Alternating current fault breaking method, circuit breaker, power equipment and storage medium

Abstract

The invention relates to an alternating current fault breaking method and device, power equipment and a computer readable storage medium. The method is applied to the circuit breaker, and comprises the following steps: separating a vacuum arc-extinguishing chamber contact in the circuit breaker under the condition that fault current exists and does not cross a zero point; under the condition that contact separation of the vacuum arc-extinguishing chamber reaches a preset spacing distance, a commutation branch is conducted to transfer fault current; the commutation branch is provided with a pre-charged oscillation capacitor and an oscillation inductor to provide oscillation current, and the oscillation current and the fault current are superposed to actively cross the zero point, so that the arc is extinguished; charging an oscillation capacitor in the commutation branch based on the transferred fault current; and if the oscillation capacitor reaches the preset voltage after being charged, the energy absorption branch is conducted to absorb the electric energy of the fault current. Therefore, the circuit can be cut off when fault current exists, and the time required for alternating current fault cut-off is shortened. Meanwhile, electric energy of fault current can be timely and automatically absorbed, and safety is guaranteed.

Description

Technical Field

[0001] The present application relates to the field of electric power technology, and in particular to an AC fault interruption method, device, computer equipment, computer-readable storage medium, and computer program product. Background Art

[0002] Circuit breakers are usually used to interrupt AC faults, but the interruption time is relatively long and cannot meet the requirements of new power systems. In view of this, how to shorten the interruption time of AC faults is a technical problem that needs to be solved. Summary of the invention

[0003] Based on this, it is necessary to provide an AC fault interruption method, device, power equipment, computer-readable storage medium and computer program product to address the above technical problems, so as to shorten the time required for AC fault interruption and improve the interruption efficiency.

[0004] In a first aspect, the present application provides an AC fault interruption method, which is applied to a circuit breaker, wherein the circuit breaker includes a commutation branch and an energy absorption branch, wherein the commutation branch is used to transfer current, and the energy absorption branch is used to absorb electric energy; the method includes:

[0005] In the presence of a fault current and when the fault current does not cross zero, the vacuum interrupter contacts in the circuit breaker are separated;

[0006] When the vacuum interrupter contacts are separated to a preset distance, the commutation branch is turned on to transfer the fault current; the commutation branch is provided with a pre-charged oscillation capacitor and an oscillation inductor to provide an oscillation current, and the oscillation current is superimposed on the fault current to actively cross the zero point and extinguish the arc;

[0007] The oscillation capacitor in the commutation branch is charged based on the transferred fault current; when the oscillation capacitor reaches a preset voltage after being charged, the energy absorption branch is turned on to absorb the electric energy of the fault current.

[0008] In one embodiment, in the presence of a fault current and when the fault current does not cross a zero point, separating contacts of a vacuum interrupter in a circuit breaker comprises:

[0009] Receiving an indication signal from a power control system where the circuit breaker is located;

[0010] Based on the indication signal, the vacuum interrupter contacts in the circuit breaker are separated when the fault current does not pass through the zero point.

[0011] In one embodiment, the circuit breaker further comprises a main branch, the main branch being configured to transmit current in the absence of a fault current; and the method further comprises:

[0012] When there is a fault current and the fault current does not cross the zero point, the circuit breaker is controlled to open to disconnect the main branch and maintain the open state;

[0013] When the circuit breaker remains in the open state for a preset holding time, the circuit breaker is controlled to close so that the main branch circuit is reopened;

[0014] When the main branch is reopened and fault current exists again, the circuit breaker is controlled to open again.

[0015] In one embodiment, the method further comprises:

[0016] Get the number of times the circuit breaker is opened within a preset time range;

[0017] When the number of times is greater than or equal to the preset number of times, a fault alarm is reported to the power control system where the circuit breaker is located;

[0018] Before receiving the alarm contact instruction issued by the power control system in response to the fault alarm, the circuit breaker is controlled to maintain the open state and block the closing state.

[0019] In one embodiment, when the number of times is greater than or equal to a preset number of times, reporting a fault alarm to a power control system where the circuit breaker is located includes:

[0020] Obtain the opening time corresponding to each opening of the circuit breaker within a preset time range;

[0021] Determine the opening time interval between adjacent opening times;

[0022] When the opening time interval is less than the preset time interval and the number of times is greater than or equal to the preset number of times, a fault alarm is reported to the power control system where the circuit breaker is located.

[0023] In one embodiment, when the circuit breaker remains in an open state for a preset holding time, controlling the circuit breaker to close so that the main branch is reopened includes:

[0024] Get the number of times the circuit breaker is opened within a preset time range;

[0025] When the number of times is less than the preset number of times, determining the opening holding time for the circuit breaker to maintain the opening state;

[0026] When the opening holding time reaches the preset holding time, the circuit breaker is controlled to close to reopen the main branch.

[0027] In a second aspect, the present application also provides an AC fault interruption method, which is applied to a power system, wherein the power system includes a circuit breaker; the circuit breaker includes a commutation branch and an energy absorption branch, wherein the commutation branch is used to transfer current, and the energy absorption branch is used to absorb electric energy; the method includes:

[0028] When the real-time current situation is monitored, indicating that there is a fault current and the fault current has not passed the zero point, the circuit breaker is instructed to separate the contacts of the vacuum interrupter; when the separation of the contacts of the vacuum interrupter reaches a preset interval distance, the commutation branch is turned on to transfer the fault current; the commutation branch is provided with a pre-charged oscillation capacitor and an oscillation inductor to provide an oscillation current, and the oscillation current is superimposed on the fault current to actively pass the zero point and extinguish the arc; the oscillation capacitor in the commutation branch is charged based on the transferred fault current; when the oscillation capacitor reaches a preset voltage after being charged, the energy absorption branch is turned on to absorb the electric energy of the fault current.

[0029] In a third aspect, the present application further provides a circuit breaker, comprising:

[0030] A separation module, used for separating the vacuum interrupter contacts in the circuit breaker when a fault current exists and the fault current does not cross the zero point;

[0031] The commutation module is used to conduct the commutation branch in the circuit breaker to transfer the fault current when the vacuum interrupter contacts are separated to a preset spacing distance; the commutation branch is provided with a pre-charged oscillation capacitor and an oscillation inductor to provide an oscillation current, and the oscillation current is superimposed on the fault current to actively cross the zero point and extinguish the arc;

[0032] The energy absorption module is used to charge the oscillation capacitor in the commutation branch based on the transferred fault current; when the oscillation capacitor reaches a preset voltage after being charged, the energy absorption branch in the circuit breaker is turned on to absorb the electrical energy of the fault current.

[0033] In a fourth aspect, the present application further provides an electric power device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of any one of the methods in the first aspect when executing the computer program.

[0034] In a fifth aspect, the present application further provides a computer-readable storage medium, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of any one of the methods in the first aspect when executing the computer program.

[0035] In a sixth aspect, the present application further provides a computer program product, comprising a computer program, which implements the steps of any one of the methods in the first aspect when executed by a processor.

[0036] The AC fault interruption method, circuit breaker, power equipment, computer-readable storage medium and computer program product are described above. When there is a fault current and the fault current has not passed zero, the vacuum interrupter contacts in the circuit breaker are separated, and when the vacuum interrupter contacts are separated to a preset spacing distance, the commutation branch is turned on to transfer the fault current. Since the commutation branch is provided with a pre-charged oscillation capacitor and an oscillation inductor to provide an oscillation current, the oscillation current is superimposed on the fault current to actively pass zero and extinguish the arc. Since it is an active zero crossing rather than a natural zero crossing, there is no need to wait for the current to pass zero before disconnecting the circuit. This realizes that the circuit can be disconnected when there is a fault current, thereby shortening the time required for AC fault interruption and improving the working efficiency of the circuit breaker. At the same time, since the fault current charges the oscillation capacitor in the commutation branch, and the energy absorption branch is turned on when the oscillation capacitor is charged to a preset voltage, the electric energy of the fault current can be automatically absorbed in time to ensure safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 A schematic diagram of a flow chart of an AC fault interruption method in one embodiment;

[0039] Figure 2 Another schematic diagram of a flow chart of an AC fault interrupting method in an embodiment;

[0040] Figure 3 A schematic diagram of a specific control timing of an AC fault interrupting method in an embodiment;

[0041] Figure 4 A schematic diagram of current interruption of an AC fault interruption method in one embodiment;

[0042] Figure 5 A schematic diagram of the installation position of a circuit breaker in one embodiment;

[0043] Figure 6 A schematic diagram of a topological structure of a circuit breaker in an embodiment;

[0044] Figure 7 is a structural block diagram of a circuit breaker in one embodiment;

[0045] Figure 8 FIG. 4 is a diagram showing the internal structure of an electric power device in one embodiment. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0047] Circuit breakers are the core equipment of the main protection system of the power system and play a vital role in the reliable operation of the power system. At present, SF6 circuit breakers dominate the voltage levels of 110kV and above. However, due to the strong greenhouse effect brought by SF6 gas, more environmentally friendly vacuum circuit breakers are becoming a development trend. With the rapid development of new power systems and the large-scale access of high-proportion new energy, the short-circuit current level in large energy bases and load-intensive areas continues to rise, and the problem of short-circuit current exceeding the standard is prominent, which puts higher requirements on the breaking speed and safe and stable operation of circuit breakers. Since there is an AC component in the short-circuit fault current, and the direction of the AC changes periodically, for example, for a standard sinusoidal AC, the current will pass through the zero point twice in each cycle, that is, zero crossing and zero crossing. Specifically, in a complete cycle, the current will change from positive to negative, and then back to positive again, and both conversions will pass through the zero point. The existing technology usually uses the natural characteristic of current zero crossing to interrupt the current. Therefore, the prior art usually needs to wait until the current naturally crosses the zero point before breaking the short-circuit fault current, and the fault clearing time is usually more than 50 milliseconds.

[0048] Based on the above analysis, the present application provides an AC fault interruption method, which transfers and disconnects the current after receiving the trip signal, without waiting for the zero point to interrupt the current, that is, actively crossing the zero point, thereby shortening the time required for fault current interruption and improving the interruption efficiency. The method is described below by means of multiple embodiments.

[0049] In one embodiment, an AC fault interruption method is provided. This embodiment uses the method applied to a circuit breaker as an example for illustration. It is understandable that the method can also be applied to a power system including a circuit breaker, a power control system that can interact with the circuit breaker, etc. Regarding the circuit breaker to which the method is applied in this embodiment, the circuit breaker can include a commutation branch and an energy absorption branch. The commutation branch is used to transfer current, and the energy absorption branch is used to absorb electric energy. Figure 1 As shown, the method includes step S101 and step S103, which are specifically as follows:

[0050] Step S101: when there is a fault current and the fault current does not pass through zero, separate the vacuum interrupter contacts in the circuit breaker.

[0051] Among them, the fault current is the current with a fault, such as a short-circuit current. It should be noted that the fault current is for AC, and at least part of the fault current is AC rather than DC. For the understanding of the zero point, please refer to the relevant part of the previous article and will not be repeated here.

[0052] Among them, the vacuum interrupter, also known as the vacuum switch tube, is the core component of the circuit breaker. Its main function is to quickly extinguish the arc and suppress the current after the power supply is cut off through the excellent insulation of the vacuum inside the tube; the vacuum interrupter contact is the specific component in the circuit breaker responsible for connecting and disconnecting the circuit.

[0053] For example, due to the presence of a fault current, the circuit breaker disconnects the circuit, and the circuit breaker does not need to wait for the fault current to pass through zero before performing a specific disconnection process, and can directly disconnect the circuit.

[0054] Step S102: When the vacuum interrupter contacts are separated to a preset distance, the commutation branch is turned on to transfer the fault current; the commutation branch is provided with a pre-charged oscillation capacitor and an oscillation inductor to provide an oscillation current, and the oscillation current is superimposed on the fault current to actively cross the zero point and extinguish the arc.

[0055] The preset spacing distance is the preset separation distance reached by the vacuum interrupter contacts.

[0056] Among them, the oscillation capacitor is a capacitor used to generate an oscillation signal in the internal circuit of the circuit breaker, which can be combined with the oscillation inductor to form an oscillation circuit to generate an oscillating current. It should be noted that the oscillating current here needs to meet certain conditions-it can be superimposed with the fault current to achieve active zero crossing. Among them, the active zero crossing is compared with the natural zero crossing. The natural zero crossing refers to the moment when the AC current or voltage naturally changes from the positive half cycle to the negative half cycle or from the negative half cycle to the positive half cycle in each cycle. At these moments, the value of the current or voltage is zero. The natural zero crossing has the characteristics of spontaneity, periodicity, and uncontrollability. The active zero crossing refers to actively detecting and controlling the circuit to perform switching operations when the current or voltage naturally crosses the zero point through a certain method or technology. This is an intentional control strategy. The active zero crossing has the characteristics of initiative, precision, and flexibility.

[0057] Step S103: charging the oscillating capacitor in the commutation branch based on the transferred fault current; when the oscillating capacitor reaches a preset voltage after being charged, turning on the energy absorption branch to absorb the electric energy of the fault current.

[0058] For example, after the above steps, the circuit is disconnected, but the residual fault current has not been processed. For this, the energy absorption branch in the circuit breaker can be used to absorb it. Specifically, the charging condition of the oscillating capacitor can be used as the conduction condition of the energy absorption branch. For example, when the oscillating capacitor reaches a preset voltage after being charged, it means that the circuit has been disconnected and the fault current has been transferred. Therefore, the energy absorption branch can be turned on to absorb the electrical energy of the fault current.

[0059] In this embodiment, when there is a fault current and the fault current has not passed zero, the vacuum interrupter contacts in the circuit breaker are separated, and when the vacuum interrupter contacts are separated to a preset spacing distance, the commutation branch is turned on to transfer the fault current. Since the commutation branch is provided with a pre-charged oscillation capacitor and an oscillation inductor to provide an oscillation current, the oscillation current is superimposed on the fault current to actively pass zero and extinguish the arc. Since it is an active zero crossing rather than a natural zero crossing, there is no need to wait for the current to pass zero before disconnecting the circuit, which realizes that the circuit can be disconnected when there is a fault current, thereby shortening the time required for AC fault interruption and improving the working efficiency of the circuit breaker. At the same time, since the fault current charges the oscillation capacitor in the commutation branch, and the energy absorption branch is turned on when the oscillation capacitor is charged to a preset voltage, the electric energy of the fault current can be automatically absorbed in time to ensure safety.

[0060] In one of the embodiments, the "separating the vacuum interrupter contacts in the circuit breaker when there is a fault current and the fault current has not passed through zero" in the aforementioned embodiment may include: receiving an indication signal issued by the power control system in which the circuit breaker is located; based on the indication signal, separating the vacuum interrupter contacts in the circuit breaker when the fault current has not passed through zero.

[0061] The power control system where the circuit breaker is located may be one, two, or more than one. The power control system can monitor the working condition of the power system in real time, especially the working condition of the circuit where the circuit breaker is located. When a fault current is detected in the circuit where the circuit breaker is located, an indication signal is generated and sent to the circuit breaker. Exemplarily, the power control system can interact with the circuit breaker.

[0062] Exemplarily, the indication signal may be a signal indicating that a fault current exists in the circuit breaker. Exemplarily, the indication signal may also be a signal indicating that a fault current exists in the circuit breaker and instructing the circuit breaker to perform circuit breaking related operations when the fault current does not pass through zero.

[0063] Exemplarily, the circuit breaker may receive an indication signal issued by the power control system in which it is located. When the circuit breaker receives the indication signal, it may separate the vacuum interrupter contacts in the circuit breaker based on the indication signal when the fault current does not pass through zero.

[0064] In this embodiment, the circuit breaker can receive an indication signal issued by the power control system in which it is located, and separate the contacts of the vacuum interrupter according to the indication signal when the fault current has not passed zero. This realizes the control of the on and off of the circuit breaker by the indication signal. The indication signal is issued by the power control system, which gives the power control system the control right of on and off of the circuit breaker, thereby helping to improve the accuracy and flexibility of the circuit breaker in breaking the circuit.

[0065] In one of the embodiments, the circuit breaker in the aforementioned embodiment also includes a main branch, which is used to transmit current when there is no fault current; the method in the aforementioned embodiment may also include: when there is a fault current and the fault current has not passed through zero, controlling the circuit breaker to open to disconnect the main branch and maintain the open state; when the circuit breaker maintains the open state for a preset holding time, controlling the circuit breaker to close to reopen the main branch; when the main branch is reopened and a fault current exists again, controlling the circuit breaker to open again.

[0066] Exemplarily, the circuit breaker may include a main branch in addition to the commutation branch and the energy absorption branch. The main branch is used to ensure normal conduction of the circuit in which the circuit breaker is located when there is no fault current.

[0067] For example, as described above, when there is a fault current, the circuit breaker can be disconnected, that is, opened, before the fault current passes through zero. However, considering that the fault current may correspond to a temporary fault, such as a temporary fault caused by a lightning strike that does not cause damage to the equipment, the circuit breaker can be changed from an open state to an on state at this time, thereby restoring the normal operation of the circuit. Specifically, the time for the circuit breaker to maintain the open state can be preset, that is, the preset holding time. If the circuit breaker maintains the open state for the preset holding time, the circuit breaker can be controlled to close the circuit to reopen the main branch.

[0068] Furthermore, if a fault current appears again after the circuit breaker is turned on again, the circuit breaker may be opened again. Specifically, when the main branch is turned on again and a fault current appears again, the circuit breaker is controlled to be opened again.

[0069] In this embodiment, considering that the fault current may be temporary, there is no need to disconnect the circuit breaker all the time. Based on this, when the circuit breaker remains in the open state for a preset holding time, the circuit breaker is controlled to close so that the main branch is reopened to ensure the normal operation of the circuit where the circuit breaker is located; if the main branch is reopened and there is a fault current again, it is opened again. This enables the circuit breaker to cope with actual situations such as temporary faults, while ensuring safety and not hindering the normal operation of the circuit where the circuit breaker is located.

[0070] In one of the embodiments, the method in the aforementioned embodiment further includes: obtaining the number of times the circuit breaker is opened within a preset time range; when the number is greater than or equal to the preset number, reporting a fault alarm to the power control system where the circuit breaker is located; before receiving an alarm contact instruction issued by the power control system in response to the fault alarm, controlling the circuit breaker to maintain the open state and blocking closing.

[0071] It can be seen from the above embodiments that the fault corresponding to the AC fault may be a temporary fault, but it may also be a permanent fault. If a permanent fault occurs, it is obviously inappropriate to close the circuit breaker again, but it should remain in the open or disconnected state. However, the problem is how to determine whether the fault corresponding to the fault current is a temporary fault or a permanent fault. Based on the above analysis, a possible specific solution is provided below:

[0072] For example, in the above-mentioned embodiment, it is set that the circuit breaker can be closed after being opened for a period of time, and can be opened again, that is, the circuit breaker can reciprocate between opening and closing. Based on such a design, if a permanent fault occurs, the circuit breaker may fall into a cycle of opening-closing-opening. Therefore, the frequency of opening and / or closing of the circuit breaker can be counted. If the frequency is abnormal, it means that there may be a permanent fault. At this time, intervention can be carried out to prevent the circuit breaker from falling into a cycle of opening-closing-opening. For example, the circuit breaker can be controlled to remain in the open state and block closing.

[0073] Exemplarily, the judgment can also be made based on the number of times the circuit breaker is opened within a preset time range. Specifically, when the number is greater than or equal to the preset number, it means that the fault is at least a non-temporary fault, and may be a permanent fault or a frequently occurring fault. At this time, the circuit breaker can be controlled to maintain the open state and block the closing, so as to avoid the circuit breaker falling into a cycle of opening-closing-opening.

[0074] For example, when a permanent fault or frequent faults occur, a fault alarm can be reported to the power control system where the circuit breaker is located, so as to facilitate timely handling of the fault. For example, the power control system can send the fault alarm to the corresponding staff for processing. Before receiving the alarm contact instruction issued by the power control system for the fault alarm, the circuit breaker remains in the open state and blocks the closing.

[0075] In this embodiment, considering the situation of permanent fault or frequent fault, by obtaining the number of times the circuit breaker is opened within a preset time range, if the number is greater than or equal to the preset number, a fault alarm is reported to the power control system where the circuit breaker is located, and before receiving the alarm contact instruction issued by the power control system for the fault alarm, the circuit breaker is controlled to maintain the open state and block the closing. This can prevent the circuit breaker from falling into a cycle between opening and closing, and also facilitates the timely handling of faults.

[0076] In one of the embodiments, the "reporting a fault alarm to the power control system where the circuit breaker is located when the number of times is greater than or equal to the preset number of times" in the aforementioned embodiment may include: obtaining the opening time corresponding to each opening of the circuit breaker within the preset time range; determining the opening time interval between adjacent opening times; and reporting a fault alarm to the power control system where the circuit breaker is located when the opening time interval is less than the preset time interval and the number of times is greater than or equal to the preset number of times.

[0077] For example, in the above-mentioned embodiment, the number of openings is used to determine whether to report a fault alarm to the power control system where the circuit breaker is located. However, different power systems, power usage scenarios, etc. may correspond to different preset times. Therefore, the accuracy of the preset times may be poor or the cost required to obtain a higher accuracy preset number is high. In view of this, the opening time corresponding to each opening of the circuit breaker can be used as an auxiliary.

[0078] Specifically, the opening time corresponding to each opening of the circuit breaker within the preset time range is obtained. Exemplarily, the preset time range here can be the same as the preset time range corresponding to the number of openings obtained in the aforementioned embodiment. Then the opening time interval between adjacent opening times can be determined. For example, the opening time of the first opening is T, the opening time of the second opening is T+10ms, and the opening time of the third opening is T+20ms. Then the opening time adjacent to the opening time T+10ms of the second opening is T, T+20ms, and accordingly, the opening time interval can be 10ms. After obtaining the opening time interval, it can be compared with the preset time interval. If it is less than the preset time interval and the number is greater than or equal to the preset number of times, it can be explained that the frequency of the fault current is too high or the fault current may always exist. At this time, a fault alarm can be reported to the power control system where the circuit breaker is located.

[0079] In this embodiment, by obtaining the opening time corresponding to each opening of the circuit breaker within the preset time range, the opening time interval between adjacent opening times is determined; by using the size relationship between the opening time interval and the preset time interval to assist in verifying the fault situation, specifically, if it is less than the preset time interval and the number of times is greater than or equal to the preset number of times, it can be said that the actual circuit fault situation is likely to be frequent or the fault current always exists, and at this time, a fault alarm can be reported to the power control system where the circuit breaker is located. On the one hand, the above method can reduce the requirements for the accuracy of the preset number of times and reduce the cost of determining the preset number of times. On the other hand, by comprehensively determining whether to report a fault alarm through the two aspects of the opening time interval and the number of openings, it can improve the accuracy of reporting fault alarms and avoid false alarms.

[0080] In one of the embodiments, the aforementioned embodiment of "when the circuit breaker remains in the open state for a preset holding time, controlling the circuit breaker to close so that the main branch is reopened" includes: obtaining the number of times the circuit breaker is opened within a preset time range; when the number is less than the preset number, determining the opening holding time for the circuit breaker to remain in the open state; when the opening holding time reaches the preset holding time, controlling the circuit breaker to close so that the main branch is reopened.

[0081] As mentioned above, the fault corresponding to the fault current may be temporary. If it is a temporary fault, the circuit breaker can be closed in time after opening to restore the normal operation of the circuit, but how to determine whether the fault is temporary? The following is a possible implementation method:

[0082] Whether the fault is temporary can be determined by the number of times the circuit breaker is opened. Specifically, the number of times the circuit breaker is opened within the preset time range is obtained. If the number is less than the preset number, it means that the fault is likely to be temporary. For example, the circuit breaker is opened only once within an hour, and the opening is caused by a sudden lightning strike. Assuming that the preset number is 5 times and the corresponding preset holding time after each opening of the circuit breaker within the hour is 10 minutes, since the actual opening number is 1, which is obviously less than the preset number of 5 times, it can be determined that the corresponding fault is temporary.

[0083] Furthermore, if the number of times is less than a preset number of times, the opening holding time for the circuit breaker to maintain the opening state can be determined. When the opening holding time reaches the preset holding time, the circuit breaker can be closed to reopen the main branch.

[0084] In this embodiment, the number of openings within a preset time is used to determine whether the main branch needs to be reopened. If the number is less than the preset number, the main branch can be reopened. This can achieve timely closing of the circuit after the fault disappears to restore the circuit conduction, avoiding the circuit breaker being in an open state all the time and affecting the normal operation of the circuit.

[0085] In an exemplary embodiment, an AC fault interrupting method is provided, which is applied to an electric power system, wherein the electric power system includes a circuit breaker; the circuit breaker includes a commutation branch and an energy absorption branch, wherein the commutation branch is used to transfer current, and the energy absorption branch is used to absorb electric energy; the method includes: obtaining the real-time current status of the electric power system; generating an indication signal when the real-time current status indicates the presence of a fault current; based on the indication signal, instructing the circuit breaker to separate the contacts of a vacuum arc chamber when the fault current has not passed through zero; when the separation of the contacts of the vacuum arc chamber reaches a preset spacing distance, turning on the commutation branch to transfer the fault current; the commutation branch is provided with a pre-charged oscillation capacitor and an oscillation inductor to provide an oscillation current, and the oscillation current is superimposed on the fault current to actively pass through zero and extinguish the arc; charging the oscillation capacitor in the commutation branch based on the transferred fault current; when the oscillation capacitor reaches a preset voltage after being charged, turning on the energy absorption branch to absorb the electric energy of the fault current.

[0086] Exemplarily, the power system may instruct the circuit breaker to execute the steps of the AC fault interrupting method in the above embodiment through an indication signal.

[0087] In this embodiment, the real-time current situation is monitored by the power system. When there is a fault current, an indication signal is generated and sent to the circuit breaker, thereby instructing the circuit breaker to perform the steps of the AC fault breaking method. This realizes that the circuit can be disconnected when there is a fault current, thereby shortening the time required for AC fault breaking, improving the working efficiency of the circuit breaker, and being able to automatically absorb the electric energy of the fault current in a timely manner to ensure safety.

[0088] In an exemplary embodiment, a fault current interruption method is provided. The method is based on a circuit breaker with high-frequency oscillation artificial zero-crossing technology, which realizes the interruption of the current before the natural zero-crossing point occurs, so as to reduce the short-circuit fault current interruption time and prevent the electrical equipment from being subjected to high current stress for too long. Figure 2 As shown, the overall process of the method is given, and combined with Figure 3 As shown in the figure, the timing of the above process is given, which specifically includes the following contents:

[0089] At time t1, a short-circuit fault occurs and the short-circuit current begins to increase;

[0090] At time t2, after the online monitoring system detects a short-circuit fault in the power system, it will send a trip signal to the circuit breaker;

[0091] At time t3, after the circuit breaker receives the opening signal, the operating mechanism starts to drive the moving and static contacts of the vacuum interrupter to separate;

[0092] At time t4, the contacts of the vacuum interrupter separate to a sufficient gap distance, the commutation branch is turned on, and the current is transferred;

[0093] At time t5, the current is disconnected.

[0094] See also Figure 4 As shown, a schematic diagram of current interruption based on the above method is given. In the figure, even if the current does not reach the zero point, the current interruption can be achieved.

[0095] The short-circuit current and breaking time in the above method are explained below:

[0096] The short-circuit fault current is composed of a large sinusoidal component and a decaying DC offset. Among the different fault conditions, the single-phase ground short-circuit fault is the most common, accounting for more than 80% of the total number of short-circuits, and the three-phase short-circuit fault is the most serious. When a three-phase short-circuit fault occurs in the power system, the short-circuit current expression is shown in the following formula (1).

[0097] (1)

[0098] In formula (1), the first term is the sinusoidal component (periodic component), and the second term is the DC component (free component, non-periodic component). pm is the amplitude of the short-circuit current periodic component; α is the initial phase angle of the power supply voltage; is the circuit impedance angle; T a =L / R is the free component decay time constant. R is the line resistance; L is the line reactance; I m is the initial value of the short-circuit current periodic component; w is the angular frequency of the power supply voltage; is the circuit impedance angle before short circuit; t is the time.

[0099] The short-circuit current breaking time is calculated by formula (2):

[0100] t=t op +t br (2),

[0101] In formula (2), t op is the main protection action time, t br is the circuit breaker opening time.

[0102] The time taken for the circuit breaker to open is calculated by formula (3):

[0103] t br =t delay +t dis +t zero (3),

[0104] Among them, t delay is the time required for the relay protection to send the opening signal to the circuit breaker, t dis It is the time required for the circuit breaker operating mechanism to pull the contacts apart to a sufficient distance, t zero It is the time required from the time the commutation branch is turned on to the time the commutation is completed and until the current flowing through the vacuum interrupter of the circuit breaker passes through zero.

[0105] The following is an explanation of the device for disconnection in the above method, the circuit breaker:

[0106] like Figure 5 As shown, an installation position of the circuit breaker used in the above method is provided, and the circuit breaker can be installed between the transformer and the disconnector.

[0107] like Figure 6 As shown, a possible circuit breaker structure is provided, which may include a commutation branch, an energy absorption branch and a main branch. When there is no fault, the AC current can flow in the main branch; when there is a fault, the main branch is disconnected. The specific working principle of the circuit breaker is as follows:

[0108] When the circuit breaker receives the trip signal, the operating mechanism drives the moving and static contacts of the vacuum interrupter to separate until the contacts reach a sufficient distance and the commutation branch is turned on. The pre-charged oscillation capacitor and oscillation inductor will form an oscillation circuit through the vacuum switch, generating a high-frequency oscillation current in the opposite direction of the main circuit current. The oscillation current is superimposed on the fault current flowing through the vacuum switch to produce an artificial zero crossing point, extinguishing the arc. The fault current is then transferred to the commutation branch, charging the oscillation capacitor so that the voltage at both ends continues to rise until the voltage at both ends of the vacuum switch reaches the action voltage of the arrester, causing the energy absorption branch to be turned on, and the fault current continues to transfer. Finally, the residual energy in the system is absorbed by the arrester.

[0109] In the event of a permanent fault in the system, the circuit breaker will first break the fault current, wait for a certain period of time, and then close the main circuit mechanical switch. If the online monitoring system detects the fault current again, the circuit breaker will receive a trigger signal and repeat the current breaking process. In the event of a short-term fault such as a lightning strike in the system, the circuit breaker will first break the fault current, wait for a certain period of time, and then close the main circuit mechanical switch. The system current flows through the main circuit mechanical switch, and the DC circuit breaker is always closed.

[0110] The above method can realize current interruption before the short-circuit current crosses the zero point, ensuring reliable current interruption while greatly reducing the current interruption time of the circuit breaker. At the same time, the circuit breaker with high-frequency oscillation artificial zero-crossing technology can complete the opening-closing-opening operation in a short time and realize the reclosing function.

[0111] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned 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 does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can 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 to be 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.

[0112] Based on the same inventive concept, the embodiment of the present application also provides an AC fault interrupting device for implementing the AC fault interrupting method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more AC fault interrupting device embodiments provided below can refer to the limitations on the AC fault interrupting method above, and will not be repeated here.

[0113] In an exemplary embodiment, Figure 7 As shown, a circuit breaker 700 is provided, comprising:

[0114] A separation module 701, used for separating the vacuum interrupter contacts in the circuit breaker when there is a fault current and the fault current does not pass through zero;

[0115] The commutation module 702 is used to conduct the commutation branch in the circuit breaker to transfer the fault current when the vacuum interrupter contacts are separated to a preset spacing distance; the commutation branch is provided with a pre-charged oscillation capacitor and an oscillation inductor to provide an oscillation current, and the oscillation current is superimposed on the fault current to actively cross the zero point and extinguish the arc;

[0116] The energy absorption module 703 is used to charge the oscillation capacitor in the commutation branch based on the transferred fault current; when the oscillation capacitor reaches a preset voltage after being charged, the energy absorption branch in the circuit breaker is turned on to absorb the electrical energy of the fault current.

[0117] In one embodiment, the separation module 701 is further used to separate the vacuum interrupter contacts in the circuit breaker when there is a fault current and the fault current does not pass through zero, including:

[0118] Receiving an indication signal from a power control system where the circuit breaker is located;

[0119] Based on the indication signal, the vacuum interrupter contacts in the circuit breaker are separated when the fault current does not pass through the zero point.

[0120] In one embodiment, the circuit breaker further comprises a main branch, the main branch being used to transmit current in the absence of a fault current;

[0121] The separation module 701 is also used to control the circuit breaker to open to disconnect the main branch and maintain the open state when there is a fault current and the fault current has not passed the zero point; when the circuit breaker maintains the open state for a preset holding time, control the circuit breaker to close to reopen the main branch; when the main branch is reopened and the fault current exists again, control the circuit breaker to open again.

[0122] In one of the embodiments, the separation module 701 is also used to obtain the number of times the circuit breaker is opened within a preset time range; when the number is greater than or equal to the preset number, report a fault alarm to the power control system where the circuit breaker is located; before receiving an alarm contact instruction from the power control system for the fault alarm, control the circuit breaker to maintain the open state and block closing.

[0123] In one embodiment, the separation module 701 is also used to report a fault alarm to the power control system where the circuit breaker is located when the number of times is greater than or equal to a preset number of times, including: obtaining the opening time corresponding to each opening of the circuit breaker within a preset time range; determining the opening time interval between adjacent opening times; and reporting a fault alarm to the power control system where the circuit breaker is located when the opening time interval is less than the preset time interval and the number of times is greater than or equal to the preset number of times.

[0124] In one of the embodiments, the separation module 701 is also used to control the circuit breaker to close so that the main branch is reopened when the circuit breaker remains in the open state for a preset holding time, including: obtaining the number of times the circuit breaker is opened within a preset time range; when the number is less than the preset number, determining the opening holding time for the circuit breaker to remain in the open state; when the opening holding time reaches the preset holding time, controlling the circuit breaker to close so that the main branch is reopened.

[0125] Each module in the above circuit breaker can be implemented in whole or in part by software, hardware or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each module.

[0126] In an exemplary embodiment, a computer device is provided, the internal structure of which can be shown as follows: Figure 8As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data required to implement the AC fault interruption method, such as the opening time, the number of times, etc. The input / output interface of the computer device is used to exchange information between the processor and the external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, an AC fault interruption method is implemented.

[0127] Those skilled in the art will understand that Figure 8 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0128] In an exemplary embodiment, an electric power device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0129] In an exemplary embodiment, the present application further provides a computer-readable storage medium, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0130] In an exemplary embodiment, the present application further provides a computer program product, including a computer program, which implements the steps in the above-mentioned method embodiments when executed by a processor.

[0131] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0132] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0133] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. An AC fault interruption method, characterized in that: Applied to a circuit breaker, the circuit breaker comprises a commutation branch and an energy absorption branch, the commutation branch is used to transfer current, and the energy absorption branch is used to absorb electric energy; the method comprises: In the case where there is a fault current and the fault current does not pass through zero, separating the vacuum interrupter contacts in the circuit breaker; When the vacuum interrupter contacts are separated to a preset distance, the commutation branch is turned on to transfer the fault current; the commutation branch is provided with a pre-charged oscillation capacitor and an oscillation inductor to provide an oscillation current, and the oscillation current is superimposed on the fault current to actively cross the zero point and extinguish the arc; The oscillation capacitor in the commutation branch is charged based on the transferred fault current; when the oscillation capacitor reaches a preset voltage after being charged, the energy absorption branch is turned on to absorb the electrical energy of the fault current.

2. The method according to claim 1, characterized in that The method of separating the vacuum interrupter contacts in the circuit breaker when a fault current exists and the fault current does not pass through zero includes: Receiving an indication signal from a power control system where the circuit breaker is located; Based on the indication signal, when the fault current does not pass through zero, the vacuum interrupter contacts in the circuit breaker are separated.

3. The method according to claim 1, characterized in that The circuit breaker further comprises a main branch, the main branch being used to transmit current in the absence of a fault current; the method further comprising: When there is a fault current and the fault current does not pass through zero, control the circuit breaker to open to disconnect the main branch and maintain the open state; When the circuit breaker remains in the open state for a preset holding time, controlling the circuit breaker to close so that the main branch is reopened; When the main branch is reopened and a fault current exists again, the circuit breaker is controlled to open again.

4. The method according to claim 3, characterized in that The method further comprises: Obtaining the number of times the circuit breaker is opened within a preset time range; When the number is greater than or equal to a preset number, reporting a fault alarm to a power control system where the circuit breaker is located; Before receiving the alarm contact instruction issued by the power control system in response to the fault alarm, the circuit breaker is controlled to maintain the open state and block the closing state.

5. The method according to claim 4, characterized in that When the number of times is greater than or equal to the preset number of times, reporting a fault alarm to the power control system where the circuit breaker is located includes: Obtaining the opening time corresponding to each opening of the circuit breaker within the preset time range; Determine the opening time interval between adjacent opening times; When the opening time interval is less than the preset time interval and the number is greater than or equal to the preset number, a fault alarm is reported to the power control system where the circuit breaker is located.

6. The method according to claim 3, characterized in that When the circuit breaker maintains the open state for a preset holding time, controlling the circuit breaker to close so that the main branch is reopened includes: Obtaining the number of times the circuit breaker is opened within a preset time range; When the number is less than the preset number, determining the opening holding time for the circuit breaker to maintain the opening state; When the opening holding time reaches the preset holding time, the circuit breaker is controlled to close so that the main branch is reopened.

7. An AC fault interruption method, characterized in that: Applied to an electric power system, the electric power system includes a circuit breaker; the circuit breaker includes a commutation branch and an energy absorption branch, the commutation branch is used to transfer current, and the energy absorption branch is used to absorb electric energy; the method includes: When the real-time current situation is monitored, indicating that there is a fault current and the fault current has not passed the zero point, the circuit breaker is instructed to separate the contacts of the vacuum interrupter; when the separation of the vacuum interrupter contacts reaches a preset spacing distance, the commutation branch is turned on to transfer the fault current; the commutation branch is provided with a pre-charged oscillation capacitor and an oscillation inductor to provide an oscillation current, and the oscillation current is superimposed on the fault current to actively pass the zero point and extinguish the arc; the oscillation capacitor in the commutation branch is charged based on the transferred fault current; when the oscillation capacitor reaches a preset voltage after being charged, the energy absorption branch is turned on to absorb the electric energy of the fault current.

8. A circuit breaker, characterized in that: The circuit breaker comprises: A separation module, used for separating the vacuum interrupter contacts in the circuit breaker when there is a fault current and the fault current does not pass through zero; A commutation module, used for conducting a commutation branch in the circuit breaker to transfer the fault current when the separation of the vacuum interrupter contacts reaches a preset spacing distance; the commutation branch is provided with a pre-charged oscillation capacitor and an oscillation inductor to provide an oscillation current, and the oscillation current is superimposed on the fault current to actively cross the zero point and extinguish the arc; The energy absorption module is used to charge the oscillation capacitor in the commutation branch based on the transferred fault current; when the oscillation capacitor reaches a preset voltage after being charged, the energy absorption branch in the circuit breaker is turned on to absorb the electrical energy of the fault current.

9. An electric power device, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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