A subway low-voltage power distribution protection device

Abstract

A low-voltage power distribution protector for subways, belonging to the field of power distribution protectors, includes a signal acquisition and conditioning circuit; an overcurrent detection and delay circuit, an instantaneous overcurrent detection circuit, and a leakage current detection and delay circuit connected to the signal acquisition and conditioning circuit; a logic synthesis and voting circuit connected to the overcurrent detection and delay circuit, the instantaneous overcurrent detection circuit, and the leakage current detection and delay circuit; a tripping drive and execution mechanism and a fault indication and latching circuit connected to the logic synthesis and voting circuit; and a power supply and self-test circuit for power supply and self-testing. This invention achieves high reliability, high safety, and easy maintenance of low-voltage power distribution protection functions for subways through a comprehensive hardware design, fault-safety features, fast response, status indication, anti-interference, and self-testing mechanisms.

Description

Technical Field

[0001] This utility model belongs to the technical field of power distribution protection devices, specifically relating to a low-voltage power distribution protection device for subways. Background Technology

[0002] The subway low-voltage power distribution protector is a hardwired logic control system based on current and voltage detection. Its core working principle is: continuously monitor the current and voltage of the line, and when any parameter exceeds a preset threshold, the corresponding timer starts, and after the timeout, it drives the tripping mechanism to cut off the circuit.

[0003] Currently, existing low-voltage power distribution protection devices for subways mainly have the following technical problems:

[0004] 1. Fail-safe design;

[0005] In existing subway low-voltage power distribution protection devices, many electronic components exhibit unpredictable failure modes. For example, a comparator failure may result in a permanent low-level output ("no fault" signal). When the protector itself experiences a latent fault, the system may mistakenly assume everything is normal, losing its protective function and ultimately leading to the escalation of the fault, causing equipment damage or fire. This does not comply with the highest level of safety principles for rail transit.

[0006] 2. Weak anti-interference ability;

[0007] The subway environment is an extremely harsh electromagnetic environment, with strong interference from frequency converters, large motors, and switch operations. Microprocessor-based digital systems are highly sensitive to high-frequency noise. Despite software filtering and hardware shielding, there is still a risk that interference may cause incorrect sampling data or malfunctioning logic, leading to erroneous operations and affecting the normal operation of the subway.

[0008] 3. Power supply dependence;

[0009] Traditional electronic trip units require a continuous power supply to maintain operation. If the auxiliary power supply of the protector fails, the entire protection function will be completely ineffective, losing its last line of defense. Utility Model Content

[0010] Therefore, in order to solve the technical problems existing in the current subway low-voltage power distribution protector, this utility model provides a subway low-voltage power distribution protector.

[0011] The technical solution adopted by this utility model to solve the technical problem is as follows:

[0012] This utility model provides a low-voltage power distribution protection device for subways, which specifically includes:

[0013] Signal acquisition and conditioning circuit;

[0014] Overcurrent detection and delay circuit, instantaneous overcurrent detection circuit, and leakage current detection and delay circuit are connected to the signal acquisition and conditioning circuit.

[0015] Logic synthesis and voting circuit connected to overcurrent detection and delay circuit, instantaneous overcurrent detection circuit, and leakage current detection and delay circuit;

[0016] The tripping drive and actuator, and the fault indication and latching circuit are connected to the logic synthesis and voting circuits;

[0017] The power supply and self-test circuit is connected to the signal acquisition and conditioning circuit, overcurrent detection and delay circuit, instantaneous trip detection circuit, leakage current detection and delay circuit, logic synthesis and voting circuit, trip drive and actuator, and fault indication and latching circuit.

[0018] Furthermore, the signal acquisition and conditioning circuit includes: a current transformer connected to the main circuit, a first precision sampling resistor connected to the current transformer, a first operational amplifier connected to the first precision sampling resistor, a first RC low-pass filter connected to the first operational amplifier, a zero-sequence current transformer connected to the main circuit, a second precision sampling resistor connected to the zero-sequence current transformer, a second operational amplifier connected to the second precision sampling resistor, a second RC low-pass filter connected to the second operational amplifier, a first resistor connected to the main circuit, and a voltage follower connected to the first resistor.

[0019] Furthermore, the overcurrent detection and delay circuit includes: a first voltage comparator connected to a first RC low-pass filter, a first voltage regulator chip connected to the first voltage comparator, a first constant current source connected to the first voltage regulator chip, a first capacitor connected to the first constant current source, and a second voltage comparator connected to the first capacitor.

[0020] Furthermore, the instantaneous fast-break detection circuit includes: a third voltage comparator connected to the voltage follower, a second voltage regulator chip connected to the third voltage comparator, and a first diode connected to the second voltage regulator chip.

[0021] Furthermore, the leakage current detection and delay circuit includes: a fourth voltage comparator connected to the second RC low-pass filter, a third voltage regulator chip connected to the fourth voltage comparator, a second constant current source connected to the third voltage regulator chip, a second capacitor connected to the second constant current source, and a fifth voltage comparator connected to the second capacitor.

[0022] Furthermore, the logic synthesis and voting circuit includes: an OR gate chip and a second diode connected to the OR gate chip; the OR gate chip is connected to a second voltage comparator, a first diode, and a fifth voltage comparator, respectively.

[0023] Furthermore, the tripping drive and actuator includes: a power transistor connected to the second diode, a tripping coil connected to the power transistor, and a magnetic latching relay connected to the tripping coil.

[0024] Furthermore, the fault indication and latching circuit includes: an overload trigger connected to the second diode, a short-circuit trigger connected to the second diode, a leakage trigger connected to the second diode, an overload red light connected to the overload trigger, a short-circuit yellow light connected to the short-circuit trigger, a leakage blue light connected to the leakage trigger, and a manual reset button connected to the overload trigger, the short-circuit trigger, and the leakage trigger.

[0025] Furthermore, the power supply and self-test circuit includes: a linear power supply module connected to the main circuit, a power-on reset circuit connected to the linear power supply module, and a 555 timer connected to the power-on reset circuit.

[0026] Furthermore, the power-on reset circuit is connected to the overload red light, the short-circuit yellow light, and the leakage blue light, respectively; the 555 timer is connected to the OR gate logic chip.

[0027] The beneficial effects of this utility model are:

[0028] 1. Fail-safe design;

[0029] In this invention, any failure (open circuit, short circuit, power loss) of any key component (such as sensor, comparator, power supply) will cause the system to be directed to the safety side (i.e. tripping or alarm), which greatly improves the safety level of the system and meets the design requirements of rail transit and other systems with stringent safety requirements.

[0030] 2. Fast response and high precision;

[0031] This invention uses a high-precision reference source and voltage comparator to ensure accurate action threshold; the short-circuit instantaneous response time can reach the microsecond level; overcurrent and leakage protection achieve adjustable delay through constant current source + capacitor charging, with fast and controllable response speed, effectively limiting fault current and protecting equipment and lines.

[0032] 3. Three-stage selective protection;

[0033] This invention can achieve three-stage protection characteristics: long delay for overload, short delay for short circuit, and instantaneous fast trip. It can be used in conjunction with upstream and downstream protectors to achieve selective tripping, avoid cascading tripping, and improve power supply continuity.

[0034] 4. Status indication and latching functions;

[0035] The tripping cause (overload, short circuit, leakage) is clearly indicated by the trigger and LED indicator; the manual reset button ensures that the fault information is continuously displayed until the reset is confirmed, which makes it easier for maintenance personnel to quickly locate the fault type and improve maintenance efficiency.

[0036] 5. Strong anti-interference ability;

[0037] This invention employs RC low-pass filtering, voltage follower, and precision sampling resistors to suppress noise. Its excellent PCB layout and shielding design adapt to the harsh EMC environment of the subway, effectively preventing malfunctions and improving the system's stability under strong electromagnetic interference.

[0038] 6. The tripping mechanism is energy-efficient and reliable;

[0039] This invention uses a magnetic latching relay, which can maintain the open state without continuous power supply after tripping, saving energy, improving reliability, and conforming to the fail-safe principle. Attached Figure Description

[0040] Figure 1 This utility model provides a structural block diagram of a subway low-voltage power distribution protector.

[0041] Figure 2 This utility model provides a circuit connection diagram for a subway low-voltage power distribution protector.

[0042] In the diagram, the signal acquisition and conditioning circuit 1, current transformer 101, first precision sampling resistor 102, first operational amplifier 103, first RC low-pass filter 104, zero-sequence current transformer 105, second precision sampling resistor 106, second operational amplifier 107, second RC low-pass filter 108, first resistor 109, voltage follower 110, overcurrent detection and delay circuit 2, first voltage comparator 201, first voltage regulator chip 202, first constant current source 203, first capacitor 204, second voltage comparator 205, instantaneous overcurrent detection circuit 3, third voltage comparator 301, second voltage regulator chip 302, first diode 303, and leakage current detection and delay circuit are also included. Circuit 4, Fourth Voltage Comparator 401, Third Voltage Regulator Chip 402, Second Constant Current Source 403, Second Capacitor 404, Fifth Voltage Comparator 405, Logic Synthesis and Voting Circuit 5, OR Gate Logic Gate Chip 501, Second Diode 502, Trip Drive and Actuation Mechanism 6, Power Transistor 601, Trip Coil 602, Magnetic Latching Relay 603, Fault Indication and Latching Circuit 7, Overload Trigger 701, Short Circuit Trigger 702, Leakage Trigger 703, Overload Red Light 704, Short Circuit Yellow Light 705, Leakage Blue Light 706, Manual Reset Button 707, Power Supply and Self-Test Circuit 8, Linear Power Supply Module 801, Power-On Reset Circuit 802, 555 Timer 803. Detailed Implementation

[0043] The present invention will be further described in detail below with reference to the accompanying drawings.

[0044] See Figure 1 and Figure 2 As described above, the low-voltage power distribution protector for subways provided by this utility model mainly includes the following modules:

[0045] The circuit comprises: signal acquisition and conditioning circuit 1, overcurrent detection and delay circuit 2, instantaneous overcurrent detection circuit 3, leakage current detection and delay circuit 4, logic synthesis and voting circuit 5, trip drive and actuator 6, fault indication and latching circuit 7, and power supply and self-test circuit 8. Specifically, signal acquisition and conditioning circuit 1 is connected to overcurrent detection and delay circuit 2, instantaneous overcurrent detection circuit 3, and leakage current detection and delay circuit 4. Overcurrent detection and delay circuit 2, instantaneous overcurrent detection circuit 3, and leakage current detection and delay circuit 4 are all connected to logic synthesis and voting circuit 5. Logic synthesis and voting circuit 5 is connected to trip drive and actuator 6 and fault indication and latching circuit 7. All four circuits—signal acquisition and conditioning circuit 1, overcurrent detection and delay circuit 2, instantaneous overcurrent detection circuit 3, leakage current detection and delay circuit 4, logic synthesis and voting circuit 5, trip drive and actuator 6, and fault indication and latching circuit 7—are connected to power supply and self-test circuit 8.

[0046] According to this utility model, the signal acquisition and conditioning circuit 1 is mainly used to realize current detection, residual current detection, and voltage detection. The signal acquisition and conditioning circuit 1 specifically includes: a current transformer 101, a first precision sampling resistor 102, a first operational amplifier 103, a first RC low-pass filter 104, a zero-sequence current transformer 105, a second precision sampling resistor 106, a second operational amplifier 107, a second RC low-pass filter 108, a first resistor 109, and a voltage follower 110. Current transformer 101 is connected to the main circuit. First precision sampling resistor 102 is connected to current transformer 101. First operational amplifier 103 is connected to first precision sampling resistor 102. First RC low-pass filter 104 is connected to first operational amplifier 103. Zero-sequence current transformer 105 is connected to the main circuit. Second precision sampling resistor 106 is connected to zero-sequence current transformer 105. Second operational amplifier 107 is connected to second precision sampling resistor 106. Second RC low-pass filter 108 is connected to second operational amplifier 107. First resistor 109 is connected to the main circuit. Voltage follower 110 is connected to first resistor 109.

[0047] Specifically, the current transformer 101, the first precision sampling resistor 102, the first operational amplifier 103, and the first RC low-pass filter 104 are mainly used to realize current detection. The current transformer 101 is used to isolate the measurement of the main circuit current. The current transformer 101 is connected to a first precision sampling resistor 102 to convert the current into a voltage signal. The first operational amplifier 103 is used to amplify the small voltage signal to a level suitable for comparison (such as 0-5V). The first RC low-pass filter 104 is mainly used to suppress high-frequency noise. Finally, the output voltage signal is given to the overcurrent detection and delay circuit 2.

[0048] Specifically, the first resistor 109 and the voltage follower 110 are mainly used to realize voltage detection. The first resistor 109 is a high-resistance resistor (e.g., 10kΩ). The high-resistance resistor is used to obtain the voltage signal from the main circuit. After impedance transformation by the voltage follower 110, the signal is output to the instantaneous fast-break detection circuit 3.

[0049] Specifically, the zero-sequence current transformer 105, the second precision sampling resistor 106, the second operational amplifier 107, and the second RC low-pass filter 108 are mainly used to realize residual current detection. The zero-sequence current transformer 105 is placed on all phase lines and neutral lines in the main circuit to detect leakage current in the phase lines and neutral lines in the main circuit. The zero-sequence current transformer 105 is connected to a second precision sampling resistor 106 to convert the current into a voltage signal. The second operational amplifier 107 is used to amplify the small voltage signal to a suitable comparison level (such as 0-5V). The second RC low-pass filter 108 is mainly used to suppress high-frequency noise. Finally, the output voltage signal is given to the leakage detection and delay circuit 4.

[0050] According to this utility model, the overcurrent detection and delay circuit 2 is mainly used to realize overload long delay (L) and short-circuit short delay (S) protection. The overcurrent detection and delay circuit 2 specifically includes: a first voltage comparator 201, a first voltage regulator chip 202, a first constant current source 203, a first capacitor 204, and a second voltage comparator 205. The first voltage comparator 201 is connected to a first RC low-pass filter 104, the first voltage regulator chip 202 is connected to the first voltage comparator 201, the first constant current source 203 is connected to the first voltage regulator chip 202, the first capacitor 204 is connected to the first constant current source 203, and the second voltage comparator 205 is connected to the first capacitor 204.

[0051] Specifically, the voltage V after being conditioned by signal acquisition and conditioning circuit 1 in The voltage is fed into the inverting input of the first voltage comparator 201, and the non-inverting input of the first voltage comparator 201 is connected to the first voltage regulator chip 202. The first voltage regulator chip 202 provides an adjustable reference voltage source, and the voltage V of the adjustable reference voltage source is... ref Corresponding current action threshold I set When Vin >V ref When the overcurrent occurs, the first voltage comparator 201 outputs a high level, indicating an overcurrent has occurred; conversely, when the overcurrent occurs, the first voltage comparator 201 outputs a low level, indicating no overcurrent has occurred. When the first voltage comparator 201 outputs a high level, the first constant current source 203 begins charging the first capacitor 204. The more severe the overcurrent, the greater the charging current, and the shorter the time required for the capacitor voltage to reach the next threshold. At this time, the second voltage comparator 205 detects the capacitor voltage. When it reaches the threshold, it outputs an overload trip signal to the logic synthesis and voting circuit 5.

[0052] According to this utility model, the instantaneous trip detection circuit 3 is mainly used to trip immediately without delay when a severe short circuit (extremely high current) occurs in the main circuit. The instantaneous trip detection circuit 3 specifically includes: a third voltage comparator 301, a second voltage regulator chip 302, and a first diode 303. The third voltage comparator 301 is connected to the voltage follower 110, the second voltage regulator chip 302 is connected to the third voltage comparator 301, and the first diode 303 is connected to the second voltage regulator chip 302.

[0053] Specifically, the voltage after being conditioned by signal acquisition and conditioning circuit 1 The voltage is fed into the inverting input of the third voltage comparator 301, and the non-inverting input of the third voltage comparator 301 is connected to the second voltage regulator chip 302, which provides an adjustable reference voltage source. When voltage Instantly exceeds the adjustable reference voltage source At this time, the output of the third voltage comparator 301 (short-circuit trip signal) is directly fed into the subsequent logic synthesis and voting circuit 5 through the first diode 303, bypassing all delay links.

[0054] According to this utility model, the leakage current detection and delay circuit 4 is mainly used for leakage current detection. Specifically, the leakage current detection and delay circuit 4 includes: a fourth voltage comparator 401, a third voltage regulator chip 402, a second constant current source 403, a second capacitor 404, and a fifth voltage comparator 405. The fourth voltage comparator 401 is connected to the second RC low-pass filter 108, the third voltage regulator chip 402 is connected to the fourth voltage comparator 401, the second constant current source 403 is connected to the third voltage regulator chip 402, the second capacitor 404 is connected to the second constant current source 403, and the fifth voltage comparator 405 is connected to the second capacitor 404.

[0055] Specifically, the voltage after being conditioned by signal acquisition and conditioning circuit 1 The voltage is fed into the inverting input of the fourth voltage comparator 401, and the non-inverting input of the fourth voltage comparator 401 is connected to the third voltage regulator chip 402, which provides an adjustable reference voltage source; when When the overcurrent occurs, the fourth voltage comparator 401 outputs a high level, indicating an overcurrent has occurred; conversely, when the overcurrent occurs, the fourth voltage comparator 401 outputs a low level, indicating no overcurrent has occurred. When the fourth voltage comparator 401 outputs a high level, the second constant current source 403 begins charging the second capacitor 404. The more severe the overcurrent, the greater the charging current, and the shorter the time required for the capacitor voltage to reach the next threshold. At this time, the fifth voltage comparator 405 detects the capacitor voltage. When it reaches the threshold, it outputs a leakage trip signal to the logic synthesis and voting circuit 5.

[0056] According to this utility model, the logic synthesis and voting circuit 5 is mainly used to perform "OR" logic synthesis on the trip signals of various circuits such as overload, short circuit, and leakage current. Tripping is triggered when any one of the signals is valid. Specifically, the logic synthesis and voting circuit 5 includes: an OR gate chip 501 and a second diode 502. The second diode 502 is connected to the OR gate chip 501; the OR gate chip 501 is connected to the second voltage comparator 205, the first diode 303, and the fifth voltage comparator 405, respectively.

[0057] Specifically, the signals from each path are aggregated to the OR gate chip 501 via the second diode 502. When any one of the signals is high (logic 1), the signal at the output of the OR gate chip 501 will become high.

[0058] According to this utility model, the tripping drive and actuator 6 is mainly used to generate sufficient energy to drive the main circuit circuit breaker to trip. The tripping drive and actuator 6 specifically includes: a power transistor 601, a trip coil 602, and a magnetic latching relay 603. The power transistor 601 is connected to a second diode 502, the trip coil 602 is connected to the power transistor 601, and the magnetic latching relay 603 is connected to the trip coil 602.

[0059] Specifically, the output (high level) of the logic synthesis and voting circuit 5 serves as a control signal to drive the power transistor 601 to conduct. A large current flows through a low-impedance, high-current trip coil 602, which in turn generates a strong magnetic field. This strong magnetic field drives the magnetic latching relay from the engaged state to the released state, thereby cutting off the main circuit, tripping the circuit breaker, and maintaining this state without requiring power supply.

[0060] According to this utility model, the fault indication and latching circuit 7 is mainly used to lock and display the type of fault (overload, short circuit, leakage) that caused the trip after it has been tripped. The fault indication and latching circuit 7 specifically includes: an overload trigger 701, a short circuit trigger 702, a leakage trigger 703, an overload red light 704, a short circuit yellow light 705, a leakage blue light 706, and a manual reset button 707. The overload trigger 701 is connected to the second diode 502, the short circuit trigger 702 is connected to the second diode 502, and the leakage trigger 703 is connected to the second diode 502.

[0061] 502 is connected, the overload red light 704 is connected to the overload trigger 701, the short circuit yellow light 705 is connected to the short circuit trigger 702, the leakage blue light 706 is connected to the leakage trigger 703, and the manual reset button 707 is connected to the overload trigger 701, the short circuit trigger 702, and the leakage trigger 703 respectively.

[0062] Specifically, each trip signal is used as a "set (S)" signal to set the corresponding trigger output to a high level and illuminate the corresponding LEDs (overload red light 704, short circuit yellow light 705, and leakage blue light 706). A manual reset button 707 is set up, and the pulse generated by it serves as the "reset (R)" signal for all triggers, clearing the fault indication.

[0063] According to this utility model, the power supply and self-test circuit 8 is mainly used to power the protector and perform self-testing. Specifically, the power supply and self-test circuit 8 includes: a linear power supply module 801, a power-on reset circuit 802, and a 555 timer 803. The linear power supply module 801 is connected to the main circuit, the power-on reset circuit 802 is connected to the linear power supply module 801, and the 555 timer 803 is connected to the power-on reset circuit 802. The power-on reset circuit 802 is connected to the overload red light 704, the short-circuit yellow light 705, and the leakage blue light 706, respectively; the 555 timer 803 is connected to the OR gate chip 501.

[0064] Specifically, power is drawn from the main circuit via the linear power supply module 801 to generate the ±12V and +5V voltages required for the protector's operation. The power-on reset circuit 802 monitors the stability of the voltages required for the protector's operation. After the power supply stabilizes, the power-on reset circuit 802 generates a pulse, briefly illuminating all indicator lights (overload red light 704, short circuit yellow light 705, and leakage blue light 706) to test the LEDs' functionality. The pulse generated by the power-on reset circuit 802 is connected to the RESET pin of the 555 timer 803 to ensure that the 555 timer 803 does not trigger falsely when the power supply is unstable. After the pulse generated by the power-on reset circuit 802 ends (becoming high), the RESET pin of the 555 timer 803 is released, and the 555 timer 803 begins its timing operation. If the protector cannot be reset periodically by the running signal, the 555 timer 803 outputs a trip signal to the logic synthesis and voting circuit 5 to prevent the protector from "crashing."

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A subway low-voltage power distribution protector, characterized in that, include: Signal acquisition and conditioning circuit; Overcurrent detection and delay circuit, instantaneous overcurrent detection circuit, and leakage current detection and delay circuit are connected to the signal acquisition and conditioning circuit. Logic synthesis and voting circuit connected to overcurrent detection and delay circuit, instantaneous overcurrent detection circuit, and leakage current detection and delay circuit; The tripping drive and actuator, and the fault indication and latching circuit are connected to the logic synthesis and voting circuits; The power supply and self-test circuit is connected to the signal acquisition and conditioning circuit, overcurrent detection and delay circuit, instantaneous trip detection circuit, leakage current detection and delay circuit, logic synthesis and voting circuit, trip drive and actuator, and fault indication and latching circuit.

2. The low-voltage distribution protector for metro according to claim 1, characterized in that, The signal acquisition and conditioning circuit includes: a current transformer connected to the main circuit, a first precision sampling resistor connected to the current transformer, a first operational amplifier connected to the first precision sampling resistor, a first RC low-pass filter connected to the first operational amplifier, a zero-sequence current transformer connected to the main circuit, a second precision sampling resistor connected to the zero-sequence current transformer, a second operational amplifier connected to the second precision sampling resistor, a second RC low-pass filter connected to the second operational amplifier, a first resistor connected to the main circuit, and a voltage follower connected to the first resistor.

3. The low-voltage distribution protector for metro according to claim 2, characterized in that, The overcurrent detection and delay circuit includes: a first voltage comparator connected to a first RC low-pass filter, a first voltage regulator chip connected to the first voltage comparator, a first constant current source connected to the first voltage regulator chip, a first capacitor connected to the first constant current source, and a second voltage comparator connected to the first capacitor.

4. The low-voltage distribution protector for a subway according to claim 3, characterized in that, The instantaneous fast-break detection circuit includes: a third voltage comparator connected to a voltage follower, a second voltage regulator chip connected to the third voltage comparator, and a first diode connected to the second voltage regulator chip.

5. A subway low-voltage power distribution protection device according to claim 4, characterized in that, The leakage current detection and delay circuit includes: a fourth voltage comparator connected to the second RC low-pass filter, a third voltage regulator chip connected to the fourth voltage comparator, a second constant current source connected to the third voltage regulator chip, a second capacitor connected to the second constant current source, and a fifth voltage comparator connected to the second capacitor.

6. The low-voltage distribution protector for a subway according to claim 5, wherein The logic synthesis and voting circuit includes: an OR gate chip and a second diode connected to the OR gate chip; the OR gate chip is connected to a second voltage comparator, a first diode and a fifth voltage comparator respectively.

7. The low-voltage distribution protector for a subway according to claim 6, characterized in that, The tripping drive and actuator includes: a power transistor connected to the second diode, a tripping coil connected to the power transistor, and a magnetic latching relay connected to the tripping coil.

8. The low-voltage distribution protector for a subway according to claim 6, wherein The fault indication and latching circuit includes: an overload trigger connected to the second diode, a short-circuit trigger connected to the second diode, a leakage trigger connected to the second diode, an overload red light connected to the overload trigger, a short-circuit yellow light connected to the short-circuit trigger, a leakage blue light connected to the leakage trigger, and a manual reset button connected to the overload trigger, the short-circuit trigger, and the leakage trigger.

9. The low-voltage distribution protector for a subway according to claim 8, characterized in that, The power supply and self-test circuit includes: a linear power supply module connected to the main circuit, a power-on reset circuit connected to the linear power supply module, and a 555 timer connected to the power-on reset circuit.

10. A subway low-voltage power distribution protection device according to claim 9, characterized in that, The power-on reset circuit is connected with overload red light, short circuit yellow light and leakage blue light respectively; the 555 timer is connected with or gate logic gate chip.

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