Fault detection method and device for AC-DC hybrid microgrid

Abstract

The invention provides a fault detection method and device for an AC / DC hybrid micro-grid. The implementation scheme of the fault detection method for the AC / DC hybrid micro-grid is as follows: acquiring a current signal of the AC / DC hybrid micro-grid; performing Hilbert-Huang transform on the current signal to obtain a Hilbert spectrogram; and obtaining a fault detection result of the AC / DC hybrid microgrid based on the Hilbert spectrogram.

Description

Technical Field

[0001] The present application relates to the technical field of AC / DC hybrid microgrids, and in particular to a fault detection method and device, electronic equipment, storage medium, and program product for an AC / DC hybrid microgrid. Background Art

[0002] With the rapid development of power electronics and renewable energy technologies, people's requirements for power supply reliability have gradually increased, and the distribution network has undergone great changes. This is particularly evident in the fact that large-scale distributed power sources are connected to the distribution network through AC or DC; the proportion of DC loads in user-side demand has gradually increased; and various energy storages are widely used in the distribution network to improve the regulation capacity of the distribution network.

[0003] As a new form of distribution network, AC / DC hybrid microgrid has a large-scale access to new DC loads such as distributed power sources, energy storage, and DC charging piles, which has an impact on the traditional distribution mode. The fault detection method of the traditional AC distribution network or the fault detection method of the DC distribution network is no longer suitable for the new distribution network. Based on this, a fault detection method for AC / DC hybrid microgrid is urgently needed, which is of great significance to the practical application of AC / DC hybrid microgrid. Summary of the invention

[0004] The present application aims to solve at least one of the technical problems in the background technology. To this end, one purpose of the present application is to provide a fault detection method and device for an AC / DC hybrid microgrid, an electronic device, a storage medium and a program product to quickly and accurately detect faults in an AC / DC hybrid microgrid.

[0005] An embodiment of the first aspect of the present application provides a fault detection method for an AC / DC hybrid microgrid, comprising: acquiring a current signal of the AC / DC hybrid microgrid; performing a Hilbert-Huang transform on the current signal to obtain a Hilbert spectrum; and obtaining a fault detection result of the AC / DC hybrid microgrid based on the Hilbert spectrum.

[0006] In the technical solution of the embodiment of the present application, a Hilbert-Huang transform is performed on the current signal of the AC / DC hybrid microgrid to obtain a Hilbert spectrum; and based on the Hilbert spectrum, a fault detection result of the AC / DC hybrid microgrid is obtained, so that the fault detection process of the AC / DC hybrid microgrid is simple and the fault detection result is accurate and reliable, thereby improving the rate and accuracy of fault detection of the AC / DC hybrid microgrid.

[0007] In some embodiments, the AC / DC hybrid microgrid includes an interconnected converter coupled between an AC side and a DC side, and obtaining a current signal of the AC / DC hybrid microgrid includes: obtaining a transient current signal when the interconnected converter is not locked as the current signal. By obtaining the transient current signal when the interconnected converter is not locked as the current signal for fault detection of the AC / DC hybrid microgrid, the accuracy of fault detection of the AC / DC hybrid microgrid is improved.

[0008] In some embodiments, the transient current signal includes an AC side transient current signal and / or a DC side transient current signal. During fault detection, the transient current signal includes the AC side transient current signal and the DC side transient current signal, which is beneficial to improving the accuracy of the fault detection result; when the transient current signal only includes the AC side transient current signal or the DC side transient current signal, the number of transient current signals obtained can be reduced, thereby reducing the cost of fault detection.

[0009] In some embodiments, the Hilbert spectrum includes frequency and energy amplitude; obtaining a fault detection result based on the Hilbert spectrum includes: obtaining a fault detection result based on the frequency and energy amplitude. Obtaining the fault detection result of the AC / DC hybrid microgrid according to the frequency and energy amplitude included in the Hilbert spectrum can make the fault detection process of the AC / DC hybrid microgrid simpler and improve the fault detection efficiency of the AC / DC hybrid microgrid.

[0010] In some embodiments, obtaining a fault detection result based on frequency and energy amplitude includes: obtaining a fault detection result based on frequency, a preset frequency threshold, energy amplitude, and a preset energy amplitude threshold. By obtaining a fault detection result based on frequency, a preset frequency threshold, energy amplitude, and a preset energy amplitude threshold, the fault detection process can be made simpler and the accuracy of the fault detection result can be improved.

[0011] In some embodiments, the fault detection result includes the fault type, the preset frequency threshold includes the preset frequency threshold corresponding to the fault type, and the preset energy amplitude threshold includes the preset energy amplitude threshold corresponding to the fault type; based on the frequency, the preset frequency threshold, the energy amplitude, and the preset energy amplitude threshold, the fault detection result is obtained, including: based on the frequency, the preset frequency threshold corresponding to the fault type, the energy amplitude, and the preset energy amplitude threshold corresponding to the fault type, the fault type is obtained. The fault type can be detected by obtaining the frequency, the preset frequency threshold corresponding to the fault type, the energy amplitude, and the preset energy amplitude threshold corresponding to the fault type, so that the AC / DC hybrid microgrid can be accurately located.

[0012] In some embodiments, the fault detection result includes a fault type, and the fault type includes no fault, single-phase grounding fault on the AC side, single-pole grounding fault on the DC side, and inter-pole fault on the DC side. In the fault detection of the AC / DC hybrid microgrid, the fault type includes no fault, single-phase grounding fault on the AC side, single-pole grounding fault on the DC side, and inter-pole fault on the DC side, which can further improve the accuracy of fault location of the AC / DC hybrid microgrid.

[0013] In some embodiments, the AC / DC hybrid microgrid includes an AC circuit breaker on the AC side and a DC circuit breaker on the DC side, and the method further includes: in response to the fault detection result indicating that the AC / DC hybrid microgrid has a fault, controlling at least one of the AC circuit breaker and the DC circuit breaker to disconnect. In response to the fault detection result indicating that the AC / DC hybrid microgrid has a fault, controlling at least one of the AC circuit breaker and the DC circuit breaker to disconnect can achieve rapid isolation of the fault, thereby protecting the AC / DC hybrid microgrid.

[0014] In some embodiments, after at least one of the AC circuit breaker and the DC circuit breaker is controlled to be disconnected, the interconnected converter coupled between the AC side and the DC side of the AC / DC hybrid microgrid is controlled to be locked. After at least one of the AC circuit breaker and the DC circuit breaker is controlled to be disconnected, the interconnected converter coupled between the AC side and the DC side of the AC / DC hybrid microgrid is controlled to be locked, thereby reducing the probability of damage to the interconnected converter, thereby further protecting the AC / DC hybrid microgrid.

[0015] An embodiment of the second aspect of the present application provides a fault detection device for an AC / DC hybrid microgrid, comprising: an acquisition module for acquiring a current signal of the AC / DC hybrid microgrid; a transformation module for performing a Hilbert-Huang transform on the current signal to obtain a Hilbert spectrum; and a detection module for obtaining a fault detection result of the AC / DC hybrid microgrid based on the Hilbert spectrum.

[0016] In the technical solution of the embodiment of the present application, a Hilbert-Huang transform is performed on the current signal of the AC / DC hybrid microgrid to obtain a Hilbert spectrum; and based on the Hilbert spectrum, a fault detection result of the AC / DC hybrid microgrid is obtained, so that the fault detection process of the AC / DC hybrid microgrid is simple and the fault detection result is accurate and reliable, thereby improving the rate and accuracy of fault detection of the AC / DC hybrid microgrid.

[0017] In some embodiments, the AC / DC hybrid microgrid includes an interconnected converter coupled between an AC side and a DC side; the acquisition module is further used to acquire a transient current signal when the interconnected converter is not locked as the current signal.

[0018] In some embodiments, the transient current signal includes an AC side transient current signal and / or a DC side transient current signal.

[0019] In some embodiments, the Hilbert spectrum includes frequency and energy amplitude; the detection module is further used to obtain a fault detection result based on the frequency and energy amplitude.

[0020] In some embodiments, the Hilbert spectrum includes frequency and energy amplitude; the detection module is further used to obtain a fault detection result based on the frequency and energy amplitude. The detection module is further used to obtain a fault detection result based on the frequency, a preset frequency threshold, the energy amplitude, and a preset energy amplitude threshold.

[0021] In some embodiments, the fault detection result includes the fault type, the preset frequency threshold includes the preset frequency threshold corresponding to the fault type, and the preset energy amplitude threshold includes the preset energy amplitude threshold corresponding to the fault type; the detection module is also used to obtain the fault type based on the frequency, the preset frequency threshold corresponding to the fault type, the energy amplitude and the preset energy amplitude threshold corresponding to the fault type.

[0022] In some embodiments, the fault detection result includes a fault type, and the fault type includes no fault, an AC side single-phase grounding fault, a DC side single-pole grounding fault, and a DC side inter-pole fault.

[0023] In some embodiments, the AC / DC hybrid microgrid includes an AC circuit breaker on the AC side and a DC circuit breaker on the DC side, and the device also includes: a first control module, which is used to control at least one of the AC circuit breaker and the DC circuit breaker to disconnect in response to a fault detection result indicating that there is a fault in the AC / DC hybrid microgrid.

[0024] In some embodiments, the device further includes: a second control module for controlling the interconnection converter coupled between the AC side and the DC side of the AC / DC hybrid microgrid to be locked after controlling at least one of the AC circuit breaker and the DC circuit breaker to be disconnected.

[0025] An embodiment of the third aspect of the present application provides a computing device, comprising at least one processor; and at least one memory communicatively connected to the at least one processor, wherein the at least one memory stores instructions, and when the instructions are executed individually or collectively by the at least one processor, the computing device executes any one of the above methods.

[0026] An embodiment of the fourth aspect of the present application provides a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, any of the above methods is implemented.

[0027] An embodiment of the fifth aspect of the present application provides a computer program product, including a computer-readable code, or a non-volatile computer-readable storage medium carrying the computer-readable code. When the computer-readable code runs in an electronic device, a processor in the electronic device executes any one of the above methods.

[0028] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0030] Figure 1 A flow chart of a fault detection method for an AC / DC hybrid microgrid according to some embodiments of the present application;

[0031] Figure 2 A schematic diagram of an AC / DC hybrid microgrid according to some embodiments of the present application;

[0032] Figure 3 A schematic diagram of a Hilbert spectrum of some embodiments of the present application;

[0033] Figure 4 A structural block diagram of a fault detection device for an AC / DC hybrid microgrid in some embodiments of the present application;

[0034] Figure 5 A block diagram of a computing device according to some embodiments of the present application. DETAILED DESCRIPTION

[0035] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0037] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0038] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0039] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0040] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0041] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0042] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0043] At present, traditional AC microgrids have the advantage of adapting to changes in different voltage levels, and the generators are easy to maintain. They are the main distribution network mode in current industry and life. With the continuous development of power electronics technology, the demand for investment in energy storage devices and distributed power sources is increasing, and the proportion of DC loads is increasing. DC microgrids can improve the transmission efficiency, power quality, power supply reliability and renewable energy absorption capacity of the power system, and have broad future prospects in residential and commercial power supply.

[0044] The AC / DC hybrid microgrid takes into account both AC microgrid and DC microgrid. It is more suitable for grid investment with a large number of energy storage devices, distributed power sources and various loads. It is an important research direction of smart microgrid.

[0045] Since the interconnection process between the AC system and the DC system in the AC / DC hybrid microgrid usually adopts an interconnected converter topology, there is a strong electrical coupling between the two, especially the existence of the insulated-gate bipolar transistor (IGBT), the AC / DC faults interact with each other, resulting in the AC / DC hybrid microgrid fault characteristics being different from those of the AC system and the DC system. When a short circuit fault occurs in the AC / DC hybrid microgrid line, it will cause voltage drop, current surge, power quality deterioration and other effects. If the detection and protection are not timely, it will cause damage to the equipment and even cause the entire large power grid system to collapse. A fast and effective fault diagnosis solution is the prerequisite for system recovery after a fault.

[0046] Based on the above considerations, in order to detect faults in AC / DC hybrid power grids, the commonly used signal decomposition methods include wavelet transform and Fourier transform. However, the above signal decomposition methods have the disadvantages of requiring the basis function to be determined in advance, not being applicable to nonlinear signals, and not being able to perform feature extraction, and Fourier transform can only perform two-dimensional representation of the signal.

[0047] Based on this, the present application proposes a fault detection method for an AC / DC hybrid microgrid, by performing a Hilbert-Huang transform on the current signal of the AC / DC hybrid microgrid to obtain a Hilbert spectrum; and based on the Hilbert spectrum, a fault detection result of the AC / DC hybrid microgrid is obtained, so that the fault detection process of the AC / DC hybrid microgrid is simple and the fault detection result is accurate and reliable, thereby improving the rate and accuracy of fault detection of the AC / DC hybrid microgrid.

[0048] According to one aspect of the present application, a fault detection method for an AC / DC hybrid microgrid is provided.

[0049] Figure 1 This is a flow chart of a fault detection method for an AC / DC hybrid microgrid in some embodiments of the present application. Figure 1As shown, the fault detection method of the AC / DC hybrid microgrid includes: step S110, obtaining the current signal of the AC / DC hybrid microgrid; step S120, performing Hilbert-Huang transform on the current signal to obtain a Hilbert spectrum; step S130, obtaining the fault detection result of the AC / DC hybrid microgrid based on the Hilbert spectrum.

[0050] In the example, Figure 2 Schematic diagram of an AC / DC hybrid microgrid according to some embodiments of the present application, such as Figure 2 As shown, the AC / DC hybrid microgrid may include a DC system (DC side microgrid), an AC system (AC side microgrid) and an interconnected converter. The AC system may include an AC load and an energy storage device, and the DC system may include a DC load, an energy storage device and a distributed power source. The AC system is connected to the AC grid, and the AC system and the DC system are coupled through an interconnected converter.

[0051] In the example, the current signal of the AC / DC hybrid microgrid may be a current signal of an AC system, which may be Figure 2 The current signal obtained at the A1, B1 and C1 positions in the AC / DC hybrid microgrid can be the current signal of the DC system, which can be Figure 2 The current signal obtained at the D1 and E1 positions in the AC / DC hybrid microgrid can also include the current signal of the AC system and the current signal of the DC system at the same time, which can be Figure 2 The current signals obtained at the positions A1, B1, C1, D1 and E1 in the figure can be obtained by setting current sensors at the positions A1, B1, C1, D1 and E1.

[0052] In the example, Hilbert-Huang Transform (HHT) is a joint time-frequency domain analysis method with the adaptability of basis functions, suitable for detecting nonlinear and non-stationary signals, and capable of feature extraction. HHT decomposes complex signals from empirical modes into several intrinsic mode functions (IMFs), and performs Hilbert transform on IMFs to make the instantaneous frequency of the signal a single component, thereby calculating the instantaneous frequency, instantaneous amplitude and energy of each IMF, and obtaining the time-frequency distribution of the original signal, that is, the Hilbert spectrum. Figure 3 dimensional distribution, high resolution, and can fully reflect the essential characteristics of the signal.

[0053] When an AC / DC hybrid microgrid fails, it is usually accompanied by a sudden change in current, and the current signal shows time-varying or non-stationary characteristics. When an AC / DC hybrid microgrid fails, the Hilbert Huang transform is performed on the current signal to obtain the Hilbert spectrum. The Hilbert spectrum changes significantly under different faults. Through the three-dimensional distribution of time, frequency and energy, it has high resolution and can fully reflect the essential characteristics of the current signal.

[0054] The time-frequency characteristics of the current in the AC / DC hybrid grid when a fault occurs are different from those of the current in the AC / DC hybrid grid when the grid is in normal operation. Therefore, the fault detection result of the AC / DC hybrid microgrid can be obtained through the Hilbert spectrum. Figure 3 Schematic diagram of the Hilbert spectrum of some embodiments of the present application, such as Figure 3 As shown in the figure, the distribution of frequency and energy amplitude of the Hilbert spectrum of DC side single-pole grounding fault, DC side inter-pole fault, AC side single-phase grounding fault Hilbert spectrum and normal fault Hilbert spectrum all show different characteristics. Therefore, based on the Hilbert spectrum, the fault detection result of the AC / DC hybrid microgrid can be obtained. The fault detection result can include whether a fault occurs. After determining that a fault occurs in the AC / DC hybrid grid, the fault detection result can also include the specific fault type.

[0055] In the embodiment of the present application, compared with the traditional time-domain fault detection, the overcurrent protection of Hilbert Huang transformation is not easily affected by high impedance and operation mode, and has no threshold selection problem; compared with the current change rate protection, it is not easily disturbed by noise signals; compared with the distance protection, it can identify the DC side pole-to-pole fault; compared with the direction longitudinal protection, there is no communication requirement; compared with the differential current protection, it is easy to identify the DC side pole-to-pole fault. The time-domain fault detection method has the advantages of simple calculation, rapid detection, and sensitive response. Therefore, by performing Hilbert Huang transformation on the current signal of the AC / DC hybrid microgrid, the Hilbert spectrum is obtained; and based on the Hilbert spectrum, the fault detection result of the AC / DC hybrid microgrid is obtained, so that the fault detection process of the AC / DC hybrid microgrid is simple and the fault detection result is accurate and reliable, thereby improving the rate and accuracy of fault detection of the AC / DC hybrid microgrid.

[0056] According to some embodiments of the present application, an AC / DC hybrid microgrid includes an interconnected converter coupled between an AC side and a DC side, and obtaining a current signal of the AC / DC hybrid microgrid includes: obtaining a transient current signal when the interconnected converter is not locked as a current signal.

[0057] In the example, the current signal when a fault occurs in the AC / DC hybrid microgrid may be caused by the combined action of the DC system and the AC system, resulting in the current signal being too large when a fault occurs in the AC / DC hybrid microgrid, and the peak value of the transient current signal is much larger than the maximum tolerance value of the IGBT in the AC / DC hybrid microgrid. Therefore, the transient current signal during locking is not suitable for fault detection of the AC / DC hybrid microgrid. In order to protect the IGBT in the AC / DC hybrid microgrid and perform fast and accurate fault detection on the AC / DC hybrid microgrid, the embodiment of the present application uses the transient current signal when the interconnected converter is not locked as the current signal for fault detection of the AC / DC hybrid microgrid.

[0058] According to the embodiments of the present application, the current signal when the interconnected converter is not locked after a fault is the starting signal. The fault of the current signal in this process is more significant than the fault of the current signal in the locked state. The transient current signal when the interconnected converter is not locked has higher accuracy in fault detection. Therefore, by obtaining the transient current signal when the interconnected converter is not locked as the current signal for fault detection of the AC / DC hybrid microgrid, the accuracy of fault detection of the AC / DC hybrid microgrid is improved.

[0059] According to some embodiments of the present application, the transient current signal includes an AC side transient current signal and / or a DC side transient current signal.

[0060] For example, the AC side transient current signal may be Figure 2 The current signals obtained at the A1, B1 and C1 positions in the DC side can be Figure 2 The current signal obtained at the D1 or E1 position in the circuit.

[0061] In the example, when fault detection is performed on an AC / DC hybrid microgrid, only an AC side transient current signal may be obtained, only a DC side transient current signal may be obtained, or both an AC side transient current signal and a DC side transient current signal may be obtained simultaneously. Both the AC side transient current signal and the DC side transient current signal may be obtained by current sensors pre-set in the AC / DC hybrid microgrid.

[0062] For example, inter-pole faults and single-phase grounding faults can be detected through transient current signals on the AC side and transient current signals on the DC side, which is conducive to the accurate detection of specific faults. However, when the fault detection accuracy is not much different, the same fault measurement point is used for detection. The AC single-phase grounding fault and the DC bipolar grounding fault can be detected through the DC side transient current signal.

[0063] In an embodiment of the present application, during fault detection, the transient current signal includes an AC side transient current signal and a DC side transient current signal, which is beneficial to improving the accuracy of the fault detection result; when the transient current signal only includes an AC side transient current signal or a DC side transient current signal, the number of transient current signals obtained can be reduced, thereby reducing the cost of fault detection.

[0064] According to some embodiments of the present application, the Hilbert spectrum includes frequency and energy amplitude; and obtaining a fault detection result based on the Hilbert spectrum includes: obtaining a fault detection result based on frequency and energy amplitude.

[0065] In the embodiments of the present application, Figure 3 As shown, the Hilbert spectrum includes frequency and energy amplitude. When the fault detection result of the AC / DC hybrid microgrid is obtained based on the Hilbert spectrum, the fault detection result of the AC / DC hybrid microgrid can be directly obtained according to the specific values ​​of the frequency and energy amplitude, or the fault detection result of the AC / DC hybrid microgrid can be obtained according to the frequency, energy amplitude and the corresponding preset threshold.

[0066] In an embodiment of the present application, the fault detection result of the AC / DC hybrid microgrid is obtained according to the frequency and energy amplitude included in the Hilbert spectrum, which can make the fault detection process of the AC / DC hybrid microgrid simpler and improve the fault detection efficiency of the AC / DC hybrid microgrid.

[0067] According to some embodiments of the present application, a fault detection result is obtained based on frequency and energy amplitude, including: obtaining a fault detection result based on frequency, a preset frequency threshold, energy amplitude and a preset energy amplitude threshold.

[0068] For example, before fault detection is performed on the AC / DC hybrid microgrid, MATLAB or Simulink software may be used to perform simulation verification on the AC / DC hybrid microgrid. The simulation system parameters during the simulation verification are the same as the parameters of the AC / DC hybrid microgrid, as shown in the following table.

[0069] Simulation system parameter list

[0070]

[0071] The Hilbert spectrum is obtained by simulation, and the frequency and energy amplitude in the Hilbert spectrum corresponding to various faults are summarized to obtain the frequency threshold and energy amplitude threshold corresponding to the fault detection result, and the frequency threshold and energy amplitude threshold corresponding to the fault detection result are used as the preset frequency threshold and preset energy amplitude threshold. The preset frequency threshold and preset energy amplitude threshold can include maximum and minimum values.

[0072] The frequency is compared with a preset frequency threshold, and the energy amplitude is compared with a preset energy amplitude threshold. When the frequency meets the preset frequency threshold and the energy amplitude meets the preset energy amplitude threshold, a fault detection result is determined.

[0073] In the embodiment of the present application, by obtaining a fault detection result based on frequency, a preset frequency threshold, an energy amplitude and a preset energy amplitude threshold, the fault detection process can be simplified and the accuracy of the fault detection result can be improved.

[0074] According to some embodiments of the present application, the fault detection result includes the fault type, the preset frequency threshold includes the preset frequency threshold corresponding to the fault type, and the preset energy amplitude threshold includes the preset energy amplitude threshold corresponding to the fault type; based on the frequency, the preset frequency threshold, the energy amplitude and the preset energy amplitude threshold, the fault detection result is obtained, including:

[0075] The fault type is obtained based on the frequency, the preset frequency threshold corresponding to the fault type, the energy amplitude, and the preset energy amplitude threshold corresponding to the fault type.

[0076] In the embodiment of the present application, the fault type may include no fault, single-pole grounding, inter-pole short circuit, single-phase grounding, double-pole grounding, single-pole low-resistance grounding, single-pole high-resistance grounding, and power change. Using the simulation system parameters in the above embodiment, a fault simulation can be performed to obtain a simulation result list, which may include energy amplitudes and frequencies corresponding to the fault types.

[0077] Simulation results list

[0078]

[0079] As can be seen from the above table, the frequency spectrum characteristics of the Hilbert spectrum under different fault conditions are significantly different from those under normal working conditions, and there are also significant differences in the frequency distribution and energy amplitude of the Hilbert spectrum of different faults. Under normal working conditions, the frequency distribution is around 500Hz; the frequency of single-pole grounding faults is mainly distributed between 4kHz and 6kHz; the frequency of inter-pole faults and single-phase grounding faults is mainly distributed around 500Hz. Compared with normal working conditions, the frequency is mainly concentrated between 5ms and 15ms after the fault occurs; the inter-pole fault 500Hz is mainly distributed in the energy amplitude of 70-90, and the single-phase grounding fault 500Hz is mainly distributed in the energy amplitude of 15 to 25. The 500Hz energy amplitude of both is lower than that of normal working conditions. In this way, different AC and DC fault conditions can be identified, so as to accurately locate, isolate and protect quickly.

[0080] In the example, the energy amplitude corresponding to the fault type is used as the preset frequency threshold corresponding to the fault type, and the frequency corresponding to the fault type is used as the preset frequency threshold corresponding to the fault type. When the frequency meets the preset frequency threshold corresponding to the fault type, and the energy amplitude meets the preset energy amplitude threshold corresponding to the fault type, the fault type is determined.

[0081] In the embodiment of the present application, the fault type is obtained by the frequency, the preset frequency threshold corresponding to the fault type, the energy amplitude and the preset energy amplitude threshold corresponding to the fault type, and the fault type can be detected, so that the AC / DC hybrid microgrid can be accurately located.

[0082] According to some embodiments of the present application, the fault detection result includes a fault type, and the fault type includes no fault, a single-phase grounding fault on the AC side, a single-pole grounding fault on the DC side, and an inter-pole fault on the DC side.

[0083] In the example, Figure 2 As shown, the AC side single-phase grounding fault refers to Figure 2 Any phase A, B, or C in the AC side circuit is grounded. A single-pole grounding fault on the DC side means Figure 2 If any of the P, O, or N poles in the DC side circuit is grounded, the DC side pole fault means Figure 2 A short circuit occurs between any two poles of P, O, and N in the DC side circuit.

[0084] No fault, single-phase grounding fault on the AC side, single-pole grounding fault on the DC side, and inter-pole fault on the DC side are the most common fault types in AC / DC hybrid microgrids. In order to ensure the normal operation of AC / DC hybrid microgrids, at least the above fault types need to be detected in the fault detection of AC / DC hybrid microgrids.

[0085] In an embodiment of the present application, in the fault detection of the AC / DC hybrid microgrid, the fault types include no fault, single-phase grounding fault on the AC side, single-pole grounding fault on the DC side, and inter-pole fault on the DC side, which can further improve the accuracy of fault location of the AC / DC hybrid microgrid.

[0086] According to some embodiments of the present application, an AC / DC hybrid microgrid includes an AC circuit breaker on the AC side and a DC circuit breaker on the DC side, and the method further includes: in response to a fault detection result indicating that a fault exists in the AC / DC hybrid microgrid, controlling at least one of the AC circuit breaker and the DC circuit breaker to disconnect.

[0087] In the example, a circuit breaker refers to a switch device that can close, carry and interrupt the current under normal circuit conditions and can close, carry and interrupt the current under abnormal circuit conditions within a specified time. Circuit breakers can be divided into high-voltage circuit breakers and low-voltage circuit breakers according to their scope of use.

[0088] In the example, the circuit breaker is set on the busbar on the AC side or the busbar on the DC side. In addition, the circuit breaker can also be set at the rear end of the capacitor in the AC / DC hybrid microgrid. In response to the fault detection result indicating that the AC / DC hybrid microgrid has a fault, at least one of the AC circuit breaker and the DC circuit breaker is controlled to be disconnected to achieve fault isolation of the AC / DC hybrid microgrid.

[0089] In an embodiment of the present application, in response to a fault detection result indicating that a fault exists in the AC / DC hybrid microgrid, at least one of the AC circuit breaker and the DC circuit breaker is controlled to be disconnected, so that the fault can be quickly isolated, thereby protecting the AC / DC hybrid microgrid.

[0090] According to some embodiments of the present application, the method further includes: after controlling at least one of the AC circuit breaker and the DC circuit breaker to be disconnected, controlling an interconnected converter coupled between the AC side and the DC side of the AC / DC hybrid microgrid to be locked.

[0091] In the example, the interconnected converter lockout may refer to the lockout of the insulated-gate bipolar transistor (IGBT) included in the interconnected converter. After controlling at least one of the AC circuit breaker and the DC circuit breaker to be disconnected, a micro-current may still flow in the interconnected converter. If the interconnected converter is not locked out, components in the interconnected converter may be damaged.

[0092] If a fault occurs, the interconnected converter will be locked immediately, and the entire AC / DC hybrid microgrid will expand the fault range, seriously affecting the power supply reliability of the AC / DC hybrid microgrid. In actual projects, after the fault occurs, the interconnected converter will briefly maintain its normal working state, but the transient process of the fault is very fast, often only tens of milliseconds, and the interconnected converter cannot respond to the sudden fault current during the transient process in time, resulting in damage; therefore, in actual fault detection, the AC / DC hybrid microgrid is fault-detected when the interconnected converter is not locked, so as to send an on / off signal command to control the AC / DC circuit breaker, and achieve rapid fault isolation and protection.

[0093] After controlling at least one of the AC circuit breaker and the DC circuit breaker to be opened, the IGBTs at other locations in the AC / DC hybrid microgrid can also be controlled to be locked.

[0094] In an embodiment of the present application, after controlling at least one of the AC circuit breaker and the DC circuit breaker to disconnect, the interconnected converter coupled between the AC side and the DC side of the AC / DC hybrid microgrid is controlled to be locked, thereby reducing the probability of damage to the interconnected converter and further protecting the AC / DC hybrid microgrid.

[0095] According to another aspect of the present application, a fault detection device for an AC / DC hybrid microgrid is also provided.

[0096] Figure 4 4 is a structural block diagram of a fault detection device 400 for an AC / DC hybrid microgrid according to some embodiments of the present application. Figure 4 As shown, the fault detection device 400 for an AC / DC hybrid microgrid includes an acquisition module 410, a transformation module 420, and a detection module 430. The acquisition module 410 is used to acquire the current signal of the AC / DC hybrid microgrid; the transformation module 420 is used to perform Hilbert-Huang transform on the current signal to obtain a Hilbert spectrum; and the detection module 430 is used to obtain a fault detection result of the AC / DC hybrid microgrid based on the Hilbert spectrum.

[0097] According to an embodiment of the present application, a Hilbert spectrum is obtained by performing a Hilbert-Huang transform on a current signal of an AC / DC hybrid microgrid; and based on the Hilbert spectrum, a fault detection result of the AC / DC hybrid microgrid is obtained, so that the fault detection process of the AC / DC hybrid microgrid is simple and the fault detection result is accurate and reliable, thereby improving the rate and accuracy of fault detection of the AC / DC hybrid microgrid.

[0098] In one embodiment, the AC / DC hybrid microgrid includes an interconnected converter coupled between an AC side and a DC side; the acquisition module 410 is further used to acquire a transient current signal when the interconnected converter is not locked as the current signal.

[0099] In one embodiment, the transient current signal includes an AC side transient current signal and / or a DC side transient current signal.

[0100] In one embodiment, the Hilbert spectrum includes frequency and energy amplitude; the detection module 430 is further configured to obtain a fault detection result based on the frequency and energy amplitude.

[0101] In one embodiment, the detection module 430 is further configured to obtain a fault detection result based on the frequency, the preset frequency threshold, the energy amplitude, and the preset energy amplitude threshold.

[0102] In one embodiment, the fault detection result includes the fault type, the preset frequency threshold includes the preset frequency threshold corresponding to the fault type, and the preset energy amplitude threshold includes the preset energy amplitude threshold corresponding to the fault type; the detection module 430 is also used to obtain the fault type based on the frequency, the preset frequency threshold corresponding to the fault type, the energy amplitude and the preset energy amplitude threshold corresponding to the fault type.

[0103] In one embodiment, the fault detection result includes a fault type, and the fault type includes no fault, an AC side single-phase grounding fault, a DC side single-pole grounding fault, and a DC side inter-pole fault.

[0104] In one embodiment, the AC / DC hybrid microgrid includes an AC circuit breaker on the AC side and a DC circuit breaker on the DC side, and the fault detection device 400 of the AC / DC hybrid microgrid also includes: a first control module, which is used to control at least one of the AC circuit breaker and the DC circuit breaker to disconnect in response to the fault detection result indicating that there is a fault in the AC / DC hybrid microgrid.

[0105] In one embodiment, the fault detection device 400 for an AC / DC hybrid microgrid further includes: a second control module, configured to control the locking of an interconnected converter coupled between the AC side and the DC side of the AC / DC hybrid microgrid after controlling at least one of the AC circuit breaker and the DC circuit breaker to be disconnected.

[0106] It should be understood that the above reference Figure 4 The modules described can be compared with the reference Figure 1 The various steps in the described method embodiment correspond to each other. Therefore, the operations, features and advantages described above for the method embodiment are also applicable to the fault detection device 400 and the modules included therein. For the sake of brevity, some operations, features and advantages are not repeated here.

[0107] Although specific functions are discussed above with reference to specific modules, it should be noted that the functions of the various modules discussed herein may be divided into multiple modules, and / or at least some functions of multiple modules may be combined into a single module. The specific module discussed herein performing an action includes the specific module itself performing the action, or alternatively the specific module calling or otherwise accessing another component or module that performs the action (or performs the action in conjunction with the specific module). Therefore, the specific module that performs an action may include the specific module itself that performs the action and / or another module that the specific module calls or otherwise accesses to perform the action.

[0108] It should also be understood that various techniques may be described herein in the general context of software hardware elements or program modules. Figure 4 The various modules described may be implemented in hardware or in hardware in combination with software and / or firmware. For example, the modules may be implemented as computer program code / instructions configured to be executed in one or more processors and stored in a computer-readable storage medium. Alternatively, the modules may be implemented as hardware logic / circuits.

[0109] According to another aspect of the present application, a computing device is also provided, comprising at least one processor; and at least one memory communicatively connected to the at least one processor, wherein the at least one memory stores instructions, and when the instructions are executed individually or collectively by the at least one processor, the computing device executes any one of the methods in the aforementioned embodiments.

[0110] Figure 5 4 is a block diagram of a computing device 500 according to some embodiments of the present application. For example, the above-mentioned AC / DC hybrid microgrid fault detection device can be fully or at least partially implemented by the computing device 500 or a similar device or system.

[0111] The computing device 500 can be a variety of different types of devices. Examples of computing device 500 include, but are not limited to, desktop computers, server computers, laptop or netbook computers, mobile devices (e.g., tablet computers, cellular or other wireless phones (e.g., smart phones), notepad computers, mobile stations), wearable devices (e.g., glasses, watches), entertainment devices (e.g., entertainment appliances, set-top boxes communicatively coupled to a display device, game consoles), televisions or other display devices, automotive computers, and the like.

[0112] The computing device 500 may include at least one processor 502, memory 504, communication interface(s) 506, a display device 508, other input / output (I / O) devices 510, and one or more mass storage devices 512, all capable of communicating with one another, such as via a system bus 514 or other appropriate connections.

[0113] The processor 502 may be a single processing unit or multiple processing units, all of which may include a single or multiple computing units or multiple cores. The processor 502 may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuits, and / or any device that manipulates signals based on operating instructions. Among other capabilities, the processor 502 may be configured to obtain and execute computer-readable instructions stored in the memory 504, mass storage device 512, or other computer-readable media, such as program code of an operating system 516, program code of an application program 518, program code of other programs 520, and the like.

[0114] The memory 504 and the mass storage device 512 are examples of computer-readable storage media for storing instructions that are executed by the processor 502 to implement the various functions described above. For example, the memory 504 may generally include both volatile memory and non-volatile memory (e.g., RAM, ROM, etc.). In addition, the mass storage device 512 may generally include a hard drive, a solid-state drive, a removable medium, including external and removable drives, a memory card, a flash memory, a floppy disk, an optical disk (e.g., a CD, a DVD), a storage array, a network attached storage, a storage area network, etc. The memory 504 and the mass storage device 512 may all be collectively referred to herein as memory or computer-readable storage media, and may be a non-transitory medium capable of storing computer-readable, processor-executable program instructions as computer program code, which may be executed by the processor 502 as a specific machine configured to implement the operations and functions described in the examples herein.

[0115] A plurality of programs may be stored on the mass storage device 512. These programs include an operating system 516, one or more application programs 518, other programs 520, and program data 522, and they may be loaded into the memory 504 for execution. Examples of such applications or program modules may include, for example, computer program logic (e.g., computer program code or instructions) for implementing the following components / functions: a fault detection method for an AC / DC hybrid microgrid (including any suitable steps of the method), and / or other embodiments described herein.

[0116] Although in Figure 5 504 of computing device 500, but operating system 516, application programs 518, other programs 520, and program data 522, or portions thereof, may be implemented using any form of computer-readable media accessible by computing device 500. As used herein, "computer-readable media" includes at least two types of computer-readable media, namely, computer-readable storage media and communication media.

[0117] Computer-readable storage media include volatile and non-volatile, removable and non-removable media implemented by any method or technology for storing information, such as computer-readable instructions, data structures, program modules, or other data. Computer-readable storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD), or other optical storage device, magnetic cassette, magnetic tape, magnetic disk storage device or other magnetic storage device, or any other non-transmission medium that can be used to store information for access by a computing device. In contrast, communication media can embody computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transmission mechanism. Computer-readable storage media as defined herein do not include communication media.

[0118] One or more communication interfaces 506 are used to exchange data with other devices, such as through a network, direct connection, etc. Such communication interfaces can be one or more of the following: any type of network interface (e.g., a network interface card (NIC)), a wired or wireless (such as IEEE 802.11 wireless LAN (WLAN)) wireless interface, a Worldwide Interoperability for Microwave Access (Wi-MAX) interface, an Ethernet interface, a Universal Serial Bus (USB) interface, a cellular network interface, a Bluetooth™ interface, a Near Field Communication (NFC) interface, etc. The communication interface 506 can facilitate communication within a variety of network and protocol types, including wired networks (e.g., LAN, cable, etc.) and wireless networks (e.g., WLAN, cellular, satellite, etc.), the Internet, etc. The communication interface 506 can also provide communication with external storage devices (not shown) such as storage arrays, network attached storage, storage area networks, etc.

[0119] In some examples, a display device 508 such as a monitor may be included for displaying information and images to the user. Other I / O devices 510 may be devices that receive various inputs from the user and provide various outputs to the user, and may include touch input devices, gesture input devices, cameras, keyboards, remote controls, mice, printers, audio input / output devices, and the like.

[0120] The technology described herein can be supported by these various configurations of the computing device 500, and is not limited to the specific examples of the technology described herein. For example, the functionality can also be implemented in whole or in part on the "cloud" by using a distributed system. The cloud includes and / or represents a platform for resources. The platform abstracts the underlying functionality of the hardware (e.g., server) and software resources of the cloud. Resources can include applications and / or data that can be used when performing computing processing on a server away from the computing device 500. Resources can also include services provided over the Internet and / or through a subscriber network such as a cellular or Wi-Fi network. The platform can abstract resources and functions to connect the computing device 500 to other computing devices. Therefore, the implementation of the functions described herein can be distributed throughout the cloud. For example, the functions can be implemented partially on the computing device 500 and partially through a platform that abstracts the functions of the cloud.

[0121] According to another aspect of the present application, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the method of any one of the aforementioned embodiments is implemented during execution.

[0122] According to another aspect of the present application, a computer program product is also provided, including a computer-readable code, or a non-volatile computer-readable storage medium carrying the computer-readable code. When the computer-readable code runs in an electronic device, a processor in the electronic device executes a method for implementing any one of the aforementioned embodiments.

[0123] It should be understood that, although the steps in the flowcharts involved in the above embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0124] According to an embodiment of the present application, a fault in an AC / DC hybrid microgrid may be detected by the following method.

[0125] The AC / DC hybrid microgrid may include an interconnected converter coupled between an AC side and a DC side, an AC circuit breaker on the AC side, and a DC circuit breaker on the DC side.

[0126] First, an AC side transient current signal and / or a DC side transient current signal when the interconnected converter is not locked is obtained.

[0127] Next, a Hilbert-Huang transform is performed on the transient current signal on the AC side and / or the transient current signal on the DC side when the interconnected converter is not locked, to obtain a Hilbert spectrum, which includes frequency and energy amplitude.

[0128] Based on the frequency in the Hilbert spectrum, the preset frequency threshold corresponding to the fault type, the energy amplitude in the Hilbert spectrum and the preset energy amplitude threshold corresponding to the fault type, the fault type of the AC / DC hybrid microgrid is obtained, wherein the fault type may include no fault, single-phase grounding fault on the AC side, single-pole grounding fault on the DC side, and inter-pole fault on the DC side.

[0129] Next, in response to the fault detection result indicating that the AC / DC hybrid microgrid has a fault, at least one of the AC circuit breaker and the DC circuit breaker can be controlled to be disconnected. After at least one of the AC circuit breaker and the DC circuit breaker is controlled to be disconnected, the interconnection converter coupled between the AC side and the DC side of the AC / DC hybrid microgrid is controlled to be locked.

[0130] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A fault detection method for an AC / DC hybrid microgrid, It is characterized in that include: Acquiring a current signal of the AC / DC hybrid microgrid; Performing Hilbert-Huang transform on the current signal to obtain a Hilbert spectrum; Based on the Hilbert spectrum, a fault detection result of the AC / DC hybrid microgrid is obtained.

2. The method according to claim 1, It is characterized in that The AC / DC hybrid microgrid includes an interconnected converter coupled between an AC side and a DC side, and obtaining a current signal of the AC / DC hybrid microgrid includes: A transient current signal when the interconnected converter is not locked is obtained as the current signal.

3. The method according to claim 2, It is characterized in that The transient current signal includes an AC side transient current signal and / or a DC side transient current signal.

4. The method according to any one of claims 1 to 3, It is characterized in that The Hilbert spectrum includes frequency and energy amplitude; The fault detection result obtained based on the Hilbert spectrum includes: The fault detection result is obtained based on the frequency and the energy amplitude.

5. The method according to claim 4, It is characterized in that The obtaining the fault detection result based on the frequency and the energy amplitude includes: The fault detection result is obtained based on the frequency, the preset frequency threshold, the energy amplitude and the preset energy amplitude threshold.

6. The method according to claim 5, It is characterized in that The fault detection result includes a fault type, the preset frequency threshold includes a preset frequency threshold corresponding to the fault type, and the preset energy amplitude threshold includes a preset energy amplitude threshold corresponding to the fault type; The obtaining of the fault detection result based on the frequency, the preset frequency threshold, the energy amplitude and the preset energy amplitude threshold comprises: The fault type is obtained based on the frequency, the preset frequency threshold corresponding to the fault type, the energy amplitude, and the preset energy amplitude threshold corresponding to the fault type.

7. The method according to any one of claims 1 to 6, It is characterized in that The fault detection result includes a fault type, and the fault type includes no fault, an AC side single-phase grounding fault, a DC side single-pole grounding fault, and a DC side inter-pole fault.

8. The method according to any one of claims 1 to 7, It is characterized in that The AC / DC hybrid microgrid includes an AC circuit breaker on an AC side and a DC circuit breaker on a DC side, and the method further includes: In response to the fault detection result indicating that a fault exists in the AC / DC hybrid microgrid, at least one of the AC circuit breaker and the DC circuit breaker is controlled to be disconnected.

9. The method according to claim 8, It is characterized in that The method further comprises: After controlling at least one of the AC circuit breaker and the DC circuit breaker to be opened, controlling an interconnection converter coupled between an AC side and a DC side of the AC / DC hybrid microgrid to be locked.

10. A fault detection device for an AC / DC hybrid microgrid, It is characterized in that include: An acquisition module, used to acquire a current signal of the AC / DC hybrid microgrid; A transformation module, used for performing Hilbert-Huang transformation on the current signal to obtain a Hilbert spectrum; The detection module is used to obtain a fault detection result of the AC / DC hybrid microgrid based on the Hilbert spectrum.

11. The device according to claim 10, It is characterized in that The AC / DC hybrid microgrid includes an interconnected converter coupled between an AC side and a DC side; The acquisition module is also used to acquire a transient current signal when the interconnected converter is not locked as the current signal.

12. The device according to claim 11, It is characterized in that The transient current signal includes an AC side transient current signal and / or a DC side transient current signal.

13. The device according to any one of claims 9 to 12, It is characterized in that The Hilbert spectrum includes frequency and energy amplitude; The detection module is further configured to obtain the fault detection result based on the frequency and the energy amplitude.

14. The device according to claim 13, It is characterized in that The detection module is also used to obtain the fault detection result based on the frequency, the preset frequency threshold, the energy amplitude and the preset energy amplitude threshold.

15. The device according to claim 14, It is characterized in that The fault detection result includes a fault type, the preset frequency threshold includes a preset frequency threshold corresponding to the fault type, and the preset energy amplitude threshold includes a preset energy amplitude threshold corresponding to the fault type; The detection module is further configured to obtain the fault type based on the frequency, a preset frequency threshold corresponding to the fault type, the energy amplitude, and a preset energy amplitude threshold corresponding to the fault type.

16. The device according to any one of claims 9 to 15, It is characterized in that The fault detection result includes a fault type, and the fault type includes no fault, an AC side single-phase grounding fault, a DC side single-pole grounding fault, and a DC side inter-pole fault.

17. The device according to any one of claims 9 to 16, It is characterized in that The AC / DC hybrid microgrid includes an AC circuit breaker on the AC side and a DC circuit breaker on the DC side, and the device also includes: The first control module is configured to control at least one of the AC circuit breaker and the DC circuit breaker to be disconnected in response to the fault detection result indicating that a fault exists in the AC / DC hybrid microgrid.

18. The device according to claim 17, It is characterized in that The device also includes: The second control module is used to control the interconnection converter coupled between the AC side and the DC side of the AC / DC hybrid microgrid to be locked after controlling at least one of the AC circuit breaker and the DC circuit breaker to be disconnected.

19. A computing device, It is characterized in that include: at least one processor; as well as At least one memory is communicatively connected to the at least one processor, the at least one memory stores instructions, and when the instructions are executed by the at least one processor individually or collectively, the computing device performs the method of any one of claims 1 to 9.

20. A computer-readable storage medium, It is characterized in that Instructions are stored, which, when executed individually or collectively by one or more processors of a computing device, cause the computing device to perform the method of any one of claims 1 to 9.

21. A computer program product, It is characterized in that The method comprises instructions which, when executed individually or collectively by one or more processors of a computing device, cause the computing device to perform the method of any one of claims 1 to 9.

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