Generator excitation loop silicon controlled rectifier current abnormity on-line inspection device

Abstract

The utility model discloses a generator excitation loop silicon controlled rectifier current abnormity on-line inspection device, which comprises a first acquisition module, a second acquisition module and an automatic alarm module, and is characterized in that the first acquisition module is correspondingly connected with a first rectifier bridge in a generator excitation loop; the second acquisition module is correspondingly connected with a second rectifier bridge in a generator excitation loop, and the first acquisition module and the second acquisition module are respectively connected with the automatic alarm module. And the automatic alarm module comprises a numerical deviation comparison function block comparison circuit, a time control function block timing circuit, a trigger reset function block circuit and an alarm unit which are connected in sequence. The utility model solves the technical problem that the prior art lacks a device for remotely monitoring the excitation circuit of the generator in real time and cannot directly detect the fault of the excitation system.

Description

Technical Field

[0001] The utility model relates to the technical field of excitation system protection, in particular to an online inspection device for abnormal thyristor current in an excitation circuit of a generator. Background Art

[0002] The excitation thyristor system of a large synchronous generator is composed of two three-phase fully controlled rectifier bridges in parallel. Only when the temperature of the thyristor is high, the wind pressure is low, the pulse control air switch trips, the branch fuse is blown, and the pulse alarm circuit is triggered, the thyristor rectifier cabinet is only equipped with two DC ammeters to measure the total output current of the two rectifier bridges on site. When the output current of the two rectifier bridges differs greatly, there is no remote centralized control monitoring alarm, and it is not easy for the operating personnel to find out in time when the current of a thyristor is abnormal and has no output. Long-term abnormal operation will bring unexpected demagnetization risks to the generator and unplanned shutdown of the unit. Due to the parallel operation of the dual rectifier bridges, the abnormality of the thyristor element of a single rectifier bridge cannot be judged by the waveform detection of the oscilloscope in parallel, and the detection operation is unsafe. The abnormal current of a thyristor is not easy to find online quickly, which is a long-term problem that cannot be solved. It is necessary to shut down the entire excitation thyristor rectifier device for comprehensive inspection and testing.

[0003] The excitation thyristor rectifier cabinet of a large synchronous generator is only equipped with two DC ammeters to measure the total output current of the two rectifier bridges on site. When the output current of the two rectifier bridges differs greatly, there is no remote centralized control alarm, and the abnormal current of a thyristor and no output are not easy to be discovered by the operating personnel. Long-term abnormal operation will bring unexpected demagnetization risks to the generator and unplanned shutdown of the unit. Moreover, the abnormal current of a thyristor is not easy to find online quickly and safely, and the entire excitation thyristor rectifier device needs to be shut down for comprehensive inspection and testing. Utility Model Content

[0004] The utility model provides an abnormal online inspection device for thyristor current of a generator excitation circuit, so as to solve the technical problem that there is a lack of a device for remotely monitoring the generator excitation circuit in real time and the excitation system fault cannot be directly detected.

[0005] In order to solve the above technical problems, the embodiment of the utility model provides an online inspection device for abnormal thyristor current in the excitation circuit of a generator, comprising a first acquisition module, a second acquisition module and an automatic alarm module, wherein:

[0006] The first acquisition module is connected to the first rectifier bridge in the generator excitation circuit, the second acquisition module is connected to the second rectifier bridge in the generator excitation circuit, the first acquisition module and the second acquisition module are connected to the automatic alarm module respectively, and the automatic alarm module includes a comparison circuit, a timing circuit, a trigger reset circuit and an alarm unit connected in sequence.

[0007] The first acquisition module and the second acquisition module respectively collect the output current of the first rectifier bridge and the second rectifier bridge, output them to the automatic alarm module, and pass through the comparison circuit, the timing circuit and the trigger reset circuit in sequence. When the output current is abnormal, the trigger reset circuit outputs a level signal to the alarm unit, thereby alarming the staff and realizing online inspection of abnormalities.

[0008] As a preferred solution, the first acquisition module includes a first current measuring unit, the first current measuring unit includes a first shunt, both ends of the first shunt are respectively connected to the DC positive output end of the first rectifier bridge, and the first shunt is connected in parallel with the DC positive output end of the first rectifier bridge.

[0009] The first shunt is used to detect the output current of the first rectifier bridge. It is connected to the DC positive output terminal of the first rectifier bridge, shortening the distance between the collection point and the first shunt, reducing the measurement line loss, and improving the accuracy of the measurement result.

[0010] As a preferred embodiment, the first acquisition module also includes a first current transmission unit, which includes a first current transmitter, a first input end of the first current transmitter is connected to the first end of the first shunt, a second input end of the first current transmitter is connected to the second end of the first shunt, and an output end of the first current transmitter is connected to the first input end of the automatic alarm module.

[0011] The first current transmitter receives the measurement result output by the first shunt, and converts the measurement result to remotely output the monitoring result, thereby realizing remote monitoring and early warning.

[0012] As a preferred embodiment, the second acquisition module includes a second current measuring unit, the second current measuring unit includes a second shunt, both ends of the second shunt are respectively connected to the DC positive output end of the second rectifier bridge, and the second shunt is connected in parallel with the DC positive output end of the second rectifier bridge.

[0013] The second shunt is used to detect the output current of the second rectifier bridge. It is connected to the DC positive output terminal of the second rectifier bridge, shortening the distance between the collection point and the second shunt, reducing the measurement line loss, and improving the accuracy of the measurement result.

[0014] As a preferred embodiment, the second acquisition module also includes a second current transmission unit, which includes a second current transmitter, a first input end of the second current transmitter is connected to the first end of the second shunt, a second input end of the second current transmitter is connected to the second end of the second shunt, and an output end of the second current transmitter is connected to the second input end of the automatic alarm module.

[0015] The second current transmitter receives the measurement result output by the second shunt, and converts the measurement result to remotely output the monitoring result, thereby realizing remote monitoring and early warning. The automatic alarm module receives the output current of the first rectifier bridge and the second rectifier bridge respectively and compares them, thereby realizing real-time monitoring.

[0016] As a preferred embodiment, the comparison circuit includes an operational amplifier and a resistor component, and the resistor component includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor. The first input terminal of the automatic alarm module is connected to the first input terminal of the comparison circuit through the first resistor, the second input terminal of the automatic alarm module is connected to the second input terminal of the comparison circuit through the second resistor, the non-inverting input terminal of the operational amplifier is connected to the first input terminal of the comparison circuit through the third resistor, the non-inverting input terminal of the operational amplifier is also connected to the output terminal of the operational amplifier through the sixth resistor, the same-inverting input terminal of the operational amplifier is connected to the second input terminal of the automatic alarm module through the fourth resistor, and the same-inverting input terminal of the operational amplifier is also grounded through the fifth resistor.

[0017] The operational amplifier and the resistor component form a subtractor, wherein the first resistor and the second resistor convert the input current signal into a voltage signal, and the subtractor outputs a voltage difference, thereby obtaining a voltage difference corresponding to the output current difference of the two rectifier bridges.

[0018] As a preferred embodiment, the comparison circuit also includes a comparator, the same-direction input terminal of the comparator is connected to the output terminal of the operational amplifier, the opposite-direction input terminal of the comparator is connected to a reference power supply, and the output terminal of the comparator is the output terminal of the comparison circuit.

[0019] The comparator compares the voltage difference output by the subtractor with the reference value output by the reference power supply. When the voltage difference is greater than the reference value, it is determined that a problem occurs, thereby outputting a level signal.

[0020] As a preferred solution, the timing circuit includes a timing chip, the input end of the timing chip is connected to the output end of the comparison circuit, and the control output end of the timing chip is the output end of the timing circuit.

[0021] The timing chip is used to avoid misjudgment of voltage differences caused by current fluctuations.

[0022] As a preferred embodiment, the trigger reset circuit includes a single-chip microcomputer chip, the input end of the single-chip microcomputer chip is connected to the output end of the timing circuit, the output end of the single-chip microcomputer chip is the output end of the trigger reset circuit, and the single-chip microcomputer chip also includes a reset input end.

[0023] As a preferred solution, the alarm unit includes an alarm light sign, and a control end of the alarm light sign is connected to a signal output end of the trigger reset circuit.

[0024] When a rectifier bridge fails, the trigger reset circuit receives the signal and outputs a trigger signal to the alarm unit, which gives an audible and visual alarm through the alarm light sign, allowing the staff to quickly understand the fault in the generator excitation circuit.

[0025] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0026] 1. The utility model measures the output current of the rectifier bridge in the generator excitation circuit in real time through the acquisition module and transmits it to the automatic alarm module, so that the automatic alarm module can make automatic judgments, realize remote monitoring of the generator excitation circuit, reduce the safety risks brought to the generator set by the long-term abnormal operation of the thyristor components in the rectifier bridge, and improve the safety of the excitation system operation;

[0027] 2. The utility model can work simultaneously with the generator excitation circuit, and does not need to shut down when fault detection occurs, thus avoiding the problem of unplanned shutdown of the generator set and improving the working efficiency of the generator set;

[0028] 3. The utility model can provide sound and light alarm reminders through the automatic alarm module, so that the staff can carry out follow-up processing according to the situation, thereby improving the speed of handling faults in the excitation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 : A connection diagram of the acquisition module provided by the embodiment of the utility model;

[0030] Figure 2 : A connection diagram of the automatic alarm module provided by the embodiment of the utility model;

[0031] Figure 3 : A structural schematic diagram of an automatic alarm module provided by an embodiment of the utility model;

[0032] Among them, the figure numbers of the drawings in the specification are as follows: 1. First acquisition module, 1.1. First current measurement unit, 1.2. First current transmission unit, 2. Second acquisition module, 2.1. Second current measurement unit, 2.2. Second current transmission unit, 3. Automatic alarm module, 3.1. Comparison circuit, 3.2. Timing circuit, 3.3. Trigger reset circuit, 3.4. Alarm unit. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0034] Embodiment 1

[0035] The present invention provides an online inspection device for abnormal thyristor current in a generator excitation circuit, comprising a first acquisition module 1, a second acquisition module 2 and an automatic alarm module 3, wherein the first acquisition module 1 and the second acquisition module 2 are respectively used to acquire the output current of the first rectifier bridge and the second rectifier bridge in the generator excitation circuit, and output the acquired data to the automatic alarm module 3, and the automatic alarm module 3 is used to determine whether the generator excitation circuit is faulty.

[0036] Reference Figure 1 As shown, Figure 1 A connection diagram of the acquisition module provided for an embodiment of the utility model, as shown in the figure, the first acquisition module 1 corresponds to the first rectifier bridge in the generator excitation circuit and is connected to the output end of the first rectifier bridge, the second acquisition module 2 corresponds to the second rectifier bridge in the generator excitation circuit and is connected to the output end of the second rectifier bridge.

[0037] The first acquisition module 1 includes a first current measurement unit 1.1, and the first current measurement unit 1.1 includes a first shunt. Both ends of the first shunt are connected to the DC positive output terminal of the first rectifier bridge, which shortens the distance between the acquisition point and the first shunt, reduces the measurement line loss, and improves the accuracy of the measurement result. The first shunt is connected in parallel with the DC positive output terminal of the first rectifier bridge to collect the current output from the DC positive output terminal of the first rectifier bridge. The output signal of the first shunt is a 75mV / 500A millivolt voltage signal.

[0038] The first acquisition module 1 also includes a first current transmitter unit 1.2, which is connected to the first current measurement unit 1.1, and includes a first current transmitter, a first input end of the first current transmitter is connected to a first end of the first shunt, and a second input end of the first current transmitter is connected to a second end of the first shunt, for receiving an output signal of the first shunt.

[0039] The first current transmitter is powered by an input power supply, and its third input terminal is connected to the positive electrode of the input power supply, and the fourth input terminal is connected to the negative electrode of the input power supply. In this embodiment, the input power supply is taken from a switch cabinet equipped with an online inspection device for abnormal thyristor current in the generator excitation circuit, which is a DC 220V control power supply.

[0040] The first current transducer converts the 75mV / 500A millivolt voltage signal output by the first shunt into a 4-20mA signal and outputs it through the output terminal. The output terminal of the first current transducer includes a fifth port and a sixth port, and both output terminals are connected to the first input terminal of the automatic alarm module 3.

[0041] In this embodiment, the base of the first current transmitter is a terminal block bayonet type, which can be directly installed in the vacant position of the switch cabinet terminal block, and has the advantages of convenient installation and low cost. In other embodiments, the structure of the first current transmitter can also be changed according to the actual use scenario.

[0042] The second acquisition module 2 includes a second current measuring unit 2.1, and the second current measuring unit 2.1 includes a second shunt, and both ends of the second shunt are connected to the DC positive output end of the second rectifier bridge, which shortens the distance between the acquisition point and the second shunt, reduces the measurement line loss, and improves the accuracy of the measurement result. The second shunt is connected in parallel with the DC positive output end of the second rectifier bridge to collect the current output from the DC positive output end of the second rectifier bridge. The output signal of the second shunt is a 75mV / 500A millivolt voltage signal.

[0043] The second acquisition module 2 also includes a second current transmitter unit 2.2, which is connected to the second current measurement unit 2.1, and includes a second current transmitter, a first input end of the second current transmitter is connected to the first end of the second shunt, and a second input end of the second current transmitter is connected to the second end of the second shunt, for receiving an output signal of the second shunt.

[0044] The second current transmitter is also powered by the input power supply, the third input terminal of the second current transmitter is connected to the positive electrode of the input power supply, and the fourth input terminal of the second current transmitter is connected to the negative electrode of the input power supply.

[0045] The second current transducer converts the 75mV / 500A millivolt voltage signal output by the second shunt into a 4-20mA signal and outputs it through the output terminal. The output terminal of the second current transducer includes a fifth port and a sixth port, and both output terminals are connected to the second input terminal of the automatic alarm module 3.

[0046] In this embodiment, the second current transmitter base is a terminal block bayonet type, which can be directly installed in the vacant position of the switch cabinet terminal block, and has the advantages of convenient installation and low cost. In other embodiments, the structure of the second current transmitter can also be changed according to the actual use scenario.

[0047] Reference Figure 2 As shown, Figure 2A connection diagram of the automatic alarm module provided for an embodiment of the utility model, as shown in the figure, the automatic alarm module 3 in this embodiment includes a DCS system AI card, which includes multiple input terminals, wherein the first input terminal is connected to the output terminal of the first current transmitter, and the second input terminal is connected to the output terminal of the second current transmitter, respectively receiving the 4-20mA signal output by the current transmitter.

[0048] refer to Figure 3 As shown, Figure 3 A structural diagram of an automatic alarm module provided by an embodiment of the utility model, as shown in the figure, the automatic alarm module 3 includes a comparison circuit 3.1, a timing circuit 3.2, a trigger reset circuit 3.3 and an alarm unit 3.4 connected in sequence.

[0049] The comparison circuit 3.1 converts the received analog signal into a digital signal and compares the signal. The comparison circuit 3.1 includes an operational amplifier and a resistor component, wherein the resistor component includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor.

[0050] The first input terminal of the automatic alarm module 3 is connected to the first input terminal of the comparison circuit 3.1 through the first resistor, and the second input terminal of the automatic alarm module 3 is connected to the second input terminal of the comparison circuit 3.1 through the second resistor. The first resistor and the second resistor convert the current signal inputted from the first input terminal and the second input terminal into a voltage signal respectively for subsequent comparison.

[0051] The non-inverting input terminal of the operational amplifier is connected to the first input terminal of the comparison circuit 3.1 through the third resistor, the non-inverting input terminal of the operational amplifier is also connected to the output terminal of the operational amplifier through the sixth resistor, the non-inverting input terminal of the operational amplifier is connected to the second input terminal of the automatic alarm module through the fourth resistor, and the non-inverting input terminal of the operational amplifier is also grounded through the fifth resistor. The operational amplifier and the resistor component form a subtractor, and when the resistance values ​​of the third resistor and the fourth resistor are the same, the voltage output by the operational amplifier is the difference between the input voltages of the first input terminal and the second input terminal of the comparison circuit 3.1.

[0052] The comparison circuit 3.1 also includes a comparator, the same-direction input terminal of the comparator is connected to the output terminal of the operational amplifier, and receives the voltage difference output by the operational amplifier. The opposite-direction input terminal of the comparator is connected to the reference power supply, and the voltage output by the reference power supply can be determined according to the actual application requirements. In this embodiment, the standard for judging whether the generator excitation circuit has a fault is that the reference error of the output current difference between the first rectifier bridge and the second rectifier bridge is greater than 5%, that is, when the rated current of the rectifier bridge is 500A, the current difference is greater than 25A. According to the fault standard and the resistance values ​​of the first resistor and the second resistor, the corresponding reference power supply can be selected.

[0053] The comparator compares the voltage difference output by the operational amplifier with the voltage of the reference power supply. When the voltage difference is less than the voltage of the reference power supply, it is determined that the excitation circuit of the generator is not faulty, and the comparator outputs a low-level signal. When the voltage difference is greater than the voltage of the reference power supply, it is determined that the excitation circuit of the generator is faulty, and the comparator outputs a high-level signal. The output end of the comparator is the output end of the comparison circuit 3.1, and the output end of the comparison circuit 3.1 is connected to the input end of the timing circuit 3.2. When the comparison circuit 3.1 outputs a low-level signal, the timing circuit 3.2 is not triggered; when the comparison circuit 3.1 outputs a high-level signal, the timing circuit 3.2 starts to work.

[0054] In other embodiments, the comparison circuit 3.1 may also include other different circuit structures to achieve the same function.

[0055] The timing circuit 3.2 includes a timing chip, the input end of which is connected to the output end of the comparison circuit 3.1. It starts timing after receiving a high-level signal until receiving the next low-level signal, and judges the fault condition of the generator excitation circuit according to the timing time. The control output end of the timing chip is the output end of the timing circuit 3.2, and the output end of the timing circuit 3.2 is connected to the input end of the trigger reset circuit 3.3.

[0056] When the timing time of the timing chip does not exceed the preset time, it is determined that the output current of the generator excitation circuit fluctuates, and no alarm is required. When the timing time of the timing chip exceeds the preset time, the thyristor element in the generator excitation circuit fails. At this time, the timing chip outputs a high-level signal from the control output terminal, thereby triggering the reset circuit 3.3 to start working. By connecting the timing circuit 3.2, it is possible to avoid misjudgment of the voltage difference caused by current fluctuations.

[0057] In other embodiments, the timing circuit 3.2 may also include other different circuit structures to achieve the same function.

[0058] The trigger reset circuit 3.3 includes a single-chip microcomputer chip, the input end of the single-chip microcomputer chip is connected to the output end of the timing circuit 3.2, and is used to receive the level signal output by the timing circuit 3.2. The output end of the single-chip microcomputer chip is the output end of the trigger reset circuit 3.3, and the output end of the trigger reset circuit 3.3 is connected to the alarm unit 3.4. The alarm unit 3.4 includes an alarm light sign, and the control end of the alarm light sign is connected to the signal output end of the trigger reset circuit 3.3.

[0059] In other embodiments, the trigger reset circuit 3.3 and the alarm unit 3.4 may also include other different circuit structures to achieve the same function.

[0060] When the single chip microcomputer receives a high level signal, it outputs a trigger signal to the alarm light sign. After receiving the trigger signal, the alarm light sign starts to work and warns the staff through sound and text display, so that the staff can quickly understand the fault of the generator excitation circuit. After receiving the warning information, the staff will handle the fault of the generator excitation circuit according to actual needs.

[0061] In this embodiment, after receiving the warning information, the staff uses a mobile high-current DC clamp meter to measure and record the output DC current of the thyristor components in the rectifier bridge of the generator excitation circuit. The specific measurement location is the main output path of the rectifier bridge between each thyristor component and the adjacent thyristor component. Whether each thyristor component is abnormal is determined based on whether the deviation between the measurement result and the preset current exceeds the preset deviation. If only one thyristor component of the rectifier bridge is detected to be abnormal, the thyristor component can be repaired online or replaced to normal without stopping the operation of the other rectifier bridge. If the thyristor components of both rectifier bridges are detected to be abnormal, the generator excitation circuit needs to be disabled and repaired.

[0062] The single-chip microcomputer chip also includes a reset input terminal. When the fault of the generator excitation circuit is processed and it is confirmed that the generator excitation circuit has returned to normal, the single-chip microcomputer chip is reset through the reset input terminal, so that the automatic alarm module 3 can work normally again.

[0063] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0064] 1. The utility model measures the output current of the rectifier bridge in the generator excitation circuit in real time through the acquisition module and transmits it to the automatic alarm module, so that the automatic alarm module can make automatic judgments, realize remote monitoring of the generator excitation circuit, reduce the safety risks brought to the generator set by the long-term abnormal operation of the thyristor components in the rectifier bridge, and improve the safety of the excitation system operation;

[0065] 2. The utility model can work simultaneously with the generator excitation circuit, and does not need to shut down when fault detection occurs, thus avoiding the problem of unplanned shutdown of the generator set and improving the working efficiency of the generator set;

[0066] 3. The utility model can provide sound and light alarm reminders through the automatic alarm module, so that the staff can carry out follow-up processing according to the situation, thereby improving the speed of handling faults in the excitation system.

[0067] The above specific embodiments further describe the purpose, technical solutions and beneficial effects of the utility model in detail. It should be understood that the above are only specific embodiments of the utility model and are not intended to limit the protection scope of the utility model. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. An online inspection device for abnormal thyristor current in a generator excitation circuit, characterized in that: It includes a first acquisition module, a second acquisition module and an automatic alarm module, wherein: The first acquisition module is connected to the first rectifier bridge in the generator excitation circuit, the second acquisition module is connected to the second rectifier bridge in the generator excitation circuit, the first acquisition module and the second acquisition module are connected to the automatic alarm module respectively, and the automatic alarm module includes a comparison circuit, a timing circuit, a trigger reset circuit and an alarm unit connected in sequence.

2. The device for detecting abnormal thyristor current in the excitation circuit of a generator according to claim 1, characterized in that: The first acquisition module includes a first current measuring unit, the first current measuring unit includes a first shunt, two ends of the first shunt are respectively connected to the DC positive output end of the first rectifier bridge, and the first shunt is connected in parallel with the DC positive output end of the first rectifier bridge.

3. The device for detecting abnormal thyristor current in the excitation circuit of a generator according to claim 2, characterized in that: The first acquisition module also includes a first current transmitter unit, which includes a first current transmitter, a first input end of the first current transmitter is connected to a first end of the first shunt, a second input end of the first current transmitter is connected to a second end of the first shunt, and an output end of the first current transmitter is connected to a first input end of the automatic alarm module.

4. The device for detecting abnormal thyristor current in the excitation circuit of a generator according to claim 1, characterized in that: The second acquisition module includes a second current measuring unit, the second current measuring unit includes a second shunt, both ends of the second shunt are respectively connected to the DC positive output end of the second rectifier bridge, and the second shunt is connected in parallel with the DC positive output end of the second rectifier bridge.

5. The device for online inspection of abnormal thyristor current in the excitation circuit of a generator according to claim 4, characterized in that: The second acquisition module also includes a second current transmitter unit, which includes a second current transmitter, a first input end of the second current transmitter is connected to the first end of the second shunt, a second input end of the second current transmitter is connected to the second end of the second shunt, and an output end of the second current transmitter is connected to the second input end of the automatic alarm module.

6. The device for detecting abnormal thyristor current in the excitation circuit of a generator according to claim 1, characterized in that: The comparison circuit includes an operational amplifier and a resistor component, and the resistor component includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor. The first input terminal of the automatic alarm module is connected to the first input terminal of the comparison circuit through the first resistor, and the second input terminal of the automatic alarm module is connected to the second input terminal of the comparison circuit through the second resistor. The non-inverting input terminal of the operational amplifier is connected to the first input terminal of the comparison circuit through the third resistor, and the non-inverting input terminal of the operational amplifier is also connected to the output terminal of the operational amplifier through the sixth resistor. The same-inverting input terminal of the operational amplifier is connected to the second input terminal of the automatic alarm module through the fourth resistor, and the same-inverting input terminal of the operational amplifier is also grounded through the fifth resistor.

7. The device for online inspection of abnormal thyristor current in the excitation circuit of a generator according to claim 6, characterized in that: The comparison circuit also includes a comparator, the same-direction input terminal of the comparator is connected to the output terminal of the operational amplifier, the opposite-direction input terminal of the comparator is connected to a reference power supply, and the output terminal of the comparator is the output terminal of the comparison circuit.

8. The device for online inspection of abnormal thyristor current in the excitation circuit of a generator according to claim 1, characterized in that: The timing circuit comprises a timing chip, an input end of the timing chip is connected to an output end of the comparison circuit, and a control output end of the timing chip is an output end of the timing circuit.

9. The device for online inspection of abnormal thyristor current in the excitation circuit of a generator according to claim 1, characterized in that: The trigger reset circuit includes a single-chip microcomputer chip, the input end of the single-chip microcomputer chip is connected to the output end of the timing circuit, the output end of the single-chip microcomputer chip is the output end of the trigger reset circuit, and the single-chip microcomputer chip also includes a reset input end.

10. The device for online inspection of abnormal thyristor current in the excitation circuit of a generator according to claim 1, characterized in that: The alarm unit comprises an alarm light sign, and a control end of the alarm light sign is connected to an output end of the trigger reset circuit.

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