Remote control loop voltage loss detection circuit and power distribution automation system

Abstract

The invention provides a remote control loop voltage loss detection circuit and a power distribution automation system, and relates to the technical field of power distribution automation. The remote control loop voltage loss detection circuit comprises a voltage acquisition module, a microcontroller and a wireless communication module, the voltage acquisition module converts a voltage signal from a power distribution control loop circuit breaker into a logic level and then transmits the logic level to the microcontroller, and the microcontroller judges whether a power supply of the circuit breaker loses voltage or not based on the logic level. Under the condition of voltage loss, an alarm signal is sent to the master station system through the wireless communication module, and the alarm signal is sent to the power distribution automation terminal equipment, so that the power distribution automation terminal equipment uploads the alarm signal to the master station system; after the master station system receives the alarm signal, the alarm information is displayed on an interface, and voice alarm is triggered. According to the embodiment of the invention, local and remote synchronous alarm can be realized, and the probability of losing alarm signals is reduced.

Description

Technical Field

[0001] The present disclosure relates to the technical field of distribution automation, and particularly to a voltage loss detection circuit for a remote control loop and a distribution automation system. Background Art

[0002] The distribution automation system is an important part of the modern power system, aiming to improve power supply reliability, improve power quality, and optimize the operation efficiency of the power grid. Through the integration of advanced communication technologies, control technologies, and information technologies, this system realizes the comprehensive monitoring and intelligent management of the distribution network. Among them, the DTU (Distribution Terminal Unit), as one of the core components of the distribution automation system, undertakes key functions such as data acquisition, status monitoring, fault location, and remote control. The stable operation of the DTU is crucial for ensuring the safety and reliability of the distribution network.

[0003] In the distribution automation system, the normal operation of the DTU depends on a stable DC power supply. An ideal power supply should ensure the stability of voltage and current to avoid equipment failures or abnormal operations caused by voltage fluctuations or voltage loss. However, in practical applications, due to various unforeseen factors, such as instantaneous disturbances in the power system, environmental changes, or equipment aging, etc., the DC power supply may become unstable, which may cause the air switch of the remote control loop to trip due to voltage loss. In this case, the DTU will not be able to maintain an online state, thus seriously affecting the fault location ability and self-healing ability of the distribution network.

[0004] Existing technologies provide various voltage loss detection schemes, but these methods still have certain limitations and may lose alarm signals, resulting in missed reports. Summary of the Invention

[0005] The present disclosure provides a voltage loss detection circuit for a remote control loop and a distribution automation system, which can at least to some extent reduce the probability of losing alarm signals and missing voltage loss reports.

[0006] Other features and advantages of the present disclosure will become apparent through the following detailed description, or be learned in part through the practice of the present disclosure.

[0007] According to one aspect of the present disclosure, there is provided a voltage loss detection circuit for a remote control loop, including: A voltage acquisition module, including an RC (Resistor-Capacitor) low-pass filter circuit and an optocoupler connected to each other; a voltage signal from the circuit breaker of the distribution control loop is input to the RC low-pass filter circuit, and the RC low-pass filter circuit is used to filter out high-frequency interference in the voltage signal and then output it to the optocoupler. The optocoupler converts the voltage signal with high-frequency interference filtered out into a logic level and then transmits it to the microcontroller; The microcontroller is connected to the communication port of the distribution automation terminal device, and the microcontroller is also connected to the wireless communication module; the microcontroller determines whether the power supply of the circuit breaker is out of voltage based on the logic level, and in the case of out-of-voltage, sends an alarm signal to the master station system through the wireless communication module, and sends an alarm signal to the distribution automation terminal device, so that the distribution automation terminal device uploads the alarm signal to the master station system; after receiving the alarm signal, the master station system displays the alarm information on the interface and triggers a voice alarm. The power supply module is connected to the microcontroller and the wireless communication module.

[0008] In an embodiment of the present disclosure, the remote control loop out-of-voltage detection circuit further includes: an indicator light control circuit connected to the RC low-pass filter circuit; the indicator light control circuit determines whether the power supply of the circuit breaker is out of voltage based on the voltage signal with high-frequency interference filtered out, and adjusts the state of the indicator light in the case of out-of-voltage.

[0009] In an embodiment of the present disclosure, the indicator light control circuit uses resistor voltage division and a voltage comparator to convert the voltage signal with high-frequency interference filtered out into a low-voltage signal for comparison, determines whether the power supply of the circuit breaker is out of voltage, and adjusts the state of the indicator light in the case of out-of-voltage.

[0010] In an embodiment of the present disclosure, the power supply voltage of the circuit breaker being lower than 36V is considered out-of-voltage.

[0011] In an embodiment of the present disclosure, a timer is further provided between the voltage comparator and the indicator light. The timer receives the out-of-voltage trigger signal from the voltage comparator and controls the state of the indicator light based on the out-of-voltage trigger signal.

[0012] In an embodiment of the present disclosure, the power supply module includes a DC-DC (Direct Current to Direct Current) conversion circuit and a filter circuit; the DC-DC conversion circuit is connected to an external power supply, and is used to convert the 36-60V DC voltage input by the external power supply into 3.3V DC voltage and output it to the filter circuit; the filter circuit is used to filter out the clutter and output it to the microcontroller and the wireless communication module.

[0013] In an embodiment of the present disclosure, a self-resetting fuse is provided between the DC-DC conversion circuit and the external power supply.

[0014] In an embodiment of the present disclosure, a varistor is provided between the RC low-pass filter circuit and the circuit breaker.

[0015] In an embodiment of the present disclosure, a transient voltage suppression diode is used for electrostatic discharge protection at the communication interface where the microcontroller is used to connect the distribution automation terminal device.

[0016] According to another aspect of the present disclosure, a distribution automation system is provided, including the above-mentioned remote control loop voltage loss detection circuit.

[0017] For the remote control loop voltage loss detection circuit and the distribution automation system provided by the embodiments of the present disclosure, after the microcontroller determines the voltage loss, a dual safeguard mechanism is adopted to upload the alarm signal. One is to send the alarm signal to the distribution automation terminal device through the digital output port, and the distribution automation terminal device, as an edge node of the distribution automation system, uploads the alarm information to the master station system; the other is to directly send the voltage loss alarm signal to the master station system through the wireless communication module. Even if a certain communication link fails (such as the distribution automation terminal device losing network connection), the other path can still ensure the successful upload of the alarm information, ensuring that the alarm signal is not lost and avoiding the possible problems of missed reports and false reports in the traditional single-channel scheme; the remote alarm mechanism of directly sending the voltage loss alarm signal to the master station system through the wireless communication module can also enable the master station system to learn about the fault in the first time, improving the dispatching efficiency. In addition, the RC low-pass filter circuit can effectively suppress power grid harmonics and transient interference, improving the sampling accuracy; the optocoupler realizes electrical isolation, preventing high-voltage crosstalk from damaging the subsequent circuit. The output of the optocoupler is a standard logic level signal, adapting to the microcontroller I / O interface without an additional conditioning circuit; the entire voltage loss detection process is based on hardware filtering + microcontroller logic judgment, without complex algorithm processing, and the response time can reach the millisecond level, much faster than the traditional scheme based on ADC sampling and software judgment, and can upload the voltage loss alarm signal in time, providing an earlier fault warning window for the master station system.

[0018] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings here are incorporated into the specification and form a part of this specification, showing the embodiments consistent with the present disclosure, and are used together with the specification to explain the principles of the present disclosure.

[0020] Obviously, the accompanying drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1 Schematic diagram of a remote control loop voltage loss detection circuit in an embodiment of the present disclosure; Figure 2 Schematic diagram of another remote control loop voltage loss detection circuit in an embodiment of the present disclosure; Figure 3 Schematic diagram of yet another remote control loop voltage loss detection circuit in an embodiment of the present disclosure; Figure 4 Shows a schematic diagram of a distribution automation system in an embodiment of the present disclosure. Specific embodiments

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present disclosure. The following detailed description of the embodiments of the present disclosure provided in the drawings is not intended to limit the scope of the claimed present disclosure, but merely represents selected embodiments of the present disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of the present disclosure without creative efforts fall within the scope of protection of the present disclosure.

[0023] In a distribution automation system, the stability of the DC power supply directly affects the reliable operation of the DTU (Distribution Terminal Unit). The loss of voltage tripping of the air switch in the remote control circuit caused by the instability of the DC power supply is one of the main reasons for the offline of the terminal device. There are some existing schemes for monitoring the loss of voltage. One is the scheme of monitoring the loss of voltage through a relay. The voltage on the AC input side is monitored by a voltage relay, and an alarm is triggered when the voltage is lower than the threshold. However, the action accuracy of the relay in this method is greatly affected by the environment. The switch signal directly output by the relay is easily affected by power grid harmonics and pulse interference, which is prone to false alarms or missed alarms, and lacks signal conditioning function. It cannot directly match the digital input interface of the distribution automation terminal, and an additional conversion circuit needs to be added, increasing the complexity of on-site installation and maintenance. The other is the monitoring scheme based on a microprocessor. The AC voltage is sampled by an ADC, and the loss of voltage state is judged through a software algorithm. Although the accuracy is relatively high, it depends on software processing, the response speed is slow and prone to delayed alarms, and it is difficult to meet the requirements of rapid fault location.

[0024] The problems existing in the above traditional methods are obvious, such as insufficient anti-interference ability, poor signal compatibility, low system integration, slow response speed, which are prone to misjudgment of faults, and then cause the offline of the terminal device, affecting the fault location and self-healing ability of the distribution network. There is still room for optimization in the reliability, response speed, and integration of its hardware topology.

[0025] Regarding the defects existing in the above solutions and the proposed solutions, they are all the results obtained by the inventors after practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed by the present disclosure for the above problems in the following text should be the contributions made by the inventors to the present disclosure during the process of the present disclosure.

[0026] The following will describe the specific embodiments of this example in detail with reference to the accompanying drawings and embodiments.

[0027] Figure 1A voltage loss detection circuit for a remote control loop in an embodiment of the present disclosure is shown as follows. Figure 1 As shown, the voltage loss detection circuit for the remote control loop provided in the embodiment of the present disclosure includes a voltage acquisition module 10, a microcontroller 20, a wireless communication module 30, and a power supply module 40.

[0028] The power supply module 40 is connected to the microcontroller 20 and the wireless communication module 30. In some embodiments, the power supply module 40 includes a DC-DC conversion circuit and a filtering circuit; the DC-DC conversion circuit is connected to an external power supply and is used to convert the 36-60V DC voltage input by the external power supply into a 3.3V DC voltage and output it to the filtering circuit; the filtering circuit is used to filter out the clutter and output a stable DC voltage to the microcontroller 20 and the wireless communication module. The embodiment of the present disclosure supports a wide voltage range (36-60V) and can adapt to various on-site environments.

[0029] In some embodiments, a self-resetting fuse is provided between the DC-DC conversion circuit and the external power supply. In the embodiment of the present disclosure, a self-resetting fuse (also known as a resettable fuse or PPTC) is provided between the DC-DC conversion circuit and the external power supply. The self-resetting fuse can rapidly increase the resistance when the current exceeds the set value, thereby limiting the further increase of the current, which is crucial for protecting the DC-DC converter from the large current impact caused by short circuits or other electrical faults. Different from the traditional fuse that melts once, after the overcurrent event occurs, once the current returns to the normal level, the resistance of the self-resetting fuse will automatically return to the low-resistance state without manual replacement. This provides great convenience for maintenance, especially important in application scenarios that are difficult to reach or require long-term continuous operation. By preventing damage caused by overcurrent, the self-resetting fuse helps to improve the stability and reliability of the entire power supply system. It can effectively isolate the faulty part and prevent the fault from spreading to other components or systems, ensuring that the system can operate normally as much as possible even in abnormal situations. Using a self-resetting fuse can simplify the circuit design because it integrates the functions of overcurrent protection and self-recovery, reduces the need for additional protection components, and at the same time reduces the overall cost and complexity.

[0030] The voltage acquisition module 10 includes an RC low-pass filter circuit and an optocoupler connected to each other; the voltage signal from the circuit breaker of the distribution control loop is input to the RC low-pass filter circuit, and the RC low-pass filter circuit is used to filter out the high-frequency interference in the voltage signal and then output it to the optocoupler. The optocoupler converts the voltage signal with high-frequency interference filtered into a logic level and then transmits it to the microcontroller 20.

[0031] In the embodiments of the present disclosure, the RC low-pass filter circuit can effectively remove high-frequency noise and transient interference in the voltage signal, improve the signal quality input to the microcontroller 20, enhance the accuracy of subsequent data processing and analysis, and reduce misreading or misjudgment caused by various electromagnetic interferences (EMIs) that may exist in the power grid. By using an optocoupler to achieve electrical isolation, it can prevent transient voltages or surge currents on the high-voltage side from damaging the microcontroller 20 on the low-voltage side. This not only protects the microcontroller (MCU) 20 but also effectively reduces the common-mode interference caused by the ground loop, further enhancing the stability and reliability of the system.

[0032] In some embodiments, a varistor is provided between the RC low-pass filter circuit and the circuit breaker. A varistor is a voltage-sensitive non-linear element that presents a high-resistance state under normal operating voltage and hardly affects the circuit operation. When the voltage exceeds its clamping voltage (breakdown voltage), its resistance drops rapidly, forming a low-resistance channel to discharge the excess energy to the ground. By setting the varistor in the embodiments of the present disclosure, transient overvoltages can be effectively absorbed, the subsequent circuit can be protected, and malfunction or hardware damage caused by voltage spikes due to external interference or faults can be prevented, improving the stability and safety of the system.

[0033] The microcontroller 20 is connected to the communication port of the distribution automation terminal device, and the microcontroller 20 is also connected to the wireless communication module 30. The microcontroller 20 judges whether the power supply of the circuit breaker is out of voltage based on the logic level, and in the case of voltage loss, sends an alarm signal to the master station system through the wireless communication module 30 and sends an alarm signal to the distribution automation terminal device, so that the distribution automation terminal device uploads the alarm signal to the master station system. After receiving the alarm signal, the master station system displays the alarm information on the interface and triggers a voice alarm.

[0034] In the embodiments of the present disclosure, the microcontroller (MCU) 20 receives the voltage signal fed back by the voltage acquisition module 10 through the I / O port, and after internal processing, the signal is fed back to the digital input port of the distribution automation terminal device (DTU) on the one hand, and fed back to the master station system through the wireless communication module 30 on the other hand.

[0035] In the embodiments of the present disclosure, the microcontroller 20 uploads the alarm signal to the master station system in two ways.

[0036] Local mode: Access the communication port of the distribution automation terminal device (DTU) through the RS485 bus, and then the distribution automation terminal device (DTU) uploads the alarm information to the master station system.

[0037] Wireless mode: Transmit to the master station system through the wireless communication module 30.

[0038] When the master station system detects a voltage loss alarm in real time, it displays the alarm information on the interface and triggers a voice alarm simultaneously.

[0039] In the embodiment of the present disclosure, the microcontroller 20 uploads the alarm signal to the master station system in two ways. Even if a certain communication link fails (such as the power distribution automation terminal device loses network connection), the other path can still ensure the successful upload of the alarm information, ensuring that the alarm signal is not lost and avoiding the possible missed alarm and false alarm problems in the traditional single-channel scheme; the remote alarm mechanism that directly sends the voltage loss alarm signal to the master station system through the wireless communication module 30 can also enable the master station system to learn about the fault in the first time, improving the dispatching efficiency.

[0040] In some embodiments, a transient voltage suppression diode is used for electrostatic discharge protection at the communication interface where the microcontroller 20 is used to connect the power distribution automation terminal device.

[0041] In some embodiments, as Figure 2 shown, the voltage loss detection circuit of the remote control loop may further include an indicator light control circuit 50. The indicator light control circuit 50 is connected to the RC low-pass filter circuit; the indicator light control circuit 50 determines whether the power supply of the circuit breaker loses voltage based on the voltage signal with high-frequency interference filtered out, and adjusts the state of the indicator light in the case of voltage loss.

[0042] In some embodiments, the indicator light control circuit 50 uses resistor voltage division and a voltage comparator to convert the voltage signal with high-frequency interference filtered out into a low-voltage signal for comparison to determine whether the power supply of the circuit breaker loses voltage, and adjusts the state of the indicator light in the case of voltage loss. In some embodiments, when the power supply voltage of the circuit breaker is lower than 36V, it is considered a voltage loss. In the embodiment of the present disclosure, resistor voltage division and a voltage comparator are used to convert the monitored voltage into a low-voltage signal for comparison. When the monitored voltage is within the normal range (36 - 60V) and greater than the reference voltage, the green light is on; when the monitored voltage is lower than 36V (in the case of voltage loss) and less than the reference voltage, the red light is on.

[0043] In some embodiments, a timer is further provided between the voltage comparator and the indicator light. The timer receives the voltage loss trigger signal from the voltage comparator and controls the state of the indicator light based on the voltage loss trigger signal. By setting the timer, long-term continuous alarm can be achieved, for example, 1-hour continuous alarm can be achieved.

[0044] In the embodiment of the present disclosure, multiple protection circuits are provided. A varistor is used for overvoltage protection on the input side, a diode is used to prevent reverse connection on the output side, a self-resetting fuse is used for overcurrent protection on the power supply side, and a transient voltage suppression diode (TVS) is used for electrostatic discharge (ESD) protection at the communication interface.

[0045] The following takes a specific example to illustrate in detail the voltage loss detection circuit of the remote control loop provided by the embodiment of the present disclosure, asFigure 3 As shown in Figure 3 , the input voltage is converted into a 3.3V DC power supply through a DC-DC conversion circuit, and then input into a filtering circuit to filter out the clutter, and a stable DC power supply is output to supply the microcontroller and the wireless communication module. The voltage acquisition module acquires the voltage signal from the circuit breaker, filters out the high-frequency interference through an RC low-pass filtering circuit, and then supplies the signal to the I / O port of the microcontroller after converting the signal into a logic level (TTL) through opto-isolation. The I / O port of the microcontroller receives the voltage signal fed back by the voltage acquisition module, and after internal processing, the signal is fed back to the digital input port of the distribution automation terminal unit (DTU) on the one hand, and fed back to the master station system through the wireless communication module on the other hand.

[0046] The indicator control circuit uses resistor voltage division and a voltage comparator to convert the monitored voltage into a low-voltage signal for comparison. When the monitored voltage is within the normal range (36 - 60V) and greater than the reference voltage, the green light is on; when the monitored voltage is less than 36V (when there is a voltage loss) and less than the reference voltage, the red light is on. The delay circuit uses a timer to achieve continuous alarm for 1 hour.

[0047] In the embodiment of the present disclosure, the alarm signal is uploaded in two ways: Local mode: Access the communication port of the distribution automation terminal unit (DTU) through the RS485 bus, and then the distribution automation terminal uploads the alarm information to the master station system; Wireless mode: Transmit to the master station system through a wireless module.

[0048] When the master station system monitors a voltage loss alarm in real time, while displaying the alarm information on the interface, it triggers a voice alarm.

[0049] The embodiment of the present disclosure adopts a local + remote dual-channel alarm mechanism to achieve local and remote synchronous alarms, ensuring that alarm information is not lost; adopts a wide voltage input design (36 - 60VDC) to adapt to different on-site environments; adopts a modular design, with small size, convenient transformation, and convenient independent replacement and maintenance; through a full-hardware topology design, the voltage loss detection response speed is controlled within 15ms (superior to the traditional software solution of 100 - 200ms), ensuring that fault information is uploaded to the master station system in real time, improving the power grid fault location and self-healing capabilities, and significantly improving the fault handling efficiency.

[0050] The specific implementation steps of the embodiment of the present disclosure are as follows: 1. Before installation, first power on and debug the hardware device corresponding to the remote control loop voltage loss detection circuit. Connect the device to the output terminal of the relay in the remote control loop. If the indicator light shows green, it means that the remote control loop voltage loss detection circuit is working properly. During local debugging, configure the debugging configuration node of the distribution automation terminal unit (DTU) and conduct a fault status test. If an alarm is prompted when the remote control loop voltage loss detection circuit is powered off and the alarm is cleared when powered on, it means that the local debugging is normal. During remote transmission debugging, configure the master station node and conduct a fault status test (power off to trigger an alarm, power on to clear the alarm). If the communication is normal and the fault reporting function is normal, it is determined that the installation is completed.

[0051] 2. In the working monitoring mode, the 48V voltage of the circuit breaker is processed by the voltage acquisition module of the remote control loop voltage loss detection circuit and then sent to the indicator light control circuit for judgment. When the voltage is between 36V and 60V, it is judged to be in the normal working state and the indicator light is green. When the voltage is lower than 36V, it is judged as "tripping". At this time, the indicator light turns red, indicating an alarm state. At the same time, the voltage acquisition module also transmits the acquired signal to the microcontroller (MCU). The microcontroller (MCU) converts the "tripping" signal into a feedback signal and sends it to the distribution automation terminal unit (DTU). At the same time, the feedback signal is sent to the wireless communication module, and the wireless communication module then transmits it to the master station system. After receiving the warning signal, the master station system triggers the operation and maintenance process to notify the staff to quickly handle the fault.

[0052] The embodiments of the present disclosure can monitor the state of the power loss of the distribution automation terminal in real time, trigger an alarm signal through potential change, improve the power grid fault location and self-healing ability, and significantly improve the fault handling efficiency.

[0053] Based on the same inventive concept, an embodiment of the present disclosure also provides a distribution automation system, as Figure 4 shown. The distribution automation system includes a remote control loop voltage loss detection circuit 401. The remote control loop voltage loss detection circuit 401 can be the remote control loop voltage loss detection circuit introduced in any of the above embodiments.

[0054] Regarding the distribution automation system in the above embodiments, the specific manner in which each module performs operations has been described in detail in the embodiments related to the remote control loop voltage loss detection circuit, and will not be elaborated here in detail.

[0055] It should be noted that although several modules or units are mentioned in the above detailed description, this division is not mandatory. In fact, according to the embodiments of the present disclosure, the features and functions of the two or more modules or units described above can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided and embodied by multiple modules or units.

[0056] Some of the block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software form or implemented in one or more hardware modules or integrated circuits.

[0057] Those skilled in the art will readily conceive of other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein.

[0058] The present disclosure is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include known common general knowledge or conventional technical means in the art not disclosed in the present disclosure. The description and examples are only to be considered as exemplary, and the true scope and spirit of the present disclosure are pointed out by the appended claims.

Claims

1. A remote control loop voltage loss detection circuit, characterized in that Comprising: A voltage acquisition module, including an RC low-pass filter circuit and an optocoupler connected to each other; a voltage signal from the breaker of the distribution control loop is input to the RC low-pass filter circuit, and the RC low-pass filter circuit is used to filter out high-frequency interference in the voltage signal and then output it to the optocoupler. The optocoupler converts the voltage signal with high-frequency interference filtered out into a logic level and then transmits it to the microcontroller; The microcontroller is connected to the communication port of the distribution automation terminal device, and the microcontroller is also connected to a wireless communication module; the microcontroller determines whether the power supply of the breaker is out of voltage based on the logic level, and in the case of out-of-voltage, sends an alarm signal to the master station system through the wireless communication module, and sends an alarm signal to the distribution automation terminal device, so that the distribution automation terminal device uploads the alarm signal to the master station system; After receiving the alarm signal, the master station system displays alarm information on the interface and triggers voice alarm; A power supply module, connected to the microcontroller and the wireless communication module.

2. The remote control loop voltage loss detection circuit according to claim 1, wherein The remote control loop out-of-voltage detection circuit further includes: An indicator light control circuit, connected to the RC low-pass filter circuit; the indicator light control circuit determines whether the power supply of the breaker is out of voltage based on the voltage signal with high-frequency interference filtered out, and adjusts the state of the indicator light in the case of out-of-voltage.

3. The voltage loss detection circuit for the remote control loop according to claim 2, wherein, The indicator light control circuit uses a resistor voltage division and a voltage comparator to convert the voltage signal with high-frequency interference filtered out into a low-voltage signal for comparison, determines whether the power supply of the breaker is out of voltage, and adjusts the state of the indicator light in the case of out-of-voltage.

4. The remote control loop undervoltage detection circuit according to any one of claims 1-3, characterized in that When the power supply voltage of the breaker is lower than 36V, it is considered out of voltage.

5. The remote control loop undervoltage detection circuit according to claim 3, wherein A timer is further provided between the voltage comparator and the indicator light. The timer receives the out-of-voltage trigger signal from the voltage comparator and controls the state of the indicator light based on the out-of-voltage trigger signal.

6. The remote control loop undervoltage detection circuit according to claim 1, characterized in that, The power supply module includes a DC-DC conversion circuit and a filter circuit; The DC-DC conversion circuit is connected to an external power supply and is used to convert the 36-60V DC voltage input by the external power supply into a 3.3V DC voltage and output it to the filter circuit; the filter circuit is used to filter out clutter and output it to the microcontroller and the wireless communication module.

7. The remote control loop voltage loss detection circuit according to claim 6, characterized in that A self-resetting fuse is provided between the DC-DC conversion circuit and the external power supply.

8. The remote control loop undervoltage detection circuit according to claim 1, characterized in that, A varistor is provided between the RC low-pass filter circuit and the breaker.

9. The remote control loop voltage loss detection circuit according to claim 1, wherein The communication interface of the microcontroller for connecting to the distribution automation terminal device is protected against electrostatic discharge by a transient voltage suppression diode.

10. A distribution automation system, characterized in that, Including the remote control loop out-of-voltage detection circuit according to any one of claims 1-9.

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