CN101132127A - Electric network state detecting method used for creepage protector - Google Patents
Electric network state detecting method used for creepage protector Download PDFInfo
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- CN101132127A CN101132127A CNA2007100705055A CN200710070505A CN101132127A CN 101132127 A CN101132127 A CN 101132127A CN A2007100705055 A CNA2007100705055 A CN A2007100705055A CN 200710070505 A CN200710070505 A CN 200710070505A CN 101132127 A CN101132127 A CN 101132127A
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Abstract
This invention relates to the electric network detection method for the earth leakage protective device (ELPD). In the prior art technique, malfunction of ELPD often occurs due to the fault of detection caused by interference of electric network. This invention steps are: the electric signal from electric network is reshaped, filtered (removing interference), and then the produced new square signal is transmitted. If the new square signal, within 20mS after producing one fall-edge, produces another rise-edge, the on-state of electric network is determined; if not, being the off-state. From the time of first rise-edge of the new signal from lower to higher electrical level, the output is continuous high electrical level signal; but during other time, output is low electrical level. In this invention, network state ac signal of 50Hz is transformed into dc signal, being convenient for treatment by the earth leakage protective device.
Description
Technical field
The present invention relates to a kind of detection technique, be specifically related to a kind of electric network state detecting method that is used for earth leakage protective device.
Background technology
The total level of the two-phase earth leakage protective device that has the closing function monitoring of need leaking electricity to the electrical network in a big way guarantees the fail safe and the reliability of interior in a big way operation of power networks.The total grade of earth leakage protective device that quite a few is arranged at present also has the reclosing function except having the detection of electrical leakage function.The realization of reclosing function need detect (promptly the state to switch detects) to the state of electrical network, and total level earth leakage protective device is made the preliminary judgement of whether closing a floodgate according to testing result, in conjunction with other factors, makes action.And the interference ratio on the electrical network is bigger, is easy to detect wrong state and causes the misoperation of total level earth leakage protective device.And electrical network transmission is the alternating current of 50Hz, and a total level earth leakage protective device deals with also relatively difficulty.
Summary of the invention
Purpose of the present invention is exactly at the deficiencies in the prior art; a kind of electric network state detecting method that is used for earth leakage protective device is proposed; can realize that earth leakage protective device can detect electric network state exactly existing on the electrical network under the disturbed condition; make earth leakage protective device make correct operation; and the AC signal of electrical network can be converted to direct current signal, earth leakage protective device be handled be more prone to.
The present invention includes following steps:
1, the signal of telecommunication that will be input to electrical network in the earth leakage protective device carries out shaping, if the signal of telecommunication of input is the sine wave signal of 50Hz, the signal of telecommunication is become square-wave signal through after the shaping, and square-wave signal comprises high level and low level at interval; If the signal of telecommunication of input is a low level, then electrical network is an off-state, with direct output low level after the shaping of signal of telecommunication process.
The shaping methods that sine wave signal is converted to square-wave signal is to realize by the reverser of two series connection.
2, the high level to each cycle of the square-wave signal of step 1 shaping carries out timing, when if the high level timing time of one-period is greater than set point t (0.5 millisecond≤t≤2 milliseconds) in the square-wave signal after the shaping, then this high level time in the square-wave signal is reduced time t, as the high level output of new square-wave signal; If the high level timing time of the square-wave signal one-period after the shaping is less than set point t, then this section period is as the low level output of new square-wave signal.
If another rising edge (being that each new square-wave signal low level time is less than 20 milliseconds) occurs in 20 milliseconds in the new square-wave signal of 3 steps 2 output behind each trailing edge, then step 2 is output as continuous square-wave signal, and this moment, electric network state was conducting;
If another rising edge do not occur after 20 milliseconds behind certain trailing edge in the new square-wave signal of step 2 output, then this moment, electric network state disconnected.
Described rising edge is for being the moment of high level by low transition; Described trailing edge is that high level is converted to the low level moment.
4, under the electrical network conducting state, from new square-wave signal to first rising edge of high level constantly by low level, the high level signal that output continues, the moment that does not occur another rising edge after 20 milliseconds in new square-wave signal behind certain trailing edge begins output low level.
Step 1 realizes by waveform-shaping module among the present invention, the waveform-shaping module structure is very simple, only constitute by two reverser series connection, but can realize the function of waveform shaping well, if electric network state is conducting, then Shu Ru electric network state signal is the sine wave signal of 50Hz, becomes square-wave signal through after the shaping; If electric network state disconnects, then Shu Ru electric network state signal is a low level, still is low level after the process shaping.
Step 3 and step 4 realize that by judging continuity module and alternating current-direct current conversion module these two modules combine on circuit.Judgement continuity module is judged the new square-wave signal of step 2 output, when another rising edge occurring in 20 milliseconds behind each trailing edge in the new square-wave signal of step 2 output, then step 2 is output as continuous square-wave signal, shown that in filtering the state of electrical network is conducting under the situation about disturbing; If another rising edge do not occur after 20 milliseconds behind certain trailing edge in the new square-wave signal of step 2 output, show that then the state of electrical network this moment disconnects.Make under the electrical network conducting state by the alternating current-direct current conversion module then, from new square-wave signal to first rising edge of high level constantly by low level, the high level signal that output continues, the moment that does not occur another rising edge after 20 milliseconds in new square-wave signal behind certain trailing edge begins output low level.Finished the function of judging electric network state and being translated into direct current signal.
The inventive method is by waveform shaping, interference filtering, judgement continuity and the AC-DC conversion realization measuring ability to electric network state; after having filtered the interference on the electrical network; the alternating current status signal of 50Hz on the electrical network is changed; realized when the electrical network conducting, extracting high level signal; electrical network extracts the function of low level signal when disconnecting, offer earth leakage protective device as the basis of closing a floodgate and judging.
The present invention can get rid of the interference on the electrical network; correctly extract the state of electrical network; and the AC network status signal of 50Hz on the electrical network is converted into the direct current network status signal, make whether will carrying out the judgement of feed motion to make things convenient for earth leakage protective device according to the electric network state that extracts.
Description of drawings
Fig. 1. be The general frame of the present invention;
Fig. 2. the circuit theory diagrams of one embodiment of the invention;
Fig. 3. the transmission path node oscillogram of a detection of grid state of the present invention embodiment.
Embodiment
The The general frame of the inventive method as shown in Figure 1.The step of the inventive method comprises waveform shaping, interference filtering, judgement continuity and AC-DC conversion, is electrical network dc state signal with the grid alternating current conversion of signals of importing.
Fig. 2 is the circuit theory diagrams of one embodiment of the invention, and the inventive method is achieved by this circuit, and 1 is waveform-shaping module among the figure, and 2 is the interference filtering module, and 3 for judging continuity and AC-DC conversion module.In three modules of this circuit, used 3 kinds of d type flip flops altogether, the function of each trigger is as follows:
The function of d type flip flop a is: have D, CLK, three inputs of R and Q and Qbar output port, when CLK port input trailing edge signal, with this constantly the level signal of D port transfer to the Q port, all the other time Q port level remain unchanged; In case no matter when the R port has low level signal, the Q port is output as low level, and Qbar port level is that Q port level obtains by a reverser.
The function of d type flip flop b is: have D, CLK, three inputs of R and Q and Qbar output port, when CLK port input rising edge signal, with this constantly the level signal of D port transfer to the Q port, all the other time Q port level remain unchanged; In case no matter when the R port has low level signal, the Q port is output as low level, and Qbar port level is that Q port level obtains by a reverser.
The function of d type flip flop c is: have D, CLK, three inputs of R and Q and Qbar output port, when CLK port input rising edge signal, with this constantly the level signal of D port transfer to the Q port, all the other time Q port numerical value remain unchanged; In case no matter when the R port has high level signal, the Q port is output as low level, and Qbar port level is that Q port level obtains by a reverser.
The grid alternating current signal of input is at first handled in waveform-shaping module, and the circuit of waveform-shaping module has only two reversers, though simple in structure, can realize sine wave is converted to the function of square wave well.
In the present embodiment, the high level timing time set point t of interference filtering module is defined as 1 millisecond, has therefore used 4 d type flip flop a to constitute 1 millisecond time-delay circuit.The output of waveform-shaping module is admitted to the R end of 4 d type flip flop a and d type flip flop b, if high level appears in the signal through the waveform-shaping module shaping, then 4 d type flip flop a begin to carry out timing, when the time arrives 1 millisecond when timing, the CLK end input signal of d type flip flop b becomes high level from low level, the rising edge signal promptly appears, and the D of d type flip flop b terminates on the high level, therefore the Q end is exported high level signal, send into this moment with door two signals of 2 all be high level signal, then the interference filtering module is output as high level signal; If low level signal appears in the signal through the waveform-shaping module shaping, d type flip flop a and d type flip flop b are in cleared condition, and the interference filtering module is output as low level signal.So just realized the function that the spike of filtering high level time under 1 millisecond disturbed.
Judgement continuity module and AC-DC conversion module utilize a circuit module to realize.In case there is rising edge in the new square-wave signal of interference filtering module output, the direct current network status signal that extracts just becomes high level.Be low level only at the interference filtering module output signal, and when the direct current network status signal that extracts is high level (trailing edge from the new square-wave signal of interference filtering module output begins constantly), just can work by 20 milliseconds of circuit of time-delay that 5 d type flip flop a constitute, if high level signal (promptly another rising edge occurring in 20 milliseconds after constantly of a trailing edge from the new square-wave signal of interference filtering module output) appears in the interference filtering module output signal in 20 milliseconds, make 5 d type flip flop a be cleared, the direct current network status signal that extracts so continues to keep high level, and the state of electrical network is conducting; If a trailing edge from the new square-wave signal of interference filtering module output begins constantly, the interference filtering module output signal is a low level signal always in 20 milliseconds, will make so and door 3 output high level signals, cause d type flip flop c zero clearing, the direct current network status signal that extracts becomes low level, and this moment, the state of electrical network was disconnection.
Fig. 3 is the transmission path node oscillogram of a detection of grid state of the present invention embodiment.Waveform a is the signal after waveform-shaping module is handled, and the waveform when detecting the electrical network conducting is a square wave, is low level when detecting electrical network and disconnect, and then waveform a represents electrical network conducting when initial, disconnects conducting again then then.Waveform b is the waveform that has passed through after the interference filtering resume module, can see that the high level time of each square-wave pulse has all reduced 1 millisecond, like this with regard to filtering the many spikes on the electrical network disturb, guaranteed the correctness that circuit state extracts.Waveform c is through judging the direct current network state output signal of continuity module and AC-DC conversion module, as can be seen, the words that in 20 milliseconds an of trailing edge of waveform b square wave, have another rising edge to occur, the direct current network state output signal can keep high level, if and do not have another rising edge to occur in 20 milliseconds an of trailing edge of waveform b square wave, the direct current network state output signal will become low level so, has so just realized the function to the detection and the extraction of electric network state.
Claims (1)
1. electric network state detecting method that is used for earth leakage protective device is characterized in that this method may further comprise the steps:
(1) signal of telecommunication that will be input to electrical network in the earth leakage protective device carries out shaping, if the signal of telecommunication of input is the sine wave signal of 50Hz, the signal of telecommunication is become square-wave signal through after the shaping, and square-wave signal comprises high level and low level at interval; If the signal of telecommunication of input is a low level, then electrical network is an off-state, with direct output low level after the shaping of signal of telecommunication process;
(2) high level to each cycle of the square-wave signal of step (1) shaping carries out timing, when if the high level timing time of one-period is greater than set point t in the square-wave signal after the shaping, then this high level time in the square-wave signal is reduced time t, as the high level output of new square-wave signal; If the high level timing time of the square-wave signal one-period after the shaping is less than set point t, then this section period is as the low level output of new square-wave signal; Wherein, 0.5 millisecond≤t≤2 millisecond;
(3) if another rising edge occurs in 20 milliseconds behind each trailing edge in the new square-wave signal of step (2) output, then step (2) is output as continuous square-wave signal, judges that this moment, electric network state was conducting; If another rising edge do not occur after 20 milliseconds behind the trailing edge in the new square-wave signal of step (2) output, judge that then this moment, electric network state disconnected;
(4) under the electrical network conducting state, from new square-wave signal to first rising edge of high level constantly by low level, the high level signal that output continues, the moment that does not occur another rising edge after 20 milliseconds in new square-wave signal behind trailing edge begins output low level.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2007100705055A CN100533900C (en) | 2007-08-16 | 2007-08-16 | Electric network state detecting method used for creepage protector |
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| CNB2007100705055A CN100533900C (en) | 2007-08-16 | 2007-08-16 | Electric network state detecting method used for creepage protector |
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| CN101132127A true CN101132127A (en) | 2008-02-27 |
| CN100533900C CN100533900C (en) | 2009-08-26 |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102075086A (en) * | 2009-11-19 | 2011-05-25 | 半导体元件工业有限责任公司 | Capacitor test method and circuit therefor |
| CN106226605A (en) * | 2016-07-20 | 2016-12-14 | 中国航空工业集团公司航空动力控制系统研究所 | A kind of PWM self-sensing method |
| CN107306136A (en) * | 2016-04-25 | 2017-10-31 | Ls 产电株式会社 | The disconnection detection equipment of sine wave signal |
| CN111141926A (en) * | 2019-12-27 | 2020-05-12 | 宁波三星智能电气有限公司 | Method for detecting rotating speed of fan in charging pile |
-
2007
- 2007-08-16 CN CNB2007100705055A patent/CN100533900C/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102075086A (en) * | 2009-11-19 | 2011-05-25 | 半导体元件工业有限责任公司 | Capacitor test method and circuit therefor |
| CN102075086B (en) * | 2009-11-19 | 2014-12-17 | 半导体元件工业有限责任公司 | Capacitor test method and circuit therefor |
| CN107306136A (en) * | 2016-04-25 | 2017-10-31 | Ls 产电株式会社 | The disconnection detection equipment of sine wave signal |
| CN106226605A (en) * | 2016-07-20 | 2016-12-14 | 中国航空工业集团公司航空动力控制系统研究所 | A kind of PWM self-sensing method |
| CN106226605B (en) * | 2016-07-20 | 2019-08-13 | 中国航空工业集团公司航空动力控制系统研究所 | A kind of PWM self-sensing method |
| CN111141926A (en) * | 2019-12-27 | 2020-05-12 | 宁波三星智能电气有限公司 | Method for detecting rotating speed of fan in charging pile |
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| Publication number | Publication date |
|---|---|
| CN100533900C (en) | 2009-08-26 |
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