A short-circuit monitoring system for urban lamp post electrical boxes

Abstract

The present invention relates to the technical field of intelligent lamp poles, and proposes a short - circuit monitoring system for urban lamp pole electrical boxes, including a short - circuit current detection circuit. The short - circuit current detection circuit includes a voltage follower U4A, a voltage - dividing circuit, a dual - limit comparison circuit, and a NAND gate U6 arranged in sequence. The input end of the voltage follower U4A is used to connect to a current sensor. The voltage - dividing circuit includes a series - connected resistor R1, a potentiometer RP1, and a resistor R2. The dual - limit comparison circuit includes an operational amplifier U5A and an operational amplifier U5B. The first end of the resistor R1 is connected to the power supply +15V, the second end of the resistor R1 is connected to the non - inverting input end of the operational amplifier U5A, the inverting input end of the operational amplifier U5A is connected to the output end of the voltage follower U4A, the first end of the resistor R2 is connected to the power supply - 15V, and the second end of the resistor R2 is connected to the inverting input end of the operational amplifier U5B. Through the above - mentioned technical solution, the problem of untimely protection in the prior - art short - circuit monitoring system for urban lamp pole electrical boxes is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent lamp posts, and specifically, to a short - circuit monitoring system for urban lamp post electrical boxes. Background Art

[0002] Currently, street lamps have been installed in various cities in our country, and even on remote rural roads. Street lamps have become an indispensable part of people's current lives. While bringing convenience to people, street lamps also bring some potential hazards. For example, after long - term use of the lines in the street lamp electrical box, short - circuits may be caused due to insulation damage. In the lightest case, the street lamps are damaged, and in the most serious case, nearby items catch fire, affecting the safety of pedestrians. Therefore, it is urgent to improve the existing short - circuit monitoring circuit for urban lamp post electrical boxes. Summary of the Invention

[0003] The present invention proposes a short - circuit monitoring system for urban lamp post electrical boxes, which solves the problem of untimely protection in the short - circuit monitoring system for urban lamp post electrical boxes in the related art.

[0004] The technical solution of the present invention is as follows: It includes a short - circuit current detection circuit. The short - circuit current detection circuit includes a voltage follower U4A, a voltage - dividing circuit, a dual - limit comparison circuit, and a NAND gate U6 arranged in sequence. The input end of the voltage follower U4A is used to connect to a current sensor.

[0005] The voltage - dividing circuit includes a series connection of a resistor R1, a potentiometer RP1, and a resistor R2. The dual - limit comparison circuit includes an operational amplifier U5A and an operational amplifier U5B. The first end of the resistor R1 is connected to the power supply +15V, the second end of the resistor R1 is connected to the non - inverting input end of the operational amplifier U5A, the inverting input end of the operational amplifier U5A is connected to the output end of the voltage follower U4A, the first end of the resistor R2 is connected to the power supply - 15V, the second end of the resistor R2 is connected to the inverting input end of the operational amplifier U5B, the non - inverting input end of the operational amplifier U5B is connected to the inverting input end of the operational amplifier U5A, the output end of the operational amplifier U5A is connected to the first input end of the NAND gate U6, the output end of the operational amplifier U5B is connected to the second input end of the NAND gate U6, and the output end of the NAND gate U6 is used to control the on - off of the street lamp.

[0006] Further, it also includes a parallel connection of a resistor R3 and a capacitor C1. One end of the capacitor C1 is connected to the non - inverting input end of the voltage follower U4A, and the other end of the capacitor C1 is grounded.

[0007] Further, it also includes a first output control circuit. The first output control circuit includes a triode Q1 and a relay K1. The base of the triode Q1 is connected to the output terminal of the NAND gate U6. The emitter of the triode Q1 is grounded. The collector of the triode Q1 is connected to one end of the relay K1 coil. The other end of the relay K1 coil is connected to the power supply of 5V. The normally closed contact of the relay K1 is connected in series in the power supply circuit of the street lamp.

[0008] Further, it also includes a spark detection circuit. The spark detection circuit includes a comparator U7A, a timing circuit and a counter U9. The non-inverting input terminal of the comparator U7A is used to connect to an arc detection sensor. The inverting input terminal of the comparator U7A is connected to a reference voltage VREF1. The output terminal of the comparator U7A is connected to the input terminal of the timing circuit. The output terminal of the timing circuit is connected to the clear terminal of the counter U9. The output terminal of the comparator U7A is also connected to the clock input terminal of the counter U9. The carry output terminal of the counter U9 is connected to the base of the triode Q1 through a diode D2.

[0009] It also includes a diode D5. The anode of the diode D5 is connected to the output terminal of the NAND gate U6. The cathode of the diode D5 is connected to the base of the triode Q1.

[0010] Further, the timing circuit includes a triode Q3 and a time base chip U8. The base of the triode Q3 is connected to the output terminal of the comparator U7A. The emitter of the triode Q3 is grounded. The collector of the triode Q3 is connected to the trigger terminal of the time base chip U8. The output terminal of the time base chip U8 is connected to the clear terminal of the counter U9.

[0011] It also includes a potentiometer RP2, a resistor R7 and a capacitor C4 connected in series. One end of the potentiometer RP2 is connected to the power supply VCC. One end of the capacitor C4 is grounded. The other end of the capacitor C4 is connected to the threshold terminal and the discharge terminal of the time base chip U8.

[0012] Further, it also includes a humidity detection circuit. The humidity detection circuit includes a comparator U7B and a second output control circuit connected in sequence. The non-inverting input terminal of the comparator U7B is used to connect to a humidity sensor. The inverting input terminal of the comparator U7B is connected to a reference voltage VREF2. The output terminal of the comparator U7B is connected to the input terminal of the second output control circuit. The second output control circuit is used to control the start and stop of a dehumidification device.

[0013] Further, the second output control circuit includes a triode Q2 and a relay K2. The base of the triode Q2 is connected to the output terminal of the comparator U7B. The emitter of the triode Q2 is grounded. The collector of the triode Q2 is connected to one end of the relay K2 coil. The other end of the relay K2 coil is connected to the power supply of 5V. The normally closed contact of the relay K2 is connected in series in the power supply circuit of the dehumidification device.

[0014] Further, it also includes a reference source circuit one. The reference source circuit one includes a series connection of a resistor R10 and a resistor R6. One end of the resistor R6 is connected to the power supply of 5V, and one end of the resistor R6 is grounded. The series connection point of the resistor R10 and the resistor R6 serves as the reference voltage VREF1.

[0015] Further, it also includes a reference source circuit two. The reference source circuit two includes a series connection of a resistor R11 and a resistor R12. One end of the resistor R11 is connected to the power supply of 5V, and one end of the resistor R12 is grounded. The series connection point of the resistor R11 and the resistor R12 serves as the reference voltage VREF2.

[0016] The working principle and beneficial effects of the present invention are as follows:

[0017] The present invention is provided with a short-circuit current detection circuit for detecting the current of the street lamp circuit. Among them, the output signal of the current sensor is connected to the dual-limit comparison circuit through the voltage follower U4A, and the voltage division circuit provides a reference voltage for the dual-limit comparison circuit. Under normal circumstances, both the operational amplifier U5A and the operational amplifier U5B in the dual-limit comparison circuit output high levels, and the NAND gate U6 outputs a low level to control the street lamp to be powered on; when the current exceeds the set range, one of the operational amplifier U5A and the operational amplifier U5B will output a low level, and the NAND gate U6 outputs a high level to control the street lamp to be powered off.

[0018] The present invention realizes the timely detection of the short-circuit current of the street lamp. Among them, the voltage follower plays a role of isolation and buffering; since the current of the street lamp circuit is alternating current, in order to adapt to the detection of alternating current signals, a dual-limit comparison circuit is set, and its reference voltage is positive and negative voltages, which is used to quickly detect the over-current signals in the positive and negative half-cycles of the alternating current; the outputs of the operational amplifier U5A and the operational amplifier U5B in the dual-limit comparison circuit are respectively connected to the two input terminals of the NAND gate U6. Over-current in either the positive or negative half-cycle of the street lamp current will cause the NAND gate U6 to output a high level, thereby controlling the street lamp to be powered off. The design of the dual-limit comparison circuit in cooperation with the NAND gate U6 not only realizes the accurate detection of the short-circuit current of the street lamp, but also has a fast detection speed, which is beneficial to the timely protection of the street lamp in case of a short circuit. Description of the Drawings

[0019] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0020] Figure 1 This is the schematic diagram of the short - circuit current detection circuit in the present invention;

[0021] Figure 2 This is the schematic diagram of the first output control circuit in the present invention;

[0022] Figure 3 This is the schematic diagram of the spark detection circuit in the present invention;

[0023] Figure 4 This is the schematic diagram of the humidity detection circuit in the present invention;

[0024] In the figure: 21 is the short - circuit current detection circuit, 22 is the first output control circuit, 23 is the spark detection circuit, 231 is the timing circuit, 25 is the humidity detection circuit, 27 is the second output control circuit. Specific embodiments

[0025] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

[0026] As Figure 1 shown, the short - circuit monitoring system in this embodiment is arranged in the electrical box and includes a short - circuit current detection circuit. The short - circuit current detection circuit includes a voltage follower U4A, a voltage - dividing circuit, a dual - limit comparison circuit, and a NAND gate U6 arranged in sequence. The input end of the voltage follower U4A is used to connect to a current sensor.

[0027] The voltage - dividing circuit includes a series - connected resistor R1, a potentiometer RP1, and a resistor R2. The dual - limit comparison circuit includes an operational amplifier U5A and an operational amplifier U5B. The first end of the resistor R1 is connected to the power supply + 15V, the second end of the resistor R1 is connected to the non - inverting input end of the operational amplifier U5A, the inverting input end of the operational amplifier U5A is connected to the output end of the voltage follower U4A, the first end of the resistor R2 is connected to the power supply - 15V, the second end of the resistor R2 is connected to the inverting input end of the operational amplifier U5B, the non - inverting input end of the operational amplifier U5B is connected to the inverting input end of the operational amplifier U5A, the output end of the operational amplifier U5A is connected to the first input end of the NAND gate U6, the output end of the operational amplifier U5B is connected to the second input end of the NAND gate U6, and the output end of the NAND gate U6 is used to control the on - off of the street lamp.

[0028] In this embodiment, a short-circuit current detection circuit is provided to detect the current of the street lamp circuit. Among them, the output signal of the current sensor is connected to a dual-limit comparison circuit through a voltage follower U4A, and the voltage division circuit provides a reference voltage for the dual-limit comparison circuit. Under normal circumstances, both operational amplifiers U5A and U5B in the dual-limit comparison circuit output high levels, the NAND gate U6 outputs a low level, and the street lamp is powered on; when the current exceeds the set range, one of the operational amplifiers U5A and U5B outputs a low level, and the NAND gate U6 outputs a high level to control the street lamp to cut off power.

[0029] This embodiment realizes the timely detection of the short-circuit current of the street lamp. Among them, the voltage follower plays an isolation and buffering role; since the current of the street lamp circuit is alternating current, in order to adapt to the detection of alternating current signals, a dual-limit comparison circuit is set up, and its reference voltage is positive and negative voltages, which are used to quickly detect the over-current signals in the positive and negative half-cycles of the alternating current; the outputs of operational amplifiers U5A and U5B in the dual-limit comparison circuit are respectively connected to the two input terminals of the NAND gate U6. Over-current in either the positive or negative half-cycle of the street lamp current will cause the NAND gate U6 to output a high level, thereby controlling the street lamp to cut off power. The design of the dual-limit comparison circuit in cooperation with the NAND gate U6 not only realizes the accurate detection of the short-circuit current of the street lamp, but also has a fast detection speed, which is beneficial to the timely protection of the street lamp in case of a short circuit.

[0030] Further, as Figure 1 shown, it also includes a parallel-connected resistor R3 and capacitor C1. One end of the capacitor C1 is connected to the non-inverting input terminal of the voltage follower U4A, and the other end of the capacitor C1 is grounded.

[0031] The capacitor C1 is arranged at the non-inverting input terminal of the voltage follower U4A to play a filtering role to prevent interference signals from entering the voltage follower U4A. The resistor R3 is a matching resistor to ensure the accurate detection of over-current signals.

[0032] Further, as Figure 2 shown, it also includes a first output control circuit. The first output control circuit includes a triode Q1 and a relay K1. The base of the triode Q1 is connected to the output terminal of the NAND gate U6, the emitter of the triode Q1 is grounded, the collector of the triode Q1 is connected to one end of the relay K1 coil, the other end of the relay K1 coil is connected to the 5V power supply, and the normally closed contact of the relay K1 is connected in series in the power supply circuit of the street lamp.

[0033] Under normal circumstances, both operational amplifiers U5A and U5B in the dual-limit comparison circuit output high level, the NAND gate U6 outputs high level, the triode Q1 conducts, the coil of the relay K1 is energized, the normally closed contact of the relay K1 closes, and the street lamp is energized to work. When an overcurrent signal occurs, for example, the instantaneous value of the positive half-cycle of the current is greater than the set value, the operational amplifier U5A outputs low level, the operational amplifier U5B outputs high level, the NAND gate U6 outputs high level, the triode Q1 conducts, the coil of the relay K1 is energized, and the normally closed contact of the relay K1 disconnects, and the street lamp is powered off.

[0034] Furthermore, it also includes a spark detection circuit, as Figure 3 shown. The spark detection circuit includes a comparator U7A, a timing circuit, and a counter U9. The non-inverting input terminal of the comparator U7A is used to connect to the arc detection sensor, the inverting input terminal of the comparator U7A is connected to the reference voltage VREF1, the output terminal of the comparator U7A is connected to the input terminal of the timing circuit, the output terminal of the timing circuit is connected to the clear terminal of the counter U9, the output terminal of the comparator U7A is also connected to the clock input terminal of the counter U9, and the carry output terminal of the counter U9 is connected to the base of the triode Q1 through the diode D2.

[0035] It also includes a diode D5. The anode of the diode D5 is connected to the output terminal of the NAND gate U6, and the cathode of the diode D5 is connected to the base of the triode Q1.

[0036] A spark is a precursor to a short circuit. This embodiment also sets up a spark detection circuit. After a spark is generated, the spark signal is detected in a timely manner, and if a short circuit occurs according to the spark signal, the timeliness of short circuit detection will be further improved.

[0037] Among them, the working principle of the spark detection circuit is as follows: The output signal of the arc detection sensor is connected to the non-inverting input terminal of the comparator U7A. When a spark signal occurs, the output voltage of the arc detection sensor is greater than the reference voltage VREF1, and the output of the comparator U7A jumps to high level; the output terminal of the comparator U7A is connected to the clock input terminal CLK of the counter U9, and the counter U9 counts the rising edge pulses received. At the same time, the output terminal of the comparator U7A is connected to the timing circuit, and the timing circuit starts timing; if the counter U9 has counted up within the timing time of the timing circuit, the carry output terminal of the counter U9 is at high level, and this high-level signal is connected to the base of the triode Q1 through the diode D2, the triode Q1 conducts, the coil of the relay K1 is energized, and the normally closed contact of the relay K1 disconnects, and the street lamp is powered off.

[0038] The output terminal of the NAND gate U6 (i.e., the output terminal of the short - circuit current detection circuit) is connected to the base of the triode Q1 through the diode D5. The carry output terminal of the counter U9 (i.e., the output terminal of the spark detection circuit) is connected to the base of the triode Q1 through the diode D2. Either a short - circuit fault or a spark fault will cause the triode Q1 to conduct, the coil of the relay K1 to be energized, and the normally - closed contact of the relay K1 to open, thus disconnecting the street - lamp power supply in a timely manner.

[0039] Further, as Figure 3 shown, the timing circuit includes a triode Q3 and a timer chip U8. The base of the triode Q3 is connected to the output terminal of the comparator U7A. The emitter of the triode Q3 is grounded. The collector of the triode Q3 is connected to the trigger terminal of the timer chip U8. The output terminal of the timer chip U8 is connected to the clear terminal of the counter U9.

[0040] It also includes a potentiometer RP2, a resistor R7, and a capacitor C4 connected in series. One end of the potentiometer RP2 is connected to the power supply VCC. One end of the capacitor C4 is grounded. The other end of the capacitor C4 is connected to the threshold terminal and the discharge terminal of the timer chip U8.

[0041] When a spark fault occurs, the output voltage of the arc - light detection sensor is greater than the reference voltage VREF1. The comparator U7A outputs a high level, the triode Q3 conducts, the trigger terminal TRIG of the timer chip U8 is grounded, and the output terminal OUT of the timer chip U8 outputs a high level. If there is no spark fault within the set time, the output terminal OUT of the timer chip U8 outputs a low level, clearing the count of the counter U9, and the count output terminal RCO of the counter U9 does not act. If the number of occurrences of the spark fault exceeds the set value within the set time, the count output terminal RCO of the counter U9 outputs a high - level signal. This high - level signal is connected to the base of the triode Q1 through the diode D2, the triode Q1 conducts, the coil of the relay K1 is energized, and the normally - closed contact of the relay K1 opens, cutting off the power supply of the street lamp. Among them, the set time is determined by the sizes of the potentiometer RP2, the resistor R7, and the capacitor C4.

[0042] Further, it also includes a humidity detection circuit, as Figure 4 shown, the humidity detection circuit includes a comparator U7B and a second output control circuit connected in sequence. The non - inverting input terminal of the comparator U7B is used to connect to the humidity sensor. The inverting input terminal of the comparator U7B is connected to the reference voltage VREF2. The output terminal of the comparator U7B is connected to the input terminal of the second output control circuit. The second output control circuit is used to control the start and stop of the dehumidification device.

[0043] Further, as Figure 4As shown in the figure, the second output control circuit includes a triode Q2 and a relay K2. The base of the triode Q2 is connected to the output terminal of the comparator U7B. The emitter of the triode Q2 is grounded. The collector of the triode Q2 is connected to one end of the relay K2 coil. The other end of the relay K2 coil is connected to the power supply of 5V. The normally closed contact of the relay K2 is connected in series in the power supply circuit of the dehumidification device.

[0044] If the circuit is in a humid environment for a long time, it is easy to cause a short circuit or electric shock. In this embodiment, the humidity detection circuit is used to detect the air humidity in the electrical box. When the humidity is greater than the set value, the dehumidification device is started in time for dehumidification. Its working principle is as follows: when the humidity is too high, the output voltage of the humidity sensor is greater than the reference voltage VREF2, the comparator U7B outputs a high-level control signal, the triode Q2 conducts, the relay K2 is energized, and the dehumidification device starts to work after being energized.

[0045] Furthermore, it also includes a first reference source circuit, as Figure 3 shown. The first reference source circuit includes a series-connected resistor R10 and resistor R6. One end of the resistor R6 is connected to the power supply of 5V, one end of the resistor R6 is grounded, and the series connection point of the resistor R10 and resistor R6 serves as the reference voltage VREF1.

[0046] The resistor R10 and resistor R6 are connected in series between the power supply of 5V and the ground. The voltage division of the resistor R6 serves as the reference voltage VREF1. According to actual needs, by adjusting the resistance values of the resistor R6 and resistor R10, the magnitude of the reference voltage VREF1 can be adjusted. The circuit structure is simple and the operation is convenient.

[0047] Furthermore, it also includes a second reference source circuit, as Figure 4 shown. The second reference source circuit includes a series-connected resistor R11 and resistor R12. One end of the resistor R11 is connected to the power supply of 5V, one end of the resistor R12 is grounded, and the series connection point of the resistor R11 and resistor R12 serves as the reference voltage VREF2.

[0048] The resistor R11 and resistor R12 are connected in series between the power supply of 5V and the ground. The voltage division of the resistor R12 serves as the reference voltage VREF2. According to actual needs, by adjusting the resistance values of the resistor R11 and resistor R12, the magnitude of the reference voltage VREF2 can be adjusted. The circuit structure is simple and the operation is convenient.

[0049] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An urban lamp post electrical box short - circuit monitoring system, which is set inside the electrical box, characterized in that, it includes a short - circuit current detection circuit (21). The short - circuit current detection circuit (21) includes a voltage follower U4A, a voltage - dividing circuit, a dual - limit comparison circuit, and a NAND gate U6 arranged in sequence. The input end of the voltage follower U4A is used to connect with a current sensor, the voltage - dividing circuit includes a series - connected resistor R1, a potentiometer RP1, and a resistor R2. The dual - limit comparison circuit includes an operational amplifier U5A and an operational amplifier U5B. The first end of the resistor R1 is connected to the power supply +15V, the second end of the resistor R1 is connected to the non - inverting input end of the operational amplifier U5A, the inverting input end of the operational amplifier U5A is connected to the output end of the voltage follower U4A. The first end of the resistor R2 is connected to the power supply - 15V, the second end of the resistor R2 is connected to the inverting input end of the operational amplifier U5B, the non - inverting input end of the operational amplifier U5B is connected to the inverting input end of the operational amplifier U5A. The output end of the operational amplifier U5A is connected to the first input end of the NAND gate U6, the output end of the operational amplifier U5B is connected to the second input end of the NAND gate U6, and the output end of the NAND gate U6 is used to control the on - off of the street lamp; it also includes a first output control circuit (22). The first output control circuit (22) includes a triode Q1 and a relay K1. The base of the triode Q1 is connected to the output end of the NAND gate U6, the emitter of the triode Q1 is grounded, the collector of the triode Q1 is connected to one end of the relay K1 coil, the other end of the relay K1 coil is connected to the power supply 5V, and the normally - closed contact of the relay K1 is in series in the power supply circuit of the street lamp; it also includes a spark detection circuit (23). The spark detection circuit (23) includes a comparator U7A, a timing circuit (231), and a counter U9. The non - inverting input end of the comparator U7A is used to connect with an arc detection sensor, the inverting input end of the comparator U7A is connected to the reference voltage VREF1, the output end of the comparator U7A is connected to the input end of the timing circuit (231), the output end of the timing circuit (231) is connected to the clear end of the counter U9, the output end of the comparator U7A is also connected to the clock input end of the counter U9, and the carry - output end of the counter U9 is connected to the base of the triode Q1 through a diode D2, it also includes a diode D5. The anode of the diode D5 is connected to the output end of the NAND gate U6, and the cathode of the diode D5 is connected to the base of the triode Q1.

2. An urban lamp post electrical box short - circuit monitoring system according to claim 1, characterized in that, it also includes a parallel - connected resistor R3 and a capacitor C1. One end of the capacitor C1 is connected to the non - inverting input end of the voltage follower U4A, and the other end of the capacitor C1 is grounded.

3. An urban lamp post electrical box short - circuit monitoring system according to claim 1, characterized in that, The timing circuit (231) includes a triode Q3 and a timer chip U8. The base of the triode Q3 is connected to the output terminal of the comparator U7A. The emitter of the triode Q3 is grounded. The collector of the triode Q3 is connected to the trigger terminal of the timer chip U8. The output terminal of the timer chip U8 is connected to the clear terminal of the counter U9. It further includes a potentiometer RP2, a resistor R7, and a capacitor C4 connected in series. One end of the potentiometer RP2 is connected to the power supply VCC. One end of the capacitor C4 is grounded. The other end of the capacitor C4 is connected to the threshold terminal and the discharge terminal of the timer chip U8.

4. The short-circuit monitoring system for an urban lamp post electrical box according to claim 1, characterized in that, it further includes a humidity detection circuit (25). The humidity detection circuit (25) includes a comparator U7B and a second output control circuit (27) connected in sequence. The non-inverting input terminal of the comparator U7B is used to connect to a humidity sensor. The inverting input terminal of the comparator U7B is connected to a reference voltage VREF2. The output terminal of the comparator U7B is connected to the input terminal of the second output control circuit (27). The second output control circuit (27) is used to control the start and stop of a dehumidifying device.

5. The short-circuit monitoring system for an urban lamp post electrical box according to claim 4, characterized in that, the second output control circuit (27) includes a triode Q2 and a relay K2. The base of the triode Q2 is connected to the output terminal of the comparator U7B. The emitter of the triode Q2 is grounded. The collector of the triode Q2 is connected to one end of the coil of the relay K2. The other end of the coil of the relay K2 is connected to the power supply 5V. The normally closed contact of the relay K2 is connected in series in the power supply circuit of the dehumidifying device.

6. The short-circuit monitoring system for an urban lamp post electrical box according to claim 1, characterized in that, it further includes a reference source circuit one. The reference source circuit one includes a resistor R10 and a resistor R6 connected in series. One end of the resistor R6 is connected to the power supply 5V. One end of the resistor R6 is grounded. The series connection point of the resistor R10 and the resistor R6 serves as the reference voltage VREF1.

7. The short-circuit monitoring system for an urban lamp post electrical box according to claim 1, characterized in that, it further includes a reference source circuit two. The reference source circuit two includes a resistor R11 and a resistor R12 connected in series. One end of the resistor R11 is connected to the power supply 5V. One end of the resistor R12 is grounded. The series connection point of the resistor R11 and the resistor R12 serves as the reference voltage VREF2.

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