Load-limiting open circuit control method and system for low-voltage power line, and storage medium

Abstract

The invention relates to the technical field of low-voltage power line control, and discloses a low-voltage power line load-limiting open circuit control method and system and a storage medium, and the method comprises the steps: obtaining A, B, C and N phase currents; if at least one of the four phases of current exceeds the reference value and lasts for a first time value, the N phases are disconnected; or, if the current sum value of the four-phase current is within the reference range and lasts for a second time value, the N phase is disconnected; the power factor compensation circuit is cut out and connected into the resonance circuit; after the first delay time is continued, the N phase is connected, the resonance circuit is switched out, and the power factor compensation circuit is connected; calculating the time interval value of the latest x N-phase cut-off, and adjusting the single-phase current reference value according to the positive correlation of the average value of the time interval value; and calculating the distribution uniformity of the time point of the latest N-phase cut-off for y times on the time axis, and adjusting the total current reference range according to the positive correlation of the uniformity. The device has the advantages that the load can be limited without power failure, and mis-tripping is not easy to occur.

Description

Technical Field

[0001] The present application relates to the technical field of low-voltage power line control, and in particular to a circuit breaker control method, system and storage medium for limiting load of a low-voltage power line. Background Art

[0002] As a commonly used control and protection device, low-voltage circuit breakers are switching devices that can not only connect and disconnect normal load current and overload current, but also connect and disconnect short-circuit current. It is mainly used to protect electrical equipment and loads in power systems. It can automatically detect abnormal conditions such as overload, short circuit, undervoltage and leakage in the circuit, and quickly cut off the current to prevent equipment damage and fire. Low-voltage circuit breakers are widely used in feeder lines at all levels of low-voltage distribution systems, power supply control of various mechanical equipment, and control and protection of power terminals. The notable features of low-voltage circuit breakers include manual reset after fault disconnection, two-stage protection functions of long-delay release with inverse time characteristics and instantaneous overcurrent release, etc.

[0003] At present, many models of low-voltage circuit breakers are equipped with microcomputer-based or integrated relay protection components. During peak power consumption periods or when the user load is highly impactful, these low-voltage circuit breakers often trip due to overcurrent or overload protection. The source of the trip is only a short-term occasional overload, and there is no fault in the circuit of the low-voltage power line. Every time a low-voltage circuit breaker trips due to malfunction, emergency repair personnel must go to the site to manually close the circuit to restore power supply, wasting a lot of emergency repair manpower and material resources. How to prevent the circuit breaker from malfunctioning and tripping due to instantaneous load fluctuations while ensuring the safe operation of the equipment is an urgent problem to be solved. Summary of the invention

[0004] In order to prevent the circuit breaker from malfunctioning and tripping due to instantaneous load fluctuations while ensuring the safe operation of the equipment, the present application provides a circuit breaker control method, system and storage medium for limiting the load of a low-voltage power line.

[0005] In a first aspect, the present application provides a circuit breaker control method for limiting load on a low-voltage power line, which adopts the following technical solution:

[0006] A circuit breaker control method for limiting load on a low-voltage power line comprises the following steps:

[0007] Based on a low-voltage power line connected to a power factor compensation circuit, obtaining an A-phase current, a B-phase current, a C-phase current and an N-phase current in the low-voltage power line;

[0008] If at least one of the values ​​of the A-phase current, the B-phase current, the C-phase current and the N-phase current exceeds the preset single-phase current reference value and lasts for a set first time value, the N-phase is disconnected; or, if the sum of the currents of the A-phase current, the B-phase current, the C-phase current and the N-phase current is within a preset total current reference range and lasts for a set second time value, the N-phase is disconnected;

[0009] Cut out the power factor compensation circuit, and connect a set resonant circuit to the N-phase branch on the load side, wherein the resonant circuit is provided with at least one group and connected in parallel at both ends of the normally closed contact of the relay; each group of the resonant circuit includes at least one resonant capacitor and at least one resonant inductor, and the resonant capacitor and the resonant inductor are connected in series;

[0010] After a preset first delay time, the N phase is connected, the resonant circuit is cut out, and the power factor compensation circuit is connected;

[0011] Calculate the time intervals of the most recent x times of N-phase disconnection, and if the average value of the x-1 time intervals gradually increases, gradually increase the single-phase current reference value; if the average value of the x-1 time intervals gradually decreases, gradually decrease the single-phase current reference value;

[0012] Calculate the distribution uniformity of the time points of the most recent y N-phase cut-offs on the time axis, and adjust the total current reference range according to the positive correlation of the uniformity. The higher the uniformity, the larger the total current reference range, and the lower the uniformity, the smaller the total current reference range.

[0013] By adopting the above technical solutions and comprehensively using technical means such as real-time monitoring, intelligent adjustment and resonant circuits, it aims to improve the stability and efficiency of the power system, optimize load management strategies, and reduce unnecessary tripping and waste of manpower and material resources.

[0014] Optionally, the method further comprises the following steps:

[0015] If the sum of the A phase current, the B phase current, the C phase current and the N phase current is within the preset total current reference range, the N phase is disconnected first, and then the A phase, B phase and C phase are disconnected after a preset second delay time, wherein the duration of the first delay time is greater than the duration of the second delay time.

[0016] By adopting the above technical solutions, the flexibility and control accuracy of the system are further enhanced; not only more refined load management is achieved, but also the flexibility and response speed of the system are improved. This hierarchical protection mechanism and delayed disconnection strategy help to better protect the power system, reduce unnecessary power outages, and improve the user's power experience.

[0017] Optionally, the method further comprises the following steps:

[0018] The single-phase current reference value is adjusted inversely according to the current sum value; the larger the current sum value is, the smaller the single-phase current reference value is; the smaller the current sum value is, the larger the single-phase current reference value is.

[0019] By adopting the above technical solution, the steps of adjusting the single-phase current reference value according to the anti-correlation of current and value are further enhanced, and the system's adaptability and load management capabilities are further enhanced; the adaptive adjustment mechanism not only improves the stability and reliability of the system, but also optimizes the load distribution, improves the protection accuracy and robustness. These advantages will help to better manage power loads, reduce unnecessary tripping and waste of manpower and material resources, and improve the overall operation efficiency of the power system.

[0020] Optionally, the method further comprises the following steps:

[0021] The inductance value in the resonant circuit is adjusted according to the positive correlation between the current sum value; the larger the current sum value is, the larger the inductance value in the resonant circuit is; the smaller the current sum value is, the smaller the inductance value in the resonant circuit is.

[0022] By adopting the above technical solution, the steps of adjusting the inductance value in the resonant circuit according to the positive correlation between the current and the value provide the system with a more sophisticated adjustment means; the dynamic adjustment mechanism not only improves the stability and reliability of the system, but also optimizes the load management and enhances the system's adaptability and robustness. These advantages will help to better manage power loads, reduce unnecessary tripping and power fluctuations, and improve the overall operating efficiency of the power system.

[0023] Optionally, the method further comprises the following steps:

[0024] Acquiring a power factor reference value of the power factor compensation circuit, wherein the power factor reference value is lower than a target power factor value;

[0025] According to the current power factor value and the target power factor value, adjusting the switching logic of the capacitor in the resonant circuit;

[0026] When the current power factor value is lower than the power factor reference value, the common compensation is put into operation first and then the split compensation is put into operation, the large-capacity resonant capacitor is put into operation first, and the resonant capacitor with less number of times is put into operation first;

[0027] When the current power factor value is higher than the power factor reference value, the common compensation is cut off first and then the separate compensation, the large-capacity resonant capacitor is cut off first, and the resonant capacitor with the most times is cut off first.

[0028] By adopting the above technical solutions, the dynamic adjustment mechanism not only improves the power factor and efficiency of the power system, but also optimizes the use of capacitors, reduces power loss, and enhances the system's adaptability and stability. These advantages will help better manage power loads and improve the overall operating efficiency of the power system.

[0029] Optionally, the method further comprises the following steps:

[0030] The value of the first delay time value is adjusted in a positive correlation according to the number of times the N phases are cut off during the most recent preset inspection time period; the more times the N phases are cut off, the longer the value of the first delay time value is; the fewer times the N phases are cut off, the shorter the value of the first delay time value is.

[0031] By adopting the above technical solution, the step of adjusting the first delay time value according to the positive correlation of the number of N-phase disconnection times provides a more intelligent and adaptive adjustment mechanism for the system; the dynamic adjustment mechanism not only improves the stability and reliability of the system, but also optimizes the load management, enhances the adaptive ability of the system, reduces the maintenance cost, and improves the user experience. These advantages will help to better manage the power load and improve the overall operation efficiency of the power system.

[0032] Optionally, the method further comprises the following steps:

[0033] The value of the first time value is adjusted inversely according to the ratio between the single-phase current reference value and the current sum value when the N phase was last cut off; the larger the ratio between the single-phase current reference value and the current sum value, the shorter the value of the first time value; the smaller the ratio between the single-phase current reference value and the current sum value, the longer the value of the first time value.

[0034] By adopting the above technical solution, the step of adjusting the first time value inversely according to the ratio between the single-phase current reference value and the current sum value when the N phase was cut off most recently provides the system with a more sophisticated and intelligent adjustment means; the dynamic adjustment mechanism not only improves the response speed and stability of the system, but also optimizes the load management, enhances the system's adaptive ability, and helps reduce maintenance costs. These advantages will help better manage power loads and improve the overall operating efficiency of the power system.

[0035] Optionally, the method further comprises the following steps:

[0036] The value of the second time value is adjusted inversely according to the discrete coefficients of the m ratios between the single-phase current reference value and the current sum value when the N phases are cut off for the most recent m times; the larger the discrete coefficients of the m ratios between the single-phase current reference value and the current sum value, the smaller the value of the second time value; the smaller the discrete coefficients of the m ratios between the single-phase current reference value and the current sum value, the larger the value of the second time value.

[0037] By adopting the above technical solution, the step of adjusting the second time value in an anti-correlated manner according to the discrete coefficient of the m ratios between the single-phase current reference value and the current sum value when the N phases were cut off for the most recent m times provides a more comprehensive and in-depth adjustment mechanism for the system; the dynamic adjustment mechanism not only improves the system's sensitivity to load changes, but also enhances the system's stability and reliability, optimizes the load management strategy, improves the system's adaptive ability, and helps reduce maintenance costs. These advantages will help better manage power loads and improve the overall operating efficiency of the power system.

[0038] In a second aspect, the present application provides a circuit breaker control system for limiting load on a low-voltage power line, which adopts the following technical solution:

[0039] A circuit breaker control system for limiting load on a low-voltage power line comprises a processor, wherein the processor executes the steps of the circuit breaker control method for limiting load on a low-voltage power line as described in any one of the above.

[0040] In a third aspect, the present application provides a storage medium, which adopts the following technical solution:

[0041] A storage medium stores a program, wherein the program, when executed by a processor, implements the steps of any one of the above-mentioned methods for controlling the circuit breaker for limiting load on a low-voltage power line.

[0042] In summary, the present application includes at least one of the following beneficial technical effects:

[0043] Fine-tuning and responding: By introducing a variety of dynamic adjustment mechanisms, including adjusting the first delay time value according to the number of N-phase cut-offs, adjusting the first time value according to the ratio between the single-phase current reference value and the current sum value, and adjusting the second time value according to the discrete coefficient of the ratio between the single-phase current reference value and the current sum value when the N phases are cut off for the most recent m times, the present application realizes fine-tuning and fast response to the power load. These adjustment mechanisms can flexibly adjust the circuit breaker control strategy according to the real-time load conditions and the severity of load changes, thereby improving the stability and reliability of the power system.

[0044] Enhanced system adaptability: The technical solution in this application fully considers the complexity and variability of the power system. By introducing an adaptive adjustment mechanism, the system can automatically adjust control parameters according to load changes and abnormal conditions. This adaptive capability helps the system better adapt to various complex power environments and improves the overall reliability and efficiency of the power system.

[0045] Optimize load management and reduce losses: By optimizing the circuit breaker control strategy, this application reduces unnecessary tripping and power fluctuations, thereby reducing losses to power equipment and lines. This helps to extend the service life of equipment and lines, reduce maintenance costs, and also improve the energy efficiency of the power system.

[0046] Improve user experience: Stable power supply is the basis for ensuring the normal life and production activities of users. This application reduces power outages caused by load fluctuations and abnormal situations through refined regulation and adaptive control, thereby improving the user's power experience.

[0047] Easy to implement and expand: The technical solution proposed in this application is not only easy to implement in the existing power system, but also has good scalability. With the development of the power system and the complexity of load changes, the technical solution in this application can be further optimized and expanded to adapt to a wider range of power application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a step diagram of the circuit breaker control method for limiting load of low-voltage power lines of the present application.

[0049] Figure 2 It is a circuit diagram of an embodiment of the present application.

[0050] Figure numerals: 1. Insulating shell; 2. Power supply side terminal; 3. Load side terminal; 4. Mechanical overcurrent release; 5. Current transformer; 6. Three-phase four-level rectifier bridge stack; 7. Relay; 8. Resonant capacitor; 9. Resonant inductor; 10. Phase-splitting tripping connecting rod. DETAILED DESCRIPTION

[0051] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings.

[0052] In the description of this specification, the description with reference to the terms "certain embodiments", "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0053] The present application embodiment discloses a circuit breaker control method for limiting load of a low-voltage power line, referring to Figure 1 and Figure 2 , including the following steps:

[0054] Based on a low-voltage power line connected with a power factor compensation circuit, an A-phase current, a B-phase current, a C-phase current and an N-phase current in the low-voltage power line are obtained.

[0055] If at least one of the A-phase current, B-phase current, C-phase current and N-phase current exceeds the preset single-phase current reference value and lasts for the set first time value, the N-phase is disconnected; or, if the current sum of the A-phase current, B-phase current, C-phase current and N-phase current is within the preset total current reference range and lasts for the set second time value, the N-phase is disconnected. Assume the total current reference range, for example, A1 to A2. If the current sum is within the preset total current reference range of A1 to A2, the operation of disconnecting the N-phase is performed.

[0056] The power factor compensation circuit is cut out, and a set resonant circuit is connected to the N-phase branch on the load side. The resonant circuit is provided with at least one group and connected in parallel at both ends of the normally closed contact of the relay; each group of resonant circuits includes at least one resonant capacitor and at least one resonant inductor, and the resonant capacitor and the resonant inductor are connected in series. The accompanying drawings of this embodiment are shown by taking a resonant capacitor and a resonant inductor connected in series and then connected in parallel at both ends of the normally closed contact of the relay as an example. In other implementations, there can also be multiple series-parallel relationships.

[0057] After the preset first delay time lasts, the N phase is connected, the resonant circuit is cut out, and the power factor compensation circuit is connected. The first delay time is 2-5 seconds, such as 3 seconds.

[0058] Calculate the time interval values ​​of the most recent x times of N-phase disconnection. If the average value of the x-1 time interval values ​​gradually increases, gradually increase the single-phase current reference value. If the average value of the x-1 time interval values ​​gradually decreases, gradually decrease the single-phase current reference value. Assume that the time interval values ​​of the most recent 10 times (x=10) of N-phase disconnection are recorded. Calculate the average value of these 9 (x-1) time interval values. If the average value gradually increases; for example, from 5 minutes to 10 minutes, it indicates that the load change tends to be stable, and the single-phase current reference value can be gradually increased; for example, from 10A to 11A. If the average value gradually decreases; for example, from 10 minutes to 5 minutes, it indicates that the load fluctuation is intensified, and the single-phase current reference value needs to be gradually reduced; for example, from 10A to 9A.

[0059] Calculate the distribution uniformity of the time points of the most recent y N-phase cut-offs on the time axis, and adjust the total current reference range according to the positive correlation of the uniformity. The higher the uniformity, the larger the total current reference range, and the lower the uniformity, the smaller the total current reference range. Assume that the time points of the most recent 20 (y=20) N-phase cut-offs are recorded. Calculate the distribution uniformity of these time points on the time axis; indicators such as standard deviation and coefficient of variation can be used to measure. If the uniformity is high; for example, the standard deviation is small, it means that the distribution of the time points of the N-phase cut-off is relatively uniform, and the load changes are relatively stable. The total current reference range can be gradually expanded; for example, from 20A to 40A to 18A to 42A. If the uniformity is low; for example, the standard deviation is large, it means that the distribution of the time points of the N-phase cut-off is relatively concentrated, and the load changes may be more drastic, and the total current reference range needs to be gradually reduced; for example, from 20A to 40A to 22A to 38A.

[0060] By real-time monitoring and adjustment of current parameters, overload conditions in power lines can be detected and handled in a timely manner to avoid unnecessary tripping. The access to the resonant circuit helps stabilize the frequency response of the power system and reduce power fluctuations caused by load fluctuations. Dynamically adjusting the current reference value according to the actual load conditions can manage the power load more flexibly and improve the utilization efficiency of power resources. By analyzing the time interval and distribution uniformity of the N-phase cut-off, the load management strategy can be further optimized to reduce the impact of load fluctuations on the power system. Through intelligent control strategies, the waste of manpower and material resources for emergency repairs caused by false tripping can be reduced. Improving the stability and efficiency of the power system can reduce the economic losses caused by power failures.

[0061] Reference Figure 2In this embodiment, the load-limited anti-tripping low-voltage circuit breaker includes an insulating housing 1, a power-side terminal 2, a load-side terminal 3, a mechanical overcurrent release 4, a current transformer 5, a three-phase four-level rectifier bridge stack 6, a relay 7, a resonant capacitor 8, a resonant inductor 9, and a phase-splitting tripping connecting rod 10. The power-side terminal 2 and the load-side terminal 3 are arranged in a row on both sides of the insulating housing 1, and the mechanical overcurrent release 4, the current transformer 5, the three-phase four-level rectifier bridge stack 6, the relay 7, the resonant capacitor 8, and the resonant inductor 9 are all arranged inside the insulating housing 1. The power supply side terminal 2, the load side terminal 3 and the mechanical overcurrent release 4 are all four-stage structures. The current transformer 5 is composed of four of the same specifications. The primary side is all sleeved on the ABCN phase power supply side terminal 2 connecting electric bar, and the secondary side is connected to the AC side of the three-phase four-stage rectifier bridge stack 6 in sequence. The DC side of the three-phase four-stage rectifier bridge stack 6 is connected to the coil of the relay 7. The relay 7 is an instantaneous action delayed return type with a delay time of 2-5 seconds. The contact of the relay 7 is a normally closed contact, which is connected in series with the zero-phase electric bar of the power supply side terminal 2. The resonant capacitor 8 and the resonant inductor 9 are connected in series and then connected in parallel with the normally closed contact of the relay 7. The resonant frequency of the resonant capacitor 8 and the resonant inductor 9 is the power frequency. The operating handle of the mechanical overcurrent release 4 is provided with a phase-splitting tripping connecting rod 10. The phase-splitting tripping connecting rod 10 has a zero-phase tripping priority mechanism to realize the zero line tripping of all four levels. If any phase in the three phases trips, the other two phases maintain the closed state. The insulating shell 1 is filled with insulating thermal conductive liquid, which is composed of a mixture of carbon tetrachloride, transformer oil, alumina ceramic powder, glycerin and mercury, and the mass ratio of carbon tetrachloride, transformer oil, alumina ceramic powder, glycerin and mercury is 1:3:1:0.5:0.7; the inner surface of the insulating shell 1 is coated with a non-ionic surfactant.

[0062] This circuit breaker can limit the load without tripping when the low-voltage circuit breaker occasionally crosses the line. It can automatically stop the harmonic equipment that often causes overload to reduce the load without interrupting the power supply. At the same time, it improves the internal heat dissipation effect of the circuit breaker, and will not trip due to a large instantaneous current in a certain phase. At the same time, it improves the heat dissipation of the internal contacts of the circuit breaker. This application overcomes the inevitable problem of the prior art that the trip sensitivity of "the more it trips, the easier it is to trip" continues to increase with the occurrence of tripping events, greatly improving the power supply reliability and safety of the distribution system. At the same time, when a phase is overloaded, it allows single-phase tripping to maintain the normal operation of the other two phases without tripping, thereby maximizing the reliability of power supply.

[0063] A large number of studies have found that many distribution system overloads are caused by harmonic equipment. Harmonic equipment often forms a large current in the zero phase to trip the circuit breaker, and the actual total load is not large. Therefore, the present invention detects the three-phase and zero-phase currents. After passing through the rectifier bridge, as long as one phase or the overall load current is too large, the zero-phase circuit is first disconnected by the relay. At this time, the resonant circuit is connected to the zero phase, and the normal three-phase unbalanced component is unlimited at the resonant frequency, which will not cause three-phase imbalance, but the harmonic current is limited by the inductor, so that the harmonic equipment that causes overload cannot work normally and shuts down. At this time, the relay is reset after a short delay, and the power supply is completely restored to normal. During this period, ordinary load equipment, three-phase balanced equipment and harmonic-free equipment have no effect, which achieves the effect of limiting load without tripping. The technical solution of the present invention realizes that when the low-voltage circuit breaker occasionally crosses the line, it can limit the load without tripping, and automatically stops the harmonic equipment that often causes overload to reduce the load without interrupting the power supply. At the same time, when a phase is overloaded, single-phase tripping is allowed to maintain the normal operation of the other two phases without tripping, thereby maximizing the reliability of power supply.

[0064] In addition, in order to further improve the reliability of the circuit breaker, the heat dissipation problem of the internal thermal components of the circuit breaker must be solved. The heat dissipation effect of filling the circuit breaker with liquid is very significant, but the circuit breaker cannot be completely sealed. The present invention uses a variety of composite materials to form a heat dissipation insulating liquid with high surface tension, combined with the hydrophobic coating inside the plastic shell, so that the injected liquid cannot leak out even if there are holes and gaps due to the lotus leaf effect. This greatly improves the heat dissipation effect inside the circuit breaker and will not trip due to a large instantaneous current in a certain phase. At the same time, because the heat dissipation of the internal contacts of the circuit breaker is improved, the problem of the trip sensitivity of the existing technology, which is inevitable, that "the more it trips, the easier it trips", continues to increase with the occurrence of tripping events, is overcome, and the power supply reliability and safety of the distribution system are greatly improved.

[0065] The method further comprises the steps of:

[0066] If the sum of the currents of phase A, phase B, phase C and phase N is within the preset total current reference range, phase N is disconnected first, and then phase A, phase B and phase C are disconnected after a preset second delay time, wherein the first delay time is longer than the second delay time. The second delay time is 1-2 seconds, such as 1.5 seconds.

[0067] By disconnecting the N phase first and then disconnecting the A phase, B phase and C phase with a delay, the system implements a hierarchical protection mechanism. This mechanism can first try to reduce the load by disconnecting the neutral line (N phase) when the load overload or abnormal situation first occurs. If the situation does not improve, all phase lines will be further disconnected to more comprehensively protect the power system. The delayed disconnection strategy helps to reduce unnecessary full power outages. In some cases, a short-term load overload may be only temporary. By disconnecting the N phase first and observing for a period of time, the system may avoid unnecessary full power outages, thereby reducing the impact on users. By setting different delay times, such as the first delay time being greater than the second delay time, the system can flexibly adjust the response strategy according to actual conditions. This flexibility helps to better adapt to various complex load conditions and improve the stability and reliability of the power system. When a load overload or abnormal situation is detected, the system can take measures step by step according to the preset process, first try a lighter intervention (disconnecting the N phase), and then gradually upgrade as needed (disconnecting all phase lines after a delay). This process-based processing method helps to optimize the fault handling process and improve processing efficiency.

[0068] The method further comprises the steps of:

[0069] The single-phase current reference value is adjusted according to the anti-correlation of the current sum value; the larger the current sum value, the smaller the single-phase current reference value; the smaller the current sum value, the larger the single-phase current reference value. Specifically, the single-phase current reference value can be obtained by looking up a table.

[0070] By adjusting the single-phase current reference value in an anti-correlation manner, the system can automatically adjust the protection threshold according to the real-time load conditions. This adaptive mechanism helps the system better cope with various load changes and improve the stability and reliability of the power system. When the current sum is large, reducing the single-phase current reference value can more effectively limit the load and prevent overload. When the current sum is small, increasing the single-phase current reference value helps to make full use of power resources and improve the rationality of load distribution. The anti-correlation adjustment strategy enables the system to adjust the protection parameters more accurately when the load changes, thereby reducing the possibility of false tripping. This helps to reduce the waste of manpower and material resources for emergency repairs caused by false tripping and improve the operating efficiency of the power system. By dynamically adjusting the single-phase current reference value, the system can better adapt to various complex load conditions and enhance the robustness and anti-disturbance capability of the system. This helps the system to respond quickly and maintain stable operation when faced with sudden load changes or abnormal conditions.

[0071] The method further comprises the steps of:

[0072] The inductance value in the resonant circuit is adjusted according to the positive correlation between the current and the value; the larger the current and the value, the larger the inductance value in the resonant circuit; the smaller the current and the value, the smaller the inductance value in the resonant circuit. Each resonant circuit can be connected in series with a thyristor to control the amount of resonant inductance added or removed from the circuit breaker, thereby adjusting the inductance value.

[0073] By dynamically adjusting the inductance value in the resonant circuit, the system can better control the frequency response of the power system. When the current and value are large, increasing the inductance value helps to suppress power fluctuations and improve the stability of the system. The dynamic adjustment of the inductance value enables the system to flexibly adjust the parameters of the resonant circuit according to the load conditions, thereby optimizing load management. When the load is heavy, reducing power fluctuations by increasing the inductance value helps to protect power equipment and loads. The introduction enables the system to automatically adjust the parameters of the resonant circuit according to the real-time load conditions, enhancing the system's adaptive ability. This adaptive mechanism helps the system better cope with various load changes and improve the reliability and efficiency of the power system. The adjustment of the inductance value in the resonant circuit can also effectively reduce the impact of harmonics in the power system. By optimizing the inductance value, the generation and propagation of harmonic currents can be reduced, thereby reducing the damage of harmonics to power equipment and loads. Dynamically adjusting the inductance value in the resonant circuit enables the system to better adapt to various complex load conditions and enhances the robustness of the system. This helps the system to respond quickly and maintain stable operation when faced with sudden load changes or abnormal conditions.

[0074] When there are multiple resonant capacitors and resonant inductors, the method further includes the following steps:

[0075] Obtaining a power factor reference value of a power factor compensation circuit, wherein the power factor reference value is lower than a target power factor value;

[0076] According to the current power factor value and the target power factor value, adjusting the switching logic of the capacitor in the resonant circuit;

[0077] When the current power factor value is lower than the power factor reference value, the common compensation is put into operation first and then the split compensation, the large-capacity resonant capacitor is put into operation first, and then the resonant capacitor with less number of times is put into operation first;

[0078] When the current power factor value is higher than the power factor reference value, the common compensation is cut off first and then the separate compensation, the large-capacity resonant capacitor is cut off first, and the resonant capacitor with the most times is cut off first.

[0079] By dynamically adjusting the switching logic of the capacitors in the resonant circuit, the system can more effectively compensate the power factor and make the power factor of the power system closer to the target value. This helps to improve the efficiency and stability of the power system. Switching the capacitors according to the principle of "first switching on the resonant capacitors with fewer times, and first cutting off the resonant capacitors with more times" helps to extend the service life of the capacitors. Because capacitors that are frequently switched are more likely to be damaged, switching according to this logic can reduce the number of capacitor switching, thereby reducing the damage rate. Improving the power factor helps to reduce the flow of reactive power in the power system, thereby reducing power loss. This is of great significance for improving the energy efficiency and energy saving of the power system. The introduction of this step enables the system to dynamically adjust the switching logic of the capacitors according to the real-time power factor value, enhancing the system's adaptive ability. This adaptive mechanism helps the system better cope with various load changes and power factor fluctuations. By optimizing the switching logic of the capacitors, the system can more effectively control the frequency response and voltage fluctuations of the power system, thereby improving the stability of the system.

[0080] The method further comprises the steps of:

[0081] According to the number of N-phase cut-offs in the most recent preset inspection time period, the value of the first delay time value is positively correlated; the more the number of cut-offs, the longer the value of the first delay time value; the fewer the number of cut-offs, the shorter the value of the first delay time value. For example, if the most recent preset inspection time period is within 10 hours, the number of N-phase cut-offs is 2, and the first delay time value is 3 seconds; if the number of N-phase cut-offs is 3 within 10 hours, the first delay time value is 4 seconds; the specific value can be obtained by looking up the table.

[0082] By dynamically adjusting the first delay time value according to the number of N-phase cut-offs, the system can better cope with frequent load fluctuations and overload conditions. When the number of N-phase cut-offs is large, extending the first delay time value can reduce the impact on the power system caused by frequent tripping, thereby improving the stability of the system. The introduction of this step enables the system to flexibly adjust the circuit breaker control strategy according to the real-time load situation and the number of N-phase cut-offs. When the load is heavy or the number of N-phase cut-offs is large, extending the first delay time value to give the system more buffer time helps to optimize load management and reduce unnecessary tripping. The system can automatically adjust the first delay time value according to the change of the number of N-phase cut-offs, which reflects the adaptive ability of the system. This adaptive mechanism helps the system better adapt to various load changes and abnormal conditions and improve the reliability and efficiency of the power system. By optimizing the circuit breaker control strategy and reducing unnecessary tripping and power fluctuations, the loss of power equipment and lines can be reduced. This helps to extend the service life of equipment and lines and reduce maintenance costs. Reducing the number of tripping and power fluctuations can improve the user's power experience. Stable power supply helps to ensure the normal life and production activities of users and improve user satisfaction.

[0083] The method further comprises the steps of:

[0084] The value of the first time value is adjusted inversely according to the ratio between the single-phase current reference value and the current sum value when the N phase is cut off most recently; the larger the ratio between the single-phase current reference value and the current sum value, the shorter the value of the first time value; the smaller the ratio between the single-phase current reference value and the current sum value, the longer the value of the first time value. The specific value of the first time value can be obtained by looking up a table.

[0085] In the case of light load, by shortening the first time value, the system can return to normal working state faster, and the response speed of the system is improved. This helps to reduce load fluctuations and power losses caused by system delays. In the case of heavy load, extending the first time value can provide more buffer time for the system, which helps to reduce the impact on the power system caused by frequent tripping, thereby enhancing the stability of the system. The introduction of this step enables the system to flexibly adjust the strategy of circuit breaker control according to the real-time load situation and the ratio between the single-phase current reference value and the current sum value. This helps to optimize load management and reduce unnecessary tripping and power fluctuations. The system can automatically adjust the first time value according to the change of the ratio between the single-phase current reference value and the current sum value, which reflects the adaptive ability of the system. This adaptive mechanism helps the system better adapt to various load changes and abnormal conditions, and improves the reliability and efficiency of the power system. By optimizing the strategy of circuit breaker control and reducing unnecessary tripping and power fluctuations, the loss to power equipment and lines can be reduced. This helps to extend the service life of equipment and lines and reduce maintenance costs.

[0086] The method further comprises the steps of:

[0087] According to the discrete coefficients of the m ratios between the single-phase current reference value and the current sum value when the N phase is cut off for the most recent m times, the value of the second time value is adjusted in an anti-correlated manner; the larger the discrete coefficients of the m ratios between the single-phase current reference value and the current sum value, the smaller the value of the second time value; the smaller the discrete coefficients of the m ratios between the single-phase current reference value and the current sum value, the larger the value of the second time value. The specific value of the second time value can be obtained by looking up a table.

[0088] By introducing a discrete coefficient to reflect the severity of load changes, the system can more accurately determine the load fluctuations. When the load changes drastically, the system can respond quickly and shorten the second time value to reduce the impact on the power system. When the load changes relatively smoothly, extending the second time value can provide more buffer time for the system, which helps to reduce the impact on the power system caused by frequent tripping, thereby enhancing the stability and reliability of the system. The introduction of this step enables the system to flexibly adjust the circuit breaker control strategy according to the severity of the load change. When the load changes drastically, the system can respond faster; when the load changes smoothly, the system can provide a longer buffer time. This helps to optimize load management and reduce unnecessary tripping and power fluctuations. The system can automatically adjust the second time value according to the discrete coefficient of load changes, which reflects the system's adaptive ability. This adaptive mechanism helps the system better adapt to various load changes and abnormal conditions and improve the overall reliability and efficiency of the power system.

[0089] An embodiment of the present application further discloses a circuit breaker control system for limiting load on a low-voltage power line, comprising a processor, wherein the processor executes the steps of the circuit breaker control method for limiting load on a low-voltage power line as described in any one of the above.

[0090] The embodiment of the present application further discloses a storage medium, in which a program is stored. When the program is executed by a processor, the steps of the circuit breaker control method for limiting load on a low-voltage power line are implemented.

[0091] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A circuit breaker control method for limiting load of a low voltage power line, characterized in that: Based on a low-voltage power line connected to a power factor compensation circuit, obtaining an A-phase current, a B-phase current, a C-phase current and an N-phase current in the low-voltage power line; If at least one value among the A-phase current, the B-phase current, the C-phase current and the N-phase current exceeds the preset single-phase current reference value and lasts for a set first time value, disconnecting the N-phase; Alternatively, if the sum of the A-phase current, the B-phase current, the C-phase current and the N-phase current is within a preset total current reference range and lasts for a set second time value, disconnecting the N-phase; Cut out the power factor compensation circuit, and connect a set resonant circuit to the N-phase branch on the load side, wherein the resonant circuit is provided with at least one group and connected in parallel at both ends of the normally closed contact of the relay; each group of the resonant circuit includes at least one resonant capacitor and at least one resonant inductor, and the resonant capacitor and the resonant inductor are connected in series; After a preset first delay time, the N phase is connected, the resonant circuit is cut out, and the power factor compensation circuit is connected; Calculate the time intervals of the most recent x times of N-phase disconnection, and if the average value of the x-1 time intervals gradually increases, gradually increase the single-phase current reference value; if the average value of the x-1 time intervals gradually decreases, gradually decrease the single-phase current reference value; Calculate the distribution uniformity of the time points of the most recent y N-phase cut-offs on the time axis, and adjust the total current reference range according to the positive correlation of the uniformity. The higher the uniformity, the larger the total current reference range, and the lower the uniformity, the smaller the total current reference range.

2. The circuit breaker control method for limiting load of a low-voltage power line according to claim 1, characterized in that: The method further comprises the steps of: If the sum of the A phase current, the B phase current, the C phase current and the N phase current is within the preset total current reference range, the N phase is disconnected first, and then the A phase, B phase and C phase are disconnected after a preset second delay time, wherein the duration of the first delay time is greater than the duration of the second delay time.

3. The circuit breaker control method for limiting load of a low-voltage power line according to claim 2, characterized in that: The method further comprises the steps of: The single-phase current reference value is adjusted inversely according to the current sum value; the larger the current sum value is, the smaller the single-phase current reference value is; the smaller the current sum value is, the larger the single-phase current reference value is.

4. The circuit breaker control method for limiting load of a low-voltage power line according to claim 2, characterized in that: The method further comprises the steps of: The inductance value in the resonant circuit is adjusted according to the positive correlation between the current sum value; the larger the current sum value is, the larger the inductance value in the resonant circuit is; the smaller the current sum value is, the smaller the inductance value in the resonant circuit is.

5. The circuit breaker control method for limiting load of a low-voltage power line according to claim 1, characterized in that: The method further comprises the steps of: Acquiring a power factor reference value of the power factor compensation circuit, wherein the power factor reference value is lower than a target power factor value; According to the current power factor value and the target power factor value, adjusting the switching logic of the capacitor in the resonant circuit; When the current power factor value is lower than the power factor reference value, the common compensation is put into operation first and then the split compensation is put into operation, the large-capacity resonant capacitor is put into operation first, and the resonant capacitor with less number of times is put into operation first; When the current power factor value is higher than the power factor reference value, the common compensation is cut off first and then the separate compensation, the large-capacity resonant capacitor is cut off first, and the resonant capacitor with the most times is cut off first.

6. The circuit breaker control method for limiting load of a low-voltage power line according to claim 2, characterized in that: The method further comprises the steps of: According to the number of times the N phases are cut off in the most recent preset inspection time period, the value of the first delay time value is positively correlated; the more the number of times the N phases are cut off, the longer the value of the first delay time value is; The smaller the number of cut-off times is, the shorter the first delay time value is.

7. The circuit breaker control method for limiting load of a low-voltage power line according to claim 2, characterized in that: The method further comprises the steps of: The value of the first time value is adjusted inversely according to the ratio between the single-phase current reference value and the current sum value when the N phase was last cut off; the larger the ratio between the single-phase current reference value and the current sum value, the shorter the value of the first time value; the smaller the ratio between the single-phase current reference value and the current sum value, the longer the value of the first time value.

8. The circuit breaker control method for limiting load of a low-voltage power line according to claim 2, characterized in that: The method further comprises the steps of: The value of the second time value is adjusted inversely according to the discrete coefficients of the m ratios between the single-phase current reference value and the current sum value when the N phases are cut off for the most recent m times; the larger the discrete coefficients of the m ratios between the single-phase current reference value and the current sum value, the smaller the value of the second time value; the smaller the discrete coefficients of the m ratios between the single-phase current reference value and the current sum value, the larger the value of the second time value.

9. A circuit breaker control system for limiting load on a low voltage power line, characterized in that: The method comprises a processor, wherein the steps of the circuit breaker control method for limiting load of a low-voltage power line as claimed in any one of claims 1 to 8 are executed in the processor.

10. A storage medium, characterized in that: The medium stores a program, and when the program is executed by a processor, the steps of the circuit breaker control method for limiting load on a low-voltage power line according to any one of claims 1 to 8 are implemented.

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