A Fault Detection and Grounding Protection System for Large Capacity Pulse Power Devices

Abstract

The present invention discloses a fault detection and grounding protection system for a large-capacity pulse power device in the field of pulse power technology and application, comprising a preliminary detection module, a secondary verification module and a protection module; the preliminary detection module is used to determine the position of a faulty capacitor by the position where a reverse current appears, and output a first fault signal, and according to the first fault information, limit the current injected into the faulty capacitor; the secondary verification module is used to detect all capacitors, obtain fault characteristic signals of all capacitors, and output a second fault signal according to the distribution of the numerical values ​​of the fault characteristic information; the protection module is used to determine the position of the faulty capacitor according to the first fault signal and the second fault signal, and perform grounding protection on non-faulty capacitors, and is used to solve the problem in the prior art that when a Rogowski coil is used for fault detection, the electromagnetic field generated by the capacitor fault current affects the Rogowski coil detection data, resulting in low accuracy.

Description

Technical Field

[0001] The invention belongs to the field of pulse power technology and application, and in particular is a fault detection and grounding protection system for a large-capacity pulse power device. Background Art

[0002] A large-capacity pulse power device, or high-power pulse power supply, is a power supply device that can generate high-energy, short-duration pulse current. Its working principle is mainly based on the principle of electromagnetic induction and the application of semiconductor switching devices. It converts electrical energy into pulse energy through energy storage elements (such as capacitors, inductors, etc.), and then consumes energy through loads (such as resistors, inductors, capacitors, etc.). After the switch of the pulse power supply is turned on, the energy storage element begins to charge, and when the switch is turned off, the energy storage element begins to discharge, generating high-energy, short-duration pulse current.

[0003] In large-capacity pulse power devices, short-circuit failure of capacitors is a more serious fault. The fault current generated by the faulty capacitor may cause damage to the pulse power device, greatly shortening the life of the pulse power device. At the same time, it may also break down the capacitor and cause damage to surrounding personnel.

[0004] In the prior art, Rogowski coils are often used to detect faults in large-capacity pulse power devices. The working principle is to put a flexible annular coil on a conductor. When a constantly changing current passes through the conductor, a changing magnetic field will be induced around it. The Rogowski coil is in a constantly changing magnetic field, which will generate an induced electromotive force, that is, a changing current will be generated inside the coil. By matching an integrator, the waveform of the measured current can be obtained. Although this method is easy to operate and is not easy to affect the circuit under test, since this method requires the Rogowski coil to be put on the appropriate position of the circuit under test, when the short-circuit circuit does not pass through the Rogowski coil, this method is difficult to detect the short-circuit circuit, and because the fault current generated by the capacitor after the fault will generate a huge electromagnetic field, this electromagnetic field may affect the accuracy of the method.

[0005] At the same time, in the prior art, a damping protection capacitor is often connected in series in the circuit. The damping protection capacitor suppresses the electromagnetic pulse caused by the capacitor failure, consumes energy, protects the device, and reduces the risk of fault current breaking through the capacitor. However, during normal use of the device, the current still needs to pass through the damping protection capacitor, and the damping protection capacitor still consumes the energy of the current, thereby increasing the energy consumption of the pulse power device. Summary of the invention

[0006] The purpose of the present invention is to provide a fault detection and grounding protection system for a large-capacity pulse power device, which is used to solve the problem in the prior art that the electromagnetic field generated by the capacitor fault current affects the accuracy of the Rogowski coil detection data due to the use of Rogowski coil for fault detection.

[0007] In order to achieve the above-mentioned object, the technical solution of the present invention is as follows: a fault detection and grounding protection system for a large-capacity pulse power device, comprising a preliminary detection module, a secondary verification module and a protection module;

[0008] The preliminary detection module is used to determine the position of the faulty capacitor by the position where the reverse current appears, and output a first fault signal, and limit the current injected into the faulty capacitor according to the first fault information;

[0009] The secondary verification module is used to detect all capacitors, obtain fault characteristic signals of all capacitors, and output a second fault signal according to the distribution of the numerical values ​​of the fault characteristic information;

[0010] The protection module is used to determine the position of the faulty capacitor according to the first fault signal and the second fault signal, and cut off the current injected into the faulty capacitor, while performing grounding protection on the non-faulty capacitor.

[0011] Further, the second verification module includes a first acquisition module and a data processing module;

[0012] The first acquisition module is used to collect the operating status signals of all capacitors;

[0013] The data processing module is used to perform wavelet transform on the operation status signal to obtain the corresponding wavelet domain, obtain the fault characteristic signal according to the fault characteristic parameters in the wavelet domain, and output the second fault signal according to the distribution of the numerical value of the fault characteristic information.

[0014] Further, the preliminary detection module includes a second acquisition module, a judgment module and a restriction module;

[0015] The second acquisition module is used to collect current signals of all capacitors;

[0016] The judgment module is used to compare the direction of the current signal, obtain the position of the faulty capacitor according to the position where the reverse current appears, isolate the position of the faulty capacitor and output a first fault signal;

[0017] The limiting module is used to control the current injected into the fault capacitor according to the first fault signal.

[0018] Furthermore, the preliminary detection module includes a first judgment circuit, a forward diode, a reverse diode, a light-emitting diode and a damping protection capacitor. The positive pole of the reverse diode is electrically connected to the negative pole of the light-emitting diode, the positive pole of the light-emitting diode is electrically connected to the negative pole of the forward diode, the positive pole of the forward diode is electrically connected to the negative pole of the reverse diode, and the damping protection capacitor is electrically connected to a plurality of first button switches. The first judgment circuit controls the opening and closing of the first button switches according to the light signal generated by the light-emitting diode.

[0019] Furthermore, the protection module includes a second button switch, a grounding switch, an isolating switch and a trigger circuit. The grounding switch and the second button switch are electrically connected to the first judgment circuit. The trigger circuit controls the opening and closing of the second button switch, the isolating switch and the grounding switch according to the optical signal and the second fault signal.

[0020] Furthermore, it also includes an alarm module, which is used to issue an alarm according to the first fault signal and the second fault signal.

[0021] Furthermore, the alarm module can also be used to give an alarm when the duration of the first fault signal is greater than a preset value.

[0022] Furthermore, the protection module can also be used to connect a protection resistor to the circuit of the non-faulty capacitor to increase the resistance of the non-faulty capacitor circuit when the first fault signal occurs.

[0023] Furthermore, the second verification module also includes a monitoring module, which analyzes and predicts the fault characteristic signal and outputs prediction information, and the alarm module issues an alarm based on the prediction information.

[0024] Further, the preliminary detection module limits the current injected into the faulty capacitor according to the prediction information.

[0025] The technical principles and beneficial effects of the above scheme are as follows:

[0026] This solution determines the location of the faulty capacitor through the setting of a preliminary detection module and the reverse current that appears in the circuit when a short-circuit fault occurs, and limits the current injected into the faulty capacitor only when the capacitor fails. Compared with the prior art, during normal use of the capacitor, the damping protection capacitor used to limit the current injected into the faulty capacitor does not increase the energy consumption of the circuit, thereby reducing the energy consumption of the pulse power device.

[0027] The setting of the secondary verification module in this scheme analyzes the distribution state of the size of the fault characteristic signals of all capacitors based on the principle that the abnormal current generated by the faulty capacitor will generate a huge electromagnetic field and affect the surrounding capacitors, so as to accurately select the faulty capacitors. Compared with the existing technology, this scheme can screen out capacitors with fault characteristics affected by the faulty capacitors, avoid cutting off the current of these capacitors, and reduce the impact of this scheme on non-faulty capacitors.

[0028] In this solution, the capacitor is tested twice independently through a preliminary detection module and a secondary verification module. Compared with the existing technology, this solution can effectively improve the accuracy of the test.

[0029] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A structural diagram of an embodiment of a fault detection and grounding protection system for a large-capacity pulse power device according to the present invention;

[0031] Figure 2 A structural diagram of a second verification module of an embodiment of a fault detection and grounding protection system for a large-capacity pulse power device of the present invention;

[0032] Figure 3 A preliminary detection module structure diagram of an embodiment of a fault detection and grounding protection system for a large-capacity pulse power device according to the present invention;

[0033] Figure 4 The circuit diagram of the preliminary inspection module of the fault detection and grounding protection system embodiment of the present invention for large-capacity pulse power devices.

[0034] The figure marks in the drawings of the specification include: preliminary inspection module 1, secondary verification module 2, protection module 3, alarm module 4, first acquisition module 5, data processing module 6, second acquisition module 7, judgment module 8, and restriction module 9. DETAILED DESCRIPTION

[0035] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0036] In the description of the present invention, it is to be understood that the terms “longitudinal”, “lateral”, “vertical”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside” and “outside” etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0037] In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0038] The following is further described in detail through specific implementation methods:

[0039] Embodiment 1:

[0040] As attached Figure 1 -Attached Figure 3 As shown: A fault detection and grounding protection system for a large-capacity pulse power device includes a preliminary detection module 1, a secondary verification module 2 and a protection module 3.

[0041] The preliminary detection module is used to determine the location of the faulty capacitor by the location where the reverse circuit appears, and output a first fault signal, and limit the current injected into the faulty capacitor according to the first fault information. At the same time, the preliminary inspection module can also be used to limit the current injected into the faulty capacitor according to the prediction information.

[0042] Specifically, the preliminary detection module includes a second acquisition module 7, a judgment module 8 and a limiting module 9. The second acquisition module 7 is used to collect current signals of all capacitors; the judgment module 8 is used to compare the direction of the current signal, obtain the position of the faulty capacitor according to the position where the reverse current appears, and output the first fault signal according to the position of the faulty capacitor; the limiting module 9 is used to control the current injected into the faulty capacitor according to the first fault signal.

[0043] The specific steps for initially determining the location of the faulty capacitor and limiting the current injected into the faulty capacitor are as follows:

[0044] During the operation of the pulse power device, the current passes through the preliminary detection module. When a capacitor in the pulse power device has a short-circuit fault, a short-circuit current is generated. When the short-circuit current flows through the non-faulty capacitor, a reverse current is generated. By collecting the current direction of each capacitor, the position of the faulty capacitor can be obtained, that is, the first fault signal.

[0045] When the first fault signal appears and the prediction information indicates that a capacitor is about to have a short circuit fault, the limiting module 9 damps the capacitor to mitigate the impact of transient overvoltage on the capacitor and reduce the occurrence of capacitor breakdown at the moment of short circuit.

[0046] The secondary verification module 2 is used to detect all capacitors, obtain fault characteristic signals of all capacitors, and output a second fault signal according to the distribution of the numerical values ​​of the fault characteristic information.

[0047] Specifically, the second verification module includes a first acquisition module 5 and a data processing module 6; the first acquisition module 5 is used to collect the operating status signals of all capacitors; the data processing module 6 is used to perform wavelet transform on the operating status signals to obtain the corresponding wavelet domain, and obtain the fault characteristic signal according to the fault characteristic parameters in the wavelet domain, and output the second fault signal according to the distribution of the numerical value of the fault characteristic information. The second verification module also includes a monitoring module, which analyzes and predicts the fault characteristic signal and outputs the prediction information.

[0048] The specific steps of the secondary verification module 2 to detect the location of the faulty capacitor are as follows:

[0049] After the first fault information appears, the first acquisition module 5 acquires the operating status signals of all capacitors, and the data processing module 6 performs wavelet transform processing on the operating status signals to obtain the wavelet domain, extracts the fault characteristic parameters in the wavelet domain, and identifies the faulty capacitor through the fault characteristic parameters, that is, the fault characteristic signal. After the capacitor fails, the abnormal change of its current will be accompanied by the change of the surrounding electromagnetic field, thereby causing interference to the surrounding capacitors, so that the value of the fault characteristic signal of the capacitors around the faulty capacitor increases with the decrease of the distance from the faulty capacitor, and the fault characteristic signal of the faulty capacitor is much larger than that of the capacitors around it. Therefore, the detailed location of the capacitor with short circuit fault is obtained through the fault characteristic signals of all capacitors, that is, the second fault signal.

[0050] Before the first fault information appears, the first acquisition module 5 collects the operating status signals of all capacitors, the data processing module 6 obtains the fault characteristic signal according to the operating status signal, and the monitoring module analyzes the fault characteristic signal to obtain the trend of the capacitor short circuit fault, that is, the prediction information.

[0051] The protection module 3 is used to determine the position of the faulty capacitor according to the first fault signal and the second fault signal, and cut off the current injected into the faulty capacitor, and at the same time perform grounding protection on the non-faulty capacitor. In this embodiment, a grounding body and a grounding wire are used to perform grounding protection on the non-faulty capacitor. The protection module 3 can also connect a protection resistor to the circuit of the non-faulty capacitor when the first fault signal occurs to increase the resistance of the non-faulty capacitor circuit. In this implementation, the capacitor is connected to the protection resistor in parallel, and the protection resistor and the non-faulty capacitor are electrically connected to an isolating switch.

[0052] The specific steps of the protection module 3 to protect the pulse power device circuit are as follows:

[0053] After obtaining the first fault signal and the second fault signal, the positions of the faulty capacitor in the first fault signal and the second fault signal are compared to determine the exact position of the faulty capacitor, cut off the current of the faulty capacitor, and at the same time, conduct the short-circuit current in the pulse power device into the soil through the grounding wire and the grounding body to perform grounding protection.

[0054] After the first fault signal appears, the protection module 3 adjusts the opening and closing of the two isolating switches to connect the protection resistor into the circuit of the non-faulty capacitor, thereby increasing the resistance of the non-faulty capacitor and shortening the reverse current decay time, so that surrounding personnel can quickly detect and repair the pulse power device.

[0055] The device also includes an alarm module 4, which includes an indicator light and a buzzer alarm. The alarm module 4 is used to give an alarm according to the first fault signal and the second fault signal. The alarm module 4 can also be used to receive the first fault signal and give an alarm when the duration of the first fault signal is greater than a preset value. At the same time, the alarm module 4 can also give an alarm according to the prediction information.

[0056] The specific steps of alarm module 4 alarm are as follows:

[0057] After the first fault signal and the second fault signal are generated, the alarm module 4 alerts the surrounding personnel by lighting up the warning light corresponding to the faulty capacitor, reminding the surrounding personnel to stay away from the pulse power device after the short circuit to avoid the risk of electric shock, and reminds the surrounding personnel to cut off the power supply of the device in time to reduce the impact of reverse current on the surrounding non-faulty capacitors.

[0058] At the same time, after the first fault signal appears, the duration of the first fault signal is calculated. When the duration exceeds the preset value, the short-circuit current may be too large, resulting in the failure of the grounding protection, or the protection module 3 fails, and the injection of the faulty capacitor and the grounding protection are not cut off in time. At this time, the buzzer alarm corresponding to the faulty capacitor is activated, and the surrounding personnel are reminded again, further reducing the probability of the surrounding personnel encountering the danger of electric shock.

[0059] When a capacitor is about to short-circuit in the prediction information, the warning light of the corresponding capacitor is turned on to warn the surrounding personnel, so that they can inspect and repair the capacitor and reduce the damage caused by the capacitor short-circuit, which may affect the normal use of the pulse power device.

[0060] In this scheme, two fault detections are performed to increase the accuracy of the detection results. In the secondary verification module 2, the electromagnetic field generated by the abnormal current of the faulty capacitor will affect the surrounding equipment. By detecting the fault characteristic signals of all capacitors and finding the adjacent capacitors that show a step-like change, the position of the faulty capacitor can be determined more accurately, thereby accurately cutting off the current of the faulty capacitor and reducing the impact on non-faulty capacitors.

[0061] Embodiment 2:

[0062] This embodiment provides another implementation scheme. Figure 4 As shown, the preliminary detection module includes a first judgment circuit, a forward diode, a reverse diode, a light emitting diode and a damping protection capacitor. The positive electrode of the reverse diode is connected in series with the negative electrode of the light emitting diode. The reverse diode and the light emitting diode are both connected in parallel with the forward diode. The first judgment circuit includes a phototransistor. The phototransistor is connected in series with the light emitting diode. The damping protection capacitor is connected in series with the forward diode. The damping protection capacitor is electrically connected to a first button switch. The damping protection capacitor is also connected in parallel with another button switch. The first judgment circuit controls the opening and closing of the first button switch according to the light signal generated by the light emitting diode. The reverse diode, the forward diode and the light emitting diode are equivalent to the second acquisition module 7. The first judgment circuit is equivalent to the judgment module 8, and the damping protection capacitor and the first button switch are equivalent to the limiting module 9.

[0063] The protection module 3 includes a second button switch, a grounding switch, an isolating switch and a trigger circuit. The isolating switch, the grounding switch and the second button switch are all electrically connected to the first judgment circuit. The trigger circuit controls the opening and closing of the second button switch, the isolating switch and the grounding switch according to the optical signal and the second fault signal.

[0064] The operation of the circuit is as follows:

[0065] During the movement of the capacitor, the current of the capacitor circuit is synchronously injected into the forward diode and the reverse diode. When the capacitor is in a normal state, the current passes through the forward diode. At this time, the damping protection capacitor is not connected to the capacitor circuit. When a short circuit fault occurs in the capacitor, a reverse current appears in the capacitor circuit. The reverse current can enter the light-emitting diode through the reverse diode, causing the light-emitting diode to emit light and generate a light signal. After the first judgment circuit receives the light signal, it controls the first button switch to connect the damping protection capacitor to the capacitor circuit and the current in the damping capacitor, thereby limiting the current injected into the faulty capacitor. After the second verification module outputs the second fault signal, the trigger circuit determines the exact position of the faulty capacitor according to the light signal and the second fault signal, and cuts off the current injected into the faulty capacitor by controlling the second button switch to avoid the current breakdown of the faulty capacitor. At the same time, the grounding switch and the isolating switch are controlled to be closed, so that the current is injected into the soil.

[0066] In this solution, the damping protection capacitor is connected in series by changing the way it is connected to the circuit so that it is only connected to the circuit during a short circuit failure of the capacitor to damp the reverse current. Compared with the method of directly connecting to the circuit in the prior art, this method is less likely to increase the energy consumption of the circuit during normal use of the capacitor.

[0067] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and / or characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A fault detection and grounding protection system for a large-capacity pulse power device, characterized in that: It includes a preliminary detection module, a secondary verification module and a protection module; The preliminary detection module is used to determine the position of the faulty capacitor by the position where the reverse current appears, and output a first fault signal. According to the first fault information, the current injected into the faulty capacitor is limited. The preliminary detection module includes a first judgment circuit, a forward diode, a reverse diode, a light-emitting diode and a damping protection capacitor. The anode of the reverse diode is electrically connected to the cathode of the light-emitting diode, the anode of the light-emitting diode is electrically connected to the cathode of the forward diode, the anode of the forward diode is electrically connected to the cathode of the reverse diode, and the damping protection capacitor is electrically connected to a plurality of first button switches. The first judgment circuit controls the opening and closing of the first button switches according to the light signal generated by the light-emitting diode. The secondary verification module is used to detect all capacitors, obtain fault characteristic signals of all capacitors, and output a second fault signal according to the distribution of the numerical values ​​of the fault characteristic information. The second verification module includes a first acquisition module and a data processing module; The first acquisition module is used to collect the operating status signals of all capacitors; the data processing module is used to perform wavelet transform on the operating status signals to obtain the corresponding wavelet domain, and obtain the fault characteristic signal according to the fault characteristic parameters in the wavelet domain, and output the second fault signal according to the distribution of the numerical value of the fault characteristic information; The protection module is used to determine the position of the faulty capacitor according to the first fault signal and the second fault signal, and cut off the current injected into the faulty capacitor, while performing grounding protection on the non-faulty capacitor.

2. The fault detection and grounding protection system for a large-capacity pulse power device according to claim 1, characterized in that: The preliminary detection module includes a second acquisition module, a judgment module and a restriction module; The second acquisition module is used to collect current signals of all capacitors; The judgment module is used to compare the direction of the current signal, obtain the position of the faulty capacitor according to the position where the reverse current appears, and output a first fault signal according to the position of the faulty capacitor; The limiting module is used to control the current injected into the fault capacitor according to the first fault signal.

3. The fault detection and grounding protection system for a large-capacity pulse power device according to claim 1, characterized in that: The protection module includes a second button switch, a grounding switch, an isolating switch and a trigger circuit. The grounding switch and the second button switch are electrically connected to the first judgment circuit. The trigger circuit controls the opening and closing of the second button switch, the isolating switch and the grounding switch according to the optical signal and the second fault signal.

4. The fault detection and grounding protection system for a large-capacity pulse power device according to claim 1, characterized in that: It also includes an alarm module, which is used to issue an alarm according to the first fault signal and the second fault signal.

5. The fault detection and grounding protection system for a large-capacity pulse power device according to claim 4, characterized in that: The alarm module can also be used to sound an alarm when the duration of the first fault signal is greater than a preset value.

6. The fault detection and grounding protection system for a large-capacity pulse power device according to claim 5, characterized in that: The protection module can also be used to connect a protection resistor to the circuit of the non-faulty capacitor to increase the resistance of the non-faulty capacitor circuit when the first fault signal occurs.

7. The fault detection and grounding protection system for a large-capacity pulse power device according to claim 6, characterized in that: The second verification module also includes a monitoring module, which analyzes and predicts the fault characteristic signal and outputs prediction information. The alarm module issues an alarm based on the prediction information.

8. The fault detection and grounding protection system for a large-capacity pulse power device according to claim 7, characterized in that: The preliminary detection module limits the current injected into the faulty capacitor based on the prediction information.

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