CN210005663U - power-off type leakage indicator - Google Patents
power-off type leakage indicator Download PDFInfo
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- CN210005663U CN210005663U CN201822249758.5U CN201822249758U CN210005663U CN 210005663 U CN210005663 U CN 210005663U CN 201822249758 U CN201822249758 U CN 201822249758U CN 210005663 U CN210005663 U CN 210005663U
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Abstract
The utility model relates to an outage formula electric leakage indicating device, including electric leakage indicator and current transformer, the electric leakage indicator includes the casing and sets up the PCB board in the casing, the integration has on the PCB board prevents heavy current impact circuit, the constant voltage circuit, voltage offset circuit, take biased differential amplification circuit, for offset voltage's integrator circuit, double-circuit comparator circuit, or circuit, parasitic charge resistance releases, central processing unit, prevent that heavy current impact circuit's output is connected with the differential amplification circuit who takes the bias, differential amplification circuit's output is connected with the integrator circuit for offset voltage, be connected with the double-circuit comparator for offset voltage's integrator circuit output, double-circuit comparator and or circuit connection, or circuit output is connected with central processing unit, parasitic charge resistance releases and or circuit output links to each other.
Description
Technical Field
The utility model relates to an kind electric leakage indicating device, concretely relates to outage formula electric leakage indicating device.
Background
The potential difference between the appliance housing and the live line is f after the connection for some reason, which leads to leakage of current.
At present, power supply systems in large rural areas and urban villages in China generally have electric leakage phenomena, and at least rural power supply systems are required to be put into total leakage protection in three-level leakage protection according to national regulations.
The product can timely and accurately capture the transient waveform of the electric leakage in a very short time (2-3 milliseconds in ) before the electric leakage causes the total leakage protection and the jump, identify the electric leakage characteristic, determine the electric leakage point and give an alarm.
At present, other leakage detectors are also available in the market, but all of them realize leakage detection based on the principle of detecting a steady-state leakage waveform, and cannot capture a transient event of power jump caused by leakage, and the transient event is the most common phenomenon in actual power distribution operation.
Through search, the chinese patent application with publication number CN108828392A discloses power-off leakage signal identification methods and power-off leakage indication devices, wherein the circuit signal acquisition process of the identification method is that the circuit signal acquisition process firstly passes through a differential amplification circuit and then is rectified by an operational amplifier full-wave rectification mode, a subtraction circuit is used again to amplify the rectified signal, and a single-path comparison is used to output the signal waveform.
SUMMERY OF THE UTILITY MODEL
The utility model aims at the problem that prior art exists, provide outage formula electric leakage indicating device, the device can eliminate the integrated circuit among the prior art because the electric wire netting disturbs the charge accumulation who causes to make sensitivity stable, and adopt the steady voltage source to provide reference voltage for double-circuit comparator, make sensitivity not change along with battery voltage change.
a power-off leakage indicator device comprises a leakage indicator and a Current Transformer (CT), the current transformer is sleeved outside an electric wire and used for collecting the residual waveform of the circuit, the electric wire comprises a live zero line in a single household electric meter box, a three-phase line and a zero line in a multi-household electric meter box, a box cable, a line cable, an overhead line (needing to be specially made), and the like, the leakage indicator is provided with an interface special for , two signal lines extending out from the current transformer are connected with the interface on the leakage indicator, the leakage indicator comprises a shell and a PCB arranged in the shell, the shell is provided with an indicator lamp, a button, a buzzer and an infrared receiver which are respectively electrically connected with a central processing unit, the PCB is integrated with a large current impact prevention circuit, a constant voltage circuit, a voltage bias circuit, a differential amplification circuit with bias, an integration circuit with respect to bias voltage, a two-way comparator circuit, or circuit, a parasitic charge discharging resistor, and a central processing unit (MCU), the output of the large current impact prevention circuit is connected with the differential amplification circuit with the bias, the integral circuit with the bias voltage, the two-way comparator circuit, or the parasitic charge discharging circuit is connected with the , and the or the two-way comparator is connected with the parasitic output of the integrated circuit.
The utility model discloses a, the prevent heavy current surge circuit for the amplitude of quick restriction collection waveform, the constant voltage circuit provides stable voltage, be used for stabilizing bias voltage and comparator reference voltage, make the two not receive the influence of battery voltage fluctuation, the voltage bias circuit is used for providing bias voltage for differential amplifier circuit, the differential amplifier circuit of taking the bias is used for eliminating common mode interference, and carry out differential amplification to the leakage signal, change positive and negative signal relative to ground into positive and negative signal relative to bias voltage, the integrator circuit relative to bias voltage is used for distinguishing active wave and interference wave for follow-up double-circuit comparator under the heavy current condition, the double-circuit comparator is used for with positive and negative voltage relative to bias voltage, positive voltage pulse square wave is arranged into to the arrangement, the or circuit is used for adding the high level positive square wave that the double-circuit comparator integrates, make the leakage wave can be gathered to no matter be in positive half cycle or negative half cycle, add the parasitic capacitance that releases, reachs the signal and send MCU processing, the parasitic resistance is used for removing the parasitic charge in the leakage waveform, the high speed comparison circuit is used for confirming whether the difference signal is through the double-circuit after the two-circuit is gathered the positive voltage direct addition, is confirmed in the double-circuit.
Preferably, the large current surge prevention circuit comprises a transient voltage suppression diode D1, a sampling resistor R8 and an integrating circuit, wherein the integrating circuit is composed of a second resistor R4 and a capacitor C10.
Preferably, the constant voltage circuit comprises a constant voltage module TL432 and a plurality of peripheral resistors distributed around the constant voltage module, the voltage bias circuit comprises voltage-dividing resistors R17, a second voltage-dividing resistor R19 and a operational amplifier U2A, a voltage-dividing resistor R17, a second voltage-dividing resistor R19 and a operational amplifier U2A are used for building a voltage follower, and the input end of the voltage follower is connected with the output end of a voltage-stabilizing source (namely the TL432 output).
Preferably, the differential amplifier circuit with bias includes a third resistor R5, a sixth resistor R9, a third diode D4, a fourth diode D5, a second operational amplifier U2B, an analog switch, and two sets of peripheral proportional resistors (R12-R15, R44-R47, respectively) distributed around the analog switch, a third diode D4 and a fourth diode D5 connected in parallel are disposed between an input positive electrode and an input negative electrode of the differential amplifier to perform an input voltage limiting function, and the second operational amplifier can be protected, the third resistor R5 and the sixth resistor R9 are respectively connected to an input positive electrode and a input negative electrode of the second operational amplifier U2B, and an input positive electrode of the second operational amplifier U2B is connected to a bias voltage ACOM through a VHC4052 chip of the analog switch and a set of peripheral proportional resistors of the analog switch, so that an effective wave of the circuit is in a positive voltage range.
The input cathode of the second operational amplifier U2B is connected with the output end of the second operational amplifier U2B through a 74VHC4052 chip of an analog switch and another groups of peripheral proportional resistors, and the differential amplification circuit has the functions of overlapping bias voltage and amplification, and has the purposes of eliminating common-mode interference at and overlapping bias voltage to enable the wave type to be in a positive voltage range at .
In the above structure, the analog switch includes a 74VHC4052 chip, a pin 3 of the 74VHC4052 chip is connected to the negative input terminal of the second operational amplifier U2B, and a pin 13 of the 74VHC4052 chip is connected to the positive input terminal of the second operational amplifier U2B. Two groups of peripheral proportional resistors are respectively marked as Y0123And X0123Proportional resistance of the outer periphery Y0123、X0123Each including four amplifying proportional resistors arranged around a 74VHC4052 chip, and a peripheral proportional resistor Y0123After being connected with the output end of the second operational amplifier U2B, the common end of the second operational amplifier is connected with the input end of an integrating circuit relative to bias voltage and a peripheral proportional resistor X0123Is connected to the bias voltage ACOM.
Preferably, the integrating circuit for the bias voltage comprises a fifth resistor R7 and a third capacitor C12 connected with the bias voltage (ACOM), an input pin of the fifth resistor R7 is connected with an output end of the differential amplifier, an output pin of the fifth resistor R7 is connected with end of the third capacitor C12 and then is simultaneously connected with an input positive pole of the comparator a and an input negative pole of the comparator B, and the other end of the third capacitor C12 is connected with the bias voltage ACOM.
The integrating circuit performs integrating filtering processing on the waveform relative to the bias voltage ACOM, and aims to distinguish effective waves from clutter under the condition that a signal source is high in current.
Preferably, the two-way comparator includes a comparator a and a comparator B, an input positive electrode of the comparator a and an input negative electrode of the comparator B are simultaneously connected to the output end of the integrating circuit with respect to the bias voltage, the input negative electrode of the comparator a and the input positive electrode of the comparator B are connected to a voltage dividing circuit composed of voltage dividing resistors, the voltage dividing circuit includes an th resistor R3, a seventh resistor R10 and an eighth resistor R16. in detail, end of the voltage dividing circuit is connected to a constant voltage source (i.e., the output end of TL 431), another end is connected to the ground through a th resistor R3, a seventh resistor R10 and an eighth resistor R16 connected in series, a connection point after the th resistor R3 is connected to the seventh resistor R10 is connected to the input negative electrode of the comparator a, a connection point after the seventh resistor R10 is connected to the eighth resistor R16 is connected to the input positive electrode of the comparator B, and the output ends of the comparator a and the comparator B are respectively connected to or the circuit.
The structure adopts a double-path comparator, and uses constant voltage reference, the purpose is two, is positive voltage square wave for converting positive and negative half-waves of a signal relative to bias voltage into MCU identification, and the other is to ensure that the measurement range is not changed under the condition of battery voltage change.
Preferably, the or circuit includes a th branch and a second branch;
the th branch comprises a fourth resistor R6, a second capacitor C11 and a th diode D2, 0 of the fourth resistor R6 is terminated with the output end of the comparator A, another is terminated with the second capacitor C11 and a th diode D2, a end of the second capacitor C11 is connected into a line between the fourth resistor R6 and the th diode D2, another end is grounded, an anode of the th diode D2 is connected with the fourth resistor R6, a cathode of the th diode D2 is connected with a PULSE identification end, a th diode D2 outputs PULSE signals corresponding to the positive half wave of the analog signal of the relative bias voltage, and output PULSEs are at high level;
the second branch circuit comprises a ninth resistor R48, a fourth capacitor C26 and a second diode D3, of the ninth resistor R48 is connected with the output end of the comparator B, another is connected with a fourth capacitor C26 and a second diode D3, of the fourth capacitor C26 is connected into a line between the ninth resistor R48 and the second diode D3, another is connected with the ground, the anode of the second diode D3 is connected with the ninth resistor R48, the cathode of the second diode D3 is connected with a PULSE identification end, the second diode D3 outputs PULSE signals corresponding to the negative half-wave of the analog signal of the relative bias voltage, and the output PULSE is at a high level;
the discharge parasitic charge resistor is a tenth resistor R49, and the OR output of the PULSE identification end is connected with a signal capturing end of the central processing unit.
In the above structure, the second capacitor C11 and the fourth resistor R6, the fourth capacitor C26 and the ninth resistor R48 form two sets of filter circuits, of the tenth resistor R49 is connected to the output of , and the other is connected to the ground.
The utility model discloses the theory of operation of device as follows: the signal collected by the input current transformer is firstly limited by a transient voltage suppression diode D1, R8 is a sampling resistor, and R4 and C10 form an integrating circuit, because the avalanche time of a transient tube D1 is very short (10)-12Second), the integral circuit needs 1mS when the voltage is fully accumulated, so when the integral circuit just begins to accumulate voltage, the transient voltage suppression diode D1 is broken and conducted, and when the integral circuit works under normal low current, the current changes slowly and sinusoidally, the integral circuit has little influence, so that a large current protection effect is achieved, and damage to the circuit caused by overlarge input current is prevented, the third diode D4 and the fourth diode D5 of the input pole of the differential operational amplifier have the function of input limit voltage, so that the operational amplifier is protected, the positive pole of the operational amplifier is connected with a bias voltage ACOM through a proportional resistor after analog switching, so that the effective wave of the circuit is in a positive voltage range, a differential circuit is adopted for reducing common mode interference, the peripheral resistor of a chip 74VHC4052 is an amplification proportional resistor, the amplification ratio is switched, the amplification ratio gear of the operational amplifier can be adjusted, differential amplification is carried out on a signal by the differential amplification circuit, after integral filtering processing is carried out through the subsequent integral circuit relative to the bias voltage, the signal is simultaneously sent to the input positive pole of a comparator A, the negative pole of the comparator B, the comparator B is connected with a parasitic voltage, the reference voltage, when the voltage A is compared with the reference voltage A, the voltage A is obtained by comparing the voltage A, the voltage A is obtained by comparing the comparison circuit, the comparison of a comparison circuit B, the comparison circuit is obtained by comparing the comparison circuit, the comparison circuit is obtained when the comparison circuit is compared with the comparison circuit, the comparison circuit is obtained when the comparison circuit is connected with the comparison circuit.
The two-way comparator uses a constant-voltage reference source for the purposes of: the bias voltage and the reference voltage of the comparator are constant (are not changed by the change of the battery voltage), so that the measurement sensitivity is ensured to be constant.
Preferably, still integrated central processing unit, rectification voltage stabilizing circuit, commercial power and the seamless switching circuit of lithium cell power supply, detection commercial power circuit that falls, lithium cell charging circuit and lithium cell on the PCB board, rectification voltage stabilizing circuit, commercial power and the seamless switching circuit of lithium cell power supply, detection commercial power circuit that falls and lithium cell all link to each other with central processing unit, lithium cell charging circuit links to each other with constant voltage power supply, rectification voltage stabilizing circuit links to each other with the transformer, commercial power and the seamless switching circuit of lithium cell power supply link to each other with rectification voltage stabilizing circuit's output voltage.
The working principle of the commercial power and lithium battery power supply seamless switching circuit is as follows: when the commercial power is available, voltage V4.0 related to the commercial power is reduced by 1.8V through 3 diodes, a triode Q8 is conducted through resistance voltage division, Q7 is cut off, a field effect transistor Q4 is cut off, a battery stops supplying power to VCC, and the VCC is supplied with power after being rectified by a transformer;
when the commercial power is lost, the V4.0 is reduced to be below 3.3V, the triode Q8 is cut off, the Q7 is conducted, the field effect transistor Q4 is conducted, and the battery recovers to supply power for VCC. The circuit protection key point lies in the adoption of three step-down diodes.
Compared with the prior art, the utility model discloses a leakage indicator has following optimization:
1. the rectifier diode that chooses for use in the former circuit has cancelled now, and former circuit is higher to this rectifier diode's performance requirement, the small difference of characteristic appears in this diode production link, all can influence the wholeness ability.
2. In the prior art, under the condition of large circuit interference, an integrating circuit has charge accumulation. The utility model discloses an integrator circuit for bias voltage can eliminate because the produced charge accumulation of random disturbance to eliminate and disturb and cause the influence to sensitivity.
3. And a voltage stabilizing source is added, so that no reference voltage fluctuation exists under the condition of battery voltage change, and stable sensitivity is ensured.
The utility model has the advantages that can find transient state electric leakage characteristic fast to the accurate electric leakage point of discovering accomplishes not have the mistake and reports, does not have the hourglass and reports.
Drawings
The present invention will be described with reference to the accompanying drawings in step .
Fig. 1 is a schematic structural diagram of embodiment 2 of the present invention;
fig. 2 is a circuit block diagram of a PCB board in embodiment 2 of the present invention;
fig. 3 is a circuit diagram of a differential amplifier circuit for preventing large current surge in embodiment 2 of the present invention;
fig. 4 is a circuit diagram of an integrating circuit and a two-way comparator circuit in embodiment 2 of the present invention;
fig. 5 is a circuit diagram of the circuit according to embodiment 2 of the present invention, or , and eliminating parasitic charge resistance;
fig. 6 is a circuit diagram of the regulator and the bias circuit in embodiment 2 of the present invention;
fig. 7 is a circuit diagram of an analog switch and a proportional resistor according to embodiment 2 of the present invention;
fig. 8 is a circuit diagram of a seamless switching circuit for power supply between a commercial power supply and a lithium battery in embodiment 2 of the present invention;
FIG. 9 is a schematic diagram of the CPU of the present invention;
FIG. 10 is a circuit diagram of the green, yellow and red alarm indicator light of the present invention;
fig. 11 is a circuit diagram of the mid-infrared receiver of the present invention;
fig. 12 is a circuit diagram of the buzzer of the present invention;
fig. 13 is a circuit diagram of the leakage detecting key of the present invention.
Fig. 14 is a circuit diagram of the middle leakage signal collecting part of the present invention.
Description of reference numerals: 1. a leakage indicator; 100. a housing; 101. a PCB board; 2. a current transformer; 3. a power switch; 4. checking a leakage key; 5. resetting the signal receiving window; 6. a green yellow red alarm indicator light.
Detailed Description
Example 1
The present embodiment provides power-off leakage indicating devices using the power-off leakage signal identification method of embodiment 1, which are configured as shown in fig. 1 and 2, and include a leakage indicator 1 and a current transformer 2(CT, i.e., a current transformer for detecting leakage current), the leakage indicator 1 has a dedicated interface , two signal lines from the current transformer 2 are connected to the interface on the leakage indicator 1, the leakage indicator 1 includes a housing 100, a PCB 101 disposed in the housing 100, the PCB 101 has a large current surge prevention circuit, a constant voltage circuit, a voltage bias circuit, a differential amplification circuit with bias voltage, an integration circuit with respect to bias voltage, a square wave surge prevention circuit, or a circuit, a leakage parasitic charge resistor, a central processing unit (preferably, STM32F030KBT6) integrated thereon, the central processing unit determines whether the signal is a leakage signal after the characteristics are confirmed by a high-speed comparison identification algorithm, determines whether the signal is a leakage signal surge prevention square wave surge prevention circuit, the square wave surge prevention circuit rapidly limits the amplitude of a collected waveform, provides a stable voltage, the voltage and the comparator output, and the surge prevention circuit provides a positive or negative surge prevention voltage for a surge voltage, the surge prevention circuit is connected to the positive voltage, the positive voltage surge prevention circuit, the positive voltage surge circuit, the positive voltage, the negative voltage, the positive voltage, the negative voltage.
And the voltage bias circuit and the constant voltage circuit are respectively connected with the differential amplification circuit and the two-way comparator. The schematic diagram of the central processing unit MCU is shown in fig. 9, and the respective order relationships can be seen in the associated circuit diagram of the module.
The working principle of the circuit is as follows:
the current transformer CT is sleeved on the outer side of the wire and used for acquiring the residual waveform of the circuit; the electric wires comprise live lines and zero lines in a single-family electric meter box, three-phase lines and zero lines of a multi-family electric meter box, incoming cables, line cables, overhead lines (specially made), and the like. The circuit for preventing large current impact receives the current residual waveform obtained by CT scanning, rapidly limits the amplitude of the acquired waveform and conveniently limits the current of the overlarge current.
As shown in FIG. 3, the circuit diagram of the large current surge prevention circuit and the differential amplification circuit includes a transient voltage suppression diode D1, a sampling resistor R8 and an integrating circuit, wherein the integrating circuit is composed of a second resistor R4 and a capacitor C10, and signals collected by the input current transformer 2 are limited through a transient voltage suppression diode D1.
The working principle is as follows: r8 is a sampling resistor, and R4 and C10 form an integrating circuit because the avalanche time of the transient tube is very short (10)-12Second), the whole full voltage of the integration circuit is 1mS, so when the integration circuit just starts to accumulate the voltage, the transient tube D1 is broken down and switched on, and when the normal low current works, the current is slowly changed in a sine way, the influence of the integration circuit is small, so that the protection effect of the large current is achieved, and the damage of the excessive input current to the circuit is prevented. The third diode D4 and the fourth diode D5 arranged at the input electrodes of the differential operational amplifier function as input limiting voltages, so that the second operational amplifier U2B can be protected.
The differential amplification circuit for adding the bias voltage comprises a third resistor R5, a sixth resistor R9, a third diode D4, a fourth diode D5, a second operational amplifier U2B, a chip 74VHC4052 of an analog switch, and peripheral proportional resistors R12-R15 and R44-R47. The third resistor R5 and the sixth resistor R9 are respectively connected with the input positive electrode and the input negative electrode of the second operational amplifier U2B, and the input positive electrode of the second operational amplifier U2B is connected with the bias voltage ACOM through a 74VHC4052 chip of the analog switch and a peripheral proportional resistor. The cathode of the input of the second operational amplifier U2B is connected to the output of the second operational amplifier U2B through a chip 74VHC4052 of the analog switch and a peripheral proportional resistor. The input anode of the second operational amplifier is connected with the bias voltage ACOM through a 74VHC4052 peripheral proportional resistor of the analog switch, and the bias voltage is superposed. After being processed by a subsequent integral filter circuit, the amplified signal flows to a two-way comparator circuit.
The biased differential amplifier circuit is used for eliminating common mode interference, differentially amplifying a leakage signal, and converting a positive signal and a negative signal relative to Ground (GND) into a positive signal and a negative signal relative to bias voltage.
The integrating circuit relative to the bias voltage comprises a fifth resistor R7 and a third capacitor C12 connected with the bias voltage ACOM, an input pin of the fifth resistor R7 is connected with an output end of a second operational amplifier U2B, an output pin of the fifth resistor R7 is connected with an end of a third capacitor C12 and then is simultaneously connected with an input positive electrode of a comparator A and an input negative electrode of a comparator B, the other end (negative electrode) of the third capacitor C12 is connected with the bias voltage ACOM, and the integrating circuit relative to the bias voltage is used for distinguishing an effective wave from an interference wave for a subsequent two-way comparator under the condition of large current and distinguishing the effective leakage wave type and the loss of the component power waveform under the condition that the battery supply voltage is reduced to be less than 2.5V.
The dual-path comparator comprises a comparator A and a comparator B, wherein the input positive pole of the comparator A and the input negative pole of the comparator B are simultaneously connected with the output end of an integrating circuit relative to bias voltage, the input negative pole of the comparator A and the input positive pole of the comparator B are connected with a voltage division circuit, the voltage division circuit is formed by connecting a resistor R3, a seventh resistor R10 and an eighth resistor R16 in series, of the voltage division circuit is connected with the output end of a voltage stabilizing source (namely the output end of TL 431), in addition, ends are grounded after passing through a resistor R3, a seventh resistor R10 and an eighth resistor R16 which are connected in series, a connecting point of a resistor R3 and a seventh resistor 387R 10 is connected with the input negative pole of the comparator A, and a connecting point of a seventh resistor R10 and an eighth resistor R16 are connected with the input positive pole of the comparator B, and the output ends of the comparator A and the comparator B are respectively connected with or in.
The working principle is as follows: the negative terminal of the comparator U2D (i.e. the comparator A) is connected with the 2V voltage generated by the resistor division, and the positive terminal of the comparator U2C (i.e. the comparator B) is connected with the 0.5V voltage generated by the resistor division. The input signal bias voltage is 1.25V. When the signal from the positive half wave with respect to the bias voltage exceeds 2V, the comparator U2D outputs a 3.3V pulse signal. And when the signal from the negative half wave with respect to the bias voltage is less than 0.5V, the comparator U2C also outputs a 3.3V pulse signal. The purpose is that positive and negative half waves relative to bias voltage are respectively processed into two positive voltage square waves.
The first branch comprises a fourth resistor R, a second capacitor C and a 2 nd diode, 3 of the fourth resistor R is connected with the output end of the comparator A, the other 4 is connected with the second capacitor C and a 5 th diode D, 7 of the second capacitor C is connected into a line between the fourth resistor R and the 8 th diode D, the other end is grounded, the positive pole of the second diode D is connected with the fourth resistor R, the negative pole of the second diode D is connected with a PULSE identification end, the second branch comprises a ninth resistor R, a fourth capacitor C and a second diode D, the output end of the ninth resistor R is connected with the output end of the comparator B, the other end is connected with the fourth capacitor C and the second diode D, the positive pole of the fourth capacitor C is connected into a line between the ninth resistor R and the second diode D, the other end is grounded, the positive pole of the second diode D is connected with the ninth resistor R, the negative pole of the fourth diode C is connected with a PULSE identification end, the positive pole of the fourth capacitor C is connected with the circuit D, the PULSE identification end or the 6 is connected with the positive pole of the fifth resistor R and the second diode D, the filter is connected with a filter for filtering the leakage signal of the leakage signal, the leakage signal leakage of the leakage of.
As shown in fig. 6, the regulator and bias circuit diagram, the constant voltage circuit, i.e. the regulator, includes a constant voltage chip TL432 and peripheral resistors R18, R20, R23, the constant voltage circuit provides stable voltage for stabilizing the bias voltage and the comparator reference voltage, so that the constant voltage circuit is not affected by the battery voltage fluctuation, the voltage bias circuit provides bias voltage for the differential amplification circuit, the voltage bias circuit includes a th voltage dividing resistor R17, a second voltage dividing resistor R19 and a th operational amplifier U2A, R17, R19 constitute a voltage dividing circuit, a th operational amplifier U2A constitute a voltage follower, the input end of the voltage bias circuit is connected with the output end of the regulator (i.e. TL432 output), the operation principle of the circuit is that the TL432 chip and the peripheral resistors provide 2.5V stable voltage, the voltage is supplied to the voltage follower LMV324(U2A) to divide the voltage to output 2.5/2V to 1.25V bias voltage, which is connected to the analog switch VHC 74 c4052 of the differential amplifier, and the peripheral resistor to form a differential amplifier with the differential amplifier for amplifying the differential voltage.
As shown in fig. 7, the analog switch circuit includes a 74VHC4052 chip, a pin 3 of the 74VHC4052 chip is connected to the negative input terminal of the second operational amplifier U2B, and a pin 13 of the 74VHC4052 chip is connected to the positive input terminal of the second operational amplifier U2B. Two groups of peripheral proportional resistors are arranged outside the 74VHC4052 chip and are respectively marked as Y0123And X0123Proportional resistance of the outer periphery Y0123、X0123Each including four proportional resistors arranged around a 74VHC4052 chip, and a peripheral proportional resistor Y0123After being connected with the output end of the second operational amplifier U2B, the common end of the second operational amplifier is connected with the input end of an integrating circuit relative to bias voltage and a peripheral proportional resistor X0123The common end of the differential amplifier is connected with a bias voltage ACOM, the analog switch has the second function that is used for adjusting the amplification proportion of the differential amplifier circuit, and the second function is used for superposing the bias voltage for the differential amplifier through the bias voltage end.
As shown in fig. 8, the circuit diagram of the seamless switching circuit between the commercial power and the lithium battery power supply has the working principle: when the commercial power is available, voltage V4.0(4V) related to the commercial power is reduced to 1.8V through 3 diodes, a triode Q8 is conducted through resistance voltage division, a triode Q7 is cut off, a field effect tube Q4 is cut off, the lithium battery stops supplying power for VCC, and the VCC is supplied with power after being rectified by a transformer; when the commercial power is lost, the V4.0 is reduced to be below 3.3V, the triode Q8 is cut off, the triode Q7 is conducted, the field-effect tube Q4 is conducted, and the lithium battery recovers to supply power for VCC. The circuit protection key point lies in the adoption of three step-down diodes.
The casing 100 is provided with a power switch, a green-yellow-red alarm indicator lamp 6, a resetting signal receiving window 5, a leakage checking button 4, a buzzer and an infrared receiver which are respectively electrically connected with the central processing unit. The buzzer can be an electromagnetic passive buzzer without a specific model, and only index parameters are met, for example: the diameter is 9mm, the height is 5.5mm, 42 ohm, 3V-5V. The infrared receiver is used for receiving the reset signal sent by the infrared remote controller. The green, yellow and red alarm indicator 6 is shown in fig. 10, the infrared receiver is shown in fig. 11, the buzzer is shown in fig. 12, and the leak detection key 4 is shown in fig. 13.
As shown in fig. 1, the casing 100 is provided with a power switch 3, a leak detection button 4, a reset signal receiving window 5, a green-yellow-red alarm indicator lamp 6, and the like. Wherein, in the green-yellow-red alarm indicator lamp 6, "1" is a power display lamp, "2" is an internal leakage indicator lamp, and "3" is a leakage jump positioning indicator lamp.
As shown in fig. 2, a rectifying and voltage stabilizing circuit, a seamless switching circuit of commercial power and lithium battery power supply, a circuit for detecting commercial power failure, a lithium battery charging circuit and a lithium battery are further integrated on the PCB, the rectifying and voltage stabilizing circuit, the seamless switching circuit of commercial power and lithium battery power supply, the circuit for detecting commercial power failure and the lithium battery are all connected with the central processing unit, the lithium battery is connected with the lithium battery charging circuit, the lithium battery charging circuit is connected with the voltage stabilizing power supply, the rectifying and voltage stabilizing circuit is connected with the transformer, and the commercial power and the seamless switching circuit of lithium battery power supply are.
The embodiment also provides power-off leakage signal identification methods, which comprise the following steps:
s0, acquiring a circuit residual current waveform: residual current (indicating leakage current) comes from a current transformer (leakage detection CT) for detecting leakage current, a conventional design is adopted, a phase line (a single phase is a live wire, and a three phase is an ABC phase line) and a zero line penetrate through the leakage detection CT, when the leakage occurs, the leakage current is collected by the leakage detection CT, and the leakage current directly enters a primary current limiting circuit unit of the circuit;
s1, collecting a circuit residual current waveform;
s2, limiting the excessive current;
s3, carrying out constant voltage bias on the differential amplifier;
s4, carrying out differential amplification with bias voltage on the processed leakage current waveform, wherein the amplification feedback resistor is selected by an analog switch;
s5, integral filtering is carried out relative to the bias voltage, so that when the battery is in power failure, effective waves and clutter are distinguished, and false alarm is prevented;
s6, adopting a two-way comparator, dividing the voltage of the reference end by using constant voltage, and comparing the voltage with the output analog voltage of the preceding stage to make the positive and negative signal waves relative to the bias voltage modified into square waves in a positive voltage range after passing through the comparator;
and S7, performing OR operation on the two paths of comparison square waves, and adding a bleeder resistor to bleed off parasitic capacitance charges in the circuit.
And S8, after the electric leakage characteristics are confirmed through a high-speed comparison and identification algorithm, whether the signal is an electric leakage signal is determined.
The working method of the power-off leakage indicating device comprises the following steps:
(1) collecting a circuit residual current waveform by using a current transformer;
(2) limiting the excessive current in the residual current waveform by using a large-current impact prevention circuit;
(3) carrying out constant voltage bias on the differential amplifier, namely providing bias voltage for the differential amplifier by using a constant voltage circuit and a voltage bias circuit and providing reference voltage for a two-way comparator;
(4) differential amplification is carried out on the processed leakage current waveform by using a differential amplification circuit with bias voltage, the bias voltage is superposed, and positive and negative wave signals relative to the ground are converted into positive and negative wave signals relative to the bias voltage;
(5) performing integral filtering by using an integral circuit relative to a bias voltage;
(6) a double-path comparator is adopted, and a constant voltage reference is adopted to convert an analog signal into two paths of over-limit positive voltage square wave signals (namely comparison signals);
(7) after the two paths of comparison signals are subjected to OR operation, square wave high levels obtained by the two paths of comparators are added, and a resistor for discharging parasitic charges is added to obtain signals, and the signals are sent to a central processing unit for processing;
(8) after the central processing unit confirms the electric leakage characteristic through a high-speed comparison and identification algorithm, whether the electric leakage characteristic is an electric leakage signal is determined, if the electric leakage signal is the electric leakage signal, the electric leakage phenomenon is indicated, and if the electric leakage signal is not the electric leakage signal, the electric leakage phenomenon is not indicated;
(9) when the electric leakage phenomenon appears, the commercial power failure detection circuit quickly judges whether the commercial power fails, when the commercial power fails, the central processing unit quickly gives an alarm red light, and meanwhile, the commercial power and the lithium battery supply seamless switching circuit seamlessly switches the commercial power supply to the lithium battery supply, when the electric leakage phenomenon does not occur, the central processing unit quickly gives an alarm to the yellow light, and the electric leakage signal is transmitted through the 433M wireless module.
The following explains the utility model in steps in combination with the actual use report of the power-off leakage indicator.
Nanjing city area, pure district, stream xi house village has installed in 2018 4 month 24 days the utility model discloses a first sample of outage formula electric leakage indicating device counts 40, to 2018 6 months 26 days, has normally operated 2 months time, and through the tracking inspection, the operational aspect of this period of time shows: the product operates stably and reliably, finds the leakage signal for many times, can accurately reflect the actual situation of the leakage, and can accurately give corresponding alarm information no matter whether the leakage fault is uninterrupted or the total leakage is caused by the leakage and the power is jumped.
The utility model discloses the input of product is used, can pinpoint electric leakage fault place, can shorten scene outage fault detection time greatly, for the electric leakage user with effective trouble voucher and foundation, for the quick recovery always leak the power supply and reduce the power failure number of times of power consumption user and reduce therefore and the complaint incident that causes provides strong guarantee.
In addition to the above embodiments, the present invention may have other embodiments. All the technical solutions formed by adopting equivalent substitutions or equivalent transformations fall within the protection scope claimed by the present invention.
Claims (8)
- The power-off leakage indicating device comprises a leakage indicator and a current transformer, wherein the current transformer is sleeved on the outer side of an electric wire, the leakage indicator comprises a shell and a PCB arranged in the shell, and the power-off leakage indicating device is characterized in that a large-current impact preventing circuit, a constant-voltage circuit, a voltage biasing circuit, a differential amplifying circuit with bias, an integrating circuit relative to bias voltage, a double-path comparator circuit or a circuit, a leakage parasitic charge resistor and a central processing unit are integrated on the PCB, the output of the large-current impact preventing circuit is connected with the differential amplifying circuit with bias, the output of the differential amplifying circuit is connected with the integrating circuit relative to bias voltage, the output of the integrating circuit relative to bias voltage is connected with the double-path comparator, the double-path comparator is connected with a circuit, the output of the circuit is connected with the central processing unit, and the leakage parasitic charge resistor is connected with the output of a circuit.
- 2. The kind of power-off leakage indicating device according to claim 1, wherein the large current surge protection circuit comprises a transient voltage suppressor (D1), a sampling resistor (R8) and an integrating circuit, and the integrating circuit is composed of a second resistor (R4) and a th capacitor (C10).
- 3. The kind of power-off leakage indicator according to claim 2, wherein the constant voltage circuit comprises a constant voltage module and several peripheral resistors distributed around the constant voltage module, the voltage bias circuit comprises a th voltage dividing resistor (R17), a second voltage dividing resistor (R19) and a th operational amplifier (U2A), and the input terminal of the voltage bias circuit is connected to the output terminal of the regulator.
- 4. The kind of power-off leakage indicator according to claim 3, wherein the biased differential amplifier circuit comprises a third resistor (R5), a sixth resistor (R9), a third diode (D4), a fourth diode (D5), a second operational amplifier (U2B), an analog switch, and two sets of peripheral proportional resistors distributed around the analog switch, the third resistor (R5) and the sixth resistor (R9) are respectively connected to the input positive and negative poles of the second operational amplifier (U2B), the input positive pole of the second operational amplifier (U2B) is connected to the bias voltage (ACOM) through a 74VHC4052 chip of the analog switch and a set of peripheral proportional resistors, and the input negative pole of the second operational amplifier (U2B) is connected to the output terminal of the second operational amplifier (U2B) through a 74VHC4052 chip of the analog switch and another set of peripheral proportional resistors.
- 5. The kind of power-off leakage indicator of claim 4, wherein the integrating circuit with respect to the bias voltage comprises a fifth resistor (R7) and a third capacitor (C12) connected to the bias voltage (ACOM), the input pin of the fifth resistor (R7) is connected to the output terminal of the differential amplifier, the output pin of the fifth resistor (R7) is connected to the terminal of the third capacitor (C12) and is simultaneously connected to the positive input terminal of the comparator A and the negative input terminal of the comparator B, and the other terminal of the third capacitor (C12) is connected to the bias voltage (ACOM).
- 6. The kind of power-off leakage indicator according to claim 5, wherein the two-way comparator comprises a comparator A and a comparator B, the positive input terminal of the comparator A and the negative input terminal of the comparator B are connected to the output terminal of the integrating circuit with respect to the bias voltage, the negative input terminal of the comparator A and the positive input terminal of the comparator B are connected to a voltage divider circuit, terminal of the voltage divider circuit is connected to the constant voltage source, and another terminal is connected to ground through a th resistor (R3), a seventh resistor (R10) and an eighth resistor (R16) connected in series, the connection point of the resistor (R3) and the seventh resistor (R10) is connected to the negative input terminal of the comparator A, the connection point of the seventh resistor (R10) and the eighth resistor (R16) is connected to the positive input terminal of the comparator B, and the output terminals of the comparator A and the comparator B are respectively connected to the or circuit.
- 7. The kind of power-off leakage indicator of claim 6, wherein the OR circuit includes a th branch and a second branch;the branch comprises a fourth resistor (R6), a second capacitor (C11) and a diode (D2), of the fourth resistor (R6) is connected with the output end of the comparator A, another is connected with the second capacitor (C11) and an diode (D2), end of the second capacitor (C11) is connected into a line between the fourth resistor (R6) and the diode (D2), another end is grounded, the anode of the diode (D2) is connected with the fourth resistor (R6), and the cathode of the diode is connected with the PULSE identification end;the second branch comprises a ninth resistor (R48), a fourth capacitor (C26) and a second diode (D3), of the ninth resistor (R48) is connected with the output end of the comparator B, another is connected with the fourth capacitor (C26) and the second diode (D3), end of the fourth capacitor (C26) is connected into a line between the ninth resistor (R48) and the second diode (D3), another end is grounded, the anode of the second diode (D3) is connected with the ninth resistor (R48), and the cathode of the second diode is connected with a PULSE identification end;the bleed-off parasitic charge resistance is a tenth resistance (R49);the output of the PULSE identification end or is connected with the signal capturing end of the central processing unit.
- 8. The A power-off leakage indicator according to claim 7, wherein the PCB further comprises a CPU, a rectifying and voltage-stabilizing circuit, a seamless switching circuit between commercial power and lithium battery power supply, a circuit for detecting commercial power failure, a lithium battery charging circuit, and a lithium battery, the rectifying and voltage-stabilizing circuit, the seamless switching circuit between commercial power and lithium battery power supply, the circuit for detecting commercial power failure, and the lithium battery are all connected to the CPU, the lithium battery charging circuit is connected to a voltage-stabilizing power supply, the rectifying and voltage-stabilizing circuit is connected to a transformer, and the seamless switching circuit between commercial power and lithium battery power supply is connected to the output voltage of the rectifying and voltage-stabilizing circuit.
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| CN201822249758.5U CN210005663U (en) | 2018-12-29 | 2018-12-29 | power-off type leakage indicator |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109633356A (en) * | 2018-12-29 | 2019-04-16 | 南京钰吉电气科技有限公司 | The recognition methods of electricity cut-off type electric leakage signal and electricity cut-off type electric leakage detector |
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2018
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109633356A (en) * | 2018-12-29 | 2019-04-16 | 南京钰吉电气科技有限公司 | The recognition methods of electricity cut-off type electric leakage signal and electricity cut-off type electric leakage detector |
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