Multi-mode arc extinction trigger device for stray current protection

Abstract

The utility model relates to the technical field of power utilization safety of urban rails, in particular to a multi-mode arc extinction trigger device for stray current protection. The system is composed of three modules: a signal detection module, a mode selection module and a driving module. The signal detection module is used for detecting an infrared trigger input signal and a voltage trigger signal. The mode selection module is used for selecting a trigger mode, the trigger board can select three trigger modes, external signal trigger can be preferentially selected through external priority trigger, and when the trigger board breaks down, the trigger board is automatically switched to a voltage trigger mode in a substitute state. And the driving module is used for converting a trigger pulse signal into a voltage rectangular wave with the width of 30S and the amplitude of DC15V, and is used for triggering reliable conduction of the three thyristors. The multi-mode arc-extinguishing trigger device is used for multi-mode arc-extinguishing trigger of stray current protection, supports multiple trigger modes, is strong in anti-interference capability and fault-tolerant capability, can control conduction of multi-track thyristors at the same time, and carries out arc-extinguishing processing on multi-track insulation joints at the same time.

Description

TECHNICAL FIELD

[0001] The utility model relates to the city rail power safety technical field, concretely is a kind of multi-mode arc extinction trigger device for stray current protection. BACKGROUND

[0002] The typical layout of metro vehicle depot and parking lot can be divided into entry-exit line area, turnout area and parking and maintenance area. In conventional design, rail insulation sectioning is arranged at positions such as main line and vehicle depot, parking lot, inside and outside of depot, front of vehicle shed, electrified and non-electrified tracks, etc., and rail sectioning return current is realized through equal return current line.

[0003] In the DC power supply system of urban rail transit, the metro power supply system generally adopts DC1500V and DC750V system. The train takes current from the catenary (or contact rail) through the pantograph (or current collector shoe), and the traction current flows back to the negative pole of the traction substation through the rail. The metro line is mainly composed of main line, vehicle depot and parking lot. The catenary in the vehicle depot and parking lot is connected with the main line catenary (or contact rail) through electrical sectioning and is powered by an independent traction substation. The main line rail is insulated from the ground to prevent traction return current from leaking to the ground and corroding metal pipes along the line. The vehicle depot and parking lot are mainly used for maintenance and repair of trains. To prevent the rail potential in the vehicle depot and parking lot from being too high to cause personal safety hazards to workers, the tracks in the train inspection depot and car wash depot are connected to the grounding grid or directly connected to the ground through an independent grounding electrode. During operation, to prevent the main line current from flowing into the ground through the rails in the vehicle depot and parking lot and causing stray current leakage, an insulating joint is usually arranged at the throat of the entry-exit section line of the vehicle depot and parking lot to isolate the main line rail, and an insulating joint is also arranged at the rail about 1km away from the throat of the entry-exit section line in the vehicle depot and parking lot to isolate the train inspection depot and car wash depot. The return current line of the traction substation in the vehicle depot and parking lot is arranged between the two insulating joints. To ensure normal return current when the train starts in the train inspection depot and to prevent damage to equipment when the train crosses the insulating joint, a unidirectional conduction device is usually connected in parallel at both ends of the insulating joint. The unidirectional conduction device is composed of multiple groups of parallel diodes (allowing current to flow only from the rail in the vehicle depot and parking lot back to the main line rail) and reverse-conducting thyristors.

[0004] The positive line rail potential is often too high, the rail potential limiter is permanently grounded, or the rail insulation is gradually damaged, thereby causing the positive line rail to leak large stray current to the ground. The unidirectional conduction device in the vehicle depot and the parking lot is often simultaneously conducted in actual application, and the grounded rail in the train inspection depot and the car washing depot provides a good return flow path for the stray current leaked from the positive line to the ground. When the train is parked in the vehicle depot and the parking lot, the stray current will flow through the weak parts of the train body, causing damage to the train body. More seriously, when the train is parked at the insulating joint, the train short-circuits the unidirectional conduction device, and most of the stray current flows back to the positive line rail through the train body, causing damage to the train equipment. When the stray current in the vehicle depot and the parking lot is serious, a series of problems such as the shell of the equipment in the depot being on fire and the ground wire being on fire will occur.

[0005] Because the power supply and the load of the traction substation on both sides of the insulating joint are inconsistent, a certain voltage exists between the two ends of the insulating joint. When the train passes through the insulating joint, the voltage and the current existing on both sides of the insulating joint reach a certain value, and an arc is formed. In order to prevent the arc from affecting the insulating joint loop, the unidirectional conduction device is provided with a thyristor arc extinguishing device. When the train passes through the insulating joint, the device detects the voltage between the two ends of the insulating joint, and when the voltage reaches a set value, the thyristor is triggered to be conductive. After the train passes through the insulating joint, the thyristor is naturally turned off.

[0006] The traditional trigger circuit mostly adopts voltage triggering, and only the voltage between the two ends of the insulating joint is used as the trigger signal. When the voltage on both sides of the insulating joint exceeds a set value, the thyristor is triggered to be conductive. The starting voltage of this kind of trigger mode cannot adapt to the working conditions on site. If the starting voltage value is set too high, although the mutual interference of the stray current between the positive line and the parking lot and the vehicle depot can be largely avoided, there will be an arc phenomenon when the train passes through the insulating joint, which will burn the train wheels and the rail. If the starting voltage value is set too low, even if there is no train passing through (the normal rail potential value of the subway positive line is 120V, and the normal rail potential value of the parking lot and the vehicle depot is 60V), the trigger board will also act, causing the positive line and the rail of the parking lot and the vehicle depot to be conductive, causing the mutual influence of the stray current, and even raising the rail-to-ground voltage in the depot, which is not conducive to the safety of the maintenance personnel in the depot.

[0007] Moreover, the trigger mode of the existing trigger board is single, the trigger set value is fixed, the reliability is not enough, there is no sufficient redundancy, the trigger board must be replaced in time after a fault occurs, the operation of the equipment on site is affected, and the trigger mode and the trigger set value cannot be set on site according to the application conditions on site, and the application environment on site cannot be fully adapted. Innovative content

[0008] To address the aforementioned problems, the purpose of this utility model is to provide a multi-mode arc-suppression triggering device for stray current protection. This device supports multiple triggering modes, has strong anti-interference capabilities and fault tolerance, and can simultaneously control the conduction of multiple thyristors while simultaneously performing arc-suppression treatment on the insulation joints of multiple channels. The technical solution is as follows:

[0009] A multi-mode arc suppression triggering device for stray current protection includes a voltage triggering circuit, an external signal detection input circuit, an external priority trigger selection circuit, and a drive module.

[0010] The voltage triggering circuit includes a resistor divider circuit, a differential circuit, and a comparator circuit. The resistor divider circuit divides the voltage at terminals A and B of the insulating joint and provides it to the operational amplifier circuit in the subsequent differential circuit for processing. The differential circuit calculates the difference between the input analog quantity and converts it into a single-ended voltage signal, which is then sent to the input terminal of the comparator circuit. The output terminal of the comparator circuit outputs a voltage trigger pulse signal, which is connected to the drive module via DIP switch B to realize single voltage triggering or combined triggering functions. It is also connected to an external priority trigger selection circuit.

[0011] The external signal detection input circuit includes an optocoupler U22, an RC circuit, and a Zener diode D22. The external trigger signal LGT+ is connected to pins 1 and 2 of the optocoupler U22 in sequence through the RC circuit and the Zener diode D22. The external trigger pulse signal is output from pin 4 of the optocoupler U22 and connected to the drive module through the DIP switch A to realize the external single trigger or combined trigger function, and also to the external priority trigger selection circuit.

[0012] The external priority trigger selection circuit includes an optocoupler U11, analog switches G1 and G2, an RC circuit, a Zener diode D11, and an NMOS transistor Q1. The external sensor status input signal EXT+ is connected to pins 1 and 2 of the optocoupler U11 via the RC circuit and Zener diode D11. Pin 3 of the optocoupler U11 is connected to pin 1 of the analog switch G2. Pin 4 of the analog switch G2 is connected to the output of the comparator circuit in the voltage trigger circuit to receive the voltage trigger pulse signal. Pin 3 of the analog switch G2 is connected to the drive module via a DIP switch C. Pin 4 of the optocoupler U11 is connected to the gate of the NMOS transistor Q1, and the source of the NMOS transistor Q1 is connected to pin 1 of the analog switch G1. Pin 4 of the analog switch G1 is connected to pin 4 of the optocoupler U22 in the external signal detection input circuit to receive the external trigger pulse signal. Pin 3 of the analog switch G1 is connected to the drive module via a DIP switch C to achieve the external priority trigger function.

[0013] The drive module is used to expand the external trigger pulse signal or voltage trigger pulse signal into a voltage rectangular wave with a set width and amplitude, and use it as the final trigger signal to trigger the conduction of the three thyristors of the thyristor arc suppression device.

[0014] Further, the driving module comprises a trigger signal holding circuit for holding the trigger signal for a set time, and the holding circuit adopts an SM74HC123D chip.

[0015] Further, the driving module comprises a driving circuit, which comprises a MOS tube VD1, a gas discharge tube D1, a rectifier diode D2 and a self-resetting fuse GDT1; a trigger signal is connected to the G pole of the MOS tube VD1 through a resistor R31, the S pole of the MOS tube VD1 is connected to a power supply, the D pole is connected to the positive pole of the rectifier diode D2, the negative pole of the diode D2 is connected to the positive pole of the gas discharge tube D1 through a resistor R32, the negative pole of the gas discharge tube D1 is connected to the A level of a thyristor and the A end of an insulation joint through the self-resetting fuse GDT1; the negative pole of the diode D2 is also connected to the G pole of the thyristor through a resistor R33, and the K pole of the thyristor is connected to the B end of the insulation joint.

[0016] The utility model discloses the beneficial effects are:

[0017] (1) the utility model discloses the arc extinguishing device of stray current protection's trigger, supports multiple trigger modes: single signal trigger, such as voltage trigger, external signal trigger (infrared pair of shots, radar detection), and combined trigger and priority signal trigger.

[0018] (2) the utility model discloses the characteristics of strong anti-interference ability, strong fault tolerance.

[0019] (3) the utility model discloses can drive 3 -way thyristor conduction, controls multiple lane's thyristor conduction simultaneously, and simultaneously gives multiple lane insulation joint arc extinguishing treatment.

[0020] (4) the utility model discloses the voltage trigger adopts the hardware double redundancy circuit design, and the system is safer and more reliable.

[0021] (5) the utility model discloses the voltage trigger gear can 0 ~ 100V stepless adjustable also can fixed gear adjustment.

[0022] (6) the utility model discloses the trigger signal can hold fixed time, avoids repeatedly starting, and influences the service life of device. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is the overall block diagram of the utility model discloses a multiple mode arc extinguishing trigger device for stray current protection.

[0024] Figure 2 It is the principle block diagram of the driving circuit.

[0025] Figure 3 It is the principle block diagram of the voltage trigger circuit.

[0026] Figure 4 Voltage trigger circuit in the principle diagram of the voltage divider circuit.

[0027] Figure 5 Voltage trigger circuit in the principle diagram of the differential circuit.

[0028] Figure 6 Voltage trigger circuit in the principle diagram of the step comparison circuit.

[0029] Figure 7 Voltage trigger circuit in the principle diagram of the stepless comparison circuit.

[0030] Figure 8 External signal detection import principle diagram.

[0031] Figure 9 Three-way thyristor trigger principle block diagram.

[0032] Figure 10 Trigger signal holding circuit diagram.

[0033] Figure 11 External priority trigger selection circuit. DETAILED DESCRIPTION

[0034] The utility model will be made further detailed explanation in combination with the drawings and specific embodiment.

[0035] The multi-mode arc-extinguishing trigger device for stray current protection has two trigger thyristor conduction modes of infrared and voltage to cope with different field requirements. The voltage trigger is to obtain the voltage across the insulating joint, and trigger the thyristor conduction when it is greater than the threshold value. At this time, the voltage across the insulating joint is equal potential, and the train wheel will not strike when passing, which can play the role of arc extinguishing to protect the steel rail from being burned. The infrared trigger principle is that the infrared sensor is installed about 3 to 5 meters in front of the insulating joint. When the train passes, the infrared signal will be blocked, and the infrared sensor will output a high level to the trigger device. The trigger device directly triggers the thyristor conduction after receiving it, which plays the role of arc extinguishing. The technical parameters of the arc-extinguishing device trigger circuit for stray current protection are shown in Table 1.

[0036] Table 1 Technical parameters of the arc-extinguishing device trigger circuit for stray current protection

[0037] Serial number Sampling voltage name Technical parameters 1 Rated power supply voltage AC 220V 2 Voltage trigger threshold DC 20~90V 8 grades adjustable, 0~100V stepless adjustable 3 Thyristor trigger interface 3-way 4 External input interface 2-way 5 State feedback 2-way, respectively "power on" and "trigger"

[0038] The trigger board is mainly composed of three modules: a trigger signal detection module, a mode selection module and a driving module. The trigger signal detection module is used for detecting external trigger import signals and voltage trigger signals. The mode selection module is used for selecting the trigger mode. The trigger board selects the trigger mode through three DIP switches (i.e. Figure 1The A, B, and C DIP switches of the mode selection module allow selection of three trigger modes. External priority triggering prioritizes external signals, automatically switching to the backup voltage triggering mode in case of failure. The drive module converts the trigger pulse signal into a 30-second, DC 15V rectangular wave as the final trigger signal (via...). Figure 10 The trigger signal holding circuit shown is then used to reliably trigger the three thyristors to conduct.

[0039] like Figure 2 The driving circuit block diagram is shown, including MOSFET VD1, gas discharge tube D1, rectifier diode D2, and resettable fuse GDT1. The trigger signal is connected to the gate (G) of MOSFET VD1 through resistor R31. The source (S) of MOSFET VD1 is connected to the power supply, and the drain (D) is connected to the positive terminal of rectifier diode D2. The negative terminal of diode D2 is connected to the positive terminal of gas discharge tube D1 through resistor R32. The negative terminal of gas discharge tube D1 is simultaneously connected to the A terminal of thyristor and the A terminal of insulating joint through resettable fuse GDT1. The negative terminal of diode D2 is also connected to the gate (G) of thyristor through resistor R33, and the base (K) of thyristor is connected to the B terminal of insulating joint.

[0040] The triggering principle is as follows: After the thyristor is connected to the triggering device, if neither voltage triggering nor external triggering is enabled, when the voltage between Uak is greater than 150V, the gas discharge tube D1 will be broken down and turned on. The voltage at end A goes directly to the thyristor control stage G after passing through resistors R2 and R3. This can be achieved by using the voltage across the external insulating joint to achieve self-triggering. Even if the power supply of the triggering device is not powered on, this function can still be effectively started, which is the last barrier to prevent arcing due to excessive voltage at the insulating joint.

[0041] like Figure 3 The voltage trigger circuit block diagram is shown. The voltage trigger employs a dual-redundancy circuit design; as long as one output is normal, the circuit can still operate normally. This design greatly improves the reliability of the voltage trigger. The voltage trigger circuit mainly consists of three parts: a resistor divider circuit, a differential circuit, and a comparator circuit. The resistor divider circuit divides the external high voltage to a suitable range for processing by the subsequent operational amplifier circuit. The differential circuit is responsible for calculating the difference between the input analog signal and the output, converting it into a single-ended signal. The comparator circuit compares this voltage signal with the voltage setting of the DIP switch. If the voltage exceeds the threshold value, it outputs a voltage trigger pulse signal TRI+. One output is sent to the driver module via DIP switch B to implement single or combined voltage triggering functions, and the other is sent to the external priority trigger selection circuit. The two outputs use two diodes connected in parallel to implement OR logic, jointly driving the thyristor to conduct.

[0042] like Figure 4The voltage obtained by the voltage dividing circuit is Uain = Uak

[0043] (R3+R4) / (R1+R2+R3+R4), and R1 / R3 = R2 / R4 = 5, which means the external signal is reduced to 1 / 6. In this circuit, the external analog signal and the internal analog signal are grounded, which provides stable conditions for the processing of analog signals by the subsequent circuit. When the voltage across the insulating section is too high, the high voltage obtained after voltage division will be clamped by the TVS, so as not to burn the subsequent circuit.

[0044] As shown in the differential circuit principle diagram of Figure 5 When R5 / R6 = R7 / R8, Udif = Uap-Uan can be derived from the differential circuit principle. This circuit can convert the external analog signal into a single-ended signal with internal common ground, and has high input impedance and low output impedance, which can also function as analog signal impedance matching and increase the driving ability of the subsequent circuit.

[0045] As shown in the principle diagram of the stepped tuning comparison circuit of Figure 6 In the operational amplifier comparison circuit, R10 has a large value and functions as introducing positive feedback. As long as the positive input terminal has a higher potential than the negative input terminal, a high level is output, and vice versa. The code switch has 8 positions, and different insulating section voltage trigger values can be set by changing the resistance of the lower dial. The 8 voltage positions set by the trigger device are shown in Table 2.

[0046] Table 2 8 voltage positions set by the trigger device

[0047] Trigger gear 1 2 3 4 5 6 7 8 Voltage amplitude (V) 20 30 40 50 60 70 80 90

[0048] The resistance values of R12-R19 are obtained by actual calculation. The circuit output has a driving capacity of 20mA, and outputs a low level when the trigger signal takes effect. An external pull-up resistor can enhance the anti-interference function and provide greater driving capacity.

[0049] As shown in the principle diagram of the non-step tuning comparison circuit of Figure 7 This comparison circuit supports non-step tuning, and the trigger voltage can be adjusted between 0-100V by changing the resistance value of the adjustable resistor RK1. Because the stepped tuning and non-step tuning circuits are in hardware dual-redundancy mode, any triggered comparison circuit can conduct the thyristor. This mode can flexibly set the trigger voltage threshold value of different requirements.

[0050] As shown in the principle diagram of the non-step tuning comparison circuit of Figure 8The external signal detection open-in principle diagram shown, including optocoupler U22, RC circuit and voltage regulator D22; external trigger signal LGT+ in turn through RC circuit and voltage regulator D22 connected to the input end of optocoupler U22 pin 1 and 2, the output end of optocoupler U22 pin 4 output external trigger pulse signal, and through the DIP switch A to the drive module for realizing external single trigger or combination trigger function, also to the external priority trigger selection circuit.

[0051] When the external infrared pair or radar detection module, this kind of module will give the sensor open-in a high level when there is a train passing, open-in detection circuit will this high level into the signal of trigger thyristor conduction. Because the field train through the interference is great, open-in bus will be inducted a great interference, and open-in circuit only adjusts the voltage regulator D22 voltage, also R21 and R22 ratio, can be flexible to set the open-in minimum voltage threshold. The low voltage induced by the field open-in line is shielded to prevent false triggering. At the same time, the RC circuit composed of capacitor C21 and front-end resistor R21 can also filter out high-frequency interference. The circuit has strong anti-interference ability and has been tested in many field environments.

[0052] As Figure 9 The three-way thyristor trigger principle diagram shows that the voltage and infrared generated trigger signal, after the circuit or logic, can drive 3-way thyristor conduction, which can control the conduction of multiple lanes of thyristor at the same time, and can be used for arc extinguishing treatment of multiple lane insulating joints. The function of voltage trigger or infrared trigger can be turned on or off through the DIP switch.

[0053] Because the trigger condition only lasts for a moment many times, such as the voltage between the insulating joints is too high to trigger the thyristor conduction, when the thyristor is turned on, the voltage between the insulating joints will be reduced to 0 in an instant, and the trigger condition will disappear, which cannot be maintained for a long time. This will cause the thyristor to be triggered repeatedly when the train passes through the insulating joint. Therefore, the trigger device is added with a trigger delay retention function.

[0054] As Figure 10 shown, when the trigger pulse signal TRI+ comes a falling edge↓, the 4th pin / Q will output a low level rectangular wave, the time length of which can be determined by the product of voltage R1 and C1. Adjusting the product of RC, the desired trigger signal retention time can be obtained. Here RC=300K*0.0001=30S, so the trigger signal can be maintained for 30S, which is basically the time of the train passing through the insulating joint at a slow speed.

[0055] In order to adapt to various application occasions, the trigger circuit can be set to multiple trigger modes, as shown in Table 3.

[0056] Table 3 Trigger mode

[0057]

[0058] As Figure 11 The external priority trigger selection circuit, mainly used to realize the function of external priority trigger. The circuit includes optocoupler U11, analog switch G1 and G2, RC circuit and voltage regulator D11, and NMOS tube Q1; the external sensor state input signal EXT+ is connected to the pins 1 and 2 of the optocoupler U11 in turn through the RC circuit and voltage regulator D11, the pin 3 of the optocoupler U11 is connected to the pin 1 of the analog switch G2; the pin 4 of the analog switch G2 is connected to the output end of the comparison circuit in the voltage trigger circuit, receiving the voltage trigger pulse signal; the pin 3 of the analog switch G2 is connected to the driving module through the DIP switch C; the pin 4 of the optocoupler U11 is connected to the gate of the NMOS tube Q1, the source of the NMOS tube Q1 is connected to the pin 1 of the analog switch G1, and the pin 4 of the analog switch G1 is connected to the pin 4 of the optocoupler U22 in the external signal detection input circuit, receiving the external trigger pulse signal; the pin 3 of the analog switch G1 is connected to the driving module through the DIP switch C, to realize the function of external priority trigger.

[0059] The mode selection truth table is as follows Table 4.

[0060] Table 4 DIP switch mode selection table

[0061]

[0062] The logic implementation is as Table 5, the external sensor has a state feedback signal to the external priority trigger selection circuit, when the external sensor (such as infrared emitter-receiver) is normal, the state feedback input is high level, at this time the output end of the optocoupler U11 is turned on, the analog switch G2 is opened, and the external signal trigger function is opened. The NMOS tube Q1 is turned on to close G1, so that the voltage signal trigger function is closed.

[0063] When the external sensor (such as infrared emitter-receiver) is abnormal, the state feedback input is low level, at this time the output end of the optocoupler U11 is turned off, the analog switch G2 is closed, and the external signal trigger function is closed. The NMOS tube Q1 is also closed to turn on G1, so that the voltage signal trigger function is opened.

[0064] Table 5 External priority trigger corresponding truth table

[0065] External trigger Voltage trigger External sensor state input = 0 (abnormal) Off On External sensor state input = 1 (normal) On Off

[0066] The analog switches G1 and G2 are respectively the conduction switches of the external signal trigger and the voltage signal trigger, and only when they are turned on, the corresponding trigger function will work. In this way, the function of external priority trigger selection is realized. The mode selection truth table is as follows Table 2.

[0067] The circuit can automatically select the external signal trigger mode through the external sensor state feedback, and can solve the problem of poor selection of the field voltage trigger gear. For example, if the voltage trigger gear is set too high, the arc extinguishing effect of the insulating joint cannot be achieved, and if it is set too low, the thyristor will be frequently triggered, causing the current of the positive line to frequently enter the vehicle depot and causing safety problems. The function of the circuit can be selected by a DIP switch.

Claims

1. A multi-mode arc suppression triggering device for stray current protection, characterized in that, It includes a voltage trigger circuit, an external signal detection input circuit, an external priority trigger selection circuit, and a drive module; The voltage triggering circuit includes a resistor divider circuit, a differential circuit, and a comparator circuit. The resistor divider circuit divides the voltage at terminals A and B of the insulating joint and provides it to the operational amplifier circuit in the subsequent differential circuit for processing. The differential circuit calculates the difference between the input analog quantity and converts it into a single-ended voltage signal, which is then sent to the input terminal of the comparator circuit. The output terminal of the comparator circuit outputs a voltage trigger pulse signal, which is connected to the drive module via DIP switch B to realize single voltage triggering or combined triggering functions. It is also connected to an external priority trigger selection circuit. The external signal detection input circuit includes an optocoupler U22, an RC circuit, and a Zener diode D22. The external trigger signal LGT+ is connected to pins 1 and 2 of the optocoupler U22 in sequence through the RC circuit and the Zener diode D22. The external trigger pulse signal is output from pin 4 of the optocoupler U22 and connected to the drive module through the DIP switch A to realize the external single trigger or combined trigger function, and also to the external priority trigger selection circuit. The external priority trigger selection circuit includes an optocoupler U11, analog switches G1 and G2, an RC circuit, a Zener diode D11, and an NMOS transistor Q1. The external sensor status input signal EXT+ is connected to pins 1 and 2 of the optocoupler U11 via the RC circuit and Zener diode D11. Pin 3 of the optocoupler U11 is connected to pin 1 of the analog switch G2. Pin 4 of the analog switch G2 is connected to the output of the comparator circuit in the voltage trigger circuit to receive the voltage trigger pulse signal. Pin 3 of the analog switch G2 is connected to the drive module via a DIP switch C. Pin 4 of the optocoupler U11 is connected to the gate of the NMOS transistor Q1, and the source of the NMOS transistor Q1 is connected to pin 1 of the analog switch G1. Pin 4 of the analog switch G1 is connected to pin 4 of the optocoupler U22 in the external signal detection input circuit to receive the external trigger pulse signal. Pin 3 of the analog switch G1 is connected to the drive module via a DIP switch C to achieve the external priority trigger function. The drive module is used to expand the external trigger pulse signal or voltage trigger pulse signal into a voltage rectangular wave with a set width and amplitude, and use it as the final trigger signal to trigger the conduction of the three thyristors of the thyristor arc suppression device.

2. The multi-mode arc suppression triggering device for stray current protection according to claim 1, characterized in that, The driving module includes a trigger signal holding circuit for holding the trigger signal for a set time. The holding circuit uses an SM74HC123D chip.

3. The multi-mode arc suppression triggering device for stray current protection according to claim 1, characterized in that, The drive module includes a drive circuit comprising a MOSFET VD1, a gas discharge tube D1, a rectifier diode D2, and a resettable fuse GDT1. A trigger signal is connected to the gate (G) of MOSFET VD1 via resistor R31. The source (S) of MOSFET VD1 is connected to the power supply, and the drain (D) is connected to the anode of rectifier diode D2. The cathode of diode D2 is connected to the anode of gas discharge tube D1 via resistor R32. The cathode of gas discharge tube D1 is simultaneously connected to the anode (A) of the thyristor and the A terminal of the insulating joint via the resettable fuse GDT1. The cathode of diode D2 is also connected to the gate (G) of the thyristor via resistor R33, and the base (K) of the thyristor is connected to the B terminal of the insulating joint.

Images