Residual current detection device for multi-pulse surge protection device

Abstract

The invention discloses a residual current detection device for a multi-pulse surge protection device, and the device comprises a surge absorption circuit, a residual current monitoring circuit, and a single-chip microcomputer. A Hall current sensor of the residual current monitoring circuit measures a magnetic field generated by leakage current of a grounding wire in a non-contact mode and converts the magnetic field into a voltage signal which is sequentially output to the subtraction circuit and the amplification circuit, the amplification circuit amplifies the voltage signal and then inputs the voltage signal into the single-chip microcomputer, and the single-chip microcomputer carries out data analysis on the magnitude of residual current. The residual current can be detected without connecting the live wire and the ground wire of the surge protection device for power supply and sampling, thereby solving the problems that the detection circuit may fail or even the live wire of the line is directly conducted with the ground wire when the existing residual current detection equipment for the multi-pulse surge protection device is directly connected with the live wire and the ground wire of the surge protection device for power supply and sampling; and potential safety hazards are caused.

Description

Technical Field

[0001] The invention relates to the technical field of multi-pulse surge protectors, and in particular to a residual current detection device for a multi-pulse surge protector. Background Art

[0002] Multi-pulse surge protector, referred to as MSPD. The residual current (also called residual current) of a multi-pulse surge protector refers to the current flowing through the PE terminal when the multi-pulse surge protector is connected according to the manufacturer's instructions and a reference voltage (the effective value of the voltage used for MSPD testing) is applied. The existing built-in residual current detection equipment is powered and sampled by directly connecting the live wire and ground wire of the surge protector. Once the lightning current is too large or exceeds the tolerance of the zinc oxide resistor, it may cause the detection circuit to fail or even the live wire of the line to be directly connected to the ground wire, causing safety hazards. Summary of the invention

[0003] The present invention provides a residual current detection device for a multi-pulse surge protector, which is used to solve the technical problem that the existing residual current detection equipment for a multi-pulse surge protector is powered and sampled by directly connecting the live wire and the ground wire of the surge protector, which may cause detection circuit failure or even direct connection between the live wire and the ground wire of the line, causing safety hazards.

[0004] In view of this, the present invention provides a residual current detection device for a multi-pulse surge protector, comprising: a surge absorption circuit, a residual current monitoring circuit and a single chip microcomputer;

[0005] Surge absorption circuits are used to direct lightning current into the ground wire;

[0006] The residual current monitoring circuit includes a Hall current sensor, a subtraction circuit and an amplifier circuit. The magnetic core of the Hall current sensor is mounted on the ground wire of the multi-pulse surge protector. The voltage output end of the Hall current sensor is connected to the in-phase input end of the subtraction circuit. The output end of the subtraction circuit is connected to the in-phase input end of the amplifier circuit. The output end of the amplifier circuit is connected to the input end of the single-chip microcomputer.

[0007] Optionally, the subtraction circuit includes a first operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor and a first capacitor;

[0008] One end of the first resistor is connected to the voltage output end of the Hall current sensor, the other end of the first resistor is connected to the non-inverting input end of the first operational amplifier, one end of the second resistor is connected to the non-inverting input end of the first operational amplifier, the other end of the second resistor is grounded, one end of the third resistor is connected to the reference voltage source, the other end of the third resistor is connected to the inverting input end of the first operational amplifier, one end of the fourth resistor is connected to the inverting input end of the first operational amplifier, the other end of the fourth resistor is connected to the output end of the first operational amplifier, one end of the first capacitor is connected to the inverting input end of the first operational amplifier, and the other end of the first capacitor is connected to the output end of the first operational amplifier.

[0009] Optionally, the amplifying circuit includes a second operational amplifier, a fifth resistor, a sixth resistor, a seventh resistor and a second capacitor;

[0010] One end of the fifth resistor is connected to the output terminal of the first operational amplifier, the other end of the fifth resistor is connected to the non-inverting input terminal of the second operational amplifier, one end of the sixth resistor is grounded, the other end of the sixth resistor is connected to the inverting input terminal of the second operational amplifier, one end of the seventh resistor is connected to the inverting input terminal of the second operational amplifier, the other end of the seventh resistor is connected to the output terminal of the second operational amplifier, one end of the second capacitor is connected to the inverting input terminal of the second operational amplifier, and the other end of the second capacitor is connected to the output terminal of the second operational amplifier.

[0011] Optionally, a lightning current monitoring circuit is also included;

[0012] The lightning current monitoring circuit includes a Rogowski coil and a signal integration circuit. The Rogowski coil is sleeved on the grounding wire of the multi-pulse surge protector, and the induction current output end of the Rogowski coil is connected to the input end of the signal integration circuit.

[0013] The signal integration circuit includes a first integration circuit, a second integration circuit and a signal amplification circuit;

[0014] The first integration circuit includes a third operational amplifier, an eighth resistor, a ninth resistor and a third capacitor, one end of the eighth resistor is connected to the positive end of the induced current output end of the Rogowski coil, the other end of the eighth resistor is connected to the inverting input end of the third operational amplifier, the non-inverting input end of the third operational amplifier is respectively connected to the ground and the negative end of the induced current output end of the Rogowski coil, one end of the ninth resistor is connected to the inverting input end of the third operational amplifier, the other end of the ninth resistor is connected to the output end of the third operational amplifier, one end of the third capacitor is connected to the inverting input end of the third operational amplifier, and the other end of the third capacitor is connected to the output end of the third operational amplifier;

[0015] The second integration circuit includes a fourth operational amplifier, a tenth resistor, an eleventh resistor, a twelfth resistor and a fourth capacitor, one end of the tenth resistor is connected to the output end of the third operational amplifier, the other end of the tenth resistor is connected to the non-inverting input end of the fourth operational amplifier, one end of the eleventh resistor is grounded, the other end of the eleventh resistor is connected to the inverting input end of the fourth operational amplifier, one end of the twelfth resistor is connected to the inverting input end of the fourth operational amplifier, the other end of the twelfth resistor is connected to the output end of the fourth operational amplifier, one end of the fourth capacitor is connected to the inverting input end of the fourth operational amplifier, and the other end of the fourth capacitor is connected to the output end of the fourth operational amplifier;

[0016] The signal amplification circuit includes a fifth operational amplifier, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor and a fifth capacitor, one end of the thirteenth resistor is connected to the output end of the fourth operational amplifier, the other end of the thirteenth resistor is connected to the non-inverting input end of the fifth operational amplifier, one end of the fourteenth resistor is connected to the non-inverting input end of the fifth operational amplifier, the other end of the fourteenth resistor is connected to a reference voltage source, one end of the fifteenth resistor is grounded, the other end of the fifteenth resistor is connected to the inverting input end of the fifth operational amplifier, one end of the sixteenth resistor is connected to the inverting input end of the fifth operational amplifier, the other end of the sixteenth resistor is connected to the output end of the fifth operational amplifier, one end of the fifth capacitor is connected to the inverting input end of the fifth operational amplifier, the other end of the fifth capacitor is connected to the inverting input end of the fifth operational amplifier, and the output end of the fifth operational amplifier is connected to the input end of the single-chip computer.

[0017] Optionally, it also includes a data storage module;

[0018] The input end of the data storage module is connected to the output end of the lightning current monitoring circuit;

[0019] The data storage module is used to store lightning current waveform data collected at a rate of 1Mhz when the transient current flowing through the grounding wire of the multi-pulse surge protector exceeds 1kA. The lightning current waveform data includes the lightning current waveform and its pulse time, number of pulses, pulse time interval, pulse amplitude and pulse steepness.

[0020] Optionally, a power supply module is also included;

[0021] The power module includes a Buck step-down circuit, which is used to provide a +5VDC power supply for the residual current detection device of the multi-pulse surge protector.

[0022] Optionally, the Buck step-down circuit includes a step-down chip, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a tenth capacitor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a twenty-first resistor, a diode, a voltage regulator and an inductor;

[0023] One end of the sixth capacitor is connected to the power supply VCC, and the other end of the sixth capacitor is grounded; one end of the seventh capacitor is connected to the power supply VCC, and the other end of the seventh capacitor is grounded;

[0024] The VIN pin of the buck chip is connected to the power supply VCC, the GND pin is grounded, the EN pin is connected to one end of the seventeenth resistor, one end of the seventeenth resistor is connected to the VIN pin, the VIA pin is floating, the IS pin is connected to one end of the eighteenth resistor, the other end of the eighteenth resistor is respectively connected to the VS pin and one end of the inductor, the VB pin is connected to one end of the eighth capacitor, the other end of the eighth capacitor is connected to the other end of the inductor, the other end of the inductor is connected to one end of the nineteenth resistor, the other end of the nineteenth resistor is grounded, one end of the ninth capacitor is connected to the other end of the inductor, the other end of the ninth capacitor is grounded, the common end of the inductor, the nineteenth resistor and the ninth capacitor is commonly connected to the +5V power supply, the FB pin of the buck chip is respectively connected to one end of the twentieth resistor and the twenty-first resistor, the other end of the twentieth resistor is grounded, the other end of the twenty-first resistor is connected to the anode of the diode, the cathode of the diode is connected to the cathode of the Zener diode, the anode of the Zener diode is connected to the other end of the eighth capacitor, one end of the tenth capacitor is connected to one end of the twenty-first resistor, and the other end of the tenth capacitor is connected to the other end of the twenty-first resistor.

[0025] Optionally, the power module further includes an LDO step-down circuit, and the LDO step-down circuit is used to provide a +3.3VDC power supply for the residual current detection device of the multi-pulse surge protector.

[0026] Optionally, outer surfaces of the Hall current sensor and the lightning current monitoring circuit are both covered with an aluminum foil shielding layer, and the aluminum foil shielding layer is connected to a guide rail for grounding via screws.

[0027] Optionally, the aluminum foil shielding layer is externally covered with a heat insulating layer made of insulating heat insulating electronic adhesive.

[0028] It can be seen from the above technical solutions that the residual current detection device for a multi-pulse surge protector provided by the present invention has the following advantages:

[0029] The multi-pulse surge protector residual current detection device provided by the present invention comprises a surge absorption circuit, a residual current monitoring circuit and a single-chip computer. The lightning current is introduced into the grounding wire through the surge absorption circuit. The magnetic field generated by the leakage current of the grounding wire is measured in a non-contact manner by the Hall current sensor of the residual current monitoring circuit and converted into a voltage signal and outputted to the subtraction circuit and the amplifier circuit in sequence. The amplifier circuit amplifies the voltage signal and inputs it into the single-chip computer. The single-chip computer performs data analysis on the size of the residual current. The residual current can be detected without connecting the live wire and the ground wire of the surge protector for power supply and sampling. The technical problem that the existing multi-pulse surge protector residual current detection equipment is directly connected to the live wire and the ground wire of the surge protector for power supply and sampling, which may cause detection circuit failure or even direct conduction between the live wire of the line and the ground wire, causing safety hazards, is solved.

[0030] At the same time, the multi-pulse surge protector residual current detection device provided by the present invention, the outer surfaces of the Hall current sensor and the lightning current monitoring circuit are covered with an aluminum foil shielding layer, the aluminum foil shielding layer is connected to the guide rail for grounding through screws, and the outside of the aluminum foil shielding layer is covered with a thermal insulation layer made of insulating and heat-insulating electronic glue, which can protect the multi-pulse surge protector residual current detection device from possible damage caused by lightning electromagnetic pulses and thermal energy and the influence on data acquisition accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 It is a structural schematic diagram of a residual current detection device for a multi-pulse surge protector provided in an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of a surge absorption circuit provided in an embodiment of the present invention;

[0034] Figure 3 A circuit schematic diagram of a switch circuit module provided in an embodiment of the present invention;

[0035] Figure 4 It is a schematic diagram of a subtraction circuit in a residual current monitoring circuit provided in an embodiment of the present invention;

[0036] Figure 5 A schematic diagram of an amplifier circuit in a residual current monitoring circuit provided in an embodiment of the present invention;

[0037] Figure 6 A circuit schematic diagram of a display screen provided in an embodiment of the present invention;

[0038] Figure 7 A schematic diagram of a signal integration circuit provided in an embodiment of the present invention;

[0039] Figure 8 A schematic diagram of a data storage module circuit provided in an embodiment of the present invention;

[0040] Fig. 9 The Buck step-down circuit schematic diagram provided in the embodiment of the present invention;

[0041] Fig.10 It is a schematic diagram of an LDO step-down circuit provided in an embodiment of the present invention;

[0042] Fig.11 The figure is a schematic diagram of the internal structure of a multi-pulse surge protector provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] For easier understanding, see Figure 1 The present invention provides an embodiment of a residual current detection device for a multi-pulse surge protector, comprising a surge absorption circuit, a residual current monitoring circuit and a single-chip microcomputer. The surge absorption circuit is used to introduce lightning current into the grounding wire. The residual current monitoring circuit comprises a Hall current sensor, a subtraction circuit and an amplifier circuit, the magnetic core of the Hall current sensor is sleeved on the grounding wire of the multi-pulse surge protector, the voltage output end of the Hall current sensor is connected to the in-phase input end of the subtraction circuit, the output end of the subtraction circuit is connected to the in-phase input end of the amplifier circuit, and the output end of the amplifier circuit is connected to the input end of the single-chip microcomputer.

[0045] It should be noted that the surge absorption circuit is used to introduce lightning current into the grounding wire. The structure of the surge absorption circuit is as follows Figure 2As shown, it includes a first pulse-specific fuse F1, a second pulse-specific fuse F2, a third pulse-specific fuse F3, a first thermal protection type varistor R31, a second thermal protection type varistor R32 and a third thermal protection type varistor R33. The first pulse-specific fuse F1 and the first thermal protection type varistor R31 are connected in series to form a first surge absorption branch, the second pulse-specific fuse F2 and the second thermal protection type varistor R32 are connected in series to form a second surge absorption branch, and the third pulse-specific fuse F3 and the third thermal protection type varistor R33 are connected in series to form a third surge absorption branch. The three surge absorption branches are connected in parallel, the common end of the first thermal protection type varistor R31, the second thermal protection type varistor R32 and the third thermal protection type varistor R33 is grounded, and the common end of the first pulse-specific fuse F1, the second pulse-specific fuse F2 and the third pulse-specific fuse F3 is connected to the AC power supply VAC. The magnetic core of the Hall current sensor is sleeved on the grounding wire of the multi-pulse surge protector. The lightning current flowing through the grounding wire of the multi-pulse surge protector will cause the magnetic field of the magnetic core of the Hall current sensor to change. When it is necessary to detect the leakage current of the multi-pulse surge protector, the single-chip microcomputer controls the Hall element of the Hall current sensor to work. The Hall element of the Hall current sensor converts the detected magnetic field into a voltage signal, which passes through the subtraction circuit and the amplification circuit respectively, and is finally output to the ADC chip of the single-chip microcomputer for processing. A switch circuit module can be set to trigger the single-chip microcomputer to detect the leakage current of the multi-pulse surge protector, such as Figure 3 As shown, one end of the switch SW1 is connected to the +3.3V power supply and one end of the filter capacitor CL, the other end of the filter capacitor CL is grounded, the other end of the switch SW1 is connected to the single-chip microcomputer through the IO18 pin of the single-chip microcomputer, the other end of the switch SW1 is connected to one end of the grounding resistor RL, and the other end of the grounding resistor RL is grounded. When the switch SW1 is pressed, the single-chip microcomputer receives a trigger signal, controls the Hall element of the Hall current sensor to work, and collects the leakage current of the multi-pulse surge protector. Figure 4As shown, the subtraction circuit includes a first operational amplifier U1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4 and a first capacitor C1. R1=R2=R3=R4=100K, C1=100pF. One end of the first resistor R1 is connected to the voltage output terminal BIAS of the Hall current sensor, the other end of the first resistor R1 is connected to the non-inverting input terminal of the first operational amplifier U1, one end of the second resistor R2 is connected to the non-inverting input terminal of the first operational amplifier U1, the other end of the second resistor R2 is grounded, one end of the third resistor R3 is connected to the reference voltage source VREF, the other end of the third resistor R3 is connected to the inverting input terminal of the first operational amplifier U1, one end of the fourth resistor R4 is connected to the inverting input terminal of the first operational amplifier U1, the other end of the fourth resistor R4 is connected to the output terminal HGAIN of the first operational amplifier U1, one end of the first capacitor C1 is connected to the inverting input terminal of the first operational amplifier U1, and the other end of the first capacitor C1 is connected to the output terminal HGAIN of the first operational amplifier U1. The subtraction circuit biases the voltage signal downward by 2.5V and inputs it to the amplifier circuit. Figure 5 As shown, the amplification circuit includes a second operational amplifier U2, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and a second capacitor C2. One end of the fifth resistor R5 is connected to the output terminal HGAIN of the first operational amplifier U1, the other end of the fifth resistor R5 is connected to the non-inverting input terminal of the second operational amplifier U2, one end of the sixth resistor R6 is grounded, the other end of the sixth resistor R6 is connected to the inverting input terminal of the second operational amplifier U2, one end of the seventh resistor R7 is connected to the inverting input terminal of the second operational amplifier U2, the other end of the seventh resistor R7 is connected to the output terminal of the second operational amplifier U2, one end of the second capacitor C2 is connected to the inverting input terminal of the second operational amplifier U2, and the other end of the second capacitor C2 is connected to the output terminal of the second operational amplifier U2. R5=R6=10K, R7=100K, C2=100pF, the amplification circuit amplifies the voltage signal of the output terminal HGAIN of the first operational amplifier U1 by 100 times, and connects the ADC chip in the single-chip microcomputer from the IO19 pin of the single-chip microcomputer for processing. When the single-chip microcomputer detects that the leakage current flowing through the ground wire of the multi-pulse surge protector exceeds 30mA, the corresponding information will be displayed on the display screen to prompt that the multi-pulse surge protector is unqualified. The single-chip microcomputer can control the display screen to display data through the SPI protocol. The display screen uses the HS91L02W2C01 chip, and its circuit principle is as follows Figure 6 shown.

[0046] The multi-pulse surge protector residual current detection device provided by the present invention comprises a surge absorption circuit, a residual current monitoring circuit and a single-chip computer. The lightning current is introduced into the grounding wire through the surge absorption circuit. The magnetic field generated by the leakage current of the grounding wire is measured in a non-contact manner by the Hall current sensor of the residual current monitoring circuit and converted into a voltage signal and outputted to the subtraction circuit and the amplifier circuit in sequence. The amplifier circuit amplifies the voltage signal and inputs it into the single-chip computer. The single-chip computer performs data analysis on the size of the residual current. The residual current can be detected without connecting the live wire and the ground wire of the surge protector for power supply and sampling. The technical problem that the existing multi-pulse surge protector residual current detection equipment is directly connected to the live wire and the ground wire of the surge protector for power supply and sampling, which may cause detection circuit failure or even direct conduction between the live wire of the line and the ground wire, causing safety hazards, is solved.

[0047] In one embodiment, the residual current detection device of the multi-pulse surge protector provided in the present invention also includes a lightning current monitoring circuit. The lightning current monitoring circuit includes a Rogowski coil and a signal integration circuit. The Rogowski coil is sleeved on the grounding wire of the multi-pulse surge protector, and the induced current output end of the Rogowski coil is connected to the input end of the signal integration circuit. The Rogowski coil is used as a current sensor. Its high transient response can sensitively monitor the natural physical parameters of the lightning current. By sleeved the Rogowski coil on the grounding wire, the induced current signal is transmitted to the signal integration circuit for processing. Figure 7 As shown, the signal integration circuit includes a first integration circuit, a second integration circuit and a signal amplification circuit. The first integration circuit includes a third operational amplifier U3, an eighth resistor R8, a ninth resistor R9 and a third capacitor C3. R8=1K, R9=200K, C3=100nF. One end of the eighth resistor R8 is connected to the positive end of the induced current output end of the Rogowski coil (corresponding to Figure 7 The other end of the eighth resistor R8 is connected to the inverting input terminal of the third operational amplifier U3, and the non-inverting input terminal of the third operational amplifier U3 is connected to the ground and the negative terminal of the induced current output terminal of the Rogowski coil (corresponding to Figure 7Pin 1 of the pin H2 in the circuit), one end of the ninth resistor R3 is connected to the inverting input terminal of the third operational amplifier U3, the other end of the ninth resistor R9 is connected to the output terminal of the third operational amplifier U3, one end of the third capacitor C3 is connected to the inverting input terminal of the third operational amplifier U3, and the other end of the third capacitor C3 is connected to the output terminal of the third operational amplifier U3. The transient current induced in the Rogowski coil will be input into the first integration circuit to convert the current signal into a voltage signal, and then input into the second integration circuit. The second integration circuit includes the fourth operational amplifier U4, the tenth resistor R10, the eleventh resistor R11, the twelfth resistor R12 and the fourth capacitor C4. R10=10.2K, R12=11K, R13=150K, C4=100pF. One end of the tenth resistor R10 is connected to the output end of the third operational amplifier U3, the other end of the tenth resistor R10 is connected to the non-inverting input end of the fourth operational amplifier U4, one end of the eleventh resistor R11 is grounded, the other end of the eleventh resistor R11 is connected to the inverting input end of the fourth operational amplifier U4, one end of the twelfth resistor R12 is connected to the inverting input end of the fourth operational amplifier U4, the other end of the twelfth resistor R12 is connected to the output end of the fourth operational amplifier R4, one end of the fourth capacitor C4 is connected to the inverting input end of the fourth operational amplifier U4, and the other end of the fourth capacitor C4 is connected to the output end of the fourth operational amplifier U4. The signal amplification circuit includes a fifth operational amplifier U5, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16 and a fifth capacitor C5. R14=R15=R16=R17=100K, C8=100pF. One end of the thirteenth resistor R13 is connected to the output end of the fourth operational amplifier U4, the other end of the thirteenth resistor R13 is connected to the non-inverting input end of the fifth operational amplifier U5, one end of the fourteenth resistor R14 is connected to the non-inverting input end of the fifth operational amplifier U5, the other end of the fourteenth resistor R14 is connected to the reference voltage source VREF, one end of the fifteenth resistor R15 is grounded, the other end of the fifteenth resistor R15 is connected to the inverting input end of the fifth operational amplifier U5, one end of the sixteenth resistor R16 is connected to the inverting input end of the fifth operational amplifier R5, the other end of the sixteenth resistor R16 is connected to the output end of the fifth operational amplifier U5, one end of the fifth capacitor C5 is connected to the inverting input end of the fifth operational amplifier U5, the other end of the fifth capacitor C5 is connected to the inverting input end of the fifth operational amplifier U5, and the output end of the fifth operational amplifier U5 is connected to the input end of the single-chip computer. The signal amplification circuit controls the voltage to 0~3.3V and inputs it to the ADC chip of the single-chip computer through the IO6 pin of the single-chip computer for processing.

[0048] In one embodiment, the residual current detection device for a multi-pulse surge protector provided in the present invention further includes a data storage module. The input end of the data storage module is connected to the output end of the lightning current monitoring circuit. The data storage module is used to store lightning current waveform data collected at a rate of 1 MHz when the transient current flowing through the grounding wire of the multi-pulse surge protector exceeds 1 kA. The lightning current waveform data includes the lightning current waveform and its pulse time, number of pulses, pulse time interval, pulse amplitude and pulse steepness. The data storage module uses a W25Q16JVSSIQ chip, and its circuit principle is as follows: Figure 8 shown.

[0049] In one embodiment, the residual current detection device for a multi-pulse surge protector provided in the present invention further includes a power module, which includes a Buck step-down circuit, and the step-down circuit is used to provide a +5VDC power supply for the internal circuit of the residual current detection device for a multi-pulse surge protector. Fig. 9 As shown, the Buck step-down circuit includes a step-down chip U6, a sixth capacitor C3, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9, a tenth capacitor C10, a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a twenty-first resistor R21, a diode D1, a voltage regulator D2 and an inductor L. One end of the sixth capacitor C6 is connected to the power supply VCC, and the other end of the sixth capacitor C6 is grounded, and one end of the seventh capacitor C7 is connected to the power supply VCC, and the other end of the seventh capacitor C7 is grounded. The VIN pin of the step-down chip U6 is connected to the power supply VCC, the GND pin is grounded, the EN pin is connected to one end of the seventeenth resistor R17, one end of the seventeenth resistor R17 is connected to the VIN pin, the VIA pin is left floating, the IS pin is connected to one end of the eighteenth resistor R18, the other end of the eighteenth resistor R18 is respectively connected to the VS pin and one end of the inductor L, the VB pin is connected to one end of the eighth capacitor C8, the other end of the eighth capacitor C8 is connected to the other end of the inductor L, the other end of the inductor L is connected to one end of the nineteenth resistor R19, the other end of the nineteenth resistor R19 is grounded, and one end of the ninth capacitor C9 is connected to the other end of the inductor L , the other end of the ninth capacitor C9 is grounded, the common end of the inductor L, the nineteenth resistor R19 and the ninth capacitor C9 is connected to the +5V power supply, the FB pin of the buck chip U6 is connected to one end of the twentieth resistor R20 and the twenty-first resistor R21 respectively, the other end of the twentieth resistor R20 is grounded, the other end of the twenty-first resistor R21 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the cathode of the voltage regulator tube D2, the anode of the voltage regulator tube D2 is connected to the other end of the eighth capacitor C8, one end of the tenth capacitor C10 is connected to one end of the twenty-first resistor R21, and the other end of the tenth capacitor C10 is connected to the other end of the twenty-first resistor R21. The buck chip U6 uses the EG1192L chip.

[0050] In one embodiment, the power module of the residual current detection device for a multi-pulse surge protector provided in the present invention further includes an LDO step-down circuit, and the LDO step-down circuit is used to provide a +3.3VDC power supply for the residual current detection device for a multi-pulse surge protector. Fig.10 As shown, the LDO buck circuit includes an LDO buck chip U7, a twenty-second resistor R22, a twenty-third resistor R23, a first electrolytic capacitor C11 and a second electrolytic capacitor C12. The LDO buck chip U7 adopts an AMS1117-3.3 chip. The ADJ pin of the LDO buck chip U7 is connected to one end of the twenty-second resistor R22, the other end of the twenty-second resistor R22 is grounded, the VOUT pin of the LDO buck chip U7 is connected to one end of the twenty-third resistor R23, the other end of the twenty-third resistor R23 is connected to one end of the twenty-second resistor R22, one end of the twenty-third resistor R23 is connected to a +3.3V power supply, the positive electrode of the first electrolytic capacitor C11 is connected to the VOUT pin of the LDO buck chip U7, the negative electrode of the first electrolytic capacitor C11 is grounded, the positive electrode of the second electrolytic capacitor C12 is connected to the VIN pin of the LDO buck chip U7, and the negative electrode of the second electrolytic capacitor C12 is grounded.

[0051] It should be noted that the residual current detection device of the multi-pulse surge protector provided in the present invention can be integrated with the multi-pulse surge protector, and the residual current detection device of the multi-pulse surge protector is built into the multi-pulse surge protector to directly collect the lightning pulse current parameters of the surge protector ground wire, which can solve the technical problem that the existing lightning current monitoring device needs to be installed on the ground wire to collect lightning current, and the operation remains unchanged. At the same time, the existing residual current (residual current) detection is a high-voltage laboratory or special instrument when leaving the factory. The residual current detection device of the multi-pulse surge protector can be integrated with the multi-pulse surge protector, and the residual current (residual current) on the working line can be measured by a Hall sensor. When a large lightning current has been experienced or under special circumstances, the residual current (residual current) can be detected multiple times to determine the qualification of the surge protector.

[0052] In one embodiment, Fig.11 As shown, the outer surfaces of the Hall current sensor and the lightning current monitoring circuit are covered with an aluminum foil shielding layer, which is connected to the rail grounding through screws. The outside of the aluminum foil shielding layer is covered with a heat-insulating layer made of insulating heat-insulating electronic glue. The Rogowski coil and the Hall current sensor are looped on the grounding wire of the MSPD, and at the same time, the Hall current sensor and the lightning current monitoring circuit are covered with an aluminum foil shielding layer, which is connected to the rail grounding through external screws, and then the outside of the aluminum foil shielding layer is covered with a heat-insulating layer made of insulating heat-insulating electronic glue to prevent the high heat generated by the lightning current from affecting the residual current detection device of the multi-pulse surge protector.

[0053] The terms "first", "second", etc. in the specification of the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0054] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A residual current detection device for a multi-pulse surge protector, characterized in that: include: Surge absorption circuit, residual current monitoring circuit and single chip microcomputer; Surge absorption circuits are used to direct lightning current into the ground wire; The residual current monitoring circuit includes a Hall current sensor, a subtraction circuit and an amplifier circuit. The magnetic core of the Hall current sensor is mounted on the ground wire of the multi-pulse surge protector. The voltage output end of the Hall current sensor is connected to the in-phase input end of the subtraction circuit. The output end of the subtraction circuit is connected to the in-phase input end of the amplifier circuit. The output end of the amplifier circuit is connected to the input end of the single-chip microcomputer.

2. The residual current detection device for a multi-pulse surge protector according to claim 1, characterized in that: The subtraction circuit includes a first operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor and a first capacitor; One end of the first resistor is connected to the voltage output end of the Hall current sensor, the other end of the first resistor is connected to the non-inverting input end of the first operational amplifier, one end of the second resistor is connected to the non-inverting input end of the first operational amplifier, the other end of the second resistor is grounded, one end of the third resistor is connected to the reference voltage source, the other end of the third resistor is connected to the inverting input end of the first operational amplifier, one end of the fourth resistor is connected to the inverting input end of the first operational amplifier, the other end of the fourth resistor is connected to the output end of the first operational amplifier, one end of the first capacitor is connected to the inverting input end of the first operational amplifier, and the other end of the first capacitor is connected to the output end of the first operational amplifier.

3. The residual current detection device for a multi-pulse surge protector according to claim 2, characterized in that: The amplifying circuit includes a second operational amplifier, a fifth resistor, a sixth resistor, a seventh resistor and a second capacitor; One end of the fifth resistor is connected to the output terminal of the first operational amplifier, the other end of the fifth resistor is connected to the non-inverting input terminal of the second operational amplifier, one end of the sixth resistor is grounded, the other end of the sixth resistor is connected to the inverting input terminal of the second operational amplifier, one end of the seventh resistor is connected to the inverting input terminal of the second operational amplifier, the other end of the seventh resistor is connected to the output terminal of the second operational amplifier, one end of the second capacitor is connected to the inverting input terminal of the second operational amplifier, and the other end of the second capacitor is connected to the output terminal of the second operational amplifier.

4. The residual current detection device for a multi-pulse surge protector according to claim 1, characterized in that: Also includes a lightning current monitoring circuit; The lightning current monitoring circuit includes a Rogowski coil and a signal integration circuit. The Rogowski coil is sleeved on the grounding wire of the multi-pulse surge protector, and the induction current output end of the Rogowski coil is connected to the input end of the signal integration circuit. The signal integration circuit includes a first integration circuit, a second integration circuit and a signal amplification circuit; The first integration circuit includes a third operational amplifier, an eighth resistor, a ninth resistor and a third capacitor, one end of the eighth resistor is connected to the positive end of the induced current output end of the Rogowski coil, the other end of the eighth resistor is connected to the inverting input end of the third operational amplifier, the non-inverting input end of the third operational amplifier is respectively connected to the ground and the negative end of the induced current output end of the Rogowski coil, one end of the ninth resistor is connected to the inverting input end of the third operational amplifier, the other end of the ninth resistor is connected to the output end of the third operational amplifier, one end of the third capacitor is connected to the inverting input end of the third operational amplifier, and the other end of the third capacitor is connected to the output end of the third operational amplifier; The second integration circuit includes a fourth operational amplifier, a tenth resistor, an eleventh resistor, a twelfth resistor and a fourth capacitor, one end of the tenth resistor is connected to the output end of the third operational amplifier, the other end of the tenth resistor is connected to the non-inverting input end of the fourth operational amplifier, one end of the eleventh resistor is grounded, the other end of the eleventh resistor is connected to the inverting input end of the fourth operational amplifier, one end of the twelfth resistor is connected to the inverting input end of the fourth operational amplifier, the other end of the twelfth resistor is connected to the output end of the fourth operational amplifier, one end of the fourth capacitor is connected to the inverting input end of the fourth operational amplifier, and the other end of the fourth capacitor is connected to the output end of the fourth operational amplifier; The signal amplification circuit includes a fifth operational amplifier, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor and a fifth capacitor, one end of the thirteenth resistor is connected to the output end of the fourth operational amplifier, the other end of the thirteenth resistor is connected to the non-inverting input end of the fifth operational amplifier, one end of the fourteenth resistor is connected to the non-inverting input end of the fifth operational amplifier, the other end of the fourteenth resistor is connected to a reference voltage source, one end of the fifteenth resistor is grounded, the other end of the fifteenth resistor is connected to the inverting input end of the fifth operational amplifier, one end of the sixteenth resistor is connected to the inverting input end of the fifth operational amplifier, the other end of the sixteenth resistor is connected to the output end of the fifth operational amplifier, one end of the fifth capacitor is connected to the inverting input end of the fifth operational amplifier, the other end of the fifth capacitor is connected to the inverting input end of the fifth operational amplifier, and the output end of the fifth operational amplifier is connected to the input end of the single-chip computer.

5. The residual current detection device for a multi-pulse surge protector according to claim 4, characterized in that: Also included is a data storage module; The input end of the data storage module is connected to the output end of the lightning current monitoring circuit; The data storage module is used to store lightning current waveform data collected at a rate of 1Mhz when the transient current flowing through the grounding wire of the multi-pulse surge protector exceeds 1kA. The lightning current waveform data includes the lightning current waveform and its pulse time, number of pulses, pulse time interval, pulse amplitude and pulse steepness.

6. The residual current detection device for a multi-pulse surge protector according to claim 1, characterized in that: Also includes a power module; The power module includes a Buck step-down circuit, which is used to provide a +5VDC power supply for the residual current detection device of the multi-pulse surge protector.

7. The residual current detection device for a multi-pulse surge protector according to claim 6, characterized in that: The Buck step-down circuit includes a step-down chip, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a tenth capacitor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a twenty-first resistor, a diode, a voltage regulator and an inductor; One end of the sixth capacitor is connected to the power supply VCC, and the other end of the sixth capacitor is grounded; one end of the seventh capacitor is connected to the power supply VCC, and the other end of the seventh capacitor is grounded; The VIN pin of the buck chip is connected to the power supply VCC, the GND pin is grounded, the EN pin is connected to one end of the seventeenth resistor, one end of the seventeenth resistor is connected to the VIN pin, the VIA pin is floating, the IS pin is connected to one end of the eighteenth resistor, the other end of the eighteenth resistor is respectively connected to the VS pin and one end of the inductor, the VB pin is connected to one end of the eighth capacitor, the other end of the eighth capacitor is connected to the other end of the inductor, the other end of the inductor is connected to one end of the nineteenth resistor, the other end of the nineteenth resistor is grounded, one end of the ninth capacitor is connected to the other end of the inductor, the other end of the ninth capacitor is grounded, the common end of the inductor, the nineteenth resistor and the ninth capacitor is commonly connected to the +5V power supply, the FB pin of the buck chip is respectively connected to one end of the twentieth resistor and the twenty-first resistor, the other end of the twentieth resistor is grounded, the other end of the twenty-first resistor is connected to the anode of the diode, the cathode of the diode is connected to the cathode of the Zener diode, the anode of the Zener diode is connected to the other end of the eighth capacitor, one end of the tenth capacitor is connected to one end of the twenty-first resistor, and the other end of the tenth capacitor is connected to the other end of the twenty-first resistor.

8. The residual current detection device for a multi-pulse surge protector according to claim 6, characterized in that: The power module also includes an LDO step-down circuit, which is used to provide a +3.3VDC power supply for the residual current detection device of the multi-pulse surge protector.

9. The residual current detection device for a multi-pulse surge protector according to claim 4, characterized in that: The outer surfaces of the Hall current sensor and the lightning current monitoring circuit are covered with an aluminum foil shielding layer, and the aluminum foil shielding layer is connected to the guide rail for grounding through screws.

10. The residual current detection device for a multi-pulse surge protector according to claim 9, characterized in that: The aluminum foil shield is covered with a thermal insulation layer made of insulating electronic adhesive.

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