Circuit and device for judging slow fusing of fuse
By constructing a slow-blow fuse detection circuit, the slow-blow of the primary circuit fuse of the voltage transformer can be accurately detected, solving the problem that the excitation regulator cannot detect it in time, ensuring stable generator operation and reducing the risk of unit tripping.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-17
- Publication Date
- 2026-03-20
AI Technical Summary
When a slow-speed fuse blows in the primary circuit of the generator terminal voltage transformer, the excitation regulator cannot detect it in time, leading to fluctuations in terminal voltage, active power, and reactive power, and even causing the unit to trip, threatening the safe and stable operation of the generator.
A slow-blow fuse detection circuit is constructed. It receives two current transformer signals through a signal processing unit, calculates the absolute value of the voltage difference, outputs a warning signal using a comparison unit, and outputs a slow-blow reminder signal when it receives a normal operation prompt signal from the excitation regulator. Combined with a delay unit, it promptly informs the excitation regulator and the nuclear power plant's DCS system.
It enables the excitation regulator to accurately detect slow fuse blowing, switch channels in a timely manner, avoid false strong excitation faults in the unit, ensure stable unit operation, and reduce operational risks.
Smart Images
Figure CN224019963U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to generator excitation regulator control technical field especially relates to a fuse slow speed fusing judgment circuit and device. BACKGROUND
[0002] After the unit carries out the grid, if the generator terminal voltage mutual inductor (abbreviation PT) primary circuit fuse causes the slow speed fusing accident and causes the generator terminal voltage to drop and has not reached the criterion of PT broken line, the excitation regulator cannot normally detect, so will not carry out the channel switching, cannot take the measures, will lead to the generator terminal voltage, active power, reactive power to appear the large fluctuation, even causes the unit to trip, seriously threatens the generator safety, stable operation. SUMMARY
[0003] The utility model solves the technical problem, provides a kind of fuse slow speed fusing judgment circuit and device.
[0004] The utility model solves the technical problem and adopts the technical scheme that a kind of fuse slow speed fusing judgment circuit is structured, comprising:
[0005] signal processing unit for accessing the two-way mutual inductor sensing signals input to excitation regulator and processing the two-way mutual inductor sensing signals to form first voltage signal and second voltage signal;
[0006] difference unit connected with the signal processing unit, for calculating the voltage difference absolute value between the first voltage signal and the second voltage signal;
[0007] comparison unit connected with the difference unit, for outputting early warning signal when the voltage difference absolute value is greater than set voltage;
[0008] and gate unit connected with the comparison unit, for outputting slow fusing reminding signal when receiving the early warning signal and normal operation prompt signal from the excitation regulator output simultaneously;And
[0009] delay unit connected with the and gate unit, for delaying the slow fusing reminding signal and inputting the slow fusing reminding signal after delay to the excitation regulator and nuclear power plant DCS system.
[0010] Preferably, the signal processing unit includes:
[0011] a first isolation and amplification unit connected with the difference unit, for accessing one of the transformer sensing signals input to the excitation regulator and outputting the first voltage signal; and
[0012] a second isolation and amplification unit connected with the difference unit, for accessing the other transformer sensing signal input to the excitation regulator and outputting the second voltage signal.
[0013] Preferably, the first isolation and amplification unit comprises a first transformer T1, a first resistor R1 and a first inverting amplification unit; a primary of the first transformer T1 is connected to one end of the first resistor R1, the other end of the first resistor R1 is used for connecting to a primary circuit of one of the voltage transformers of the excitation regulator, a secondary of the first transformer T1 is connected to an inverting input of the first inverting amplification unit, and an output of the first inverting amplification unit is connected to the difference unit.
[0014] The second isolation and amplification unit comprises a second transformer T2, a second resistor R2 and a second inverting amplification unit; a primary of the second transformer T2 is connected to one end of the second resistor R2, the other end of the second resistor R2 is used for connecting to a primary circuit of the other voltage transformer of the excitation regulator, a secondary of the second transformer T2 is connected to an inverting input of the second inverting amplification unit, and an output of the second inverting amplification unit is connected to the difference unit.
[0015] Preferably, the difference unit comprises a subtractor U3 and an absolute value unit D1; a first input and a second input of the subtractor U3 are connected to outputs of the first inverting amplification unit and the second inverting amplification unit respectively, an output of the subtractor U3 is connected to an AC input of the absolute value unit D1, and a DC input of the absolute value unit D1 is connected to the comparison unit.
[0016] Preferably, the comparison unit comprises a comparator U4; a first input of the comparator U4 is connected to the difference unit, a second input is used for accessing the set voltage, and an output is connected to the AND gate unit.
[0017] Preferably, the AND gate unit comprises a first relay XR1, a first switch K1, a second switch K2 and a third switch K3; an excitation coil of the first relay XR1 is connected to the comparison unit, a normally open contact circuit of the first relay XR1 is connected to the delay unit through the first switch K1, the second switch K2 and the third switch K3, and the first switch K1, the second switch K2 and the third switch K3 are also used for connecting the excitation regulator to be closed at the same time when the normal operation prompt signal is received.
[0018] Preferably, the first switch K1 comprises a second relay, the second switch K2 comprises a third relay, and the third switch K3 comprises a fourth relay.
[0019] The excitation coils of the second relay, the third relay and the fourth relay are used for connecting the excitation regulator, and the normally open contact loop of the first relay XR1 is connected to the delay unit through the contact loops of the second relay, the third relay and the fourth relay.
[0020] Preferably, the delay unit comprises a delay relay XT1 and a fifth relay XT2, the excitation coil of the delay relay XT1 is connected with the AND gate unit, the normally open contact loop of the delay relay XT1 is connected with the excitation coil of the fifth relay XT2, the first normally open contact loop of the fifth relay XT2 is used for connecting the excitation regulator, and the second normally open contact loop of the fifth relay XT2 is used for connecting the nuclear power plant DCS system.
[0021] Preferably, the delay time range of the delay relay XT1 is 0.3-0.7 seconds.
[0022] The utility model also provides a fuse slow speed fusing judgment device, including above described fuse slow speed fusing judgment circuit.
[0023] The utility model has the advantages that a fuse slow speed fusing judgment circuit is provided, which can help the excitation regulator to accurately determine whether the fuse on the primary loop of the two voltage transformers connected with the excitation regulator has a slow speed fusing accident, and timely informs the excitation regulator, so that the excitation regulator can timely switch the channel, and the nuclear power plant DCS system is also timely informed to alert the staff to handle the exception as soon as possible, avoid the fault of misstrong excitation of the unit caused by the slow speed fusing accident, and thus minimize the risk of stable operation of the unit and provide the stability of the unit. BRIEF DESCRIPTION OF DRAWINGS
[0024] The utility model will be further described in connection with the drawings and examples, and the drawings are as follows:
[0025] Figure 1 It is the circuit structure block diagram of the fuse slow speed fusing judgment circuit in some embodiments of the utility model;
[0026] Figure 2 It is the circuit principle diagram of the fuse slow speed fusing judgment circuit in some embodiments of the utility model. DETAILED DESCRIPTION
[0027] In order to have more clear understanding on the technical features, purposes and effects of the utility model, the specific implementation mode of the utility model will be described in detail by referring to the drawings.
[0028] In the following description, it needs to be understood that the directions or positional relationships indicated by "front", "back", "upper", "lower", "left", "right", "vertical", "horizontal", "vertical", "horizontal", "top", "bottom", "inner", "outer", "head", "tail" and the like are based on the directions or positional relationships shown in the drawings, constructed and operated in a particular direction, only for the convenience of describing the technical solutions, and not indicating that the indicated device or element must have a particular direction, therefore cannot be understood as a limitation to the present application.
[0029] Figure 1 The circuit structure diagram of the fuse slow melting judgment circuit in some embodiments of the present application is shown in the figure. The fuse slow melting judgment circuit can help the excitation regulator in the nuclear power plant to judge whether the fuse on the primary circuit of the two voltage transformers in the channel connected with the excitation regulator appears a slow melting accident, and send the slow melting reminding signal to the excitation regulator. As shown in the figure, the fuse slow melting judgment circuit can include a signal processing unit 1, a difference unit 2, a comparison unit 3, an AND gate unit 4 and a delay unit 5. Figure 1
[0030] The signal processing unit 1 is used to access the two transformer sensing signals input to the excitation regulator, and process the two transformer sensing signals to form first and second voltage signals. Wherein, the processing work of the two transformer sensing signals can include but not limited to signal isolation, signal amplification and signal filtering, etc.
[0031] In some embodiments, as shown in the figure, the signal processing unit 1 can include a first isolation and amplification unit 11 and a second isolation and amplification unit 12. Figure 2
[0032] As shown in the figure, the first isolation and amplification unit 11 is connected with the difference unit 2, and the first isolation and amplification unit 11 is used to access one of the transformer sensing signals UAB input to the excitation regulator and output the first voltage signal. Figure 2
[0033] Specifically, as shown in the figure, the first isolation and amplification unit 11 can include a first isolation unit 111 and a first amplification unit 112. Figure 2 As shown, the first isolation and amplification unit 11 can include a first transformer T1, a first resistor R1 and a first inverting amplification unit 111. One end of the primary of the first transformer T1 is connected to one end of the first resistor R1, the other end of the first resistor R1 is used to be connected to one end of a primary circuit of one of the voltage transformers of the excitation regulator, the other end of the primary of the first transformer T1 is connected to the other end of the primary circuit of the voltage transformer (i.e. the voltage transformer outputting the mutual inductor sensing signal UAB), the secondary of the first transformer T1 is connected to the inverting input of the first inverting amplification unit 111, and the output of the first inverting amplification unit 111 is connected to the difference unit 2. It can be understood that the first resistor R1 functions as a voltage divider, which can reduce the voltage amplitude of the mutual inductor sensing signal UAB input to the first transformer T1. The first transformer T1 functions as signal isolation, which improves the signal anti-interference capability, and the secondary of the first transformer T1 outputs the isolated mutual inductor sensing signal UAB to the first inverting amplification unit 111. Since the voltage amplitude of the isolated mutual inductor sensing signal UAB is low, it is not conducive to accurate detection and related operation of the subsequent circuit, so the voltage amplitude of the received isolated mutual inductor sensing signal UAB needs to be amplified by the first inverting amplification unit 111, so as to improve the reliability of the excitation regulator.
[0034] More specifically, as shown in Figure 2 The first inverting amplification unit 111 can include a first inverting amplifier U1 and a third resistor R3, the negative input of the first inverting amplifier U1 is connected to one end of the secondary of the first transformer T1, the positive input of the first inverting amplifier U1 and the other end of the secondary of the first transformer T1 are grounded (not shown), the negative input of the first inverting amplifier U1 is also connected to the output of the first inverting amplifier U1 through the third resistor R3, and the output of the first inverting amplifier U1 is connected to the difference unit 2 to input the first voltage signal thereto. Among them, the third resistor R3 is a feedback loop, which can control the amplification factor of the first inverting amplification unit 111 by adjusting its resistance value. Of course, the first inverting amplification unit 111 can also use existing inverting amplification circuits or modules instead.
[0035] As shown in Figure 2 The second isolation and amplification unit 12 is connected with the difference unit 2, and the second isolation and amplification unit 12 is used to input another mutual inductor sensing signal Uab input to the excitation regulator and output a second voltage signal.
[0036] Specifically, as shown in Figure 2As shown, the second isolation and amplification unit 12 can include a second transformer T2, a second resistor R2 and a second inverting amplification unit 121. One end of the primary of the second transformer T2 is connected to one end of the second resistor R2, the other end of the second resistor R2 is used to be connected to one end of the primary of the other voltage transformer of the excitation regulator, the other end of the primary of the second transformer T2 is connected to the other end of the primary of the voltage transformer (i.e. the voltage transformer outputting the mutual inductor sensing signal Uab), the secondary of the second transformer T2 is connected to the inverting input of the second inverting amplification unit 121, and the output of the second inverting amplification unit 121 is connected to the difference unit 2. It should be noted that the structure and working principle of the second isolation and amplification unit 12 and the first isolation and amplification unit 11 are the same, please refer to each other, and will not be repeated here.
[0037] More specifically, as shown, Figure 2 The second inverting amplification unit 121 can include a second inverting amplifier U2 and a fourth resistor R4, the negative input of the second inverting amplifier U2 is connected to one end of the secondary of the second transformer T2, the positive input of the second inverting amplifier U2 and the other end of the secondary of the second transformer T2 are grounded (not shown), the negative input of the second inverting amplifier U2 is also connected to the output of the second inverting amplifier U2 through the fourth resistor R4, and the output of the second inverting amplifier U2 is connected to the difference unit 2 to input the second voltage signal thereto. Of course, the second inverting amplification unit 121 can also use existing inverting amplification circuits or modules instead.
[0038] As shown, Figure 1 The difference unit 2 is connected to the signal processing unit 1, and the difference unit 2 is used to calculate the absolute value of the voltage difference between the first voltage signal and the second voltage signal.
[0039] In some embodiments, as shown, Figure 2 The difference unit 2 can include a subtracter U3 and an absolute value unit D1, the first input and the second input of the subtracter U3 are respectively connected to the output of the first inverting amplification unit 111 and the output of the second inverting amplification unit 121, the output of the subtracter U3 is connected to the AC input of the absolute value unit D1, and the DC input of the absolute value unit D1 is connected to the comparison unit 3. In this embodiment, the subtracter U3 can be an existing subtracter or a subtraction circuit, as long as it can calculate the voltage difference between the first voltage signal and the second voltage signal. Since the voltage difference can be a positive voltage or a negative voltage, it is not conducive to compare the comparison unit 3 directly with the set voltage, so the absolute value unit D1 can convert the voltage difference into a positive absolute value to form the absolute value of the voltage difference. Specifically, the absolute value unit D1 can be a rectifier bridge or an existing voltage absolute value circuit, as long as it can convert the voltage difference into an absolute value. The set voltage can be set according to the requirements. In addition, the set voltage can be provided by a reference source or other voltage stabilizing circuit, which is not limited here.
[0040] As shown in Figure 1 , the comparison unit 3 is connected with the difference unit 2, and the comparison unit 3 is used to output a pre-warning signal when the absolute value of the voltage difference is greater than the set voltage.
[0041] In some embodiments, as shown in Figure 2 , the comparison unit 3 can include a comparator U4. The first input terminal of the comparator U4 is connected with the difference unit 2, the second input terminal of the comparator U4 is used to access the set voltage, and the output terminal of the comparator U4 is connected with the AND gate unit 4. In the present embodiment, the comparator U4 can be an existing voltage comparator, and of course an existing voltage comparison circuit can be used instead. The comparator U4 can compare the absolute value of the voltage difference with the set voltage, and output a corresponding level, for example, output a high level as a pre-warning signal when the absolute value of the voltage difference is greater than the set voltage.
[0042] As shown in Figure 1 , the AND gate unit 4 is connected with the comparison unit 3, and the AND gate unit 4 is used to output a slow-fuse reminder signal when the pre-warning signal and the normal operation prompt signal from the excitation regulator output are received at the same time. It should be noted that since the generator is in an abnormal operation state (such as engineering test, overhaul, etc.), there may be a voltage difference between the two voltage transformers connected to the excitation regulator. In order to avoid misoperation of the excitation regulator, it is necessary to ensure that the generator is in a normal operation state before the pre-warning signal is sent to the next stage and takes effect.
[0043] In some embodiments, as shown in Figure 2 , the AND gate unit 4 can include a first relay XR1, a first switch K1, a second switch K2, and a third switch K3. The excitation coil of the first relay XR1 is connected with the comparison unit 3, and the normally open contact loop of the first relay XR1 is connected to the delay unit 5 through the first switch K1, the second switch K2, and the third switch K3. The first switch K1, the second switch K2, and the third switch K3 are also used to connect the excitation regulator to be closed at the same time when the normal operation prompt signal is received.
[0044] Specifically, the first switch K1 can include a second relay. The excitation coil of the second relay is used to connect the excitation prompt signal end of the excitation regulator (not shown). It should be noted that in the prior art, when the generator is excited, the excitation regulator outputs an excitation prompt signal to the nuclear power plant DCS system (i.e. the nuclear power plant distributed control system), which informs the nuclear power plant DCS system that the generator has been excited, i.e. the excitation prompt signal can indicate that the generator is in normal operation. When the generator is excited, the contact loop of the second relay is closed. In addition, if the excitation prompt signal indicates that the generator is excited at a low level, then the second relay can use an existing normally closed relay. Conversely, if the excitation prompt signal indicates that the generator is excited at a high level, then the second relay can use an existing normally open relay.
[0045] Correspondingly, the second switch K2 can include a third relay. The magnet coil of the third relay is used to connect the abnormal prompt signal end (not shown) of the field regulator. It should be noted that, in the prior art, in order to ensure whether the other channels of the field regulator are abnormal, and whether the generator is running normally, the field regulator needs to output an abnormal prompt signal end to the nuclear power plant DCS system, so as to inform the nuclear power plant DCS system whether the field regulator is abnormal, and when the other channels of the field regulator are not abnormal, the contact loop of the third relay is closed. In addition, if the abnormal prompt signal indicates that the other channels are not abnormal at a low level, the third relay can use the existing normally closed relay, and vice versa, if the abnormal prompt signal indicates that the other channels are not abnormal at a high level, the third relay can use the existing normally open relay.
[0046] Correspondingly, the third switch K3 can include a fourth relay. The magnet coil of the fourth relay is used to connect the field switch state signal end (not shown) of the field regulator. It should be noted that, in the prior art, the field regulator will feed back the field switch state signal to the nuclear power plant DCS system, and when the generator is running normally, the field switch must be in the closed state, and when the field switch is closed, the contact loop of the fourth relay is closed. In addition, if the field switch state signal indicates that the field switch is closed at a low level, the fourth relay can use the existing normally closed relay, and vice versa, if the field switch state signal indicates that the field switch is closed at a high level, the fourth relay can use the existing normally open relay.
[0047] As shown in Figure 1 The normally open contact loop of the first relay XR1 is connected to the delay unit 5 through the contact loop of the second relay, the contact loop of the third relay and the contact loop of the fourth relay.
[0048] In this embodiment, the working principle of the AND gate unit 4 is as follows: when the first relay XR1 receives a pre-warning signal (high level), the first relay XR1 is excited; and when the generator is running normally, the contact loops of the second relay, the third relay and the fourth relay are all closed, that is, the AND gate unit 4 outputs a closed dry contact signal as a slow melting reminder signal.
[0049] As shown in Figure 1As shown, the delay unit 5 is connected with the AND gate unit 4, and the delay unit 5 is used for delaying the slow melting reminding signal and inputting the delayed slow melting reminding signal to the excitation regulator and the nuclear power plant DCS system. It should be noted that when the excitation regulator learns that the fuse of the voltage transformer of the current channel melts slowly, the excitation regulator will switch the channel to other channels and inform the nuclear power plant DCS system of the slow melting accident, so that the nuclear power plant DCS system can prompt the staff to handle the fault in time through the existing prompt device (such as a monitoring screen). In addition, since the two-way transformer sensing signals may have a large instantaneous pressure difference due to interference, which may be misjudged as a slow melting accident, and the delay is to ensure that the duration of the slow melting reminding signal is not less than the delay time, and the slow melting accident is determined, and it can be understood that in this way, the slow melting reminding signal can be prevented from being misissued to the excitation regulator and the nuclear power plant DCS system.
[0050] In some embodiments, as shown in Figure 2 As shown, the delay unit 5 can include a delay relay XT1 and a fifth relay XT2, one end of the excitation coil of the delay relay XT1 is grounded through the AND gate unit 4, the other end of the excitation coil of the delay relay XT1 is connected to a power supply, the normally open contact loop of the delay relay XT1 is connected to the excitation coil of the fifth relay XT2, the first normally open contact loop of the fifth relay XT2 is used for connecting the excitation regulator, and the second normally open contact loop of the fifth relay XT2 is used for connecting the nuclear power plant DCS system. When the AND gate unit 4 outputs the slow melting reminding signal and the duration is not less than the delay time, the excitation coil of the delay relay XT1 is excited after a delay time, so as to control the excitation of the fifth relay XT2, and then output the slow melting reminding signal to the excitation regulator and the nuclear power plant DCS system.
[0051] Optionally, the delay time of the delay relay XT1 ranges from 0.3 seconds to 0.7 seconds, and the delay time of the delay relay XT1 is preferably 0.5 seconds.
[0052] It can be understood that the slow melting fuse judgment device can help the excitation regulator to accurately determine whether the fuse of the primary circuit of the two-way voltage transformer connected with the excitation regulator melts slowly, and timely informs the excitation regulator, so that the excitation regulator can switch the channel in time, and also informs the nuclear power plant DCS system in time, so as to alert the staff to handle the abnormality as soon as possible, avoid the fault of misstrong excitation of the unit caused by the slow melting accident, and thus minimize the risk of stable operation of the unit and provide the stability of the unit.
[0053] The utility model also provides a fuse slow melting judgment device, including the fuse slow melting judgment circuit provided by the utility model embodiment.
[0054] It can be understood that the above embodiment only expresses the preferred embodiment of the utility model, the description is more specific and detailed, but it can not be understood as the limitation of the utility model patent scope; it should be pointed out that for ordinary skilled person in the art, the above technical features can be freely combined without departing from the concept of the utility model, and a number of deformations and improvements can be made, which belong to the protection scope of the utility model; therefore, any equivalent transformation and modification within the scope of the utility model patent claim should belong to the scope of the utility model patent claim.
Claims
1. A fuse slow-fuse detection circuit, characterized in that, include: A signal processing unit (1) is used to receive two current transformer sensing signals input to the excitation regulator and process the two current transformer sensing signals to form a first voltage signal and a second voltage signal. A difference calculation unit (2) connected to the signal processing unit (1) for calculating the absolute value of the voltage difference between the first voltage signal and the second voltage signal; A comparison unit (3) connected to the difference unit (2) and used to output a warning signal when the absolute value of the pressure difference is greater than the set voltage; An AND gate unit (4) connected to the comparison unit (3) for outputting a slow-blow reminder signal when both the warning signal and the normal operation reminder signal output from the excitation regulator are received simultaneously; and A delay unit (5) connected to the AND gate unit (4) is used to delay the slow-blow reminder signal and input the delayed slow-blow reminder signal to the excitation regulator and the nuclear power plant DCS system.
2. The fuse slow-fuse detection circuit according to claim 1, characterized in that, The signal processing unit (1) includes: A first isolation and amplification unit (11) connected to the difference unit (2) and used to receive one of the current transformer sensing signals input to the excitation regulator and output the first voltage signal; and A second isolation and amplification unit (12) is connected to the difference unit (2) and is used to receive another current transformer sensing signal input to the excitation regulator and output the second voltage signal.
3. The fuse slow-fuse detection circuit according to claim 2, characterized in that, The first isolation and amplification unit (11) includes a first transformer T1, a first resistor R1 and a first inverting amplification unit (111); the primary winding of the first transformer T1 is connected to one end of the first resistor R1, the other end of the first resistor R1 is used to connect to the primary circuit of one of the voltage transformers of the excitation regulator, the secondary winding of the first transformer T1 is connected to the inverting input terminal of the first inverting amplification unit (111), and the output terminal of the first inverting amplification unit (111) is connected to the difference unit (2); The second isolation and amplification unit (12) includes a second transformer T2, a second resistor R2, and a second inverting amplification unit (121); the primary winding of the second transformer T2 is connected to one end of the second resistor R2, and the other end of the second resistor R2 is used to connect to the primary circuit of another voltage transformer of the excitation regulator; the secondary winding of the second transformer T2 is connected to the inverting input terminal of the second inverting amplification unit (121), and the output terminal of the second inverting amplification unit (121) is connected to the difference unit (2).
4. The fuse slow-fuse detection circuit according to claim 3, characterized in that, The difference unit (2) includes a subtractor U3 and an absolute value unit D1. The first input terminal and the second input terminal of the subtractor U3 are respectively connected to the output terminal of the first inverting amplifier unit (111) and the output terminal of the second inverting amplifier unit (121). The output terminal of the subtractor U3 is connected to the AC input terminal of the absolute value unit D1, and the DC input terminal of the absolute value unit D1 is connected to the comparison unit (3).
5. The fuse slow-fuse detection circuit according to claim 1, characterized in that, The comparison unit (3) includes a comparator U4, the first input terminal of which is connected to the difference unit (2), the second input terminal is used to connect to the set voltage, and the output terminal is connected to the AND gate unit (4).
6. The fuse slow-fuse detection circuit according to claim 1, characterized in that, The AND gate unit (4) includes a first relay XR1, a first switch K1, a second switch K2, and a third switch K3. The excitation coil of the first relay XR1 is connected to the comparison unit (3). The normally open contact circuit of the first relay XR1 is connected to the delay unit (5) via the first switch K1, the second switch K2, and the third switch K3. The first switch K1, the second switch K2, and the third switch K3 are also used to connect the excitation regulator to close simultaneously when the normal operation prompt signal is received.
7. The fuse slow-fuse detection circuit according to claim 6, characterized in that, The first switch K1 includes a second relay, the second switch K2 includes a third relay, and the third switch K3 includes a fourth relay; The excitation coils of the second relay, the third relay, and the fourth relay are respectively used to connect to the excitation regulator, and the normally open contact circuit of the first relay XR1 is connected to the delay unit (5) through the contact circuits of the second relay, the third relay, and the fourth relay.
8. The fuse slow-fuse detection circuit according to any one of claims 1 to 7, characterized in that, The delay unit (5) includes a delay relay XT1 and a fifth relay XT2. The excitation coil of the delay relay XT1 is connected to the AND gate unit (4). The normally open contact circuit of the delay relay XT1 is connected to the excitation coil of the fifth relay XT2. The first normally open contact circuit of the fifth relay XT2 is used to connect to the excitation regulator. The second normally open contact circuit of the fifth relay XT2 is used to connect to the nuclear power plant DCS system.
9. The fuse slow-fuse detection circuit according to claim 8, characterized in that, The delay time range of the delay relay XT1 is 0.3 seconds to 0.7 seconds.
10. A device for determining slow-speed fuse failure, characterized in that, Includes the fuse slow-blow detection circuit as described in any one of claims 1 to 9.