/2Kth time sampled value and k+N/2 sampling are represented respectively
Value；I represents the current value of sampled point；IMRepresent Half-cycle Fourier Algorithmfor and the differential electricity of full wave Fourier algorithm sampled value at kth point
Flow fundamental wave value, KdzIt is the threshold value for judging excitation surge current；INRepresent the differential electricity that the full wave Fourier algorithm at kth point is calculated
Flow fundamental wave value.
AD controllers, the register of microcontroller by toggle switch are set, overcurrent, short circuit timer T1 is opened and shoves and determine
When device T2 delay.
In order to solve the limitation of braking principle, the present invention makees on the algorithm of each harmonic component of difference current with more
Change, widely applied full wave Fourier algorithm in original engineering is changed to Half-cycle Fourier Algorithmfor, since its algorithm data window is only half
A power frequency period, the response speed of algorithm is faster.
Calculus of finite differences has been used as backoff algorithm.The data window of full wave Fourier algorithm is power frequency period, and excitation surge current
Change by same period, therefore can not excitation surge current waveform be distinguished by the virtual value of full wave Fourier algorithm.But half-wave
Fourier algorithm is only to reflect the feature of waveform sample values in half period, thus Half-cycle Fourier Algorithmfor result of calculation and all-wave fourier
Algorithm result of calculation has notable difference, can preferably reflect peaked wave and interruption corner characteristics.
Identification and basis for estimation to excitation surge current.Since excitation surge current identical criterion reflects difference current fundametal compoment
Synthesis degree of asymmetry, and to sample frequency without particular/special requirement, and be not easy to be influenced by each harmonic, so we reset
Judge the threshold value of excitation surge current, by the difference of Half-cycle Fourier Algorithmfor and full wave Fourier algorithm and compared with formula draw Kdz
When=0.2, excitation surge current and fault current can be reliably distinguished.
The hardware components principle of circuit overcurrent control device is to take Current Transformer Secondary by current signal sampling module
Electric current, after send to difference current waveform comparison module and be compared, using CPU and peripheral circuit integrated computation draw a conclusion from
And buckle releaser is driven to complete protection act.The toggle switch connected with switching input module can be set whole outside device
Determine parameter.
Circuit overcurrent control device has used the measurement of DSP technologies in software section, largely instead of traditional big
Gas measuring contamination method has effectively eliminated the load effect that each analog module generates in hard ware measure, and has saved observing and controlling
Cost improves reaction speed and reliability.DSP technologies have basic advantage in terms of Digital Signal Processing, can eliminate by method
Influence of the error to measurement result precision, then high fdrequency component interference and nonlinear component, last profit are eliminated by FIR low-pass filtering
Fu's filtering is carried out to power frequency component with DFT transform, then can extract fundamental frequency exactly, accurately measure power factor.
Description of the drawings
Fig. 1 is the monnolithic case dimensional structure diagram of the present invention.
Fig. 2 is the nameplate schematic diagram of the present invention.
Fig. 3 is the hardware frame flow diagram of the present invention.
The current signal that Fig. 4 is the present invention gathers schematic diagram.
Fig. 5 is the wave simulation illustraton of model of the present invention.
Fig. 6 is the circuit board module schematic diagram of the present invention.
Drawing reference numeral：Housing -1, toggle switch -2, circuit board -3, nameplate explanation -4, installing plate -5, single chip circuit -
3.4th, switching value input circuit -3.1, current signal sample circuit -3.2, filtering and signal conditioning circuit -3.3, output switch parameter
And tripping coil driving circuit -3.5.
Specific embodiment
Below with reference to the embodiments and with reference to the accompanying drawing the technical solutions of the present invention will be further described.
Embodiment as shown in Figure 1, Figure 2, shown in Fig. 3, Fig. 4, Fig. 5, a kind of circuit overcurrent control device is opened including housing 1, dial-up
Close 2, circuit board 3, nameplate illustrates 4, installing plate 5, the boss on control device housing, can be effectively equipped with toggle switch 2 is adjusted
Control is shoved, overcurrent delay protection, quick-break, quick-break delay, delay of closing a floodgate, and parameter can be adjusted, using micro-control
Device technology processed, when line current be more than toggle switch 2 set by multiple setting current when, circuit board judges scanning frequency of going forward side by side immediately
Disconnected protection, can also carry out delay operation as needed.
The housing is formed for rectangle by high density SMC composite material pressure injections, and special material makes it run outdoors
The a variety of mal-conditions of Shi Shiying, can not only anticorrosive and good insulation preformance, fracture toughness is strong.The installing plate and housing one
Connection, it is solid and reliable, 6 frock holes of Φ are provided with, are easily installed.
On the front boss of the housing, toggle switch is installed, can be by adjusting upper-lower position be switched, setting parameter is fixed
Value.The circuit board is installed in housing, is connected with toggle switch.The nameplate illustrates the definite value of clear embodiment
Setting means.
The circuit board samples electricity including single chip circuit (3.4), switching value input circuit (3.1), current signal
Road (3.2), filtering and signal conditioning circuit (3.3), output switch parameter and tripping coil driving circuit (3.5) composition, and switch
The toggle switch (2) that amount input circuit (3.1) is connected, can set setting parameter outside device.As shown in Figure 6.
Criterion：The present invention first passes around the theory analysis of difference current wave character, draws excitation surge current criterion, both by half
The difference (a) of ripple fourier algorithm and full wave Fourier algorithm can be used for distinguishing excitation surge current and internal fault current, and anti-locking apparatus misses
Action, formula are as follows：
In formula (a), N be per power frequency period sampling number, ik、ik+N/2Represent that kth time sampled value is adopted with k+N/2 times respectively
Sample value.In formula (a), IMIt represents formula (a) calculated value at kth point, represents by Half-cycle Fourier Algorithmfor and full wave Fourier algorithm calculating
Obtained difference current fundamental wave value, wherein KdzIt is the threshold value formula (b) for judging excitation surge current, takes 0.2 can be dependably distinguished from encouraging
Magnetic shoves and fault current.
Emulation：The waveform characteristic of excitation surge current in order to better understand, emulation during transformer during no-load closing of the present invention, relates to
And the operating condition to actual track, now by taking real transformer on 10kV circuits as an example, simulation model is shown in Fig. 5.
Hardware principle：As shown in figure 3, circuit overcurrent control device of the present invention is by microcontroller MEGA48PA and periphery electricity
Road (3.4), switching value input circuit (3.1), current signal sample circuit (3.2), filtering and signal conditioning circuit (3.3) are opened
Pass amount output and tripping coil driving circuit (3.5) composition.The inrush current control is used primarily on outdoor aerial circuit without single
Only power supply power supply, meanwhile, it is used cooperatively together with vacuum circuit breaker again, therefore, current transformer in vacuum circuit breaker
The transformed device minitype CT 3 of secondary current is converted to the power supply for being suitable for the controller.
Tripping coil driving circuit is different according to the operating mechanism of vacuum circuit breaker, and driving method is also different (to be refused herein
It repeats).Spring operating mechanism is generally used at present.On operating principle, spring operating mechanism is by tripping coil impact lock dress
It puts, completes sub-switching operation.
As shown in figure 4, when the magnitude of current gathers, minitype CT 1 and CT2 first is by the big electricity of line current mutual inductor secondary side
Stream signal is converted into low current signal, then becomes voltage signal by adjustable resistance.Since the present invention is it is desirable that electric current, electricity
Fundamental wave and second harmonic signal in pressure is, it is necessary to which filter circuit filters the harmonic wave of 3 times or more in signal.Therefore, the present invention uses
Second order voltage controlled voltage source low-frequency filter circuit, it has the maximum attenuation frequency of -40dB/10 frequencys multiplication and is decaying to greatest extent
During garbage signal so that useful signal is smaller be subject to being influenced.
Software principle：Software section mainly samples line current, the state current by calculating identification circuit
And different delay times (such as Fig. 2) is realized according to the setting of toggle switch.
The present invention is AD converted using ADC inside microcontroller and (is converted analog signals into digital signal), specific steps
For：
1) initialize, AD controllers, register are set, open overcurrent, short circuit timer T1 and the timer T2 that shoves；
2) to A, two tunnel analog channel of C phase currents gathers at 24 points respectively；
3) A, C biphase current are calculated and judges whether current effective value is more than setting valve, otherwise exits this subroutine module；
It is that discrete fourier decomposition is carried out to the phase current for being more than setting valve, Half-cycle Fourier Algorithmfor and full wave Fourier algorithm sampling is obtained
Difference (the ratio for the difference current fundamental wave value that formula a) and full wave Fourier algorithm are calculated of value.
If ratio is more than threshold value (the formula b), then it is assumed that shove in circuit, determine overcurrent, short circuit of excitation surge current
When device T1 reset, resampling A, C phase current two-way analog channel, return to step 3；If ratio is less than the door of excitation surge current
Value, it is believed that occur overcurrent, short-circuit conditions in circuit, timer T1 is reset to shoving, and also only samples A, C phase current two-way mould again
Intend passage, return to step 3.One of them of both T1 or T2 time then, it was demonstrated that occur continuing within the time of setting
Property shove or overcurrent, short circuit, then send at this time separating brake instruction.
Claims (10)
1. including housing (1), circuit board (3), installing plate (5), circuit is equipped in housing (1) for a kind of circuit overcurrent control device
Plate (3), installing plate (5) are connected with housing (1)；It is characterized in that：Housing (1) is equipped with toggle switch (2), toggle switch (2)
It is connected with circuit board (3).
2. circuit overcurrent control device described in accordance with the claim 1, it is characterised in that：The housing (1) is SMC composite materials
Square casing.
3. circuit overcurrent control device described in accordance with the claim 1, it is characterised in that：On the front boss of the housing (1)
Install toggle switch (2).
4. circuit overcurrent control device described in accordance with the claim 1, it is characterised in that：The housing is equipped with nameplate explanation
(4)。
5. circuit overcurrent control device described in accordance with the claim 1, it is characterised in that：The installing plate (5) is logical with housing (1)
Cross the connection of frock hole.
6. circuit overcurrent control device described in accordance with the claim 1, it is characterised in that：The circuit board (3) includes order and connects
The current signal sampling module, microcontroller, output switch parameter and the tripping coil driving circuit that connect and what is be connected with microcontroller open
Measure input circuit in pass；The switching value input circuit includes toggle switch (2), and the toggle switch (2) is connected with microcontroller.
7. according to the circuit overcurrent control device described in claim 6, it is characterised in that：The current signal sampling module includes
Current signal sample circuit, filtering and the signal conditioning circuit being linked in sequence；The current signal sample circuit accesses electric current, filter
Involve signal conditioning circuit to be connected with microcontroller.
8. circuit overcurrent control method, which is characterized in that comprise the following steps：
1) current signal sampling module acquisition A, C phase current of circuit board (3)；
2) discrete fourier decomposition is carried out respectively to A, C biphase current of the current effective value more than setting valve, every phase current is obtained
Half-cycle Fourier Algorithmfor and full wave Fourier algorithm sampled value difference current fundamental wave value and pass through full wave Fourier algorithm per phase current
The ratio for the difference current fundamental wave value being calculated；
If any one ratio in biphase current is more than the threshold value of excitation surge current, then it is assumed that is shoved in circuit；Otherwise, recognize
To occur overcurrent, short-circuit conditions in circuit；
3) when in the time of setting any phase current continuously occur shoving or overcurrent, short circuit, then send separating brake instruction at this time, drive
Dynamic output switch parameter and tripping coil driving circuit complete protection act.
9. according to the circuit overcurrent control method described in claim 8, which is characterized in that the Half-cycle Fourier Algorithmfor and all-wave Fu
The difference current fundamental wave value of family name's algorithm sampled value is obtained by following formula：
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The ratio of difference current fundamental wave value：
In formula, N be per power frequency period sampling number, ik、ik+N/2Kth time sampled value and k+N/2 sampled value are represented respectively；i
Represent the current value of sampled point；IMRepresent Half-cycle Fourier Algorithmfor and the difference current base of full wave Fourier algorithm sampled value at kth point
Wave number, KdzIt is the threshold value for judging excitation surge current；INRepresent the difference current base that the full wave Fourier algorithm at kth point is calculated
Wave number.
10. according to the circuit overcurrent control method described in claim 8, which is characterized in that set monolithic by toggle switch (2)
AD controllers, the register of machine open the delay of overcurrent, short circuit timer T1 and the timer T2 that shoves.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810095632.9A CN108054726A (en) | 2018-01-31 | 2018-01-31 | A kind of circuit overcurrent control device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810095632.9A CN108054726A (en) | 2018-01-31 | 2018-01-31 | A kind of circuit overcurrent control device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN108054726A true CN108054726A (en) | 2018-05-18 |
Family
ID=62125113
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810095632.9A Pending CN108054726A (en) | 2018-01-31 | 2018-01-31 | A kind of circuit overcurrent control device |
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| CN (1) | CN108054726A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101242096A (en) * | 2008-02-04 | 2008-08-13 | 南京因泰莱配电自动化设备有限公司 | Current protection control method and device |
| CN101262129A (en) * | 2008-04-24 | 2008-09-10 | 南京因泰莱配电自动化设备有限公司 | Current protection control method and device for 24kV vacuum breaker |
| CN206806260U (en) * | 2017-04-18 | 2017-12-26 | 河南华盛隆源电气有限公司 | A kind of outdoor inrush current control |
| CN207947601U (en) * | 2018-01-31 | 2018-10-09 | 大连北方真空开关有限公司 | A kind of circuit overcurrent control device |
-
2018
- 2018-01-31 CN CN201810095632.9A patent/CN108054726A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101242096A (en) * | 2008-02-04 | 2008-08-13 | 南京因泰莱配电自动化设备有限公司 | Current protection control method and device |
| CN101262129A (en) * | 2008-04-24 | 2008-09-10 | 南京因泰莱配电自动化设备有限公司 | Current protection control method and device for 24kV vacuum breaker |
| CN206806260U (en) * | 2017-04-18 | 2017-12-26 | 河南华盛隆源电气有限公司 | A kind of outdoor inrush current control |
| CN207947601U (en) * | 2018-01-31 | 2018-10-09 | 大连北方真空开关有限公司 | A kind of circuit overcurrent control device |
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