Fault positioning method of power supply network and fault positioning device of power supply network

Abstract

The invention provides a power supply network fault positioning method and a power supply network fault positioning device. In the fault positioning method, since the frequency of the electric excitation is smaller than the resonant frequency of each capacitor, the current almost only flows through the short-circuit capacitor when the electric excitation is applied, so that the voltages at the two ends of different detection capacitors before the short-circuit capacitor are obviously changed; the voltages at the two ends of different detection capacitors after the short-circuit capacitor hardly change, so that if a certain range meets the condition, the short-circuit capacitor can be determined to be in the range; and short-circuit fault detection is carried out on each capacitor in the range, so that fault positioning of the capacitors can be realized. According to the invention, short-circuit fault detection is only carried out on each capacitor in the determined range where the short-circuit capacitor is located, so that the number of the capacitors for short-circuit fault detection is reduced, and the fault positioning cost of the capacitors on the power supply network is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of fault detection, and in particular to a method and a device for locating a fault of a power supply network. Background Art

[0002] Normally, there are many capacitors connected in parallel on the power supply network in modern electronic and electrical systems, which play the role of energy storage and filtering. If a short circuit failure occurs in a parallel capacitor, it is necessary to locate the capacitor fault in order to conduct the next step of failure cause analysis.

[0003] At present, the exhaustive testing method is generally used to locate the fault of capacitors with short-circuit faults, that is, to locate the fault of the short-circuited capacitor, each capacitor is removed from the circuit board in turn, and then the change in the ground resistance of the power supply network is measured, and then this process is repeated until the short-circuited capacitor is located. However, under normal circumstances, some major power supply networks may have hundreds of capacitors in parallel, and the labor cost and time cost of exhaustive testing are very high, resulting in a high cost of capacitor fault location; in addition, the method of removing capacitors destroys the original state of the circuit board and may introduce new interference factors, which may cause secondary damage.

[0004] Therefore, how to reduce the cost of fault location of capacitors on a power supply network is a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of this, the present invention provides a method and device for locating a fault of a power supply network, so as to reduce the cost of locating the fault of a capacitor on the power supply network.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0007] On one hand, the present application provides a method for locating a fault in a power supply network, wherein at least two capacitors are connected in parallel on the power supply network; the method for locating a fault in the power supply network comprises:

[0008] Applying electrical excitation across the two ends of any of the capacitors; the frequency of the electrical excitation is less than the resonant frequency of each of the capacitors;

[0009] Taking the target capacitor as the midpoint, the voltage of the capacitor on each side is detected in an intermittent manner; the target capacitor is the capacitor to which the electrical excitation is applied;

[0010] If there is a detection capacitor whose voltage across both ends is the same as the voltage across both ends of the next detection capacitor on the same side and is different from the voltage across both ends of the previous detection capacitor on the same side, then short circuit fault detection is performed on each of the capacitors between the previous detection capacitor on the same side and the next detection capacitor on the same side of the detection capacitor; the detection capacitors on one side are the capacitors for voltage detection on that side; and the detection capacitors on the same side are arranged in order from near to far from the target capacitor.

[0011] Optionally, while there is the step of performing short circuit fault detection on each of the capacitors between the previous detection capacitor and the next detection capacitor on the same side of the detection capacitor, the method further includes:

[0012] A short circuit fault detection is performed on the previous detection capacitor and the next detection capacitor on the same side of the detection capacitor.

[0013] Optionally, if there is no detection capacitor whose voltage across both ends is the same as the voltage across both ends of the next detection capacitor on the same side and different from the voltage across both ends of the previous detection capacitor on the same side, then short-circuit fault detection is performed on each capacitor between the last detection capacitor on each side and the previous detection capacitor on the same side, and / or short-circuit fault detection is performed on each capacitor between the first detection capacitor on each side and the next detection capacitor on the same side.

[0014] Optionally, if the capacitor between the two detection capacitors on the same side does not have a short circuit fault, and the change in the voltage across the two detection capacitors is equal to the minimum measurement value of the voltage detection, a short circuit fault detection is performed on each of the capacitors between the previous detection capacitor on the same side and the next detection capacitor on the same side of the detection capacitor, including:

[0015] A short circuit fault detection is performed on each of the capacitors between the detection capacitor and the next detection capacitor on the same side thereof.

[0016] Optionally, the target capacitor is the capacitor located in the middle of all the capacitors.

[0017] Optionally, the electrical excitation includes: current or voltage.

[0018] Optionally, voltage detection is performed in an intermittent manner, including:

[0019] The voltage of the capacitor is detected once every at least one of the capacitors.

[0020] Optionally, performing short circuit fault detection on the capacitor includes:

[0021] Obtaining a resonance curve of the capacitor;

[0022] According to the resonance curve, determining whether the resonance curve has an extreme point within a preset range of the resonance frequency of the capacitor;

[0023] If the resonance curve does not have an extreme point within the preset range of the resonance frequency of the capacitor, it is determined that a short circuit fault occurs in the capacitor.

[0024] Optionally, obtaining a resonance curve of the capacitor includes:

[0025] At least two currents of different frequencies are applied to both ends of the capacitor respectively, and voltage detection is performed on the capacitor respectively; the frequency range covered by all currents applied to the capacitor exceeds the preset range of the resonant frequency;

[0026] The resonance curve is obtained according to all voltage detection results.

[0027] On the other hand, the present application provides a fault location device for a power supply network, comprising: a controller, an excitation application module and a voltage detection module; wherein:

[0028] Each output terminal of the excitation applying module is respectively connected to each capacitor connected in parallel on the power supply network;

[0029] Each detection end of the voltage detection module is connected to each capacitor respectively, and the output end of the voltage detection module is connected to the input end of the controller;

[0030] The excitation applying module and the voltage detecting module are both controlled by the controller, and the controller is used to execute the fault locating method of the power supply network as described in any one of the above aspects of the present application.

[0031] It can be seen from the above technical solution that the present invention provides a method for locating a fault in a power supply network. In the fault locating method, since the frequency of the electrical excitation is less than the resonant frequency of each capacitor, when the electrical excitation is applied, the current almost only flows through the short-circuited capacitor, so that the voltages at both ends of different detection capacitors before the short-circuited capacitor will change significantly, and the voltages at both ends of different detection capacitors after the short-circuited capacitor will hardly change. Therefore, if the change in the voltages at both ends of different detection capacitors within a certain range meets the above situation, it can be determined that the short-circuited capacitor is within this range; and since short-circuit fault detection will be performed on each capacitor within this range thereafter, the fault location of the capacitor can be achieved. Since the present application only performs short-circuit fault detection on each capacitor within the range where the determined short-circuited capacitor is located, the number of capacitors for short-circuit fault detection is reduced, thereby reducing the cost of fault location of capacitors on the power supply network. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0033] Figure 1 It is a connection diagram of capacitors on the power supply network;

[0034] Figure 2-Figure 5 A schematic diagram of the flow chart of four implementation methods of the power supply network fault location method provided in the embodiments of the present application;

[0035] Figure 6 A schematic diagram of a flow chart of an implementation method of short-circuit fault detection for a capacitor provided in an embodiment of the present application;

[0036] Figure 7 A schematic diagram of a flow chart of an implementation method of obtaining the resonance curve of the capacitor provided in an embodiment of the present application;

[0037] Figure 8 A schematic structural diagram of an implementation of a fault location device for a power supply network provided in an embodiment of the present application. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0039] In this application, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0040] Typically, there are at least two capacitors connected in parallel on the power network, such as Figure 1 As shown. In practical applications, capacitors are not ideal components and can be equivalent to RCL series circuits, such as Figure 1 As shown in A. Specifically, the impedance of the capacitor decreases with the increase of frequency, that is, it shows capacitance. When the frequency reaches a certain point, the impedance of the capacitor reaches the minimum value. The frequency of this point is called the resonant frequency. After that, the impedance of the capacitor increases with the increase of frequency, that is, it shows inductance.

[0041] It should be noted that a short circuit failure of a capacitor is equivalent to a short circuit of the capacitor in the equivalent RCL series circuit, that is, in the RCL series circuit equivalent to the capacitor, the inductor and the resistor are connected in series, such as Figure 1 As shown in C.

[0042] In practical applications, the trace impedance between two capacitors is not an ideal component, and it can be equivalent to a series circuit of resistors and inductors, such as Figure 1 In addition, there is a distributed equivalent capacitance, which can be equivalent to a parallel circuit of capacitors and resistors, such as Figure 1 As shown in B.

[0043] Generally, the impedance of the series circuit of the resistor and the inductor is made as large as possible to have a more obvious suppressing effect on the current. In other words, the voltage drop of the series circuit of the resistor and the inductor is easier to detect.

[0044] The resistance is very small but close to the resistance in the RCL series circuit equivalent to the capacitor. In addition, usually, in the series circuit of the resistor and inductor, the inductance is smaller than or close to the inductance in the RCL series circuit equivalent to the capacitor.

[0045] Normally, in a parallel circuit of capacitors and resistors, the resistance of the resistor is extremely large and its influence on the circuit can be ignored, so it can be ignored. In addition, normally, in a parallel circuit of capacitors and resistors, the capacitance of the capacitor is generally in the range of fF to pF, while the minimum capacitance of the capacitor is generally 100nF, which is an order of magnitude difference, so it can also be ignored.

[0046] In order to reduce the cost of locating the fault of the capacitor on the power supply network, another embodiment of the present application provides a method for locating the fault of the power supply network, and its specific structure is as follows: Figure 2 As shown, the specific steps include:

[0047] S110 , applying electrical excitation across both ends of any capacitor.

[0048] The frequency of the electrical excitation is less than the resonant frequency of each capacitor. In other words, the frequency of the electrical excitation is less than the minimum value of the resonant frequencies of all capacitors. For example, taking three capacitors as an example, the resonant frequencies of the three capacitors are 0.30 MHz, 0.20 MHz, and 0.10 MHz, respectively, then the frequency of the electrical excitation should be less than 0.10 MHz.

[0049] Optionally, the electrical excitation may be current or voltage. In practical applications, this includes but is not limited to these. No specific limitation is made here and it may be determined according to specific circumstances. All of these are within the scope of protection of this application.

[0050] S120 , taking the target capacitor as the midpoint, intermittently detecting the voltage of the capacitors on each side.

[0051] The target capacitor is a capacitor to which electrical excitation is applied.

[0052] In addition, the capacitors on one side of the target capacitor include the target capacitor and all capacitors on that side of the target capacitor; and the capacitors on one side of the target capacitor are arranged in order from near to far from the target capacitor, that is, the first capacitor refers to the capacitor closest to the target capacitor, that is, the first capacitor is the target capacitor, and the last capacitor refers to the capacitor farthest from the target capacitor, and so on.

[0053] Furthermore, intermittently performing voltage detection on the capacitors on one side specifically means: performing voltage detection on multiple capacitors on one side, and there should be at least one capacitor between two adjacent capacitors for voltage detection, that is, not performing voltage detection on every capacitor on one side. For example, if it is assumed that the capacitors on one side include seven capacitors, then voltage detection is performed on the first capacitor, the fourth capacitor, and the seventh capacitor on the side, respectively.

[0054] In addition, the number of capacitors that should be spaced at least between two adjacent capacitors for voltage detection is set based on the wiring impedance between the capacitors and the voltage detection accuracy, and is not specifically limited here.

[0055] It should be noted that, usually, when performing voltage detection on the capacitors on each side in an intermittent manner, it is required to include performing voltage detection on the first capacitor and the last capacitor on each side, so as to cover all the capacitors on that side.

[0056] Optionally, when performing voltage detection, the voltage detection may be performed on one capacitor at a time, or on multiple capacitors at the same time. This is not specifically limited here and may be determined according to the specific circumstances, all within the protection scope of this application.

[0057] In a specific example, the target capacitor is a capacitor located in the middle of all the capacitors.

[0058] It should be noted that if voltage detection is performed on one capacitor at a time, since the target capacitor is located in the middle of all capacitors, it is possible to more quickly determine whether there is a detection capacitor whose voltage across both ends is the same as the voltage across both ends of the next detection capacitor on the same side and different from the voltage across both ends of the previous detection capacitor on the same side. Therefore, the implementation shown in this example is regarded as a preferred implementation.

[0059] The above example only shows one implementation method of the target capacitor. In practical applications, the target capacitor is any one of all capacitors and is within the protection scope of this application. No specific limitation is made here and it can be determined according to the specific situation.

[0060] S130, determine whether there is a detection capacitor whose voltage across both ends is the same as the voltage across both ends of the next detection capacitor on the same side and different from the voltage across both ends of the previous detection capacitor on the same side.

[0061] If there is a detection capacitor whose voltage across both ends is the same as the voltage across both ends of the next detection capacitor on the same side and is different from the voltage across both ends of the previous detection capacitor on the same side, execute step S140; if there is no detection capacitor whose voltage across both ends is the same as the voltage across both ends of the next detection capacitor on the same side and is different from the voltage across both ends of the previous detection capacitor on the same side, stop executing the fault location method.

[0062] The detection capacitor on one side is a capacitor for voltage detection on that side. For example, if it is assumed that the first capacitor, the fourth capacitor, and the seventh capacitor on one side are detected respectively, then the first capacitor, the fourth capacitor, and the seventh capacitor on that side are the detection capacitors on that side.

[0063] In addition, the detection capacitors on the same side are arranged in order from near to far from the target capacitor, that is, on the same side, the first detection capacitor refers to the detection capacitor closest to the target capacitor, the last detection capacitor refers to the detection capacitor farthest from the target capacitor, and so on. For example, assuming that the capacitors on one side include seven capacitors, and the first capacitor, the fourth capacitor, and the seventh capacitor on the side are all detection capacitors, then the first capacitor on the side is the first detection capacitor on the side, the fourth capacitor on the side is the second detection capacitor on the side, and the seventh capacitor on the side is the last detection capacitor on the side.

[0064] It can be inferred from this that the next detection capacitor on the same side of a detection capacitor refers to: a detection capacitor that is on the same side as the detection capacitor and is slightly farther away from the target capacitor than the distance between the detection capacitor and the target capacitor; the previous detection capacitor on the same side of a detection capacitor is the same as the above and will not be repeated here.

[0065] For example, if the detection capacitor is the second detection capacitor, then the next detection capacitor on the same side of the detection capacitor refers to the third detection capacitor, and the previous detection capacitor on the same side of the detection capacitor refers to the first detection capacitor.

[0066] S140, performing short circuit fault detection on each capacitor between a previous detection capacitor and a next detection capacitor on the same side of the detection capacitor.

[0067] For example, assuming that the previous detection capacitor on the same side of the detection capacitor is the first capacitor on this side, and the next detection capacitor on the same side of the detection capacitor is the seventh capacitor on this side, short-circuit fault detection is performed on each capacitor between the first capacitor on this side and the seventh capacitor on this side, that is, short-circuit fault detection is performed on the second capacitor, the third capacitor, the fourth capacitor, the fifth capacitor, and the sixth capacitor on this side.

[0068] The short-circuit fault detection of the capacitor is to detect whether the capacitor has a short-circuit fault. Since the short-circuit fault detection will be described in detail below, it will not be described here.

[0069] Since the frequency of electrical excitation is lower than the resonant frequency of each capacitor, normal capacitors are capacitive under electrical excitation. Since the capacitor is short-circuited in the equivalent circuit of the short-circuited capacitor, that is, the short-circuited capacitor is inductive, the impedance of the normal capacitor under electrical excitation is much greater than that of the short-circuited capacitor. Therefore, the current mainly flows to the short-circuited capacitor under electrical excitation.

[0070] Since the current mainly flows to the short-circuited capacitor under electrical excitation, current flows through the routing impedance between the target capacitor and the short-circuited capacitor, while almost no current flows through the routing impedance between the short-circuited capacitor and the capacitor on the same side behind it. Since the routing impedance between capacitors cannot be ignored, a voltage drop will be formed in the routing impedance between the target capacitor and the short-circuited capacitor, while no voltage drop will be formed in the routing impedance between the short-circuited capacitor and the capacitor on the same side behind it. Therefore, there is a significant change in the voltage across different detection capacitors before the short-circuited capacitor, while there is almost no change in the voltage across different detection capacitors after the short-circuited capacitor.

[0071] Since the voltages across different detection capacitors change significantly before the short-circuited capacitor, and the voltages across different detection capacitors change almost unchanged after the short-circuited capacitor, if there is a detection capacitor whose voltage across both ends is the same as the voltage across both ends of the next detection capacitor on the same side and different from the voltage across both ends of the previous detection capacitor on the same side, that is, if the change in the voltage across both ends of different detection capacitors within a certain range meets the above situation, it can be determined that the short-circuited capacitor is between the previous detection capacitor and the next capacitor on the same side of the detection capacitor, and it can be determined that the short-circuited capacitor is within this range.

[0072] Since short-circuit fault detection is then performed on each capacitor within the range, it is possible to accurately determine which capacitor has a short-circuit fault, that is, to locate the fault of the capacitor on the power supply network.

[0073] Since the present application only performs short-circuit fault detection on each capacitor within the range where the determined short-circuited capacitor is located, the number of capacitors for short-circuit fault detection is reduced, thereby reducing the cost of fault location of capacitors on the power supply network.

[0074] It should be noted that a short-circuited capacitor refers to a capacitor that has a short-circuit fault, and a normal capacitor refers to a capacitor that has not a short-circuit fault.

[0075] Another embodiment of the present application provides another implementation of a method for locating a fault in a power supply network, and the specific process is as follows: Figure 3 As shown, this embodiment, while executing step S140 in the above embodiment, also includes the following steps:

[0076] S210 , performing short circuit fault detection on the previous detection capacitor and the next detection capacitor on the same side of the detection capacitor.

[0077] For example, assuming that the previous detection capacitor on the same side of the detection capacitor is the first capacitor on this side, and the next detection capacitor on the same side of the detection capacitor is the seventh capacitor on this side, short circuit fault detection is performed on both the first capacitor on this side and the seventh capacitor on this side.

[0078] It should be noted that, since short-circuit fault detection will be described in detail below, it will not be described here in detail.

[0079] Since step S210 is added in this embodiment, short-circuit fault detection can be performed on the previous detection capacitor and the next detection capacitor on the same side of the detection capacitor. Therefore, in special circumstances, that is, when the short-circuited capacitor happens to be the previous detection capacitor or the next detection capacitor on the same side of the detection capacitor, the short-circuited capacitor can be detected in this embodiment, thereby making the fault location method applicable to more situations.

[0080] The above is only one implementation of the fault location method for the power supply network. In practical applications, including but not limited to this, no specific limitation is made here and it can be determined according to the specific situation, all of which are within the protection scope of this application.

[0081] In practical applications, there are two special cases where the above embodiment may result in false detection, that is, the short-circuited capacitor cannot be detected.

[0082] The first special case is that the short-circuited capacitor is between the last detection capacitor and the second-to-last detection capacitor on one side. Since there is no detection capacitor behind, that is, voltage detection cannot be continued, so in the first special case, the voltage across the last detection capacitor cannot be the same as the voltage across the next detection capacitor on the same side, so the above embodiment will not perform short-circuit fault detection on each capacitor between the last detection capacitor and the second-to-last detection capacitor on the side, so the above embodiment will result in false detection, that is, the short-circuited capacitor cannot be detected.

[0083] The second special case is: the short-circuited capacitor is between the first detection capacitor and the second detection capacitor on one side. Since the voltage detection accuracy may be low, in the second special case, the voltage across the second detection capacitor is approximately equal to the voltage across the first detection capacitor, and there is no detection capacitor before the first detection capacitor on this side, so the voltage across the first detection capacitor cannot be the same as the voltage across the previous detection capacitor on the same side, so the above embodiment will not perform short-circuit fault detection on each capacitor between the first detection capacitor and the second detection capacitor on this side, and then the above embodiment will result in false detection, that is, the short-circuited capacitor cannot be detected.

[0084] Another embodiment of the present application provides another implementation of a method for locating a fault in a power supply network, and the specific process is as follows: Figure 4 As shown, in the above embodiment, in the case where the voltage across the two ends of a detection capacitor is not the same as the voltage across the two ends of the next detection capacitor on the same side and is different from the voltage across the two ends of the previous detection capacitor on the same side, the embodiment further includes the following steps:

[0085] S310, perform short circuit fault detection on each capacitor between the last detection capacitor on each side and the previous detection capacitor on the same side, and / or perform short circuit fault detection on each capacitor between the first detection capacitor on each side and the next detection capacitor on the same side.

[0086] For example, assuming that the last detection capacitor on one side is the seventh capacitor on that side, and the previous detection capacitor of the last detection capacitor on that side is the fourth capacitor on that side, then short-circuit fault detection is performed on each capacitor between the last detection capacitor on each side and the previous detection capacitor on the same side. Specifically, short-circuit fault detection is performed on each capacitor between the fourth capacitor on that side and the seventh capacitor on that side, that is, short-circuit fault detection is performed on the fifth capacitor on that side and the sixth capacitor on that side.

[0087] For example, assuming that the first detection capacitor on one side is the first capacitor on that side, and the detection capacitor before and after the first detection capacitor on that side is the fourth capacitor on that side, then a short circuit fault detection is performed on each capacitor between the first detection capacitor on each side and the next detection capacitor on the same side. Specifically, a short circuit fault detection is performed on each capacitor between the first capacitor on that side and the fourth capacitor on that side, that is, a short circuit fault detection is performed on the second capacitor on that side and the third capacitor on that side.

[0088] Since step S310 is added in this embodiment, short-circuit fault detection can be additionally performed on each capacitor between the last detection capacitor on each side and the previous detection capacitor on the same side, and / or short-circuit fault detection can be performed on each capacitor between the first detection capacitor on each side and the next detection capacitor on the same side. Therefore, short-circuited capacitors can be detected in the above two special cases, so that the fault location method can be applied to more situations.

[0089] Another embodiment of the present application provides a specific implementation of step S140, which is applicable to the following situation: no short-circuit failure occurs in the capacitor between the two detection capacitors on the same side, and the change in the voltage across the two detection capacitors is equal to the minimum measurement value of the voltage detection. In other words, if a short-circuit failure occurs in the capacitor between the two detection capacitors, the change in the voltage across the two detection capacitors is almost equal to zero, that is, the voltage across the two detection capacitors is approximately equal.

[0090] The specific process of this implementation is as follows Figure 5 As shown, the specific steps include:

[0091] S410, performing short circuit fault detection on each capacitor between the detection capacitor and the next detection capacitor on the same side.

[0092] It should be noted that the next detection capacitor on the same side of the detection capacitor has been described in detail above and will not be repeated here; in addition, short-circuit fault detection will be described in detail below and will not be repeated here.

[0093] Since this embodiment only performs short-circuit fault detection on each capacitor between the detection capacitor and the next detection capacitor on the same side, this embodiment further reduces the number of capacitors for short-circuit fault detection, thereby further reducing the cost of fault locating capacitors on the power supply network.

[0094] Another embodiment of the present application provides an implementation method for performing voltage detection in an intermittent manner, specifically: performing capacitor voltage detection once every at least one capacitor is separated. In other words, the number of capacitors separated between any two adjacent detection capacitors is the same, and the number of separated capacitors is at least one.

[0095] For example, assuming that the capacitors on one side include seven capacitors, if the voltage of the capacitors is detected once every other capacitor, the voltage of the first capacitor, the third capacitor, the fifth capacitor, and the seventh capacitor are detected respectively.

[0096] In this embodiment, since the number of capacitors between any two adjacent detection capacitors is the same, the approximate range of the short-circuited capacitors determined first is more accurate, thereby improving the efficiency of subsequent short-circuit fault detection one by one, and further improving the speed of determining the short-circuited capacitors.

[0097] Another embodiment of the present application provides an implementation method for detecting a short circuit fault of a capacitor, and the specific process is as follows: Figure 6 As shown, the specific steps include:

[0098] S510: Obtain a resonance curve of the capacitor.

[0099] The above resonance curve is used to reflect the changes of electrical quantities such as current, voltage, impedance, etc. of the capacitor with frequency.

[0100] S520: According to the resonance curve, determine whether an extreme point appears in the resonance curve within a preset range of the resonance frequency of the capacitor.

[0101] If the resonance curve does not have an extreme point within the preset range of the resonance frequency of the capacitor, step S530 is executed; if the resonance curve has an extreme point within the preset range of the resonance frequency of the capacitor, step S540 is executed.

[0102] Among them, the resonant frequency of the capacitor refers to the resonant frequency of the capacitor without the influence of other inductors and capacitors. In practical applications, it can be found in the capacitor manual.

[0103] In addition, within the preset range of the resonant frequency of the capacitor, it means: near the resonant frequency of the capacitor, for example, assuming that the above resonant frequency is 0.3MHz, then the preset range of the above resonant frequency is: 0.2MHz~0.4MHz. In actual applications, the preset range is set according to actual conditions and is not specifically limited here.

[0104] S530: Determine whether a short circuit fault occurs in the capacitor.

[0105] S540: Determine that the capacitor has no short circuit fault.

[0106] If the capacitor does not have a short circuit fault, then ignoring the impedance of the wiring between the capacitors, the above resonance curve will have an extreme point at the resonance frequency. Taking the above resonance curve as an example, which is used to reflect the curve of the voltage across the capacitor changing with the frequency, in this case, the above resonance curve will have a minimum point, that is, a low point, at the resonance frequency.

[0107] It should be noted that the extreme point that appears in this case is not necessarily one, but depends on how many individual capacitors are included in the equivalent circuit of the capacitor. If multiple individual capacitors are included, multiple extreme points will appear in this case. If one individual capacitor is included, only one extreme point will appear in this case.

[0108] In practical applications, since the wiring impedance between capacitors cannot be ignored and the equivalent circuit of the wiring impedance between capacitors includes inductance, the wiring impedance between capacitors will affect the frequency corresponding to the extreme point of the above resonance curve, even if the extreme point of the above resonance curve is offset, for example, appearing at a lower frequency.

[0109] If a short-circuit failure occurs in the capacitor, the capacitance in the equivalent circuit of the capacitor is short-circuited, so the equivalent circuit of the capacitor only includes resistance and inductance, so that the above resonance curve no longer has an extreme point at the resonance frequency.

[0110] From the above distinction, it can be seen that if the above resonance curve does not have an extreme point within the preset range of the resonant frequency of the capacitor, that is, if the above resonance curve does not have an extreme point near the resonant frequency of the capacitor, it can be determined that a short circuit fault has occurred in the capacitor; if the above resonance curve has an extreme point within the preset range of the resonant frequency of the capacitor, that is, if the above resonance curve has an extreme point near the resonant frequency of the capacitor, it can be determined that a short circuit fault has not occurred in the capacitor.

[0111] Since the fault location method for the power network provided in this embodiment does not remove the capacitor from the circuit board, this embodiment can reduce the damage to the original state of the circuit board, thereby reducing the possibility of introducing new interference factors, and further reducing the possibility of causing secondary damage.

[0112] Another embodiment of the present application provides an implementation method for obtaining the resonance curve of the capacitor, and the specific process is as follows: Figure 7 As shown, the specific steps include:

[0113] S610 , applying at least two currents of different frequencies to both ends of a capacitor respectively, and performing voltage detection on the capacitor respectively.

[0114] The frequency range covered by the total current applied to the capacitor exceeds the preset range of the above-mentioned resonant frequency.

[0115] For example, assuming that the preset range of the above-mentioned resonant frequency is 0.2MHz~0.4MHz, the frequencies of the currents applied at both ends of the capacitor are: 0.1Mhz, 0.2Mhz, 0.24Mhz, 0.28Mhz, 0.32Mhz, 0.36Mhz, 0.4Mhz, and 0.5Mhz respectively.

[0116] It should be noted that the frequency of the current applied to the capacitor can be selected more within the preset range of the above-mentioned resonant frequency, and less outside the preset range of the above-mentioned resonant frequency, so that the above-mentioned resonance curve obtained subsequently is more accurate.

[0117] S620: Obtain the above resonance curve according to all voltage detection results.

[0118] It should be noted that step S620 is already very mature in the prior art and will not be described in detail here.

[0119] The above is only one implementation method for obtaining the resonance curve of the capacitor. In practical applications, including but not limited to this, no specific limitation is made here and it may be determined according to the specific situation, all of which are within the protection scope of this application.

[0120] Another embodiment of the present application provides a fault location device for a power supply network, and its specific structure is as follows: Figure 8 As shown, it specifically includes: a controller 10 , an excitation applying module 20 and a voltage detecting module 30 .

[0121] The output ends of the excitation application module 20 are respectively connected to the capacitors 40 connected in parallel on the power supply network; the detection ends of the voltage detection module 30 are respectively connected to the capacitors 40, and the output end of the voltage detection module 30 is connected to the input end of the controller 10; the excitation application module 20 and the voltage detection module 30 are both controlled by the controller 10, and the controller 10 is used to execute the fault location method of the power supply network provided in the above embodiment.

[0122] It should be noted that the controller 10 implements the application of electrical excitation through the excitation application module 20 , and the controller 10 also implements voltage detection through the voltage detection module 30 .

[0123] Optionally, the excitation applying module 20 can be a current source, a voltage source, or a current source and a voltage source. In practical applications, this includes but is not limited to these. No specific limitation is made here and it may be determined according to the specific circumstances. All of these are within the scope of protection of this application.

[0124] Optionally, the voltage detection module 30 may include an oscilloscope, and may also include a connected amplifier and an analog-to-digital converter. In practical applications, this includes but is not limited to these. No specific limitations are made here and it may depend on the specific circumstances. All of these are within the scope of protection of this application.

[0125] Since the controller 10 in this embodiment executes the fault location method of the power supply network provided in the above embodiment, this embodiment only performs short-circuit fault detection on part of the capacitors 40, that is, the number of capacitors 40 for short-circuit fault detection is reduced, thereby reducing the cost of fault location of the capacitors 40 on the power supply network.

[0126] For the above description of the disclosed embodiments, the features recorded in each embodiment in this specification can be replaced or combined with each other, so that professionals in the field can implement or use the present application. The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with a preferred embodiment, it is not used to limit the present invention. Any technician familiar with the field can make many possible changes and modifications to the technical solution of the present invention using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A method for locating a fault in a power supply network, characterized in that: At least two capacitors are connected in parallel on the power supply network; the fault location method of the power supply network comprises: Applying electrical excitation across the two ends of any of the capacitors; the frequency of the electrical excitation is less than the resonant frequency of each of the capacitors; Taking the target capacitor as the midpoint, the voltage of the capacitor on each side is detected in an intermittent manner; the target capacitor is the capacitor to which the electrical excitation is applied; If there is a detection capacitor whose voltage across both ends is the same as the voltage across both ends of the next detection capacitor on the same side and is different from the voltage across both ends of the previous detection capacitor on the same side, then short circuit fault detection is performed on each of the capacitors between the previous detection capacitor on the same side and the next detection capacitor on the same side of the detection capacitor; the detection capacitors on one side are the capacitors for voltage detection on that side; and the detection capacitors on the same side are arranged in order from near to far from the target capacitor.

2. The method for locating a fault in a power supply network according to claim 1, characterized in that: While there is a step of performing short circuit fault detection on each of the capacitors between the previous detection capacitor and the next detection capacitor on the same side of the detection capacitor, the method further includes: A short circuit fault detection is performed on the previous detection capacitor and the next detection capacitor on the same side of the detection capacitor.

3. The method for locating a fault in a power supply network according to claim 1, characterized in that: If there is no detection capacitor whose voltage across both ends is the same as the voltage across both ends of the next detection capacitor on the same side and is different from the voltage across both ends of the previous detection capacitor on the same side, then short-circuit fault detection is performed on each capacitor between the last detection capacitor on each side and the previous detection capacitor on the same side, and / or short-circuit fault detection is performed on each capacitor between the first detection capacitor on each side and the next detection capacitor on the same side.

4. The method for locating a fault in a power supply network according to claim 1, characterized in that: If the capacitor between the two detection capacitors on the same side does not have a short circuit fault, and the change in the voltage across the two detection capacitors is equal to the minimum measurement value of the voltage detection, a short circuit fault detection is performed on each of the capacitors between the previous detection capacitor on the same side and the next detection capacitor on the same side of the detection capacitor, including: A short circuit fault detection is performed on each of the capacitors between the detection capacitor and the next detection capacitor on the same side thereof.

5. The method for locating a fault in a power supply network according to any one of claims 1 to 4, characterized in that: The target capacitor is the capacitor located at a middle position of all the capacitors.

6. The method for locating a fault in a power supply network according to any one of claims 1 to 4, characterized in that: The electrical excitation includes: current or voltage.

7. The method for locating a fault in a power supply network according to any one of claims 1 to 4, characterized in that: Voltage detection is performed in an intermittent manner, including: The voltage of the capacitor is detected once every at least one of the capacitors.

8. The method for locating a fault in a power supply network according to any one of claims 1 to 4, characterized in that: Performing short circuit fault detection on the capacitor includes: Obtaining a resonance curve of the capacitor; According to the resonance curve, determining whether the resonance curve has an extreme point within a preset range of the resonance frequency of the capacitor; If the resonance curve does not have an extreme point within the preset range of the resonance frequency of the capacitor, it is determined that a short circuit fault occurs in the capacitor.

9. The method for locating a fault in a power supply network according to claim 8, characterized in that: Obtaining a resonance curve of the capacitor, comprising: At least two currents of different frequencies are applied to both ends of the capacitor respectively, and voltage detection is performed on the capacitor respectively; the frequency range covered by all currents applied to the capacitor exceeds the preset range of the resonant frequency; The resonance curve is obtained according to all voltage detection results.

10. A fault location device for a power supply network, characterized in that: include: A controller, an excitation applying module and a voltage detecting module; wherein: Each output terminal of the excitation applying module is respectively connected to each capacitor connected in parallel on the power supply network; Each detection end of the voltage detection module is connected to each capacitor respectively, and the output end of the voltage detection module is connected to the input end of the controller; The excitation applying module and the voltage detecting module are both controlled by the controller, and the controller is used to execute the fault locating method for a power supply network according to any one of claims 1 to 9.

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