CN116754878A - Current detection device applied to lightning arrester - Google Patents
Current detection device applied to lightning arrester Download PDFInfo
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- CN116754878A CN116754878A CN202310969655.9A CN202310969655A CN116754878A CN 116754878 A CN116754878 A CN 116754878A CN 202310969655 A CN202310969655 A CN 202310969655A CN 116754878 A CN116754878 A CN 116754878A
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- lightning arrester
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- 238000001514 detection method Methods 0.000 title claims abstract description 14
- 238000012544 monitoring process Methods 0.000 claims abstract description 22
- 238000006243 chemical reaction Methods 0.000 claims abstract description 13
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical group [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 6
- 230000001629 suppression Effects 0.000 claims description 3
- 230000001052 transient effect Effects 0.000 claims description 3
- 239000011787 zinc oxide Substances 0.000 claims description 3
- 238000012423 maintenance Methods 0.000 abstract description 5
- 238000013461 design Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000011179 visual inspection Methods 0.000 description 1
- 238000001075 voltammogram Methods 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
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- 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
-
- 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
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Protection Of Static Devices (AREA)
Abstract
The invention discloses a current detection device applied to a lightning arrester, which comprises a receiving conversion unit, a reference comparison unit and a monitoring judgment unit which are electrically connected in sequence, wherein the receiving conversion unit is electrically connected with the lightning arrester, the receiving conversion unit receives lightning current on the lightning arrester and converts the received current into homopolar voltage, the reference comparison unit receives the voltage output by the receiving conversion unit, different results representing the voltage values are output according to the magnitude of the voltage values, and the monitoring judgment unit receives the results output by the reference comparison unit and monitors the duration of the same result output to judge whether the results exceed a set range or not. The current detection device applied to the lightning arrester monitors the discharge current and the discharge waveform of the lightning arrester in real time, and when the discharge current of the lightning arrester exceeds a set upper limit value, an alarm signal is output to the outside to prompt maintenance personnel to check and replace the lightning arrester, so that the risk of normal operation of a power grid caused by damage failure of the lightning arrester is avoided.
Description
Technical Field
The invention relates to the field of integrated circuits, in particular to a current detection device applied to a lightning arrester.
Background
In the power grid line, a lightning arrester is used as main lightning protection equipment, and once the lightning arrester is damaged and fails, a large amount of equipment on the power grid line is damaged by high-voltage breakdown of lightning; making the role of the arrester in the grid line particularly important. The main reason of failure of the lightning arrester is that lightning current exceeds the design limit value of the lightning arrester, so that the internal resistor disc of the lightning arrester is cracked and damaged, and the lightning arrester is generally wrapped by an external insulating layer, so that even if the internal resistor disc is damaged, the lightning arrester is difficult to find by visual inspection. Moreover, the existing counter of the conventional lightning arrester can only record the lightning strike discharge times, cannot monitor the lightning current, further cannot judge whether the lightning current exceeds the design limit value, and cannot bring effective reference to damage investigation of the lightning arrester.
Therefore, it is necessary to provide a current detecting device for lightning arresters, which can detect the magnitude of lightning current, to overcome the above-mentioned drawbacks.
Disclosure of Invention
The invention aims to provide a current detection device applied to a lightning arrester, which is used for monitoring the discharge current of the lightning arrester in real time, and outputting an alarm signal to the outside when the discharge current of the lightning arrester exceeds a set upper limit value so as to prompt maintenance personnel to check and replace the lightning arrester, thereby avoiding the risk of normal operation of a power grid caused by damage failure of the lightning arrester.
In order to achieve the above object, the present invention provides a current detection device applied to a lightning arrester, which includes a receiving and converting unit, a reference comparing unit and a monitoring and judging unit electrically connected in sequence, wherein the receiving and converting unit is electrically connected with the lightning arrester, the receiving and converting unit receives lightning current on the lightning arrester and converts the received current into voltages with the same polarity, the reference comparing unit receives the voltages output by the receiving and converting unit, outputs different results representing the voltage values according to the magnitude of the voltage values, and the monitoring and judging unit receives the results output by the reference comparing unit and monitors the duration of the same result output to judge whether the results exceed a set range.
Preferably, the receiving and converting unit comprises a voltage drop resistor, a rectifier bridge, a first resistor and a second resistor; one end of the voltage drop resistor is connected with the lightning arrester, and the other end of the voltage drop resistor is grounded; the two input ends of the rectifier bridge are respectively connected with the two ends of the voltage drop resistor, the positive output end of the rectifier bridge is connected with one end of the first resistor, and the negative output end of the rectifier bridge is grounded; the other end of the first resistor is commonly connected with one end of the second resistor and is connected with the reference contrast unit, and the other end of the second resistor is grounded.
Preferably, the voltage drop resistor is a zinc oxide resistor.
Preferably, the reference comparing unit includes a plurality of voltage comparators, each of which has a non-inverting input terminal connected to the receiving converting unit, each of which has an inverting input terminal connected to a different reference voltage, and each of which has an output terminal connected to the monitoring judging unit.
Preferably, the plurality of reference voltages are arranged in order from large to small or from small to large.
Preferably, the reference comparing unit further comprises a diode, the diode is a transient suppression protection diode, the anode of the diode is grounded, and the cathode of the diode is connected with the positive input end of each voltage comparator.
Preferably, the monitoring judging unit is a microprocessor, and outputs a warning signal when the microprocessor judges that the input result is out of the set range value.
Compared with the prior art, the current detection device for the lightning arrester receives the lightning current on the lightning arrester through the receiving and converting unit and converts the received current into the voltage with the same polarity, the reference comparison unit outputs different results representing the voltage value according to the magnitude of the voltage value, and finally the monitoring and judging unit monitors the duration of the same result output and judges whether the result exceeds a set range, so that the monitoring and judging unit can intuitively observe the magnitude of the discharge current of the lightning arrester to determine whether the lightning arrester is damaged under the current lightning condition and correspondingly inspect and maintain the lightning arrester; the risk of normal operation of the power grid caused by damage and failure of the lightning arrester is avoided, and the safety of line operation of the power grid is improved.
The invention will become more apparent from the following description taken in conjunction with the accompanying drawings which illustrate embodiments of the invention.
Drawings
Fig. 1 is a schematic structural view of a current detecting device applied to a lightning arrester according to the present invention.
Fig. 2 is a voltammogram of the drop resistance in the circuit configuration of fig. 1.
Fig. 3 is a graph of the discharge current of the arrester over time.
Detailed Description
Embodiments of the present invention will now be described with reference to the drawings, wherein like reference numerals represent like elements throughout. As described above, the invention provides a current detection device applied to a lightning arrester, which monitors the discharge current of the lightning arrester in real time, and when the discharge current of the lightning arrester exceeds a set upper limit value, an alarm signal is output to the outside to prompt maintenance personnel to check and replace the lightning arrester, so that the risk of normal operation of a power grid caused by damage failure of the lightning arrester is avoided.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a current detecting device applied to a lightning arrester according to the present invention; as shown in the figure, the current detection device applied to the lightning arrester comprises a receiving conversion unit, a reference comparison unit and a monitoring judgment unit which are electrically connected in sequence, wherein the receiving conversion unit is electrically connected with the lightning arrester, and when the lightning arrester discharges in thunder weather, the receiving conversion unit receives lightning current on the lightning arrester and converts the received current into homopolar voltage; the reference comparison unit receives the voltage output by the receiving conversion unit and outputs different results representing the voltage value according to the voltage value; the monitoring judging unit receives the result output by the reference comparing unit, and simultaneously corresponds the output result and the current, so that whether the result exceeds a set range or not is judged by monitoring the duration of the same result output, and whether the discharge current of the lightning arrester exceeds the set range or not is further determined. Therefore, through the current detection device for the lightning arrester, when the discharge current of the lightning arrester exceeds the set upper limit value, an alarm signal is output to the outside to prompt maintenance personnel to check and replace the lightning arrester, so that the risk of normal operation of a power grid caused by damage failure of the lightning arrester is avoided.
Specifically, the receiving and converting unit applied to the current detecting device of the lightning arrester comprises a voltage drop resistor MOA, a rectifier bridge DQ, a first resistor R1 and a second resistor R2; one end of the voltage drop resistor MOA is connected with the lightning arrester, and the other end of the voltage drop resistor MOA is grounded, so that when the lightning arrester discharges, the lightning arrester discharges to the ground through the voltage drop resistor MOA, thereby generating a discharge current I1 on the voltage drop resistor MOA, and generating a voltage drop Ua at two ends of the voltage drop resistor MOA, wherein the relation between the current I1 and the voltage drop Ua is shown in figure 2, but lightning has both positive and negative discharge conditions when discharging, and the flow direction of the current I1 is shown in two directions in figure 2; the two input ends of the rectifying bridge DQ are respectively connected with the two ends of the voltage drop resistor MOA, so that the voltage drop Ua on the voltage drop resistor MOA is input into the rectifying bridge DQ, the positive output end of the rectifying bridge DQ is connected with one end of the first resistor R1, and the negative output end of the rectifying bridge DQ is grounded; the other end of the first resistor R1 is commonly connected with one end of a second resistor R2 and is connected with the reference contrast unit, and the other end of the second resistor R2 is grounded. As is well known, lightning has two conditions of positive and negative discharge during discharge, so the voltage polarity of the voltage drop Ua has uncertainty, a rectifier bridge DQ is required to rectify the lightning, and the voltage drop Ua is changed into the voltage Ub with the determined voltage polarity through the rectifier bridge DQ to be output; here, ub=ua-Vt, where Vt is the forward conduction voltage of the rectifier bridge DQ, and the value thereof is usually about 0.7V, that is, ub=ua-0.7, and when the general lightning arrester is discharged, the voltage value across the voltage drop resistor MOA is much larger (hundreds or even kilovolts) than the forward conduction voltage of the rectifier bridge DQ, so ub≡ua in practical application. The first resistor R1 and the second resistor R2 divide the voltage Ub to form a voltage Vi, where vi=ub×r2/(r1+r2), and the voltage Vi is input as an input voltage to the reference comparing unit. In addition, in the receiving conversion unit, preferably, the voltage drop resistor MOA is a zinc oxide resistor, the resistance value of the resistor MOA is nonlinear, the resistor MOA has extremely high internal resistance under small current and lower internal resistance under large current, but in the invention, the characteristic is more remarkable, when the lightning current I1 fluctuates in the range of 1A to 100kA, the fluctuation of the voltage drop Ua at two ends of the resistor is only 500-1500V, so that the fluctuation of the large current can be monitored by using a smaller voltage range, and the excessive voltage output by the voltage drop Ua is avoided from exceeding the range.
The reference comparing unit comprises a plurality of voltage comparators (VC 1, VC2, … … VCn), wherein the non-inverting input end of each voltage comparator (VC 1, VC2, … … VCn) is connected with the receiving converting unit (connected between the first resistor and the second resistor), the voltage Vi is input to the non-inverting input end of each voltage comparator (VC 1, VC2, … … VCn), the inverting input end of each voltage comparator (VC 1, VC2, … … VCn) is connected with different reference voltages (Vref 1, vref2 … … Vrefn), and the output ends (Vo 1, vo2 … … Von) of each voltage comparator (VC 1, VC2, … … VCn) are respectively connected with the monitoring judging unit; in the present invention, when the voltage value (Vi) of the non-inverting input terminal of any one of the voltage comparators is larger than the voltage value (any one of Vref1, vref2 … … Vrefn) of the inverting input terminal thereof, the output terminal of the present voltage comparator outputs a high level (1), and conversely, the output terminal of the present voltage comparator outputs a low level (0). In addition, as a preferred embodiment of the present invention, several reference voltages (Vref 1, vref2 … … Vrefn) are arranged in order from large to small or from small to large, that is: vref1> Vref2> … … > Vrefn or Vref1< Vref2< … … < Vrefn, and since the voltages at the non-inverting input terminals of the voltage comparators are all the voltages Vi, the outputs of the voltage comparators (VC 1, VC2, … … VCn) are continuously changed from more than one low level to more than one high level, or from more than one high level to more than one low level, so that the continuous change of the voltage Vi value can be more conveniently distinguished. In the invention, the number (the value of n) of the voltage comparators can be specifically selected according to actual situations, and generally, the larger the value of n is, the more accurate the lightning current value and the discharge waveform are, and accordingly, the cost of the whole device can be increased, so that the number of the voltage comparators can be flexibly selected according to specific situations in the use process, and the invention is not limited specifically. In addition, as a preferred embodiment of the present invention, the reference comparing unit further includes a diode TVS, the anode of the diode TVS is grounded, and the cathode of the diode TVS is connected to the positive input terminal of each voltage comparator, in the present invention, the diode TVS is a transient suppression diode, which has a voltage clamping function, and when the reverse voltage across the diode is greater than a certain value, the diode will be in a conducting state, and the voltage limit across the diode is at a certain value, so as to protect the subsequent devices from being damaged by the input of excessive voltage, and in the present invention, the diode TVS is mainly used for protecting each voltage comparator (VC 1, VC2, … … VCn).
In the invention, the monitoring judging unit of the current detecting device applied to the lightning arrester is a microprocessor U1, and when the microprocessor U1 judges that the input result exceeds the set range value, a warning signal is output; in the present invention, the outputs of the voltage comparators (VC 1, VC2, … … VCn) are 1 or 0, but since the reference voltages input by each voltage comparator are different and the reference voltages are sequentially arranged, the output of the different voltage comparators is 1, but the representative voltages and the corresponding currents are different (the correspondence between the voltages and the currents is obtained according to ohm's law in combination with the MOA resistor pad discharge volt-ampere characteristic curve of fig. 2, which is well known to those skilled in the art), so that the corresponding current values on the microprocessor are different, when the outputs of the voltage comparators are 1 at the same time, the microprocessor only analyzes and determines whether the current value corresponding to the voltage comparator with the highest position (the voltage comparator with the largest reference voltage value) exceeds the set range, and does not need to determine the current value corresponding to each output of 1, thereby saving the determination flow and ensuring the accuracy of the monitoring and determination; for example, when the reference voltages (Vref 1, vref2 … … Vrefn) of the voltage comparators (VC 1, VC2, … … VCn) are arranged in order from large to small (Vref 1> Vref2> … … > Vrefn), when Vo3, vo4, vo5 all output 1, the microprocessor U1 only needs to monitor and determine whether the current value corresponding to Vo3 exceeds the set range; correspondingly, when the reference voltages (Vref 1, vref2 … … Vrefn) of the voltage comparators (VC 1, VC2, … … VCn) are sequentially arranged from small to large (Vref 1< Vref2< … … < Vrefn), when Vo3, vo4, vo5 all output 1, the microprocessor U1 only needs to monitor and determine whether the current value corresponding to Vo5 exceeds the set range. When the microprocessor analyzes and judges that the current value corresponding to the highest voltage comparator exceeds the set range, a warning signal is output, for example, an alarm sound is sent out, and a worker can overhaul and replace the lightning arrester according to the warning signal, so that the lightning arrester can work normally and effectively all the time, and the risk of normal operation of a power grid due to damage and failure of the lightning arrester is avoided. Meanwhile, the microprocessor U1 also monitors the duration of the output duration of each voltage comparator (VC 1, VC2, … … VCn) being 1, so as to monitor and record the duration of the corresponding discharge current, and further enhance the monitoring of the lightning current.
The working principle of the current detection device applied to the lightning arrester according to the present invention will be described with reference to fig. 2 and 3: the polarity of the voltage Ua has uncertainty due to both positive and negative discharge during lightning discharge, the voltage Ua is rectified by the rectifier bridge DQ to become a voltage Ub with a determined voltage polarity, and ub=ua-Vt in value, so that ub≡ua. The voltage Ub is divided by the first resistor R1 and the second resistor R2 to obtain a voltage Vi, vi=ub R2/(r1+r2), the voltage Vi is compared with the reference voltage Vref (Vref 1, vref2 … … Vrefn) of each voltage comparator VC (VC 1, VC2, … … VCn), if Vi > Vref, the corresponding voltage comparator VC outputs a high level 1, otherwise is a low level 0. The microprocessor U1 monitors the number of high levels and the duration of the high levels of the outputs (Vo 1 to Von) of the voltage comparator VC, thereby calculating the corresponding magnitude and duration of the lightning current, i.e., the discharge waveform (as shown in fig. 3), and thus determining whether the lightning current exceeds the maximum allowable value of the lightning arrester, and outputting an alarm signal.
In summary, in the current detection device for a lightning arrester according to the present invention, when lightning occurs, the lightning arrester discharges through the voltage drop resistor MOV, in this process, the voltage drop Ua is generated at two ends of the voltage drop resistor MOV, and the voltage Vi obtained by converting the voltage through the rectifier bridge DQ into the voltage Ub with the same polarity is input to the reference comparison unit, the reference comparison unit outputs different results of the representative voltage value according to the magnitude of the voltage Vi, and finally the monitoring and judging unit monitors the duration of the same result output and judges whether the result exceeds the set range, so that the monitoring and judging unit can intuitively observe the magnitude and duration of the discharge current of the lightning arrester to determine whether the lightning arrester is damaged under the current lightning condition, and perform corresponding inspection and maintenance on the lightning arrester; the risk of normal operation of the power grid caused by damage and failure of the lightning arrester is avoided, and the safety of line operation of the power grid is improved.
The invention has been described in connection with the preferred embodiments, but the invention is not limited to the embodiments disclosed above, but it is intended to cover various modifications, equivalent combinations according to the essence of the invention.
Claims (7)
1. The current detection device is characterized by comprising a receiving conversion unit, a reference comparison unit and a monitoring judgment unit which are electrically connected in sequence, wherein the receiving conversion unit is electrically connected with the lightning arrester, the receiving conversion unit receives lightning current on the lightning arrester and converts the received current into voltage with the same polarity, the reference comparison unit receives the voltage output by the receiving conversion unit, different results representing the voltage values are output according to the magnitude of the voltage values, and the monitoring judgment unit receives the results output by the reference comparison unit and monitors the duration of the same result output to judge whether the results exceed a set range or not.
2. The current detecting device for lightning arrester of claim 1, wherein the receiving and converting unit includes a voltage drop resistor, a rectifier bridge, a first resistor and a second resistor; one end of the voltage drop resistor is connected with the lightning arrester, and the other end of the voltage drop resistor is grounded; the two input ends of the rectifier bridge are respectively connected with the two ends of the voltage drop resistor, the positive output end of the rectifier bridge is connected with one end of the first resistor, and the negative output end of the rectifier bridge is grounded; the other end of the first resistor is commonly connected with one end of the second resistor and is connected with the reference contrast unit, and the other end of the second resistor is grounded.
3. The current detecting device for lightning arrester according to claim 2, wherein the voltage drop resistor is a zinc oxide resistor sheet.
4. The current detecting device for lightning arrester according to claim 2, wherein the reference comparing unit comprises a plurality of voltage comparators, wherein the non-inverting input end of each voltage comparator is connected with the receiving converting unit, the inverting input end of each voltage comparator is connected with different reference voltages, and the output end of each voltage comparator is respectively connected with the monitoring judging unit.
5. The current detecting device for lightning arresters according to claim 4, wherein the plurality of reference voltages are arranged in order from large to small or from small to large.
6. The device for detecting current applied to a lightning arrester according to claim 4, wherein the reference comparing unit further comprises a diode, the diode is a transient suppression protection diode, the anode of the diode is grounded, and the cathode of the diode is connected to the positive input terminal of each voltage comparator.
7. The current detecting device for lightning arrester according to claim 4, wherein the monitoring judging unit is a microprocessor, and outputs a warning signal when the microprocessor judges that the input result is out of the set range value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310969655.9A CN116754878A (en) | 2023-08-03 | 2023-08-03 | Current detection device applied to lightning arrester |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310969655.9A CN116754878A (en) | 2023-08-03 | 2023-08-03 | Current detection device applied to lightning arrester |
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| Publication Number | Publication Date |
|---|---|
| CN116754878A true CN116754878A (en) | 2023-09-15 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310969655.9A Pending CN116754878A (en) | 2023-08-03 | 2023-08-03 | Current detection device applied to lightning arrester |
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| Country | Link |
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| CN (1) | CN116754878A (en) |
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2023
- 2023-08-03 CN CN202310969655.9A patent/CN116754878A/en active Pending
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