Low voltage power line load limiting break control method, system and storage medium

Abstract

The application relates to the technical field of low-voltage power line control, and discloses a low-voltage power line load-limiting circuit breaking control method, a system and a storage medium, the method comprising the following steps: acquiring A-phase, B-phase, C-phase and N-phase currents; if at least one of the four-phase currents exceeds a reference value and lasts for a first time value, the N-phase is disconnected; or if the current sum of the four-phase currents is within a reference range and lasts for a second time value, the N-phase is disconnected; a power factor compensation circuit is cut out and a resonance circuit is connected; after lasting for a first delay time, the N-phase is connected again, the resonance circuit is cut out, and the power factor compensation circuit is connected; the time interval value of the latest x times of N-phase cutting is calculated, the single-phase current reference value is positively adjusted according to the average value of the time interval value; the distribution uniformity of the time points of the latest y times of N-phase cutting on a time axis is calculated, and the total current reference range is positively adjusted according to the uniformity. The application has the advantages of load limitation without power interruption and difficulty in mis-tripping.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of low-voltage power line control, and particularly relates to a low-voltage power line load limiting circuit breaking control method, system and storage medium. BACKGROUND

[0002] As a commonly used control and protection device, a low-voltage circuit breaker is a switching appliance that can not only turn on and break normal load current and overload current, but also turn on and break short-circuit current. It is mainly used for protecting electrical devices and loads in power systems, and 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. The low-voltage circuit breaker is widely used in low-voltage distribution systems at all levels of feeder lines, power control of various mechanical equipment and control and protection of power terminals. The significant features of the low-voltage circuit breaker include manual reset after fault disconnection, long delay release with inverse time limit characteristic, and two-section protection function of instantaneous overcurrent release.

[0003] At present, many models of low-voltage circuit breakers are equipped with microcomputer type or integrated type relay protection components. During the peak period of power consumption or when the user load has a large impact, these low-voltage circuit breakers often trip due to overcurrent or overload protection, and the source of tripping is only a short-term accidental overload, and there is no fault in the loop of the low-voltage power line. After each misoperation of the low-voltage circuit breaker, the power supply can only be restored by manually closing the circuit by the repair personnel on site, which wastes a lot of repair manpower and resources. How to make the circuit breaker not misoperate and trip due to the instantaneous fluctuation of the load under the condition of ensuring the safe operation of the equipment is a problem that needs to be solved urgently. SUMMARY

[0004] In order to make the circuit breaker not misoperate and trip due to the instantaneous fluctuation of the load under the condition of ensuring the safe operation of the equipment, the present application provides a low-voltage power line load limiting circuit breaking control method, system and storage medium.

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

[0006] A low-voltage power line load limiting circuit breaking control method, comprising the following steps:

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

[0008] If at least one of the A-phase current, the B-phase current, the C-phase current, and the N-phase current exceeds a preset single-phase current reference value, and the condition is maintained for a first time value, the N-phase is disconnected; or 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 the condition is maintained for a second time value, the N-phase is disconnected.

[0009] 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 is connected in parallel across the relay normally closed contact point; 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 the first delay time, the N-phase is turned on again, and the resonant circuit is cut out, and the power factor compensation circuit is connected.

[0011] The time interval values of the N-phase disconnection in the last x times are calculated, if the average value of x-1 time interval values gradually increases, the single-phase current reference value is gradually increased, and if the average value of x-1 time interval values gradually decreases, the single-phase current reference value is gradually decreased.

[0012] The uniformity of the time points of the N-phase disconnection in the last y times on the time axis is calculated, and the total current reference range is adjusted 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 using the above technical solutions, by comprehensively using real-time monitoring, intelligent adjustment and resonant circuit and other technical means, the stability and efficiency of the power system are improved, the load management strategy is optimized, and unnecessary tripping and waste of manpower and material resources are reduced.

[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 a preset total current reference range, the N-phase is first disconnected, and then the A-phase, the B-phase, and the C-phase are disconnected after a preset second delay time, wherein the length of the first delay time is greater than the length of the second delay time.

[0016] By using 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 delay disconnection strategy help to better protect the power system, reduce unnecessary power failure, and improve the user's power experience.

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

[0018] adjusting the single-phase current reference value inversely with 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.

[0019] By adopting the above technical solution, the step of adjusting the single-phase current reference value inversely with the current sum value further enhances the adaptability and load management capability of the system; through the adaptive adjustment mechanism, not only the stability and reliability of the system are improved, but also the load distribution is optimized, and the protection precision and robustness are improved. These advantages will help better manage power load, reduce unnecessary tripping and waste of manpower and resources, and improve the overall operation efficiency of the power system.

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

[0021] adjusting the inductance value in the resonant circuit positively with the current sum value; the larger the current sum value, the larger the inductance value in the resonant circuit; the smaller the current sum value, the smaller the inductance value in the resonant circuit.

[0022] By adopting the above technical solution, the step of adjusting the inductance value in the resonant circuit positively with the current sum value provides the system with a more refined adjustment means; the dynamic adjustment mechanism not only improves the stability and reliability of the system, but also optimizes the load management, enhances the adaptive capability and robustness of the system. These advantages will help better manage power load, reduce unnecessary tripping and power fluctuations, and improve the overall operation efficiency of the power system.

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

[0024] obtaining 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] adjusting the switching logic of the capacitor in the resonant circuit according to the current power factor value and the target power factor value;

[0026] when the current power factor value is lower than the power factor reference value, first input the common compensation and then input the separate compensation, first input the large-capacity resonant capacitor, and first input the resonant capacitor with fewer times;

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

[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 self-adaptability and stability of the system. These advantages will help better manage power load and improve the overall operation efficiency of the power system.

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

[0030] According to the number of times of cutting off the N-phase in the recent preset patrol time period, the value of the first delay time value is positively correlated; the more the number of times of cutting off, the longer the value of the first delay time value; the fewer the number of times of cutting off, the shorter the value of the first delay time value.

[0031] By adopting the above technical solutions, the step of positively correlating the first delay time value according to the number of times of cutting off the N-phase 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 load management, enhances the self-adaptability of the system, reduces maintenance costs, and improves user experience. These advantages will help better manage power load and improve the overall operation efficiency of the power system.

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

[0033] According to the ratio between the single-phase current reference value and the current sum value when the N-phase is cut off last time, the value of the first time value is inversely correlated; 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 solutions, the step of inversely correlating the first time value according to the ratio between the single-phase current reference value and the current sum value when the N-phase is cut off last time provides a more refined and intelligent adjustment means for the system; the dynamic adjustment mechanism not only improves the response speed and stability of the system, but also optimizes load management, enhances the self-adaptability of the system, and helps reduce maintenance costs. These advantages will help better manage power load and improve the overall operation efficiency of the power system.

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

[0036] The discrete coefficient 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 is inversely related to the value of the second time value; the greater the discrete coefficient 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 coefficient of the m ratios between the single-phase current reference value and the current sum value, the greater the value of the second time value.

[0037] By adopting the above technical solution, the step of inversely relating the discrete coefficient 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 to the value of the second time value provides a more comprehensive and in-depth adjustment mechanism for the system; the dynamic adjustment mechanism not only improves the sensitivity of the system to load changes, but also enhances the stability and reliability of the system, optimizes the load management strategy, improves the self-adaptability of the system, and helps to reduce maintenance costs. These advantages will help better manage power loads and improve the overall operation efficiency of the power system.

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

[0039] A low-voltage power line limited load circuit control system, comprising a processor, wherein the processor executes the steps of the low-voltage power line limited load circuit control method according to 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, wherein the storage medium stores a program, and the program is executed by a processor to implement the steps of the low-voltage power line limited load circuit control method according to any one of the above.

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

[0043] Fine adjustment and response: by introducing various dynamic adjustment mechanisms, including adjusting the first delay time value according to the number of times the N phase is cut off, 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 phase is cut off for the most recent m times, the present application realizes fine management and rapid response of power loads. These adjustment mechanisms can flexibly adjust the strategy of circuit control according to real-time load conditions and the severity of load changes, thereby improving the stability and reliability of the power system.

[0044] Enhancing 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 the control parameters according to load changes and abnormal conditions. This adaptive capability helps the system better adapt to various complex power environments, improving the overall reliability and efficiency of the power system.

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

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

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

[0048] Figure 1 is a step diagram of the low-voltage power line load limiting circuit breaking control method of the application.

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

[0050] Reference signs: 1, insulating shell; 2, power supply side terminal post; 3, load side terminal post; 4, mechanical overcurrent release; 5, current transformer; 6, three-phase four-stage rectifier bridge stack; 7, relay; 8, resonance capacitor; 9, resonance inductor; 10, split-phase tripping connecting rod. DETAILED DESCRIPTION

[0051] The embodiments of the application are described in detail below, and examples of the embodiments are shown in the accompanying drawings.

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

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

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

[0055] If at least one 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 current 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, and lasts for a set second time value, the N-phase is disconnected. Assuming that the total current reference range is, 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 the 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 is connected in parallel across the normally closed contact point of the relay; each group of resonant circuits comprises at least one resonant capacitor and at least one resonant inductor, and the resonant capacitor and the resonant inductor are connected in series. The embodiment of the drawings takes an example of one resonant capacitor and one resonant inductor connected in series and then connected in parallel across the normally closed contact point of the relay for display, and in other embodiments, it can also be in a plurality of series-parallel connection relationship.

[0057] After the preset first delay time, the N-phase is turned on again, and the resonant circuit is cut out and the power factor compensation circuit is connected. The first delay time is 2-5 seconds, for example, 3 seconds.

[0058] The time interval values of the last x N-phase cutouts are calculated. If the average of the x-1 time interval values gradually increases, the single-phase current reference value is gradually increased. If the average of the x-1 time interval values gradually decreases, the single-phase current reference value is gradually decreased. Suppose that the time interval values of the last 10 (x = 10) N-phase cutouts are recorded. The average of the 9 (x-1) time interval values is calculated. If the average 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 gradually decreases; for example, from 10 minutes to 5 minutes, it indicates that the load fluctuation intensifies, and the single-phase current reference value needs to be gradually decreased; for example, from 10A to 9A.

[0059] The uniformity of the distribution of the time points of the last y N-phase cutouts on the time axis is calculated. According to the positive correlation between the uniformity and the total current reference range, the higher the uniformity, the larger the total current reference range, and the lower the uniformity, the smaller the total current reference range. Suppose that the time points of the last 20 (y = 20) N-phase cutouts are recorded. The uniformity of the distribution of these time points on the time axis is calculated; indicators such as standard deviation and coefficient of variation can be used to measure it. If the uniformity is high; for example, the standard deviation is small, it indicates that the distribution of the time points of the N-phase cutouts is relatively uniform, and the load change is relatively stable, and 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 indicates that the distribution of the time points of the N-phase cutouts is relatively concentrated, and the load change may be relatively intense, 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 adjusting the current parameters, the overload in the power line can be found and handled in time, avoiding unnecessary tripping. The connection of the resonant circuit helps to stabilize the frequency response of the power system and reduce power fluctuations caused by load fluctuations. Dynamic adjustment of the current reference value according to the actual situation of the load can more flexibly manage the power load and improve the utilization efficiency of power resources. By analyzing the time interval and distribution uniformity of N-phase cutouts, the load management strategy can be further optimized, and the impact of load fluctuations on the power system can be reduced. Through intelligent control strategy, the waste of manpower and material resources caused by false tripping can be reduced. Improving the stability and efficiency of the power system can reduce economic losses caused by power failures.

[0061] Reference Figure 2In the embodiment, the load-limiting anti-tripping low-voltage circuit breaker comprises an insulating shell 1, a power supply side terminal post 2, a load side terminal post 3, a mechanical overcurrent release 4, a current transformer 5, a three-phase four-stage rectifier bridge stack 6, a relay 7, a resonance capacitor 8, a resonance inductor 9, and a phase-by-phase tripping connecting rod 10. The power supply side terminal post 2 and the load side terminal post 3 are arranged in a column on both sides of the insulating shell 1, and the mechanical overcurrent release 4, the current transformer 5, the three-phase four-stage rectifier bridge stack 6, the relay 7, the resonance capacitor 8, and the resonance inductor 9 are all arranged inside the insulating shell 1. The power supply side terminal post 2, the load side terminal post 3, and the mechanical overcurrent release 4 all have a four-stage structure, the current transformer 5 has four same specifications, the primary side of each of which is sleeved on the ABCN phase power supply side terminal post 2, the secondary side is sequentially connected with the alternating current side of the three-phase four-stage rectifier bridge stack 6, the direct current side of the three-phase four-stage rectifier bridge stack 6 is connected with the coil of the relay 7, the relay 7 is a instantaneous action delay return type, the delay time is 2-5 seconds, the contact of the relay 7 is a normally closed contact, which is connected in series with the zero-phase power supply side terminal post 2, the resonance capacitor 8 and the resonance inductor 9 are connected in parallel with the normally closed contact of the relay 7, and the resonance frequency of the resonance capacitor 8 and the resonance inductor 9 is the power frequency. The operating handle of the mechanical overcurrent release 4 is provided with the phase-by-phase tripping connecting rod 10, the phase-by-phase tripping connecting rod 10 has a zero-phase tripping priority mechanism to realize that all the four stages are tripped when the zero-phase tripping occurs, and when any phase of the three phases is tripped, the other two phases are maintained in the closed state. The insulating shell 1 is filled with insulating heat-conducting liquid, the insulating heat-conducting liquid is composed of carbon tetrachloride, transformer oil, aluminum oxide ceramic powder, glycerol, and mercury, and the mass ratio of the carbon tetrachloride, the transformer oil, the aluminum oxide ceramic powder, the glycerol, and the mercury is 1:3:1:0.5:0.7, and the inner surface of the insulating shell 1 is coated with a non-ionic surfactant.

[0062] The circuit breaker realizes that the low-voltage circuit breaker does not trip when the load overflows, limits the load, automatically stops the work of the harmonic device that often causes overload, reduces the load, does not interrupt the power supply, improves the heat dissipation effect inside the circuit breaker, does not mis-trip due to the instantaneous large current of a certain phase, and improves the heat dissipation of the contact inside the circuit breaker. The application overcomes the problem that the tripping sensitivity inevitably increases with the occurrence of tripping events in the prior art, greatly improves the power supply reliability and safety of the power distribution system, allows single-phase tripping when a certain phase is overloaded, maintains the normal operation of the other two phases, and maximizes the power supply reliability.

[0063] A large number of studies found that many power distribution system overload is caused by harmonic equipment, harmonic equipment often in zero-phase form a large current to make the circuit breaker trip, the actual load total is not big. Therefore, the present application detects three-phase and zero-phase current, through the rectifier bridge, as long as one phase or the overall load current is too large, first through the relay to disconnect the zero-phase loop. At this time, the resonant circuit is connected to the zero-phase, and the normal three-phase unbalanced component is not limited at the resonant frequency, which will not cause three-phase unbalance, but the harmonic current is limited by the inductive element, so that the harmonic equipment that causes overload cannot work normally and stop. 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 are not affected, which realizes the effect of limiting load without tripping. The technical scheme of the present application realizes that the low-voltage circuit breaker does not trip when the occasional load overloads, but can limit the load. For harmonic equipment that often causes overload, it automatically stops working to reduce the load, without interrupting the power supply. At the same time, when one phase is overloaded, single-phase tripping is allowed to maintain normal operation of the other two phases without tripping, which maximizes 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 element of the circuit breaker must be solved. The heat dissipation effect of filling liquid in the circuit breaker is very significant, but the circuit breaker cannot be completely sealed. The present application breaks through the use of a variety of composite materials to form a high-surface-tension heat-dissipating insulating liquid, combined with the hydrophobic coating inside the plastic shell, to realize that the injected liquid cannot leak out even with holes and gaps due to the lotus effect, which greatly improves the heat dissipation effect inside the circuit breaker and prevents mis-tripping due to a momentary large current in one phase. At the same time, because the heat dissipation of the internal contacts of the circuit breaker is improved, the problem of the inevitable increase in tripping sensitivity with the occurrence of tripping events is overcome, greatly improving the reliability and safety of the power supply system.

[0065] The method further includes the following steps:

[0066] If the current 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, the N-phase is disconnected first, and then the A-phase, the B-phase and the C-phase 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 first disconnecting the N phase, then delaying the disconnection of the A, B and C phases, the system implements a hierarchical protection mechanism. This mechanism can first attempt to reduce the load by disconnecting the neutral line (N phase) when the load is overloaded or abnormal conditions appear, and if the situation does not improve, further disconnect all phase lines to more comprehensively protect the power system. The strategy of delayed disconnection helps to reduce unnecessary overall power outage. In some cases, temporary load overload may be temporary, and by first disconnecting the N phase and observing for a period of time, the system can avoid unnecessary overall power outage, 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 the actual situation. This flexibility helps to better adapt to various complex load conditions, improving the stability and reliability of the power system. When detecting load overload or abnormal conditions, the system can take measures according to the preset process, first trying lighter intervention (disconnecting the N phase), and then gradually upgrading (disconnecting all phase lines after a delay) as needed. This process-oriented approach helps to optimize the fault handling process and improve efficiency.

[0068] The method further comprises the following steps:

[0069] The single-phase current reference value is adjusted inversely related to 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. The single-phase current reference value can be obtained by table lookup.

[0070] By inversely adjusting the single-phase current reference value, the system can automatically adjust the protection threshold according to the real-time load condition. This adaptive mechanism helps the system better cope with various load changes, improving the stability and reliability of the power system. When the current sum value is large, reducing the single-phase current reference value can more effectively limit the load and prevent overload. When the current sum value is small, increasing the single-phase current reference value helps to fully utilize power resources and improve the rationality of load distribution. The inverse adjustment strategy allows the system to more accurately adjust protection parameters when the load changes, reducing the likelihood of false tripping. This helps to reduce the waste of manpower and resources caused by false tripping, improving the efficiency of the power system. By dynamically adjusting the single-phase current reference value, the system can better adapt to various complex load conditions, enhancing the robustness and disturbance rejection ability of the system. This helps the system to respond quickly and maintain stable operation when facing sudden load changes or abnormal conditions.

[0071] The method further comprises the following steps:

[0072] The inductance value in the resonant circuit is adjusted according to the positive correlation between the current sum value and the inductance value; the greater the current sum value, the greater the inductance value in the resonant circuit; the smaller the current sum value, the smaller the inductance value in the resonant circuit. Each resonant circuit can be connected in series with a thyristor to control the number of resonant inductors in 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 sum value is large, increasing the inductance value helps to suppress power fluctuations and improve system stability. Dynamic adjustment of the inductance value enables the system to flexibly adjust the parameters of the resonant circuit according to the load condition, 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 condition, enhancing the system's adaptive ability. This adaptive mechanism helps the system better cope with various load changes, improving the reliability and efficiency of the power system. Adjusting the inductance value in the resonant circuit can also effectively reduce the harmonic impact 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. Dynamic adjustment of the inductance value in the resonant circuit enables the system to better adapt to various complex load conditions, enhancing the system's robustness. This helps the system to respond quickly and maintain stable operation when facing 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 the power factor compensation circuit, wherein the power factor reference value is lower than the target power factor value;

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

[0077] When the current power factor value is lower than the power factor reference value, first put in the common compensation and then put in the separate compensation, first put in the large-capacity resonant capacitor, and first put in the resonant capacitor with fewer times;

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

[0079] By dynamically adjusting the switching logic of the capacitors in the resonant circuit, the system can more effectively compensate for the power factor, making the power factor of the power system closer to the target value. This helps to improve the efficiency and stability of the power system. According to the principle of "first switching in the resonant capacitor with less switching frequency, and first switching out the resonant capacitor with more switching frequency", the switching of the capacitors is helpful to prolong the service life of the capacitors. Because the capacitors with frequent switching are more likely to be damaged, and according to this logic, the switching frequency of the capacitors can be reduced, thereby reducing the damage rate. Improving the power factor helps to reduce the flow of reactive power in the power system, thereby reducing the loss of electric energy. This is of great significance to improve 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 adaptive ability of the system. This adaptive mechanism helps the system to 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 fluctuation of the power system, thereby improving the stability of the system.

[0080] The method further comprises the following steps:

[0081] According to the number of times of cutting off N-phase in the recent preset patrol time period, the value of the first delay time value is positively adjusted; the more the number of times of cutting off, the longer the value of the first delay time value; the less the number of times of cutting off, the shorter the value of the first delay time value. For example, in the recent 10 hours, the number of times of cutting off N-phase is 2, and the first delay time value is 3 seconds; when the number of times of cutting off N-phase is 3 in 10 hours, the first delay time value is 4 seconds; the specific value can be obtained by table lookup.

[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 situations. When the number of N-phase cut-offs is high, 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 tripping 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 high, extending the first delay time value gives the system more buffer time, which helps optimize load management and reduce unnecessary tripping. The system can automatically adjust the first delay time value according to the change in 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 situations, improving the reliability and efficiency of the power system. By optimizing the tripping control strategy, reducing unnecessary tripping and power fluctuations can reduce the wear and tear on power equipment and lines. This helps extend the service life of equipment and lines, reducing maintenance costs. Reducing the number of trips and power fluctuations can improve the user's power experience. Stable power supply helps ensure normal life and production activities of users, improving user satisfaction.

[0083] The method further comprises the following steps:

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

[0085] In the case of light load, by shortening the first time value, the system can quickly recover to normal working state, improving the response speed of the system. This helps to reduce load fluctuations and power loss caused by system delay. 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 tripping control strategy according to the real-time load situation and the ratio of the single-phase current reference value to the current sum. This helps optimize load management and reduce unnecessary tripping and power fluctuations. The system can automatically adjust the first time value according to the change in the ratio of the single-phase current reference value to the current sum, which reflects the adaptive ability of the system. This adaptive mechanism helps the system better adapt to various load changes and abnormal situations, improving the reliability and efficiency of the power system. By optimizing the tripping control strategy, reducing unnecessary tripping and power fluctuations can reduce the wear and tear on power equipment and lines. This helps extend the service life of equipment and lines, reducing maintenance costs.

[0086] The method further comprises the following steps:

[0087] The value of the second time value is inversely related to the dispersion coefficient of the m ratios between the single-phase current reference value and the current sum value according to the latest m times of cutting off the N-phase. The greater the dispersion coefficient 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 dispersion coefficient of the m ratios between the single-phase current reference value and the current sum value, the greater 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 the dispersion coefficient to reflect the intensity of load change, the system can more accurately judge the fluctuation of the load. When the load changes intensively, the system can respond quickly and shorten the second time value to reduce the impact on the power system. In the case of relatively stable load change, 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 strategy of circuit breaking control according to the intensity of load change. When the load changes intensively, the system can respond faster; when the load changes smoothly, the system can provide 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 dispersion coefficient of the load change, which reflects the adaptive ability of the system. This adaptive mechanism helps the system to better adapt to various load changes and abnormal situations, improving the overall reliability and efficiency of the power system.

[0089] The embodiments of the present application also disclose a circuit breaking control system for limiting load of a low-voltage power line, comprising a processor, wherein the processor executes the steps of the circuit breaking control method for limiting load of a low-voltage power line according to any one of the above embodiments.

[0090] The embodiments of the present application also disclose a storage medium, wherein a program is stored in the storage medium, and the program is executed by a processor to implement the steps of the circuit breaking control method for limiting load of a low-voltage power line according to any one of the above embodiments.

[0091] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A circuit breaker control method for limiting load on 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 a 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; Cutting out the power factor compensation circuit, and connecting a pre-set resonant circuit to the N-phase branch on the load side, wherein at least one resonant circuit is provided and connected in parallel to both ends of the normally closed contact of the relay; each 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 disconnected, and the power factor compensation circuit is connected; Calculate the time intervals of the most recent x times the N-phase is disconnected, 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 on 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 a 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 on 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 according to the anti-correlation of the current sum value; the larger the current sum value is, the smaller the single-phase current reference value is; and 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 on 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 on a low-voltage power line according to claim 1, characterized in that: The method further comprises the steps of: Obtaining 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; adjusting the switching logic of the capacitor in the resonant circuit according to the current power factor value and the target power factor value; 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 the least 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 on 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 greater the number of times the N phases are cut off, the longer the value of the first delay time value is; The fewer the number of cutoff times, the shorter the first delay time value.

7. The circuit breaker control method for limiting load on 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 is most recently 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 on 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 phase is 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 processor executes 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.

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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