A signal monitoring circuit for solid-state switchgear in a power grid system

Abstract

This invention discloses a signal monitoring circuit for solid-state switchgear in a power grid system, relating to the field of signal detection and processing. The circuit includes an electrical signal acquisition module for acquiring electrical signals from the solid-state switchgear in the power grid system. After voltage division and isolation, three identical sampled signals are obtained. Compared with existing technologies, the advantages of this invention are: This invention uses a fully analog hardware circuit specifically designed to detect random and intermittent signal anomalies caused by mechanical loosening of the solid-state switchgear. Through parallel processing channels, one channel uses a signal loss detection module to determine signal amplitude loss in real time, while the other channel uses a signal surge detection module to reliably capture millisecond-level random spikes. This solution eliminates the need for sampling and software processing, achieving a detection response time as fast as microseconds, fundamentally avoiding the inherent sampling delay and program loop time consumption problems of digital systems. Furthermore, the circuit structure is simple, has strong anti-interference capabilities, and is low in cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of signal detection processing, and particularly relates to a signal monitoring circuit for a solid-state switch cabinet of a power grid system. BACKGROUND

[0002] In the solid-state switch cabinet of the power grid system, connection loosening caused by mechanical vibration is a common but hidden fault source. The existing monitoring system usually focuses on the steady-state measurement of electrical parameters such as the effective value of voltage and current, harmonic content, etc., and lacks special detection of random and intermittent signal abnormalities (such as transient glitches, amplitude fluctuations and phase jumps) caused by mechanical loosening.

[0003] This detection blind spot makes it difficult to discover early loosening faults in time, and they are often not detected until the fault expands to cause misoperation of the solid-state switch cabinet, damage to the equipment, even system power failure, which seriously affects the reliability and safety of the power grid, and needs to be improved. SUMMARY

[0004] The purpose of the present application is to provide a signal monitoring circuit for a solid-state switch cabinet of a power grid system to solve the problems raised in the background.

[0005] To achieve the above purpose, the present application provides the following technical scheme:

[0006] A signal monitoring circuit for a solid-state switch cabinet of a power grid system, comprising:

[0007] An electric signal acquisition module is used to acquire the electric signal of the solid-state switch cabinet in the power grid system, and after being divided and isolated, three identical sampling signals are obtained, which are output to a signal loss detection module and a signal surge detection module;

[0008] The signal loss detection module is used to receive the first sampling signal, filter out the signal higher than the normal working frequency (such as 50Hz / 60Hz) through the first low-pass filter (the cutoff frequency is slightly higher than the normal working frequency signal), obtain the first signal, and obtain the effective value of the sampling signal through the half-wave precision rectifier circuit, and judge whether there is a signal loss condition by the effective value;

[0009] The signal surge detection module is used to receive the second and third sampling signals, filter out the signal higher than the working frequency through the second low-pass filter to obtain the second signal, and realize the difference through the differential amplification circuit to obtain the high-frequency signal (i.e. the high-frequency signal mainly generated by transient glitches, amplitude fluctuations, etc.) whose frequency is higher than the normal working frequency signal, and obtain the comprehensive energy value through the full-wave precision rectifier circuit, and judge whether there is a signal surge condition by the comprehensive energy value;

[0010] The output of the electrical signal acquisition module is connected to the input of the signal loss detection module and the input of the signal surge detection module.

[0011] As a further embodiment of the present invention: the electrical signal acquisition module includes a current transformer, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first amplifier, a second amplifier, and a third amplifier. The current transformer detects the electrical signal at the solid-state switchgear. One end of the current transformer is grounded, and the other end of the current transformer is connected to one end of the first resistor. The other end of the first resistor is connected to one end of the second resistor, the non-inverting input of the first amplifier, the non-inverting input of the second amplifier, and the non-inverting input of the third amplifier. The other end of the second resistor is grounded. The inverting input of the first amplifier is connected to the output of the first amplifier and the input of the signal loss detection module through the third resistor. The inverting input of the second amplifier is connected to the output of the second amplifier and the input of the signal surge detection module through the fourth resistor. The inverting input of the third amplifier is connected to the output of the third amplifier and the input of the signal surge detection module through the fifth resistor.

[0012] As a further embodiment of the present invention: the signal loss detection module includes a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a first capacitor, a second capacitor, a fourth amplifier, a tenth resistor, an eleventh resistor, a first diode, a second diode, a fifth amplifier, a third capacitor, a twelfth resistor, a sixth amplifier, and a first buzzer. One end of the sixth resistor is connected to the output terminal of the electrical signal acquisition module, and the other end of the sixth resistor is connected to one end of the first capacitor, one end of the seventh resistor, one end of the seventh resistor, one end of the second capacitor, and the non-inverting input of the fourth amplifier. The other end of the second capacitor is grounded. The inverting input of the fourth amplifier is connected to one end of the eighth resistor and one end of the ninth resistor, and the other end of the eighth resistor is grounded. The other end of the ninth resistor is connected to the output of the fourth amplifier, the other end of the first capacitor, and one end of the tenth resistor. The other end of the tenth resistor is connected to the inverting input of the fifth amplifier, one end of the eleventh resistor, and the positive terminal of the first diode. The non-inverting input of the fifth amplifier is grounded. The negative terminal of the first diode is connected to the other end of the eleventh resistor, the negative terminal of the second diode, one end of the third capacitor, one end of the twelfth resistor, and the inverting input of the sixth amplifier. The other end of the third capacitor is grounded, the other end of the twelfth resistor is grounded, the positive terminal of the second diode is connected to the output of the fifth amplifier, the non-inverting input of the sixth amplifier is connected to the first reference voltage, the output of the sixth amplifier is connected to one end of the first buzzer, and the other end of the first buzzer is grounded.

[0013] As a further embodiment of the present invention: the signal surge detection module includes:

[0014] The high-frequency signal acquisition unit is used to receive the second and third sampling signals. The second sampling signal is filtered out by the second low-pass filter to remove signals higher than the operating frequency, and the second signal is obtained. The third sampling signal and the second signal are differentially amplified by a differential amplifier circuit to obtain a high-frequency signal with a frequency higher than the normal power frequency signal (i.e., a high-frequency signal mainly generated by transient glitches, amplitude fluctuations and other abnormalities).

[0015] The integrated energy value acquisition unit is used to convert high-frequency signals into integrated energy values ​​through a full-wave precision rectifier circuit;

[0016] The alarm unit is used to determine the magnitude of the comprehensive energy value and the second reference voltage. If the comprehensive energy value is greater than the second reference voltage, it is determined that there is a sudden increase in signal and an alarm is triggered.

[0017] The input terminal of the high-frequency signal acquisition unit is connected to the output terminal of the electrical signal acquisition module, the output terminal of the high-frequency signal acquisition unit is connected to the input terminal of the comprehensive energy value acquisition unit, and the output terminal of the comprehensive energy value acquisition unit is connected to the input terminal of the alarm unit.

[0018] As a further embodiment of the present invention: the high-frequency signal acquisition unit includes a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a fourth capacitor, a fifth capacitor, a seventh amplifier, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, an eighth amplifier, and a twentieth resistor. One end of the thirteenth resistor is connected to the output terminal of the electrical signal acquisition module. The other end of the thirteenth resistor is connected to one end of the fourth capacitor and one end of the fourteenth resistor. The other end of the fourteenth resistor is connected to one end of the fifth capacitor and the non-inverting input of the seventh amplifier. The other end of the fifth capacitor is grounded. The inverting input of the seventh amplifier is connected to one end of the fifteenth resistor and one end of the sixteenth resistor. The other end of the fifteenth resistor is grounded. The other end of the sixteenth resistor is connected to the output terminal of the seventh amplifier, the other end of the fourth capacitor, and one end of the seventeenth resistor. The other end of the seventeenth resistor is connected to the inverting input of the eighth amplifier and one end of the twentieth resistor. The non-inverting input of the eighth amplifier is connected to one end of the eighteenth resistor and one end of the nineteenth resistor. The other end of the nineteenth resistor is grounded. The other end of the eighteenth resistor is connected to the output terminal of the electrical signal acquisition module. The output terminal of the eighth amplifier is connected to the other end of the twentieth resistor and the input terminal of the comprehensive energy value acquisition unit.

[0019] As a further embodiment of the present invention: the integrated energy value acquisition unit includes a 21st resistor, a 22nd resistor, a 23rd resistor, a 24th resistor, a 9th amplifier, a 3rd diode, a 4th diode, a 25th resistor, a 6th capacitor, a 10th amplifier, and a 26th resistor. One end of the 21st resistor is connected to one end of the 22nd resistor and the output terminal of the high-frequency signal acquisition unit. The other end of the 21st resistor is connected to one end of the 23rd resistor, the cathode of the 3rd diode, and the inverting input of the 9th amplifier. The non-inverting input of the 9th amplifier is grounded. The output terminal of the 9th amplifier is connected to the cathode of the 4th diode. The anode of the 4th diode is connected to the anode of the 3rd diode, the other end of the 23rd resistor, and one end of the 24th resistor. The other end of the 24th resistor is connected to the other end of the 22nd resistor, one end of the 25th resistor, and the inverting input of the 10th amplifier. The non-inverting input of the 10th amplifier is grounded. The output terminal of the 10th amplifier is connected to the other end of the 25th resistor, one end of the 6th capacitor, one end of the 26th resistor, and the input terminal of the alarm unit. The other end of the 6th capacitor and the other end of the 26th resistor are grounded.

[0020] As a further embodiment of the present invention: the alarm unit includes an eleventh amplifier and a second buzzer. The non-inverting input of the eleventh amplifier is connected to the output of the integrated energy value acquisition unit, the inverting input of the eleventh amplifier is connected to the second reference voltage, the output of the eleventh amplifier is connected to one end of the second buzzer, and the other end of the second buzzer is grounded.

[0021] Compared with existing technologies, the advantages of this invention are as follows: This invention adopts a fully analog hardware circuit, specifically designed to detect random and intermittent signal anomalies (specifically transient glitches and rapid signal loss) caused by mechanical loosening in solid-state switchgear. Through parallel processing channels, one channel uses a signal loss detection module to determine the signal amplitude loss in real time, while the other channel uses a signal surge detection module to reliably capture millisecond-level random glitches. This solution requires no sampling or software processing, and the detection response time is as fast as microseconds, fundamentally avoiding the inherent sampling delay and program loop time consumption problems of digital systems. Moreover, the circuit structure is simple, has strong anti-interference capabilities, and is low in cost. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a signal monitoring circuit for a solid-state switchgear in a power grid system.

[0023] Figure 2 This is the circuit diagram of the electrical signal acquisition module.

[0024] Figure 3 This is the circuit diagram of the signal loss detection module.

[0025] Figure 4 This is the circuit diagram for the signal surge detection module. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0027] Please see Figure 1 A signal monitoring circuit for a solid-state switchgear in a power grid system, comprising:

[0028] The electrical signal acquisition module 1 is used to acquire electrical signals from solid-state switchgear in the power grid system. After voltage division and isolation, three identical sampling signals are obtained and the sampling signals are output to the signal loss detection module 2 and the signal surge detection module 3.

[0029] The signal missing detection module 2 is used to receive the first sampling signal, filter out signals with frequencies higher than the normal operating frequency (such as 50Hz / 60Hz) through the first low-pass filter (the cutoff frequency is slightly higher than the normal power frequency signal) to obtain the first signal, and obtain the effective value of the sampling signal through the half-wave precision rectifier circuit. The magnitude of the effective value is used to determine whether there is a signal missing condition.

[0030] The signal surge detection module 3 is used to receive the second and third sampling signals. The second sampling signal is filtered out by the second low-pass filter to remove signals higher than the operating frequency, thus obtaining the second signal. The third sampling signal and the second signal are differentially amplified by a differential amplifier circuit to obtain a high-frequency signal with a frequency higher than the normal power frequency signal (i.e., a high-frequency signal mainly generated by transient glitches, amplitude fluctuations, and other anomalies). The high-frequency signal is rectified by a full-wave precision rectifier circuit to obtain a comprehensive energy value. The magnitude of the comprehensive energy value is used to determine whether there is a signal surge.

[0031] The output terminal of the electrical signal acquisition module 1 is connected to the input terminal of the signal loss detection module 2 and the input terminal of the signal surge detection module 3.

[0032] In this embodiment: Please refer to Figure 2The electrical signal acquisition module 1 includes a current transformer H, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a first amplifier U1, a second amplifier U2, and a third amplifier U3. The current transformer H detects the electrical signal at the solid-state switch cabinet. One end of the current transformer H is grounded, and the other end of the current transformer H is connected to one end of the first resistor R1. The other end of the first resistor R1 is connected to one end of the second resistor R2, the non-inverting input of the first amplifier U1, the non-inverting input of the second amplifier U2, and the non-inverting input of the third amplifier U3. The other end of the second resistor R2 is grounded. The inverting input of the first amplifier U1 is connected to the output of the first amplifier U1 and the input of the signal loss detection module 2 through the third resistor R3. The inverting input of the second amplifier U2 is connected to the output of the second amplifier U2 and the input of the signal surge detection module 3 through the fourth resistor R4. The inverting input of the third amplifier U3 is connected to the output of the third amplifier U3 and the input of the signal surge detection module 3 through the fifth resistor R5.

[0033] The current transformer H acquires the electrical signal, and divides it through the first resistor R1 and the second resistor R2. Then, it isolates and outputs the sampled voltage through three voltage followers constructed by three amplifiers, and outputs it to the subsequent circuit.

[0034] In another embodiment: the transformer H can be a voltage transformer or a current transformer.

[0035] In this embodiment: Please refer to Figure 3The signal loss detection module 2 includes a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a first capacitor C1, a second capacitor C2, a fourth amplifier U4, a tenth resistor R10, an eleventh resistor R11, a first diode D1, a second diode D2, a fifth amplifier U5, a third capacitor C3, a twelfth resistor R12, a sixth amplifier U6, and a first buzzer BUZZ1. One end of the sixth resistor R6 is connected to the output terminal of the electrical signal acquisition module 1. The other end of the sixth resistor R6 is connected to one end of the first capacitor C1, one end of the seventh resistor R7, one end of the seventh resistor R7, one end of the second capacitor C2, and the non-inverting input of the fourth amplifier U4. The other end of the second capacitor C2 is grounded. The inverting input of the fourth amplifier U4 is connected to one end of the eighth resistor R8 and one end of the ninth resistor R9. The other end of the eighth resistor R8 is grounded. The ninth resistor R9... The other end is connected to the output terminal of the fourth amplifier U4, the other end of the first capacitor C1, and one end of the tenth resistor R10. The other end of the tenth resistor R10 is connected to the inverting input of the fifth amplifier U5, one end of the eleventh resistor R11, and the positive terminal of the first diode D1. The non-inverting input of the fifth amplifier U5 is grounded. The negative terminal of the first diode D1 is connected to the other end of the eleventh resistor R11, the negative terminal of the second diode D2, one end of the third capacitor C3, one end of the twelfth resistor R12, and the inverting input of the sixth amplifier U6. The other end of the third capacitor C3 is grounded, the other end of the twelfth resistor R12 is grounded, the positive terminal of the second diode D2 is connected to the output terminal of the fifth amplifier U5, the non-inverting input of the sixth amplifier U6 is connected to the first reference voltage VREF1, and the output terminal of the sixth amplifier U6 is connected to one end of the first buzzer BUZZ1. The other end of the first buzzer BUZZ1 is grounded.

[0036] An active low-pass filter is constructed using resistors R6, R7, R8, R9, C1, C2, and amplifier U4. Its cutoff frequency is slightly higher than the power frequency (e.g., 52Hz / 62Hz) to filter out high-frequency noise that may interfere with the signal selection, retaining only the fundamental power frequency signal to obtain the first signal. This first signal enters a half-wave precision rectifier circuit consisting of amplifier U5, diode D1, diode D2, resistor R10, and resistor R11. This circuit converts the AC signal into a DC voltage proportional to its magnitude. The DC voltage is stored at capacitor C3 as the effective value. This effective value is sent to the inverting input of amplifier U6 (acting as a comparator) and compared with the first reference voltage VREF1 (representing the set signal loss threshold) at the non-inverting input. When the effective signal value is lower than the first reference voltage VREF1, it is determined that the signal is completely or significantly missing (e.g., disconnected). A high-level output is then triggered by amplifier U6, driving the first buzzer BUZZ1 to sound an alarm.

[0037] In another embodiment, an additional light-emitting tube may be provided at the first buzzer BUZZ1 for indication.

[0038] In this embodiment: Please refer to Figure 4 The signal surge detection module 3 includes:

[0039] The high-frequency signal acquisition unit is used to receive the second and third sampling signals. The second sampling signal is filtered out by the second low-pass filter to remove signals higher than the operating frequency, and the second signal is obtained. The third sampling signal and the second signal are differentially amplified by a differential amplifier circuit to obtain a high-frequency signal with a frequency higher than the normal power frequency signal (i.e., a high-frequency signal mainly generated by transient glitches, amplitude fluctuations and other abnormalities).

[0040] The integrated energy value acquisition unit is used to convert high-frequency signals into integrated energy values ​​through a full-wave precision rectifier circuit;

[0041] The alarm unit is used to determine the magnitude of the comprehensive energy value and the second reference voltage VREF2. If the comprehensive energy value is greater than the second reference voltage VREF2, it is determined that there is a sudden increase in signal and an alarm is triggered.

[0042] The input terminal of the high-frequency signal acquisition unit is connected to the output terminal of the electrical signal acquisition module 1, the output terminal of the high-frequency signal acquisition unit is connected to the input terminal of the comprehensive energy value acquisition unit, and the output terminal of the comprehensive energy value acquisition unit is connected to the input terminal of the alarm unit.

[0043] In this embodiment: Please refer to Figure 4The high-frequency signal acquisition unit includes a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a fourth capacitor C4, a fifth capacitor C5, a seventh amplifier U7, a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, an eighth amplifier U8, and a twentieth resistor R20. One end of the thirteenth resistor R13 is connected to the output terminal of the electrical signal acquisition module 1. The other end of the thirteenth resistor R13 is connected to one end of the fourth capacitor C4, one end of the fourteenth resistor R14, one end of the fourteenth resistor R14, one end of the fifth capacitor C5, and the non-inverting input of the seventh amplifier U7. The other end of the fifth capacitor C5 is grounded. The inverting input of the seventh amplifier U7 is connected to the fifteenth resistor R16. One end of resistor R15, one end of the sixteenth resistor R16, and the other end of the fifteenth resistor R15 are grounded. The other end of the sixteenth resistor R16 is connected to the output of the seventh amplifier U7, the other end of the fourth capacitor C4, one end of the seventeenth resistor R17, the other end of the seventeenth resistor R17 is connected to the inverting input of the eighth amplifier U8, one end of the twentieth resistor R20, the non-inverting input of the eighth amplifier U8 is connected to one end of the eighteenth resistor R18, one end of the nineteenth resistor R19, the other end of the nineteenth resistor R19 is grounded, the other end of the eighteenth resistor R18 is connected to the output of the electrical signal acquisition module 1, the output of the eighth amplifier U8 is connected to the other end of the twentieth resistor R20, and the input of the comprehensive energy value acquisition unit.

[0044] The second sampled signal passes through a second low-pass filter composed of resistor R13 (13th resistor), resistor R14 (14th resistor), capacitor C4 (4th capacitor), capacitor C5 (5th capacitor), resistor R15 (15th resistor), resistor R16 (16th resistor), and amplifier U7 (7th amplifier), resulting in a clean power frequency signal that has been filtered out of high-frequency glitches, which serves as the second signal. The third original sampled signal and the second signal are input together into a differential amplifier circuit composed of amplifier U8 (8th amplifier), etc. This circuit calculates the difference between the two, thereby canceling out the common-mode power frequency fundamental signal (i.e., the second signal), and the final output only retains the high-frequency signal representing transient glitches and abnormal fluctuations.

[0045] This unit is crucial for glitch detection. It requires that the characteristics of the two low-pass filters be highly consistent, and that the differential amplifier have a high common-mode rejection ratio to ensure good fundamental cancellation and accurate extraction of weak high-frequency anomalies.

[0046] In this embodiment: Please refer to Figure 4The integrated energy value acquisition unit includes resistors R21 (21st), R22 (22nd), R23 (23rd), R24 (24th), amplifier U9 (9th), diode D3 (3rd), diode D4 (4th), resistor R25 (25th), capacitor C6 (6th), amplifier U10 (10th), and resistor R26 (26th). One end of resistor R21 is connected to one end of resistor R22 and the output terminal of the high-frequency signal acquisition unit. The other end of resistor R21 is connected to one end of resistor R23, the cathode of diode D3, and the inverting input of amplifier U9. The non-inverting input of amplifier U9 is grounded. The output terminal is connected to the negative terminal of the fourth diode D4. The positive terminal of the fourth diode D4 is connected to the positive terminal of the third diode D3, the other end of the twenty-third resistor R23, one end of the twenty-fourth resistor R24, the other end of the twenty-fourth resistor R24 ​​is connected to the other end of the twenty-second resistor R22, one end of the twenty-fifth resistor R25, the inverting input of the tenth amplifier U10, the non-inverting input of the tenth amplifier U10 is grounded, the output terminal of the tenth amplifier U10 is connected to the other end of the twenty-fifth resistor R25, one end of the sixth capacitor C6, one end of the twenty-sixth resistor R26, the input terminal of the alarm unit, the other end of the sixth capacitor C6 is grounded, and the other end of the twenty-sixth resistor R26 is grounded.

[0047] The full-wave precision rectifier circuit consists of the ninth amplifier U9, the tenth amplifier U10, the third diode D3, the fourth diode D4, the twenty-first resistor R21, the twenty-second resistor R22, the twenty-third resistor R23, the twenty-fourth resistor R24, and the twenty-fifth resistor R25. It overcomes the dead-zone voltage problem of ordinary diodes and can linearly rectify high-frequency signals in both positive and negative half-cycles, outputting a unipolar pulsating voltage.

[0048] The pulsating voltage is smoothed by an integrating circuit consisting of resistor R25 (25th resistor) and capacitor C6 (6th capacitor). The integrating circuit integrates the signal, and its output voltage is proportional to the energy of the input high-frequency signal over a short period of time (the sum of amplitude and duration), forming a comprehensive energy value.

[0049] This unit quantizes random, irregular spur signals into stable energy values ​​for easier subsequent judgment. The integral time constant (RC value) determines the detection sensitivity and response speed, and needs to be designed according to the expected width of the spurs.

[0050] In this embodiment: Please refer to Figure 4The alarm unit includes an eleventh amplifier U11 and a second buzzer BUZZ2. The non-inverting input of the eleventh amplifier U11 is connected to the output of the integrated energy value acquisition unit, the inverting input of the eleventh amplifier U11 is connected to the second reference voltage VREF2, the output of the eleventh amplifier U11 is connected to one end of the second buzzer BUZZ2, and the other end of the second buzzer BUZZ2 is grounded.

[0051] The eleventh amplifier, U11, functions as a voltage comparator. The overall energy value is input to the non-inverting input of the comparator and compared with the second reference voltage VREF2 (representing the set glitch energy threshold) at the inverting input. When the glitch energy exceeds the threshold, the comparator outputs a high level, driving the second buzzer, BUZZ2, to sound an alarm. A dedicated comparator with a fast response time should be selected to achieve a microsecond-level alarm response and ensure the capture of brief glitch events.

[0052] In another embodiment: the first buzzer BUZZ1 and the second buzzer BUZZ2 can share one, and the sixth amplifier U6 and the eleventh amplifier U11 can jointly drive one buzzer.

[0053] The working principle of this invention is as follows: The electrical signal acquisition module 1 is used to acquire electrical signals from the solid-state switchgear in the power grid system. After voltage division and isolation, three identical sampling signals are obtained. The sampling signals are then output to the signal loss detection module 2 and the signal surge detection module 3. The signal loss detection module 2 is used to receive the first sampling signal. The signal higher than the normal working frequency (e.g., 50Hz / 60Hz) is filtered out by the first low-pass filter (the cutoff frequency is slightly higher than the normal power frequency signal) to obtain the first signal. The first signal is passed through a half-wave precision rectifier circuit to obtain the effective value of the sampling signal. The magnitude of the effective value is used to determine whether there is a signal loss. The signal surge detection module 3 is used to receive the second and third sampling signals. The second sampling signal is passed through a second low-pass filter to filter out the signal higher than the working frequency to obtain the second signal. The third sampling signal and the second signal are differentially amplified by a differential amplifier circuit to obtain a high-frequency signal with a frequency higher than the normal power frequency signal (i.e., a high-frequency signal mainly generated by transient glitches, amplitude fluctuations, and other anomalies). The high-frequency signal is passed through a full-wave precision rectifier circuit to obtain the comprehensive energy value. The magnitude of the comprehensive energy value is used to determine whether there is a signal surge.

[0054] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and not restrictive.

[0055] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A signal monitoring circuit for a solid-state switchgear in a power grid system, characterized in that, The solid-state switchgear signal monitoring circuit of this power grid system includes: The electrical signal acquisition module is used to acquire electrical signals from solid-state switchgear in the power grid system. After voltage division and isolation, three identical sampling signals are obtained, and the sampling signals are output to the signal loss detection module and the signal surge detection module. The signal missing detection module is used to receive the first sampling signal, filter out signals with frequencies higher than the normal operating frequency through the first low-pass filter to obtain the first signal, and obtain the effective value of the sampling signal through the half-wave precision rectifier circuit. The magnitude of the effective value is used to determine whether there is a signal missing condition. The signal surge detection module is used to receive the second and third sampling signals. The second sampling signal is filtered out by the second low-pass filter to remove signals higher than the operating frequency, and the second signal is obtained. The third sampling signal and the second signal are differentially amplified by a differential amplifier circuit to obtain a high-frequency signal with a frequency higher than the normal power frequency signal. The high-frequency signal is rectified by a full-wave precision rectifier circuit to obtain a comprehensive energy value. The magnitude of the comprehensive energy value is used to determine whether there is a signal surge. The output of the electrical signal acquisition module is connected to the input of the signal loss detection module and the input of the signal surge detection module.

2. The signal monitoring circuit for a solid-state switchgear in a power grid system according to claim 1, characterized in that, The electrical signal acquisition module includes a current transformer, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first amplifier, a second amplifier, and a third amplifier. The current transformer detects the electrical signal at the solid-state switchgear. One end of the current transformer is grounded, and the other end of the current transformer is connected to one end of the first resistor. The other end of the first resistor is connected to one end of the second resistor, the non-inverting input of the first amplifier, the non-inverting input of the second amplifier, and the non-inverting input of the third amplifier. The other end of the second resistor is grounded. The inverting input of the first amplifier is connected to the output of the first amplifier and the input of the signal loss detection module through the third resistor. The inverting input of the second amplifier is connected to the output of the second amplifier and the input of the signal surge detection module through the fourth resistor. The inverting input of the third amplifier is connected to the output of the third amplifier and the input of the signal surge detection module through the fifth resistor.

3. The power grid system solid-state switchgear signal monitoring circuit according to claim 1, characterized in that, The signal loss detection module includes a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a first capacitor, a second capacitor, a fourth amplifier, a tenth resistor, an eleventh resistor, a first diode, a second diode, a fifth amplifier, a third capacitor, a twelfth resistor, a sixth amplifier, and a first buzzer. One end of the sixth resistor is connected to the output terminal of the electrical signal acquisition module. The other end of the sixth resistor is connected to one end of the first capacitor, one end of the seventh resistor, one end of the seventh resistor, one end of the second capacitor, and the non-inverting input of the fourth amplifier. The other end of the second capacitor is grounded. The inverting input of the fourth amplifier is connected to one end of the eighth resistor and one end of the ninth resistor. The other end of the eighth resistor is grounded. The first amplifier is connected to the output terminal of the fourth amplifier, the other end of the first capacitor, and one end of the tenth resistor. The other end of the tenth resistor is connected to the inverting input of the fifth amplifier, one end of the eleventh resistor, and the positive terminal of the first diode. The non-inverting input of the fifth amplifier is grounded. The negative terminal of the first diode is connected to the other end of the eleventh resistor, the negative terminal of the second diode, one end of the third capacitor, one end of the twelfth resistor, and the inverting input of the sixth amplifier. The other end of the third capacitor is grounded, the other end of the twelfth resistor is grounded, the positive terminal of the second diode is connected to the output terminal of the fifth amplifier, the non-inverting input of the sixth amplifier is connected to the first reference voltage, and the output terminal of the sixth amplifier is connected to one end of the first buzzer. The other end of the first buzzer is grounded.

4. The signal monitoring circuit for a solid-state switchgear in a power grid system according to any one of claims 1 to 3, characterized in that, The signal surge detection module includes: The high-frequency signal acquisition unit is used to receive the second and third sampling signals. The second sampling signal is filtered out by the second low-pass filter to remove signals higher than the working frequency, and the second signal is obtained. The third sampling signal and the second signal are differentially amplified by a differential amplifier circuit to obtain a high-frequency signal with a frequency higher than the normal power frequency signal. The integrated energy value acquisition unit is used to convert high-frequency signals into integrated energy values ​​through a full-wave precision rectifier circuit; The alarm unit is used to determine the magnitude of the comprehensive energy value and the second reference voltage. If the comprehensive energy value is greater than the second reference voltage, it is determined that there is a sudden increase in signal and an alarm is triggered. The input terminal of the high-frequency signal acquisition unit is connected to the output terminal of the electrical signal acquisition module, the output terminal of the high-frequency signal acquisition unit is connected to the input terminal of the comprehensive energy value acquisition unit, and the output terminal of the comprehensive energy value acquisition unit is connected to the input terminal of the alarm unit.

5. The power grid system solid-state switchgear signal monitoring circuit according to claim 4, characterized in that, The high-frequency signal acquisition unit includes a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a fourth capacitor, a fifth capacitor, a seventh amplifier, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, an eighth amplifier, and a twentieth resistor. One end of the thirteenth resistor is connected to the output terminal of the electrical signal acquisition module. The other end of the thirteenth resistor is connected to one end of the fourth capacitor and one end of the fourteenth resistor. The other end of the fourteenth resistor is connected to one end of the fifth capacitor and the non-inverting input of the seventh amplifier. The other end of the fifth capacitor is grounded. The inverting input of the seventh amplifier is connected to one end of the fifteenth resistor and one end of the sixteenth resistor. The other end of the fifteenth resistor is grounded. The other end of the sixteenth resistor is connected to the output terminal of the seventh amplifier, the other end of the fourth capacitor, and one end of the seventeenth resistor. The other end of the seventeenth resistor is connected to the inverting input of the eighth amplifier and one end of the twentieth resistor. The non-inverting input of the eighth amplifier is connected to one end of the eighteenth resistor and one end of the nineteenth resistor. The other end of the nineteenth resistor is grounded. The other end of the eighteenth resistor is connected to the output terminal of the electrical signal acquisition module. The output terminal of the eighth amplifier is connected to the other end of the twentieth resistor and the input terminal of the comprehensive energy value acquisition unit.

6. The signal monitoring circuit for a solid-state switchgear in a power grid system according to claim 4, characterized in that, The integrated energy value acquisition unit includes a 21st resistor, a 22nd resistor, a 23rd resistor, a 24th resistor, a 9th amplifier, a 3rd diode, a 4th diode, a 25th resistor, a 6th capacitor, a 10th amplifier, and a 26th resistor. One end of the 21st resistor is connected to one end of the 22nd resistor and the output terminal of the high-frequency signal acquisition unit. The other end of the 21st resistor is connected to one end of the 23rd resistor, the cathode of the 3rd diode, and the inverting input of the 9th amplifier. The non-inverting input of the 9th amplifier is grounded. The output terminal of the 9th amplifier is connected to the cathode of the 4th diode. The anode of the 4th diode is connected to the anode of the 3rd diode, the other end of the 23rd resistor, one end of the 24th resistor, the other end of the 24th resistor, the other end of the 22nd resistor, one end of the 25th resistor, the inverting input of the 10th amplifier, and the non-inverting input of the 10th amplifier is grounded. The output terminal of the 10th amplifier is connected to the other end of the 25th resistor, one end of the 6th capacitor, one end of the 26th resistor, and the input terminal of the alarm unit. The other end of the 6th capacitor and the other end of the 26th resistor are grounded.

7. The signal monitoring circuit for a solid-state switchgear in a power grid system according to claim 4, characterized in that, The alarm unit includes an eleventh amplifier and a second buzzer. The non-inverting input of the eleventh amplifier is connected to the output of the integrated energy value acquisition unit, the inverting input of the eleventh amplifier is connected to the second reference voltage, the output of the eleventh amplifier is connected to one end of the second buzzer, and the other end of the second buzzer is grounded.

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