Short-circuit fault current limiter and control method thereof

Abstract

The invention discloses a short-circuit fault current limiter and a control method thereof. The current limiter comprises a capacitor, two IGBT (Insulated Gate Bipolar Translator) modules and four diode groups, when the line has no short-circuit fault, the two IGBT tubes are controlled to be conducted, and line current flows from the first end of the line to the second end of the line through one IGBT module or flows reversely through the second IGBT module; when a short-circuit fault occurs at the first end of the line, the two IGBTs are controlled to be switched off, the line current flows to the first end of the line from the second end of the line through the first diode group, the capacitor and the fourth diode group, and the capacitor is charged to enable the line to present high impedance so as to restrain the short-circuit current; when a short-circuit fault occurs at the second end of the line, the two IGBTs are controlled to be turned off, the line current flows to the first end of the line from the first end of the line through the third diode group, the capacitor and the second diode group, and the capacitor is charged to enable the line to present high impedance so as to restrain the short-circuit current. The short-circuit fault current limiter is high in response speed and low in equipment cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of power grid interconnection, and in particular relates to a millisecond-level response short-circuit fault current limiter and a control method thereof. Background Art

[0002] With the transformation of energy structures and the development of power systems, regional grid interconnection is becoming increasingly widespread. Globally, countries and regions are accelerating the construction of large and robust power grids. Through the development of ultra-high voltage transmission technology and large-scale AC / DC hybrid power grids, they are achieving efficient interconnection between different grid regions. This trend has significant advantages: on the one hand, it helps optimize resource allocation, enables long-distance transmission of clean energy, and improves energy efficiency; on the other hand, through resource sharing and adjustment, it improves the overall stability and economic efficiency of the power grid and enhances the system's ability to withstand extreme weather and emergencies.

[0003] However, the increasing interconnectivity of power grids has also brought new challenges. Short-circuit currents, in particular, have become increasingly prominent and a major challenge in the operation and safety control of current power systems. Traditional power grid structures are primarily zoned, with weak connections between regions. A failure in one region has a relatively limited impact. However, with deeper regional interconnection, power grids across the country form a highly coupled, complex, and interwoven system. A short-circuit failure in one location can quickly spread to multiple regions, leading to even wider power fluctuations and even chain reactions.

[0004] Furthermore, with the large-scale integration of renewable energy and the widespread use of power electronics, the short-circuit characteristics of the power grid have undergone profound changes. Renewable energy access points often have low short-circuit capacity, making them unable to effectively support current flow during system faults. The rapid response and control logic of power electronics also make short-circuit current waveforms more complex, making them difficult for traditional protection devices to accurately identify. These factors have combined to reduce the power grid's ability to respond to short-circuit faults, increasing the risks to system operation.

[0005] To address these challenges, the industry urgently needs to conduct systematic research on power grid short-circuit issues, including establishing more accurate short-circuit analysis models, developing protection and control strategies adapted to new grid structures, and researching new technical solutions such as current limiting and zoning isolation. Short-circuit current suppression devices, currently widely used in power grids, can alleviate the increasingly severe short-circuit problem to a certain extent. However, in practice, they still face a dilemma: either their response speed is slow, making it difficult to promptly suppress the strong inrush current at the beginning of a fault; or, while their response is fast, the equipment is expensive, making it difficult to promote and apply them on a large scale and across the entire system.

[0006] Specifically, the existing short-circuit current suppression devices have the following technical problems: (1) Slow response speed, such as the current limiting reactor, whose working principle is based on introducing a fixed reactance into the circuit to limit the short-circuit current. Although its response is passive and effective immediately, the current limiting effect is mainly reflected in the steady-state stage of the fault current, and the suppression effect on the initial peak current is limited. Especially at the moment when the system fault current rises rapidly, its impedance cannot be dynamically adjusted, resulting in low current limiting efficiency. At the same time, the current limiting reactor will cause additional voltage drop and energy loss under normal operation, and even cause the system power factor to drop, affecting the power quality. Although this type of device is relatively low in cost and mature in technology, facing the complex and changeable operating characteristics of modern power grids and the rapidly developing short-circuit current level, its response speed and dynamic adaptability have gradually failed to meet the needs. (2) High equipment cost, such as high-temperature superconducting current limiters, which can usually sense system faults and act quickly within milliseconds or even microseconds, effectively suppressing the rapid rise of short-circuit current and greatly improving the system protection capability. However, it is not only technically complex, but also requires high professional capabilities of personnel and system conditions for operation and maintenance. It also needs to be equipped with a complex low-temperature cooling system, which increases the difficulty of maintenance and operating costs.

[0007] Therefore, there is an urgent need to explore a short-circuit current suppression device with a good technical and economic ratio. Summary of the Invention

[0008] In order to solve the above problems in the prior art, the present invention provides a short-circuit fault current limiter and a control method thereof. The current limiter has a fast response speed and low equipment cost.

[0009] According to a first aspect of the present invention, a short-circuit fault current limiter is provided. The current limiter comprises: a capacitor C, two IGBT modules, and four diode groups; wherein: The IGBT module includes an IGBT tube and a diode. The collector of the IGBT tube serves as the first end of the IGBT module. The emitter of the IGBT tube is connected to the anode of the diode, and the cathode of the diode serves as the second end of the IGBT module. The diode group includes a plurality of diodes connected in series, wherein the anode of the upper diode is connected to the cathode of the lower diode, the anode of the first diode serves as the first end of the diode group, and the cathode of the last diode serves as the second end of the diode group; The first end of the first IGBT module is connected to the first end of the circuit, and the second end of the first IGBT module is connected to the second end of the circuit; The first end of the second IGBT module is connected to the second end of the circuit, and the second end of the second IGBT module is connected to the first end of the circuit; The first end of the first diode group is connected to the second end of the line, and the second end of the first diode group is connected to the first end of the capacitor C; A first end of the second diode group is connected to the second end of the capacitor C, and a second end of the second diode group is connected to the second end of the line; A first end of the third diode group is connected to the first end of the line, and a second end thereof is connected to the first end of the capacitor C; A first end of the fourth diode group is connected to the second end of the capacitor C, and a second end of the fourth diode group is connected to the first end of the line; When there is no short-circuit fault in the line, the two IGBT tubes are controlled to be turned on, and the line current flows from the first end of the line through the first IGBT module to the second end of the line, or the line current flows from the second end of the line through the second IGBT module to the first end of the line; When a short circuit fault occurs at the first end of the line, the two IGBTs are controlled to be turned off, and the line current flows from the second end of the line through the first diode group, capacitor C and the fourth diode group to the first end of the line, charging capacitor C and making the line present a high impedance, thereby suppressing the short circuit current; When a short circuit fault occurs at the second end of the line, the two IGBT tubes are controlled to be turned off, and the line current flows from the first end of the line through the third diode group, capacitor C and the second diode group to the first end of the line, charging capacitor C so that the line presents high impedance, thereby suppressing the short circuit current.

[0010] In the above solution, when the first end of the line is the line sending end and the second end of the line is the line receiving end, only the first IGBT module is provided; When there is no short-circuit fault in the line, the IGBT tube is controlled to be turned on, and the line current flows from the first end of the line through the first IGBT module to the second end of the line; When a short circuit fault occurs at the first end of the line, the IGBT is controlled to be turned off, and the line current flows from the second end of the line through the first diode group, capacitor C and the fourth diode group to the first end of the line, charging capacitor C so that the line presents a high impedance, thereby suppressing the short circuit current; When a short circuit fault occurs at the second end of the line, the IGBT is controlled to be turned off, and the line current flows from the first end of the line through the third diode group, capacitor C and the second diode group to the first end of the line, charging capacitor C so that the line presents high impedance, thereby suppressing the short circuit current.

[0011] In the above solution, when the first end of the line is the line receiving end and the second end of the line is the line sending end, only the second IGBT module is provided; When there is no short-circuit fault in the line, the IGBT tube is controlled to be turned on, and the line current flows from the second end of the line through the second IGBT module to the first end of the line; When a short circuit fault occurs at the first end of the line, the IGBT is controlled to be turned off, and the line current flows from the second end of the line through the first diode group, capacitor C and the fourth diode group to the first end of the line, charging capacitor C so that the line presents a high impedance, thereby suppressing the short circuit current; When a short circuit fault occurs at the second end of the line, the IGBT is controlled to be turned off, and the line current flows from the first end of the line through the third diode group, capacitor C and the second diode group to the first end of the line, charging capacitor C so that the line presents high impedance, thereby suppressing the short circuit current.

[0012] In the above solution, the emitter of the IGBT tube of each IGBT module is connected to the anode of the diode of another IGBT module; The plurality of diodes connected in series is one diode or two or more diodes connected in series; when there is only one diode, the anode of the diode serves as the first end of the diode group, and the cathode of the diode serves as the second end of the diode group.

[0013] In the above solution, the circuit is one of the three phases, and the three-phase circuits are all set according to this phase.

[0014] According to a second aspect of the present invention, there is further provided a control method, which is applied to the short-circuit fault current limiter according to the first aspect. The method comprises: When there is no short-circuit fault in the line, the two IGBT tubes are controlled to be turned on, and the line current flows from the first end of the line through the first IGBT module to the second end of the line, or the line current flows from the second end of the line through the second IGBT module to the first end of the line; When a short circuit fault occurs at the first end of the line, the two IGBTs are controlled to be turned off, and the line current flows from the second end of the line through the first diode group, capacitor C and the fourth diode group to the first end of the line, charging capacitor C and making the line present a high impedance, thereby suppressing the short circuit current; When a short circuit fault occurs at the second end of the line, the two IGBT tubes are controlled to be turned off, and the line current flows from the first end of the line through the third diode group, capacitor C and the second diode group to the first end of the line, charging capacitor C so that the line presents high impedance, thereby suppressing the short circuit current.

[0015] According to a third aspect of the present invention, there is further provided a control method, which is applied to the short-circuit fault current limiter according to the first aspect. The method comprises: When there is no short-circuit fault in the line, the IGBT tube is controlled to be turned on, and the line current flows from the first end of the line through the first IGBT module to the second end of the line; When a short circuit fault occurs at the first end of the line, the IGBT is controlled to be turned off, and the line current flows from the second end of the line through the first diode group, capacitor C and the fourth diode group to the first end of the line, charging capacitor C so that the line presents a high impedance, thereby suppressing the short circuit current; When a short circuit fault occurs at the second end of the line, the IGBT is controlled to be turned off, and the line current flows from the first end of the line through the third diode group, capacitor C and the second diode group to the first end of the line, charging capacitor C so that the line presents high impedance, thereby suppressing the short circuit current.

[0016] According to a fourth aspect of the present invention, there is further provided a control method, which is applied to the short-circuit fault current limiter according to the first aspect, and the method comprises: When there is no short-circuit fault in the line, the IGBT tube is controlled to be turned on, and the line current flows from the second end of the line through the second IGBT module to the first end of the line; When a short circuit fault occurs at the first end of the line, the IGBT is controlled to be turned off, and the line current flows from the second end of the line through the first diode group, capacitor C and the fourth diode group to the first end of the line, charging capacitor C so that the line presents a high impedance, thereby suppressing the short circuit current; When a short circuit fault occurs at the second end of the line, the IGBT is controlled to be turned off, and the line current flows from the first end of the line through the third diode group, capacitor C and the second diode group to the first end of the line, charging capacitor C so that the line presents high impedance, thereby suppressing the short circuit current.

[0017] According to the fifth aspect of the present invention, a computer device is also provided, characterized in that it includes: a processor and a memory, the memory storing programs or instructions that can be run on the processor, and when the programs or instructions are executed by the processor, the steps of the control method described in any one of the second to fourth aspects are implemented.

[0018] According to the sixth aspect of the present invention, a computer-readable storage medium is further provided, characterized in that a program or instruction is stored thereon, and when the program or instruction is executed by a processor, the steps of the control method described in any one of the second to fourth aspects are implemented.

[0019] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art: The present invention proposes a short-circuit fault current limiter with a fast response speed. When a system short-circuit fault occurs, the fault current limiter quickly operates to limit the short-circuit current to a normal level within 0.05s. In addition, the equipment cost is low and its structural topology is simple, which gives it obvious engineering advantages over high-temperature superconducting current limiters in the manufacturing, installation and maintenance processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A simulation model diagram of a single-phase high-speed short-circuit fault current limiter provided in an embodiment of the present application; Figure 2 A simulation model diagram of another single-phase high-speed short-circuit fault current limiter provided in an embodiment of the present application; Figure 3 An equivalent circuit diagram of a single-phase short-circuit fault current limiter provided in an embodiment of the present application; Figure 4 A current diagram of a three-phase short-circuit fault current limiter not operating line provided in an embodiment of the present application; Figure 5 A three-phase short-circuit fault current limiter operating circuit current diagram provided in an embodiment of the present application; Figure 6 A partial enlarged diagram of the current in the operating circuit of a three-phase short-circuit fault current limiter provided in an embodiment of the present application; Figure 7 A three-phase short-circuit fault current limiter action circuit voltage diagram provided in an embodiment of the present application; Figure 8 A partial enlarged diagram of the voltage of the operating circuit of a three-phase short-circuit fault current limiter provided in an embodiment of the present application; Figure 9 A partial enlarged diagram of the line current of a C-phase short-circuit grounding fault current limiter not operating provided in an embodiment of the present application; Figure 10 A partial enlarged diagram of the current in the operating circuit of a C-phase short-circuit grounding fault current limiter provided in an embodiment of the present application; Figure 11 A partial enlarged diagram of the line current of a non-operating short-circuit grounding fault current limiter for phases B and C provided in an embodiment of the present application; Figure 12 This is a partial enlarged diagram of the current in the operating circuit of a two-phase B and C short-circuit grounding fault current limiter provided in an embodiment of the present application. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments provided in this application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention.

[0022] Obviously, the drawings described below are merely examples or embodiments of the present application. Those skilled in the art can, without inventive effort, apply the present application to other similar scenarios based on these drawings. Furthermore, it is also understood that, although the effort involved in such a development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, changes in design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as an insufficiency of the content disclosed in this application.

[0023] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it refer to independent or alternative embodiments that are mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments unless there is a conflict.

[0024] Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by persons of ordinary skill in the art to which this application belongs. The terms "a," "an," "an," "the," and similar expressions used herein do not denote quantitative limitations and may refer to either the singular or the plural. The terms "comprise," "include," "have," and any variations thereof, used herein, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or modules (units) is not limited to the listed steps or units but may also include steps or units not listed, or may include other steps or units inherent to the process, method, product, or apparatus. The terms "connected," "connected," "coupled," and similar expressions used herein are not limited to physical or mechanical connections but may include electrical connections, whether direct or indirect. As used herein, "plurality" means two or more. "And / or" describes an association between associated objects, indicating that three possible relationships exist. For example, "A and / or B" may mean: A exists alone; A and B exist simultaneously; or B exists alone. The character " / " generally indicates that the objects before and after are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific order for the objects.

[0025] The present application provides a short-circuit fault current limiter and a high-speed fault current limiter simulation model based on PSCAD. Its structural topology is simple, which gives it obvious engineering advantages in the manufacturing, installation and maintenance processes. Compared with complex power electronic equipment or superconducting systems, they require fewer components and have a more intuitive control system. Therefore, it not only reduces the overall manufacturing cost of the equipment, but also reduces the difficulty of on-site deployment and system integration, and has good engineering feasibility and economy. Under normal operating conditions of the power grid, its equivalent impedance in the system is extremely small, thereby effectively avoiding additional voltage drop or energy loss to the power system. Once a short-circuit fault occurs in the system, this type of device can respond quickly, thereby effectively suppressing or cutting off the short-circuit current, and preventing the fault current from further expanding and causing damage to the equipment. Its response speed can generally reach milliseconds or even faster, ensuring intervention before the short-circuit current rises significantly, minimizing the thermal stress and electromagnetic shock of the equipment, and improving the safety and stability of the entire system.

[0026] The present application provides a millisecond-level response short-circuit fault current limiter, in which the simulation model of one phase (the other two phases have the same structure) is as follows Figure 1 As shown, the single-phase current limiter includes: a capacitor C, two IGBT modules and four diode groups.

[0027] The two IGBT modules are the first IGBT module and the second IGBT module. The first IGBT module includes an IGBT tube G1 and a diode D G1 The collector of the IGBT tube G1 is connected to the first end of the line as the first end of the first IGBT module, and the emitter of the IGBT tube G1 is connected to the diode D G1 The positive electrode of diode D G1 The negative electrode of the first IGBT module is connected to the second end of the circuit as the second end of the first IGBT module. The second IGBT module includes an IGBT tube G2 and a diode D G2 The collector of IGBT tube G2 is connected to the second end of the line as the first end of the second IGBT module, and the emitter of IGBT tube G2 is connected to the diode D G2 The positive electrode of diode D G2 The cathode of the second IGBT module is used as the second end of the second IGBT module and is connected to the first end of the circuit. The diode in the IGBT module is used to prevent the IGBT tube in the IGBT module from being broken down.

[0028] The four diode groups are the first diode group, the second diode group, the third diode group, and the fourth diode group. Each diode group includes several diodes connected in series, with the anode of the previous diode connected to the cathode of the next diode. The anode of the first diode serves as the first end of the diode group, and the cathode of the last diode serves as the second end of the diode group. Specifically, when a diode group has only one diode, the anode of that diode serves as the first end of the diode group, and the cathode of that diode serves as the second end of the diode group. The number of diodes in a diode group can be two or more, and they are used for series voltage division. In practical situations, devices with lower voltage resistance can be selected.

[0029] In this embodiment, the first diode group consists of diodes D1 and D2; the second diode group consists of diodes D3 and D4; the third diode group consists of diodes D5 and D6; and the fourth diode group consists of diodes D7 and D8. The first end of the first diode group is connected to the second end of the circuit, and its second end is connected to the first end of capacitor C; the first end of the second diode group is connected to the second end of capacitor C, and its second end is connected to the second end of the circuit; the first end of the third diode group is connected to the first end of the circuit, and its second end is connected to the first end of capacitor C; and the first end of the fourth diode group is connected to the second end of capacitor C, and its second end is connected to the first end of the circuit.

[0030] When there is no short-circuit fault in the line, the two IGBT tubes are controlled to be turned on, and the line current flows from the first end of the line through the first IGBT module to the second end of the line, or the line current flows from the second end of the line through the second IGBT module to the first end of the line; when a short-circuit fault occurs at the first end of the line, the two IGBT tubes are controlled to be turned off, and the line current flows from the second end of the line through the first diode group, capacitor C and the fourth diode group to the first end of the line, charging capacitor C so that the line presents high impedance, thereby suppressing the short-circuit current; when a short-circuit fault occurs at the second end of the line, the two IGBT tubes are controlled to be turned off, and the line current flows from the first end of the line through the third diode group, capacitor C and the second diode group to the first end of the line, charging capacitor C so that the line presents high impedance, thereby suppressing the short-circuit current.

[0031] Since the short-circuit fault current limiter of this embodiment has two IGBT modules, no matter whether the first end of the line is the line sending end or the line receiving end, the short-circuit fault current limiter can realize line current transmission when there is no short-circuit fault in the line.

[0032] Preferably, Figure 1As shown, the emitter of the IGBT tube of each IGBT module is connected to the positive electrode of the diode of another IGBT module. At this time, the diode of each IGBT module is reversely connected between the emitter and collector of the IGBT tube of another IGBT module, which can protect the IGBT tube of the other IGBT module from being broken down. Specifically, the diode D G1 Protect IGBT tube G2, diode D G2 Protect IGBT tube G1.

[0033] Furthermore, if it can be determined whether the first end of the line is a line sending end or a line receiving end, only one IGBT module may be provided.

[0034] For example, Figure 2 As shown, is the line sending end voltage, is the voltage at the receiving end of the line. When there is no short-circuit fault, the first end of the line transmits power to the second section of the line. C is a capacitor; G1 is an IGBT tube; D1-D8 are diodes; is the line current; F1 and F2 are short-circuit faults.

[0035] In this embodiment, the high-speed short-circuit fault current limiter simulation model Figure 2 In the circuit, G1 is a fully controlled power electronic device (it can be controlled to be turned on and off). When there is no short circuit fault in the circuit, G1 is controlled to be turned on, and the circuit current from After G1 and D G1 Flow direction , since G1 and D G1 The on-state impedance is very small, so the loss to the system is very small. When a line short circuit fault occurs at F1, G1 is controlled to be turned off, and the line current from Flows through D2, D1, C, D8 and D7 , charging C makes the line present high impedance and thus suppresses the short-circuit current; similarly, when the line short-circuit fault occurs at F2, control G1 to turn off, and the line current from Flows through D5, D6, C, D4 and D3 , charging C makes the line present high impedance and thus suppresses short-circuit current.

[0036] Similarly, a diode D can be reversely connected between the emitter and collector of the IGBT tube G1. G2 , to protect the IGBT tube G1 and prevent it from being broken down.

[0037] Similarly, when the first end of the line is the receiving end and the second end of the line is the sending end, that is, is the line receiving terminal voltage, When the voltage is at the line's sending end, only the second IGBT module is required. When the line is not short-circuited, the IGBT is turned on, allowing the line current to flow from the second end of the line through the second IGBT module to the first end of the line. When a short-circuit occurs at the first end of the line, the IGBT is turned off, allowing the line current to flow from the second end of the line through the first diode group, capacitor C, and the fourth diode group to the first end of the line, charging capacitor C and presenting a high impedance to suppress the short-circuit current. When a short-circuit occurs at the second end of the line, the IGBT is turned off, allowing the line current to flow from the first end of the line through the third diode group, capacitor C, and the second diode group to the first end of the line, charging capacitor C and presenting a high impedance to suppress the short-circuit current. Similarly, a diode can be reversely connected between the emitter and collector of the IGBT to protect it from breakdown.

[0038] The present application also provides a control method for a short-circuit fault current limiter, which is applied to the three short-circuit fault current limiters in the above embodiments, namely, setting two IGBT modules at the same time, setting only the first IGBT module, and setting only the second IGBT module. The specific control methods corresponding to the three short-circuit fault current limiters have been described in the above embodiments and will not be repeated here.

[0039] by Figure 2 Taking the short-circuit fault current limiter as an example, a high-speed fault current limiter simulation model based on PSCAD is proposed. The power electronic switch loss is ignored, and the equivalent circuit is as follows: Figure 3 shown. Figure 3 middle, is the line sending end voltage; is the line receiving end voltage; C is the capacitance; Z is the line impedance; is the line current; F is the short circuit fault; SF is the switch.

[0040] When there is no fault in the line, switch SF is closed and the line current is for:

[0041] When a three-phase short circuit fault occurs in the line, the switch SF is closed and the line current is for:

[0042] The present invention is further described in detail below with reference to a simulation example. The simulation test process of the high-speed fault current limiter simulation model based on PSCAD is set as follows: the total simulation run time is 5s, a short circuit fault occurs at 1.0s, and the fault duration is 1s.

[0043] When a three-phase short circuit occurs in the line, the current limiter does not operate and the line current diagram is as follows: Figure 4As shown, the current diagram of the three-phase short-circuit fault current limiter action circuit is as follows Figure 5 As shown, the partial enlarged diagram of the three-phase short-circuit fault current limiter action line current is as follows Figure 6 As shown, the circuit voltage diagram of the three-phase short-circuit fault current limiter is as follows: Figure 7 As shown, the partial enlarged diagram of the voltage of the three-phase short-circuit fault current limiter action line is as follows Figure 8 As shown in the figure, the peak current is 1.074kA when the line is fault-free. When a three-phase short-circuit fault occurs, the short-circuit current has a steady-state amplitude of 71.033kA. If the fault current limiter does not operate after the fault occurs, the current will be very high and will continue to increase, which will cause great harm to the system. If the fault current limiter operates within 0.05s, the short-circuit current will be controlled to a normal level. When the line is fault-free, the peak voltage is 182.085kV. When a three-phase short-circuit fault occurs, the line voltage amplitude is close to 0 and returns to normal after the current limiter operates for about 0.05s.

[0044] The line current is partially enlarged when a phase C short circuit and ground fault occurs and the current limiter does not operate. Figure 9 As shown, the partial enlarged diagram of the current in the C phase short circuit grounding fault current limiter action line is as follows Figure 10 As shown in the figure, when a phase C short-circuit ground fault occurs, the line current amplitude is 70.947 kA without the current limiter operating. If the fault current limiter does not operate after the fault occurs, the line current amplitude is very large and will continue to be inoperative, which will cause great harm to the system. When the phase C short-circuit ground fault occurs, the fault current limiter operates, and the short-circuit current amplitude is 88.110 kA. The fault current limiter controls the short-circuit current to the normal level within 0.05 s.

[0045] The line current partial enlargement diagram is as follows: Figure 11 As shown, the partial enlarged diagram of the current in the two short-circuit grounding fault current limiters B and C is as follows: Figure 12 As shown in the figure, when a two-phase short-circuit ground fault occurs on line B and C, the line current amplitude is 70.915 kA without the current limiter operating. If the fault current limiter does not operate after the fault occurs, the line current amplitude is very large and will continue to be inoperative, which will cause great harm to the system. When a two-phase short-circuit ground fault occurs on line B and C, the short-circuit current amplitude is 88.075 kA when the fault current limiter operates. The fault current limiter controls the short-circuit current to the normal level within 0.05 s.

[0046] In addition, an embodiment of the present application also provides a computer device, including: a processor and a memory, the memory storing programs or instructions that can be run on the processor, and the steps of the control method in the above embodiment are implemented when the program or instructions are executed by the processor.

[0047] Finally, an embodiment of the present application further provides a computer-readable storage medium on which a program or instruction is stored. When the program or instruction is executed by a processor, the steps of the control method in the above embodiment are implemented.

[0048] In summary, this application proposes a short-circuit fault current limiter and a high-speed fault current limiter simulation model based on PSCAD. The proposed short-circuit fault current limiter has a fast response speed. In the event of a system fault, the fault current limiter quickly operates to limit the short-circuit current to a normal level within 0.05 seconds. Furthermore, the device is low-cost and has a simple structural topology, giving it significant engineering advantages over high-temperature superconducting current limiters in manufacturing, installation, and maintenance.

[0049] It should be noted that the various technical features of the above-described embodiments can be combined in any manner. To simplify the description, not all possible combinations of the various technical features in the above-described embodiments are described. However, as long as there are no contradictions in the combination of these technical features, they should be considered to be within the scope of this specification. In addition, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0050] Those skilled in the art will readily understand that the above-described embodiments merely represent several implementation methods of the present application, and their descriptions are relatively specific and detailed, but should not be construed as limiting the scope of the invention. It should be noted that a person of ordinary skill in the art may make several variations and improvements without departing from the concept of the present application, and these variations and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be based on the appended claims.

Claims

1. A short-circuit fault current limiter, characterized in that: The current limiter includes: a capacitor C, two IGBT modules and four diode groups; wherein: The IGBT module includes an IGBT tube and a diode. The collector of the IGBT tube serves as the first end of the IGBT module. The emitter of the IGBT tube is connected to the anode of the diode, and the cathode of the diode serves as the second end of the IGBT module. The diode group includes a plurality of diodes connected in series, wherein the anode of the upper diode is connected to the cathode of the lower diode, the anode of the first diode serves as the first end of the diode group, and the cathode of the last diode serves as the second end of the diode group; The first end of the first IGBT module is connected to the first end of the circuit, and the second end of the first IGBT module is connected to the second end of the circuit; The first end of the second IGBT module is connected to the second end of the circuit, and the second end of the second IGBT module is connected to the first end of the circuit; The first end of the first diode group is connected to the second end of the line, and the second end of the first diode group is connected to the first end of the capacitor C; A first end of the second diode group is connected to the second end of the capacitor C, and a second end of the second diode group is connected to the second end of the line; A first end of the third diode group is connected to the first end of the line, and a second end thereof is connected to the first end of the capacitor C; A first end of the fourth diode group is connected to the second end of the capacitor C, and a second end of the fourth diode group is connected to the first end of the line; When there is no short-circuit fault in the line, the two IGBT tubes are controlled to be turned on, and the line current flows from the first end of the line through the first IGBT module to the second end of the line, or the line current flows from the second end of the line through the second IGBT module to the first end of the line; When a short circuit fault occurs at the first end of the line, the two IGBTs are controlled to be turned off, and the line current flows from the second end of the line through the first diode group, capacitor C and the fourth diode group to the first end of the line, charging capacitor C and making the line present a high impedance, thereby suppressing the short circuit current; When a short circuit fault occurs at the second end of the line, the two IGBT tubes are controlled to be turned off, and the line current flows from the first end of the line through the third diode group, capacitor C and the second diode group to the first end of the line, charging capacitor C so that the line presents high impedance, thereby suppressing the short circuit current.

2. The short-circuit fault current limiter according to claim 1, characterized in that: When the first end of the line is the line sending end and the second end of the line is the line receiving end, only the first IGBT module is set; When there is no short-circuit fault in the line, the IGBT tube is controlled to be turned on, and the line current flows from the first end of the line through the first IGBT module to the second end of the line; When a short circuit fault occurs at the first end of the line, the IGBT is controlled to be turned off, and the line current flows from the second end of the line through the first diode group, capacitor C and the fourth diode group to the first end of the line, charging capacitor C so that the line presents a high impedance, thereby suppressing the short circuit current; When a short circuit fault occurs at the second end of the line, the IGBT is controlled to be turned off, and the line current flows from the first end of the line through the third diode group, capacitor C and the second diode group to the first end of the line, charging capacitor C so that the line presents high impedance, thereby suppressing the short circuit current.

3. The short-circuit fault current limiter according to claim 1, characterized in that: When the first end of the line is the line receiving end and the second end of the line is the line sending end, only the second IGBT module is set; When there is no short-circuit fault in the line, the IGBT tube is controlled to be turned on, and the line current flows from the second end of the line through the second IGBT module to the first end of the line; When a short circuit fault occurs at the first end of the line, the IGBT is controlled to be turned off, and the line current flows from the second end of the line through the first diode group, capacitor C and the fourth diode group to the first end of the line, charging capacitor C so that the line presents a high impedance, thereby suppressing the short circuit current; When a short circuit fault occurs at the second end of the line, the IGBT is controlled to be turned off, and the line current flows from the first end of the line through the third diode group, capacitor C and the second diode group to the first end of the line, charging capacitor C so that the line presents high impedance, thereby suppressing the short circuit current.

4. The short-circuit fault current limiter according to claim 1, characterized in that: The emitter of the IGBT tube of each IGBT module is connected to the positive electrode of the diode of another IGBT module; The plurality of diodes connected in series is one diode or two or more diodes connected in series; when there is only one diode, the anode of the diode serves as the first end of the diode group, and the cathode of the diode serves as the second end of the diode group.

5. The short-circuit fault current limiter according to any one of claims 1 to 4, characterized in that: The circuit is one of the three phases, and the three-phase circuits are all set according to this phase.

6. A control method, characterized in that: Applied to the short-circuit fault current limiter of claim 1, the method comprises: When there is no short-circuit fault in the line, the two IGBT tubes are controlled to be turned on, and the line current flows from the first end of the line through the first IGBT module to the second end of the line, or the line current flows from the second end of the line through the second IGBT module to the first end of the line; When a short circuit fault occurs at the first end of the line, the two IGBTs are controlled to be turned off, and the line current flows from the second end of the line through the first diode group, capacitor C and the fourth diode group to the first end of the line, charging capacitor C and making the line present a high impedance, thereby suppressing the short circuit current; When a short circuit fault occurs at the second end of the line, the two IGBT tubes are controlled to be turned off, and the line current flows from the first end of the line through the third diode group, capacitor C and the second diode group to the first end of the line, charging capacitor C so that the line presents high impedance, thereby suppressing the short circuit current.

7. A control method, characterized in that: Applied to the short-circuit fault current limiter according to claim 2, the method comprises: When there is no short-circuit fault in the line, the IGBT tube is controlled to be turned on, and the line current flows from the first end of the line through the first IGBT module to the second end of the line; When a short circuit fault occurs at the first end of the line, the IGBT is controlled to be turned off, and the line current flows from the second end of the line through the first diode group, capacitor C and the fourth diode group to the first end of the line, charging capacitor C so that the line presents a high impedance, thereby suppressing the short circuit current; When a short circuit fault occurs at the second end of the line, the IGBT is controlled to be turned off, and the line current flows from the first end of the line through the third diode group, capacitor C and the second diode group to the first end of the line, charging capacitor C so that the line presents high impedance, thereby suppressing the short circuit current.

8. A control method, characterized in that: Applied to the short-circuit fault current limiter of claim 3, the method comprises: When there is no short-circuit fault in the line, the IGBT tube is controlled to be turned on, and the line current flows from the second end of the line through the second IGBT module to the first end of the line; When a short circuit fault occurs at the first end of the line, the IGBT is controlled to be turned off, and the line current flows from the second end of the line through the first diode group, capacitor C and the fourth diode group to the first end of the line, charging capacitor C so that the line presents a high impedance, thereby suppressing the short circuit current; When a short circuit fault occurs at the second end of the line, the IGBT is controlled to be turned off, and the line current flows from the first end of the line through the third diode group, capacitor C and the second diode group to the first end of the line, charging capacitor C so that the line presents high impedance, thereby suppressing the short circuit current.

9. A computer device, characterized in that: include: A processor and a memory, wherein the memory stores programs or instructions that can be run on the processor, and when the programs or instructions are executed by the processor, the steps of the control method described in any one of claims 6 to 8 are implemented.

10. A computer-readable storage medium, characterized in that Programs or instructions are stored thereon, and when the programs or instructions are executed by the processor, the steps of the control method described in any one of claims 6 to 8 are implemented.

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