A circuit protection device for automatically monitoring operational faults

Abstract

The application discloses a circuit protection device capable of automatically monitoring operation faults, wherein a ground fault protection unit comprises a ground fault detection circuit, an alternating current power supply channel and an electromagnetic drive circuit; a self-fault monitoring unit comprises a measurement and control circuit and a fault state maintaining circuit; the measurement and control circuit starts a self-fault monitoring process at a fixed time, monitors a fault state signal returned by the electromagnetic drive circuit, realizes self-fault monitoring, and outputs an emergency interruption signal if a fault occurs to trigger an emergency trip of the ground fault protection unit; the fault state maintaining circuit comprises a clear circuit and a fault state triggering circuit; the clear circuit clears a fault state; and the fault state triggering circuit maintains fault state information output by the measurement and control circuit and generates effective warning information, so that the reliability of the circuit protection device is improved.

Description

Technical Field

[0001] This application belongs to the field of circuit protection technology, and in particular relates to a circuit protection device that automatically monitors operational faults, especially a residual current operated protection device or a ground fault circuit interruption device. This protective circuit interruption device can automatically monitor its own working status, output a warning signal when it experiences an operational fault, and take emergency power-off measures. Background Technology

[0002] Residual current operated protective devices (RCDs), or ground fault circuit interrupters, are used to detect ground fault current (GFC) in electrical appliances, instruments, devices, equipment, and electrical systems powered by the mains. When the ground fault current GFC exceeds a specified limit, the circuit protection device automatically cuts off the power supply, thereby protecting personal and property safety. In actual use, the ground fault detection circuit of an RCD or ground fault circuit interrupter often fails partially or completely, causing the protection function of the ground fault circuit interrupter to fail or resulting in the lack of warning information. Users are unaware of this, posing a safety hazard.

[0003] To address the aforementioned issues, some ground fault circuit interrupters, designed according to UL943 standards, incorporate self-fault monitoring functions to periodically diagnose their operational status and output warning signals or trip their protection mechanisms when a ground fault circuit interruption function malfunctions. However, some ground fault circuit interrupters, due to their complex circuitry and structure, or their high manufacturing difficulty and cost, can achieve forced tripping when their ground fault protection function fails. Even after forced tripping, their indicator lights may continue to flash according to the original cycle, or may not even illuminate, failing to provide an effective warning and reducing the warning effect of the circuit protection device, thus still posing a safety hazard. Summary of the Invention

[0004] This application is an extension of CN105896469B, providing a circuit protection device for automatically monitoring operational faults. The contents of CN105896469B are incorporated herein by reference. One technical problem this application aims to solve is to provide a fault state holding circuit for the protective circuit interruption device. When the ground fault protection function of the protective circuit interruption device fails, this fault state holding circuit can maintain the fault state information, keeping the indicator light illuminated for an extended period to clearly indicate that the circuit protection device has failed. Another technical problem this application aims to solve is to provide a flashing warning circuit for the protective circuit interruption device to improve the warning effect.

[0005] To solve the above-mentioned technical problems, the technical solution adopted in this application is as follows:

[0006] An automatic circuit protection device for monitoring operational faults, the circuit protection device comprising a ground fault protection unit and a self-fault monitoring unit, the ground fault protection unit comprising a ground fault detection circuit, an AC power supply channel, and an electromagnetic drive circuit, the self-fault monitoring unit comprising an automatic testing circuit, a measurement and control circuit, and an alarm circuit; the self-fault monitoring unit further comprises:

[0007] The fault state holding circuit includes a clearing circuit and a fault state triggering circuit. The clearing circuit receives a self-fault monitoring signal U_TEST periodically sent by the measurement and control circuit and sends a clearing signal U_clr. The fault state triggering circuit receives the clearing signal U_clr and an emergency interruption signal U_EI sent by the measurement and control circuit. When the ground fault protection unit fails, it outputs and holds the fault state information U_err, keeping the alarm circuit in an alarm state to indicate that the circuit protection device has failed.

[0008] Furthermore, the reset circuit includes a reset capacitor that captures the level toggling information of the self-fault monitoring signal U_TEST and is used to generate the reset signal U_clr.

[0009] Furthermore, the fault state triggering circuit includes a voltage comparator, which receives the reset signal U_clr and the emergency interrupt signal U_EI, and outputs fault state information U_err.

[0010] Furthermore, the fault status information U_err output by the fault status triggering circuit includes two states: low level and high level. The warning circuit receives the fault status information U_err. During the self-fault monitoring process, when the circuit protection device is fault-free, the warning circuit stops alarming; when the ground fault protection unit fails, the warning circuit maintains the alarm state.

[0011] This application proposes an automatic circuit protection device for monitoring operational faults. A fault state triggering circuit outputs fault state information U_err, which includes two states: low level and high level. An alarm circuit receives this fault state information U_err. During the self-fault monitoring process, when the circuit protection device is fault-free, the indicator light on the alarm circuit is off; when the ground fault protection unit fails, the indicator light on the alarm circuit flashes to improve the warning effect. The circuit of this application is simple, economical, and efficient. Attached Figure Description

[0012] Figure 1 This is a structural framework diagram of an embodiment of this application.

[0013] Figure 2 This is a circuit schematic diagram of one embodiment of this application.

[0014] Figure 3 This is another circuit schematic diagram of an embodiment of this application. Detailed Implementation

[0015] The technical solution of this application will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments do not constitute a limitation of this application.

[0016] Figure 1 This is a structural framework diagram of the circuit protection device for automatically monitoring operational faults according to this application, showing the main functional units and control relationships of the circuit protection device. The circuit protection device includes a ground fault protection unit 1 and a self-fault monitoring unit 2. The ground fault protection unit 1 implements the ground fault protection function and outputs a fault status signal U_FS to the self-fault monitoring unit 2; the self-fault monitoring unit 2 outputs a ground fault current GFC to the ground fault protection unit 1, monitors the fault status signal U_FS of the ground fault protection unit 1, and outputs an emergency interruption signal U_EI to the ground fault protection unit 1, thus realizing self-fault monitoring and emergency protection functions.

[0017] like Figure 1 As shown, the ground fault protection unit 1 includes a ground fault detection circuit 101, an AC power supply channel 102, a manual testing circuit 103, and an electromagnetic drive circuit 104. The AC power supply channel 102 includes a magnetic switch 88, AC power input terminals N1 and L1, and load terminals N2 and L2. The magnetic switch 88 is used to connect or disconnect the electrical path between the AC power input terminals and the load terminals.

[0018] The ground fault detection circuit 101 includes a ground fault current sensor 150, a neutral line repeated grounding sensor 160, a ground fault detection chip 170, and a first DC power supply 180. The ground fault current sensor 150 and the neutral line repeated grounding sensor 160 sense a ground fault current GFC appearing in the AC power channel 102 and transmit a ground fault signal to the ground fault detection chip 170. The ground fault detection chip 170 detects the ground fault signal transmitted by the ground fault current sensor 150 and the neutral line repeated grounding sensor 160 and outputs a ground fault interruption signal U_GFI. The first DC power supply 180 provides DC power V1 to the ground fault detection chip 170, and the negative terminal of the first DC power supply 180 serves as the logic ground GND of the circuit protection device.

[0019] The manual test circuit 103 outputs a ground fault current GFC to the AC power supply channel 102 to test the ground fault protection function of the ground fault protection unit 1.

[0020] The self-fault monitoring unit 2 includes an automatic test circuit 201, a measurement and control circuit 202, and an alarm circuit 203. The measurement and control circuit 202 periodically (e.g., every minute) sends a self-fault monitoring signal U_TEST to initiate the self-fault monitoring process. It controls the automatic test circuit 201 to output a ground fault current GFC to the ground fault protection unit 1 and monitors the fault status signal U_FS output by the electromagnetic drive circuit 104 in the ground fault protection unit 1 to determine the operating status of the ground fault protection unit 1. When a fault occurs in the ground fault protection unit 1, it outputs an emergency interruption signal U_EI to the electromagnetic drive circuit 104, triggering the electromagnetic drive circuit 104 to operate and causing the magnetic switch 88 to trip, thus realizing the emergency protection function. Simultaneously, the self-fault monitoring signal U_TEST is connected to the alarm circuit 203, which issues an alarm message. It should be noted that the alarm circuit 203 can be an indicator light or a voice alarm, etc. The following explanation uses an indicator light as an example.

[0021] The measurement and control circuit 202 includes an emergency protection circuit 280, a monitoring chip and auxiliary circuit 260, and a second DC power supply 270. The second DC power supply 270 provides DC power V2 to the self-fault monitoring unit 2. The monitoring chip and auxiliary circuit 260 periodically sends a self-fault monitoring signal U_TEST to initiate the self-fault monitoring process and terminates it upon receiving the fault status signal U_FS. The emergency protection circuit 280 sets a maximum running time Tmax for the self-fault monitoring process (e.g., 40ms). During the self-fault monitoring process, the emergency protection circuit 280 receives the self-fault monitoring signal U_TEST and monitors the running time Trun. When Trun is less than the maximum running time Tmax, the ground fault protection unit 1 is determined to be in a normal state; when Trun is greater than the maximum running time Tmax, the ground fault protection unit 1 is determined to be in a fault state, and the emergency interrupt signal U_EI is output to trigger the ground fault unit 1 to trip, thus realizing the emergency protection function.

[0022] The self-fault monitoring unit 2 also includes a fault status holding circuit 204, which receives the self-fault monitoring signal U_TEST and the emergency interruption signal U_EI, and outputs fault status information U_err to the warning circuit 203.

[0023] The fault state holding circuit 204 includes a reset circuit 210 and a fault state trigger circuit 290. The reset circuit 210 includes a reset capacitor 216. With the help of the reset capacitor 216, the reset circuit 210 captures the level flip information of the self-fault monitoring signal U_TEST at the moment the self-fault monitoring process starts, and outputs a reset signal U_clr.

[0024] The fault state triggering circuit 290 includes a voltage comparator 294, which receives a reset signal U_clr and an emergency interruption signal U_EI, and outputs fault state information U_err. At the moment of initiation of the self-fault monitoring process, the fault state triggering circuit 290 is reset by the reset signal U_clr, outputs and maintains the fault state information U_err, and turns off the indicator light of the warning circuit 203. When the ground fault protection unit 1 fails, on the one hand, the fault state triggering circuit 290 is set to 1 by the emergency interruption signal U_EI, outputs and maintains the fault state information U_err, and keeps the indicator light of the warning circuit 203 lit, indicating that the circuit protection device 1 has failed; on the other hand, the fault state triggering circuit 290 is momentarily reset by the periodically appearing reset signal U_clr, thereby emitting periodically changing fault state information U_err.

[0025] As can be seen from the above, the fault status holding circuit 204 outputs fault status information U_err, which includes two states: low level and high level. The warning circuit 203 receives the fault status information U_err. During the self-fault monitoring process, when the circuit protection device is fault-free, the indicator light of the warning circuit 203 is turned off; when the ground fault protection unit 1 fails, the indicator light of the warning circuit 203 flashes to improve the warning effect.

[0026] In a specific embodiment, such as Figure 2 The image shown is a specific embodiment of the circuit protection device for automatically monitoring operational faults according to this application, demonstrating... Figure 1 One circuit embodiment of each functional unit of the circuit protection device.

[0027] In AC power channel 102, AC power is input from AC power input terminals L1 and N1, and after passing through ground fault current GFC sensor 150 and neutral line repeated grounding sensor 160, it is connected to the input terminal of magnetic switch 88. The output terminal of magnetic switch 88 is connected to load terminals L2 and N2.

[0028] In the ground fault detection circuit 101, the ground fault current sensor 150, the neutral line repeated grounding sensor 160, and the ground fault detection chip 170 sense the ground fault current GFC that appears in the AC power channel 102 and output a ground fault interruption signal U_GFI. When the ground fault current GFC exceeds the tripping threshold, the ground fault interruption signal U_GFI changes from low level to high level; when the ground fault current GFC is less than the tripping threshold, the ground fault interruption signal U_GFI remains at low level.

[0029] In the ground fault detection circuit 101, the first DC power supply 180 is a bridge rectifier circuit, with its positive output connected to V1 and its negative output connected to the logic ground GND of the circuit protection device.

[0030] The electromagnetic drive circuit 104 includes a trip coil 142 and a silicon controlled rectifier (SCR). The SCR anode outputs a fault status signal U_FS, which is connected to the trip coil 142, the monitoring chip, and the auxiliary circuit 260. The cathode of the SCR is connected to logic ground GND. The ground fault interruption signal U_GFI is connected to the control electrode of the SCR via resistor 149, and the emergency interruption signal U_EI is connected to the control electrode of the SCR via diode 148. When the ground fault interruption signal U_GFI and / or the emergency interruption signal U_EI are high, the SCR is turned on, causing the fault status signal U_FS to be low. When a ground fault occurs, the SCR in the electromagnetic drive circuit 104 is in the on state, causing the trip coil 142 and the magnetic switch 88 to trip, cutting off the AC power supply to the load and socket terminals, thus achieving the ground fault protection function.

[0031] In the monitoring chip and auxiliary circuit 260, the monitoring chip 263 periodically changes U_TEST from low to high level to initiate the self-fault monitoring process and receives the fault status signal U_FS from the electromagnetic drive circuit 104. When the fault status signal U_FS changes from high to low level, the self-fault monitoring signal U_TEST immediately changes from high to low level, ending the self-fault monitoring process. On the other hand, the self-fault monitoring signal U_TEST is also connected to the warning circuit 203. During the self-fault monitoring process, when the SCR is functioning normally, regardless of whether the ground fault protection unit 1 is faulty, the level of the fault status signal U_FS will flip once, and the indicator light of the warning circuit 203 will be lit briefly and indiscriminately.

[0032] In the emergency protection circuit 280, the input resistor 281, the delay capacitor 282, and the reference voltage Ud are used to set the maximum operating time Tmax for the self-fault monitoring process. During the self-fault monitoring process, the self-fault monitoring signal U_TEST remains at a high level. The self-fault monitoring signal U_TEST charges the delay capacitor 282 through the resistor 281. When the ground fault protection unit 1 fails, the operating time Trun of the self-fault monitoring process is greater than the maximum operating time Tmax, the voltage on the delay capacitor 282 is higher than Ud, and the emergency interrupt signal U_EI changes from low level to high level. When the circuit protection device is fault-free, Trun is less than Tmax, the voltage on the delay capacitor 282 is lower than Ud, and the emergency interrupt signal U_EI remains at a low level.

[0033] In the reset circuit 210, the self-fault monitoring signal U_TEST is connected to one electrode of the reset capacitor 216 via resistor 215. The other electrode of the reset capacitor 216 is simultaneously connected to the base of transistor 217 and one electrode of resistor 218. The other electrode of resistor 218 is connected to logic ground GND. The emitter of transistor 217 is connected to logic ground GND, and the collector of transistor 217 outputs a reset signal U_clr. The reset circuit 210 utilizes the charging and discharging characteristics and DC voltage isolation characteristics of the reset capacitor 216 to acquire transient information of the self-fault monitoring signal U_TEST. The process is as follows: when the self-fault monitoring signal U_TEST changes from low to high, the potential difference across the reset capacitor 216 does not change abruptly. The self-fault monitoring signal U_TEST injects current into the base of transistor 217 through resistor 215, thereby turning on transistor 217. The reset signal U_clr connected to the collector of transistor 217 changes from high to low. Subsequently... The potential difference across the reset capacitor 216 gradually increases, and the current flowing through the reset capacitor 216 gradually decreases until the transistor 217 is cut off. After this, the level of U_clr is maintained by the fault state trigger circuit 290. When the self-fault monitoring signal U_TEST changes from high to low, the charge in the reset capacitor 216 is gradually released through resistors 215 and 218 until the potential difference across the reset capacitor 216 is zero. During this process, the base of the transistor 217 remains at a low level, the transistor remains cut off, and the state of U_clr remains unchanged. The output U_clr of the reset circuit 210 only appears when the self-fault monitoring signal U_TEST changes from low to high to obtain transient information about the rise of the self-fault monitoring signal U_TEST.

[0034] In the fault state triggering circuit 290, the voltage comparator 294 and the positive feedback resistor 293 form a positive feedback circuit. The voltage comparator 294 outputs fault state information U_err. The negative input terminal of the voltage comparator 294 is connected to the reference voltage Ub. The clear signal U_clr is connected to the positive input terminal Ua of the voltage comparator 294. The emergency interrupt signal U_EI is connected to the positive input terminal Ua of the voltage comparator 294 through the diode 291 and the resistor 292. One electrode of the resistor 293 is connected to the positive input terminal Ua of the voltage comparator 294, and the other electrode of the resistor 293 is connected to the output U_err of the voltage comparator 294. U_err is then connected to the warning circuit 203. Thus, voltage comparator 294 and its peripheral components achieve bistable (high and low level) output functionality. The process is as follows: In the initial state, the emergency interrupt signal U_EI is low, and the reset signal U_clr is high. When the reset signal U_clr changes from high to low, the voltage Ua at the positive input terminal of voltage comparator 294 is lower than its negative input terminal voltage Ub (e.g., Ua is approximately 0.3V, Ub is approximately 3V), and its fault status information U_err is low (e.g., 0.3V). Due to the positive feedback effect of resistor 293, when transistor 217 in the reset circuit 210 is turned off, the voltage Ua at the positive input terminal of voltage comparator 294 remains lower than its negative input terminal voltage Ub (Ua is approximately 0.3V, Ub is approximately 3V), and the fault status information U_e... The voltage comparator 294 remains at a low level. When the emergency interrupt signal U_EI is high (e.g., 11V), with transistor 217 off, the voltage Ua at the positive input terminal of the voltage comparator 294 is higher than its negative input terminal voltage Ub (e.g., if Ua is 6.5V, Ua>Ub). The fault status signal U_err flips from low to high (e.g., if U_err is 11V). At this time, Ua is approximately equal to U_err. Subsequently, due to the positive feedback of resistor 293 and the unidirectional conduction characteristic of diode 291, when the emergency interrupt signal U_EI changes from high to low, Ua remains unchanged (approximately equal to U_err), thus maintaining the condition that Ua>Ub. The output U_err of the voltage comparator 294 remains at a high level.

[0035] In another embodiment, such as Figure 3 As shown, another embodiment of the fault state holding circuit 204 is given. Figure 3 The fault state holding circuit 204 in the middle can realize the connection with Figure 2 The fault state holding circuit 204 in the middle has the same signal transmission function to achieve Figure 1 The aforementioned fault state retention function.

[0036] In the reset circuit 210, one electrode of resistor 215 is connected to the ground fault monitoring signal U_TEST, the other electrode of resistor 215 is connected to one electrode of reset capacitor 216, the other electrode of reset capacitor 216 is connected to one electrode of resistor 218 and the base of transistor 217, the other electrode of resistor 218 is connected to logic ground GND, the collector of transistor 217 is connected to the second DC power supply 270 (V2), and the emitter of transistor 217 outputs a reset signal U_clr. The working principle of the reset circuit 210 is as follows: When the self-fault monitoring signal U_TEST is low, resistor 215, reset capacitor 216, and resistor 218 form a discharge circuit, making the potential difference across reset capacitor 216 zero, the voltage at the base of transistor 217 0V, transistor 217 is cut off, and the voltage of U_clr is Ub_L (e.g., set to 3V); when U_TEST rises from low to high, initially, U_TEST injects current into the base of transistor 217 through resistor 215 and reset capacitor 216, causing the transistor to... When transistor 217 is momentarily turned on, its output U_clr rises instantaneously to Ub_H (e.g., 10V). Subsequently, while U_TEST remains high, the potential difference across the reset capacitor 216 gradually increases as it charges, causing the base voltage of transistor 217 to gradually decrease to 0V. Transistor 217 then turns off, and U_clr gradually returns to Ub_L. When U_TEST drops from high to low, the reset capacitor 216 discharges, transistor 217 remains off, and U_clr remains unchanged. Therefore, during the back-and-forth transition between high and low levels of U_TEST, the reset information U_clr output by the reset circuit 210 only experiences a momentary level flip (from Ub_L to Ub_H, then back to Ub_L) at the instant U_TEST transitions from low to high, thus capturing the transient information of the rising edge of the U_TEST level.

[0037] In the fault state holding circuit 290, the voltage comparator 294 and the positive feedback resistor 293 form a positive feedback circuit. The voltage comparator outputs a fault state signal U_err. The anode of the diode 291 is connected to U_EI, the cathode of the diode 291 is connected to one electrode of the resistor 292, the other electrode of the resistor 292 is connected to the resistor 295, the positive feedback resistor 293 and the positive input terminal Ua of the voltage comparator 294, the other electrode of the resistor 295 is connected to logic ground GND, the other electrode of the positive feedback resistor 293 is connected to the output U_err of the voltage comparator 294, the negative input terminal Ub of the voltage comparator 294 is connected to a voltage divider circuit composed of the second DC power supply V2, resistor 297 and resistor 296, and the negative input terminal Ub of the voltage comparator 294 is also connected to the clear signal U_clr.

[0038] The working principle of the fault status trigger circuit 290 is as follows: In the initial state, the level of the clear signal U_clr (i.e., Ub) is Ub_L (e.g., set to 3V), the emergency interrupt signal U_EI is at a low level (about 0.3V), and the fault status signal U_err is at a low level (about 0.3V). At this time, the voltage Ua at the positive input terminal of the voltage comparator 294 is Ua_1 (lower than 0.3V), the voltage Ub at the negative input terminal of the voltage comparator 294 is Ub_L, and Ua_1 < Ub_L, so the fault status signal U_err remains at a low level; at this time, when the clear signal U_clr changes from the low level Ub_L to the high level Ub_H (e.g., 10V) and then from the high level Ub_H to the low level Ub_L, Ub is always greater than Ua, and the fault status signal U_err remains at a low level; when the emergency interrupt signal U_EI changes from a low level to a high level (e.g., 11V), the voltage Ua at the positive input terminal of the voltage comparator 294 rises from Ua_1 to Ua_2 (determined by the resistor 292, the resistor 295, and the positive feedback resistor 293, e.g., set to 4.5V), its negative input terminal voltage Ub is Ub_L, and Ua > Ub, so the fault status signal U_err flips from a low level to a high level (e.g., 11V). At this time, under the action of the positive feedback resistor 293, Ua rises from Ua_2 to Ua_3 (determined by the resistor 292, the positive feedback resistor 293, and the resistor 295, e.g., set to 6.5V). Subsequently, if the emergency interrupt signal U_EI changes from a high level to a low level, due to the unidirectional conduction of the diode 291, the voltage Ua at the positive input terminal of the voltage comparator 294 drops back to Ua_4 (determined by the resistor 295 and the positive feedback resistor 293, e.g., 3.3V), and Ua_4 is still greater than Ub_L. Therefore, the fault status signal U_err remains at a high level, thus realizing the function of maintaining the fault status information; when the fault status signal U_err is at a high level, when the clear signal U_clr rises from the low level Ub_L to the high level Ub_H, the voltage Ub at the negative input terminal of the voltage comparator 294 rises from the low level Ub_L to the high level Ub_H, and Ub_H > Ua_3, that is, the voltage Ub at the negative input terminal of the voltage comparator 294 is greater than its positive input terminal voltage Ua, and the fault status signal U_err instantaneously returns to a low level.

[0039] situations Figure 2 and Figure 3In both embodiments, during each self-fault monitoring process, the warning circuit 203 receives the fault status information U_err. When the ground fault protection circuit 1 fails, the level of the fault status information U_err changes from high to low and then back to high, causing the indicator light of the warning circuit 203 to flash once. This eliminates the indiscriminate and short flashing characteristic of relying solely on the self-fault monitoring signal U_TEST output by the monitoring chip and auxiliary circuit 260, thus improving the warning effect. In this embodiment, the reset circuit 210 and the fault status triggering circuit 290 are simple, economical, and practical, effectively achieving the fault status maintenance function.

[0040] As is known to those skilled in the art, the accompanying drawings and embodiments of this application are merely illustrative of the function, structure, and principle of this application, and should not be construed as limiting the understanding of this application; moreover, the objectives of this application have been achieved. The above embodiments may be modified without departing from the principles of this application; therefore, the protection of this application should be determined by the scope described in the claims.

Claims

1. A circuit protection device for automatically monitoring operational faults, the circuit protection device comprising a ground fault protection unit (1) and a self-fault monitoring unit (2), the ground fault protection unit (1) comprising a ground fault detection circuit (101), an AC power supply channel (102), and an electromagnetic drive circuit (104), the self-fault monitoring unit (2) comprising an automatic test circuit (201), a measurement and control circuit (202), and an alarm circuit (203); characterized in that, The self-fault monitoring unit (2) also includes: The fault state holding circuit (204) includes a clearing circuit (210) and a fault state triggering circuit (290). The clearing circuit (210) receives the self-fault monitoring signal U_TEST sent by the measurement and control circuit (202) at regular intervals and sends a clearing signal U_clr. The fault state triggering circuit (290) receives the clearing signal U_clr and the emergency interruption signal U_EI sent by the measurement and control circuit (202). When the ground fault protection unit (1) fails, it outputs and holds the fault state information U_err, so that the warning circuit (203) remains in the alarm state to indicate that the circuit protection device has failed. The reset circuit (210) includes a reset capacitor (216), which captures the level toggling information of the self-fault monitoring signal U_TEST and is used to generate the reset signal U_clr. The fault state triggering circuit (290) includes a voltage comparator (294), which receives the reset signal U_clr and the emergency interrupt signal U_EI, and outputs fault state information U_err.

2. The circuit protection device for automatically monitoring operational faults as described in claim 1, characterized in that, The fault status information U_err output by the fault status triggering circuit (290) includes two states: low level and high level. The warning circuit (203) receives the fault status information U_err. During the self-fault monitoring process, when the circuit protection device is fault-free, the warning circuit (203) stops alarming; when the ground fault protection unit (1) fails, the warning circuit (203) maintains the alarm state.

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