Power distribution protection method and device for low-voltage transformer area, computer equipment and storage medium

Abstract

The invention relates to a power distribution protection method and device for a low-voltage transformer area, computer equipment and a storage medium. The method comprises the following steps: under the condition that the leakage protector detects the current residual current, determining the current type based on the change condition of the current residual current; when the current type is slowly changed residual current, the leakage protector is controlled to trip; and when the current type is the abrupt-change residual current, if a blocking signal is not detected, controlling the leakage protector to trip after delaying for a first preset time, and controlling the leakage protector to coincide after delaying for a second preset time. According to the invention, by judging the type of the current residual current, the reason for the residual current generated by the leakage protector can be distinguished, and power restoration can be carried out in time without threatening the personal safety of an electric shock, so that the timeliness of power restoration is improved.

Description

Technical Field

[0001] The present application relates to the field of power distribution technology, and in particular to a power distribution protection method, device, computer equipment and storage medium for a low-voltage area. Background Art

[0002] Low-voltage substations are located at the end of the distribution network. They are widely distributed and numerous, but their infrastructure is poor, their electricity usage is complex, and their management is relatively weak. These factors lead to frequent power outages in the substations, and the restoration of power is not only costly but also lacks timeliness. Summary of the invention

[0003] Based on this, it is necessary to provide a power distribution protection method, device, computer equipment and storage medium for low-voltage substations with high timeliness in response to the above-mentioned technical problems.

[0004] In the first aspect, the present application provides a power distribution protection method for a low-voltage substation. The method includes: when the leakage protector detects the current residual current, determining the current type based on the change of the current residual current; wherein the current type includes: slowly changing residual current and suddenly changing residual current; when the current type is the slowly changing residual current, controlling the leakage protector to trip; when the current type is the suddenly changing residual current, if the locking signal is not detected, controlling the leakage protector to trip after a first preset delay time, and controlling the leakage protector to overlap after a second preset delay time.

[0005] In one of the embodiments, after the step of when the current type is the sudden residual current, the method further includes: if a sudden change of the current residual current is detected within the first preset time, controlling the leakage protector to lock and trip.

[0006] In one of the embodiments, the method further includes: obtaining an unbalanced current and a phase current of a low-voltage magnetically controlled circuit breaker; and controlling the low-voltage magnetically controlled circuit breaker based on changes in the unbalanced current and the phase current.

[0007] In one of the embodiments, the step of controlling the low-voltage magnetically controlled circuit breaker based on the changes in the unbalanced current and the phase current includes: if the unbalanced current and the phase current are both sudden currents, controlling the low-voltage magnetically controlled circuit breaker based on the changes in the phase current.

[0008] In one embodiment, the step of controlling the low-voltage magnetically controlled circuit breaker based on the change of the phase current includes: if the change of the phase current meets the first preset change characteristic, controlling the low-voltage magnetically controlled circuit breaker not to trip; wherein, the first preset change characteristic is the change characteristic of the phase current during lightning strike or load switching; if the change of the phase current meets the second preset change characteristic, controlling the low-voltage magnetically controlled circuit breaker to trip and reclose after a delay of a third preset time; wherein, the second preset change characteristic is the change characteristic of the phase current during electric shock or grounding.

[0009] In one of the embodiments, after the step in which the leakage protector detects the current residual current, the method further includes: obtaining line status information and current environmental information; wherein the line status information includes: line load, three-phase imbalance, and line operating time, and the current environmental information includes: temperature and humidity information; and determining the cause of the line abnormality based on the line status information and the current environmental information.

[0010] In one of the embodiments, after the step in which the leakage protector detects the current residual current, the method further includes: obtaining historical current data; wherein the historical current data includes: multiple residual currents detected by the leakage protector; determining the current fault type based on the historical current data and the current residual current; adjusting the state of the leakage protector based on the current fault type; wherein the state adjustment includes: one of adjusting the leakage protector setting value, alarm slow trip control, and controlling the leakage protector closing.

[0011] In the second aspect, the present application also provides a power distribution protection device for a low-voltage substation. The device includes: a type determination module, which is used to determine the current type based on the change of the current residual current when the leakage protector detects the current residual current; wherein the current type includes: slowly changing residual current and suddenly changing residual current; a leakage protection control module, which is used to control the leakage protector to trip when the current type is the slowly changing residual current; when the current type is the suddenly changing residual current, if the locking signal is not detected, the leakage protector is controlled to trip after a first preset delay time, and the leakage protector is controlled to overlap after a second preset delay time.

[0012] In a third aspect, the present application further provides a computer device, wherein the computer device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0013] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the above method when executed by a processor.

[0014] The above-mentioned power distribution protection method, device, computer equipment and storage medium for the low-voltage substation determine the current type according to the change of the current residual current when the residual current is detected by the leakage protector, and control the leakage protector to trip or reclose after delayed tripping according to the current type. By judging the type of the current residual current, the reason why the residual current is generated by the leakage protector can be distinguished, and the power can be restored in time without threatening the personal safety of electric shock, thereby improving the timeliness of power restoration. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of a flow chart of a power distribution protection method in an embodiment;

[0016] Figure 2 A schematic diagram of the structure of three-level protection in an embodiment;

[0017] Figure 3 is a flow chart of a power distribution protection method in another embodiment;

[0018] Figure 4 is a structural schematic diagram of phase current detection in one embodiment;

[0019] Figure 5 is a flow chart of a power distribution protection method in yet another embodiment;

[0020] Figure 6 A schematic diagram of a flow chart of a power distribution protection method in yet another embodiment;

[0021] Figure 7 A schematic diagram of a module of a power distribution protection device in one embodiment;

[0022] Figure 8 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0024] As described in the background technology, power outages frequently occur in low-voltage areas. Frequent power outages are mainly caused by user faults in rural power grids, suburban areas, and overhead cable radiation under the TT wiring method, which leads to the tripping of distribution transformers. Among them, the main reasons include: leakage current generated by low-voltage transmission lines in the area (overhead lines are too low and the distance from buildings does not meet the requirements; the fixing position of poles is unreasonable, the workmanship is poor, and there are no isolation insulators; the insulation of poles, household / lead-out lines is aging or damaged, the wires are broken, the wires are broken, the poles are collapsed, etc.); household electric motor equipment generates leakage current (electrical appliances are of poor quality, such as: unqualified submersible pumps with poor insulation cause a lot of leakage current and are not easy to solve; the terminal single-phase equipment starts at high power, and when the load is unbalanced in three phases, leakage changes are detected).

[0025] In the related technology, the safety of electricity use is protected by setting up leakage protection devices. For leakage protection devices, the residual current mainly includes the following two parts: the leakage current caused by the imbalance of the three-phase capacitance to ground and the conductivity to ground parameters (static and with less impact), and the leakage current caused by the imbalance of the three-phase line voltage caused by the imbalance of the three-phase load and other reasons (dynamic and with greater impact); the single-phase grounding fault current, the current injected into the earth by the grounding point. However, the leakage protection device generally adopts the residual current identification method of "residual current amplitude ratio + delayed tripping", which cannot avoid the excessive residual current caused by three-phase imbalance, slow aging of insulation, weather and meteorological changes, quality of electrical equipment and poor insulation. Therefore, it still causes frequent power outages in low-voltage substations, and lacks timeliness when restoring power.

[0026] Based on this, the present application proposes a power distribution protection method, device, computer equipment and storage medium for a low-voltage substation to solve at least one of the above-mentioned technical problems.

[0027] In one embodiment, Figure 1 As shown, a power distribution protection method for a low voltage area is provided, and the method is applied to a power distribution control system as an example for explanation, and includes the following steps:

[0028] Step S110: when the leakage protector detects the current residual current, determine the current type based on the change of the current residual current.

[0029] Specifically, Figure 2 As shown, the leakage protector can be a leakage protector set under the three-level protection in the figure, that is, it can be a leakage protector in the total protection, branch line protection, and final protection. The leakage protector monitors the current residual current in the circuit in real time through the built-in detection device, and uses it as the current residual current. Residual current refers to the current that is not zero when the current vector sum of each phase (including the neutral line) in the low-voltage distribution line is leaking or the insulation of the equipment is damaged. Residual current will be generated.

[0030] When the residual current is detected by the leakage protector, it indicates that the corresponding line is faulty. At this time, the current type of the residual current can be determined by analyzing the change of the residual current. The change of the residual current is the speed of change of the residual current size over a period of time.

[0031] The current types include: slowly changing residual current and suddenly changing residual current.

[0032] Step S120, when the current type is a slowly varying residual current, controlling the leakage protector to trip.

[0033] Specifically, when the current type is a slowly varying residual current, it means that the current residual current is gradually changing, and the change is relatively gentle. This change is usually caused by natural factors such as weather or slow aging of lines and equipment. For example, in humid weather, the insulation performance of the line gradually decreases, resulting in a slow increase in the residual current; or the line is in long-term operation, the insulation layer gradually ages, which will also cause the residual current to change slowly. When the current type is determined to be a slowly varying residual current, it means that there are certain safety hazards in the line or equipment. Although the fault develops relatively slowly, if it is not handled in time, it may gradually deteriorate and eventually cause more serious safety accidents. For example, if the line is in a humid environment for a long time, the insulation performance continues to decline, and the residual current continues to increase, which may cause dangerous situations such as electrical fires. Therefore, in order to ensure safety, the leakage protector will be controlled to trip immediately to cut off the circuit, thereby preventing the fault from further developing and ensuring the safety of personnel and equipment.

[0034] Step S130, when the current type is a sudden residual current, if the locking signal is not detected, the leakage protector is controlled to trip after a first preset delay time, and the leakage protector is controlled to reclose after a second preset delay time.

[0035] Specifically, when the current type is a sudden residual current, it means that the residual current will increase rapidly in a very short time. This change is usually caused by a sudden fault, such as a sudden electric shock to a person, an instantaneous grounding of the line, etc. When the current type is a sudden residual current, the leakage protector will first detect whether there is a lockout signal. The lockout signal is issued after the upper protection device acts to remove the fault, and is used to prevent unnecessary repeated tripping of the lower protection device. If the lockout signal is not detected, it means that the fault may not be completely handled by the upper level or the fault only occurs within the monitoring range of this level. At this time, in order to ensure safety, the leakage protector will control the tripping after the first preset time delay. By delaying the first preset time, it can be ensured that the fault is judged more accurately and the tripping is avoided due to short-term interference. After the tripping cuts off the circuit, in order to restore power supply as soon as possible and reduce the impact of power outages on users, the leakage protector will be controlled to overlap after the second preset time delay. The second preset time is set to provide a certain time for fault handling and equipment recovery to ensure that the fault has been eliminated or the danger has been eliminated. It is understandable that in order to ensure the personal safety of people who are electrocuted, the time it takes to trip and reclose after being electrocuted, that is, the second preset time, is the minimum time (such as 1 second) for people to escape from the central electric shock scene.

[0036] The above-mentioned power distribution protection method for the low-voltage substation determines the current type according to the change of the current residual current when the residual current is detected by the residual current protector, and controls the residual current protector to trip or reclose after delayed tripping according to the current type. By judging the type of the current residual current, the cause of the residual current generated by the residual current protector can be identified, and the power can be restored in time without threatening the personal safety of electric shock, thereby improving the timeliness of power restoration.

[0037] In one embodiment, in step S130, after the step of when the current type is a sudden residual current, the power distribution protection method further includes: if a sudden change in the current residual current is detected within a first preset time, controlling the leakage protector to lock and trip.

[0038] Specifically, when it is determined that the current type is a sudden residual current, continue to monitor whether the current residual current mutates again within the first preset time. If the current residual current mutates again within the first preset time, it means that the upper protection device has detected the fault and has cut off the faulty line. Therefore, the residual current in the faulty line will change, and this change can be detected by the leakage protector of the lower protection device. If the lower protection device does not lock and trip at this time, it will cause unnecessary over-tripping and expand the scope of power outage. For example, suppose a branch line has a ground fault, and the upper branch line protection device quickly acts to cut off the branch line. At this time, the residual current in the faulty line will suddenly change. If the leakage protector of the lower protection on the branch line does not lock and trip, it will cause power outages for users who should not have power outages.

[0039] In one embodiment, Figure 3 As shown, the power distribution protection method for the low voltage area also includes the following steps:

[0040] Step S210, obtaining the unbalanced current and phase current of the low voltage magnetically controlled circuit breaker.

[0041] Specifically, Figure 4 As shown in the figure, in the circuit system of the low-voltage section, the unbalanced current and phase current of the low-voltage magnetically controlled circuit breaker are obtained through measuring equipment such as current transformers (CT). For the phase current, the current values ​​of the three phases A, B, and C can be directly measured from the three-phase line; the unbalanced current can be obtained by calculating the vector sum of the three-phase currents, which reflects the imbalance degree of the three-phase load and possible abnormal conditions such as leakage.

[0042] Step S220: controlling the low voltage magnetically controlled circuit breaker based on the changes in the unbalanced current and the phase current.

[0043] Specifically, for different fault scenarios, the changes in unbalanced current and phase current will be different. By detecting this difference, the current fault can be determined, and the low-voltage magnetic circuit breaker can be controlled to perform corresponding actions to distribute power to the circuit system of the low-voltage area. And when there is no abnormality in the unbalanced current and phase current, the low-voltage magnetic circuit breaker is controlled not to operate.

[0044] In one embodiment, in step S220, the step of controlling the low-voltage magnetically controlled circuit breaker based on the changes in the unbalanced current and the phase current includes: if the unbalanced current and the phase current are both sudden currents, controlling the low-voltage magnetically controlled circuit breaker based on the changes in the phase current.

[0045] Specifically, if it is determined that both the unbalanced current and the phase current are mutation currents, that is, when the current magnitude suddenly changes, it indicates that an abnormal situation has occurred in the circuit. For example, a lightning strike will cause a drastic change in the line current in a short period of time, resulting in a sudden change in the unbalanced current and the phase current at the same time; the start or stop of large equipment will also cause a sudden change in the unbalanced current and the phase current due to its large starting current or sudden change in operating status; electric shock to personnel or line grounding will also cause a sudden change in the unbalanced current and the phase current. At this point, the corresponding fault can be identified based on the change in the phase current, thereby controlling the state of the low-voltage magnetically controlled circuit breaker.

[0046] In one embodiment, the step of controlling a low-voltage magnetically controlled circuit breaker based on changes in phase current includes: if the changes in the phase current meet a first preset change characteristic, controlling the low-voltage magnetically controlled circuit breaker not to trip; wherein the first preset change characteristic is a change characteristic of the phase current during lightning strikes or load switching.

[0047] Specifically, during normal operation, the phase current has its specific fluctuation range and law. When lightning strikes or load is switched, the phase current will mutate. When lightning strikes, the strong lightning shock will instantly change the electromagnetic field in the line, causing the phase current to suddenly increase or fluctuate. This change is often a short spike pulse; when large equipment is started or stopped, the load switching will also cause the phase current to mutate due to the large starting current of the equipment or the sudden change of the operating state, but as the equipment enters a stable operating state, the current will gradually return to normal. When the unbalanced current and the phase current are both sudden currents, the phase current will be compared with the pre-set first preset change characteristics to determine whether they are consistent. If the change of the phase current meets the first preset change characteristics, the low-voltage magnetically controlled circuit breaker is controlled not to trip. This is because the current change caused by lightning strikes or load switching is more drastic in an instant, but in most cases it will not cause continuous and serious damage to the line and equipment. If the circuit breaker trips at this time, it will cause unnecessary power outages and affect the normal power consumption of users.

[0048] In one embodiment, the step of controlling a low-voltage magnetically controlled circuit breaker based on changes in phase current includes: if the changes in phase current meet a second preset change characteristic, controlling the low-voltage magnetically controlled circuit breaker to trip, and to reclose after a delay of a third preset time; wherein the second preset change characteristic is a change characteristic of the phase current during electric shock or grounding.

[0049] Specifically, electric shock and grounding faults can cause current leakage, which will not only pose a serious threat to personal safety, but may also cause electrical fires and other dangers. The power supply must be quickly cut off to ensure safety. When an electric shock occurs, the human body is connected to the circuit to become a current path, causing abnormal changes in the phase current, and the current magnitude and phase will change; when the line is grounded, a large amount of current flows to the ground, which will also cause the phase current to fluctuate greatly and deviate from the normal range. When it is judged that the change in the phase current meets the second preset change characteristics, the low-voltage magnetic control circuit breaker will be immediately controlled to trip and cut off the fault circuit. At the same time, after tripping, it will reclose after a third preset time to provide a certain amount of time for fault troubleshooting and equipment recovery. If the fault is instantaneous, such as a person who is accidentally electrocuted and quickly detaches, after this period of time, the system returns to normal, and power supply can be restored after reclosing; if the fault still exists, the circuit breaker will detect abnormal current again after reclosing, and trip again to avoid continued danger. In some embodiments, the third preset time is the minimum time (such as 1 second) for a person to escape from the central electric shock scene.

[0050] In one embodiment, Figure 5 As shown, in step S110, after the step in which the leakage protector detects the current residual current, the power distribution protection method further includes:

[0051] Step S310, obtaining line status information and current environment information.

[0052] Specifically, when the residual current is detected by the leakage protector, it indicates that the circuit is abnormal. At this time, the line status information and current environmental information are obtained. The line status information includes: line load, three-phase imbalance, and line operation time. The line load can be collected in real time by power monitoring equipment installed on the low-voltage substation line, such as smart meters, current transformers, etc., to collect the current in the line, and then calculate the line load based on the voltage and current data. The three-phase imbalance can be monitored by the power monitoring equipment to monitor the size and phase of the three-phase current. The three-phase imbalance will cause additional heating of the line and equipment, reduce the service life of the equipment, and generate zero-sequence current, increasing the possibility of residual current abnormality. The line operation time can be obtained by recording the time when the line is put into use. As the operation time increases, the various components of the line gradually age, the insulation performance decreases, the mechanical strength of the wire decreases, and it is more likely to be damaged and broken, which will cause leakage, short circuit and other faults. The current environmental information includes: temperature and humidity information, which can be obtained by the temperature and humidity sensor installed in the substation. Ambient temperature and humidity have significant impacts on the line. When the humidity is high, the insulation performance of the line insulation material will decrease, and moisture may penetrate into the insulation layer, reducing its resistance value, resulting in an increase in leakage current. In a humid environment, water film is easily formed on the surface of the insulator of the overhead line, which deteriorates its insulation performance. Too high temperature will cause the line conductor to expand and accelerate the aging of the insulation material; too low temperature may make the conductor brittle and easy to break.

[0053] Step S320: determining the cause of the line abnormality based on the line status information and the current environment information.

[0054] Specifically, after obtaining the line status information and current environmental information, by comparing with the collected historical data, the cause of the residual current, that is, the cause of the line abnormality (serious three-phase imbalance, aging, grounding, etc.) can be determined. At the same time, by analyzing the impact of weather on each branch line, the line insulation performance can be evaluated and the line aging degree of each branch line can be analyzed. For example, if the line load is high for a long time, the three-phase imbalance is serious, and the running time is long, then there is a high possibility that the line aging will be accelerated. The insulation layer of the aging line may be damaged, resulting in leakage and abnormal residual current. In an environment with high humidity, if an abnormal increase in residual current is detected and the line has been running for a long time, it may be that the humidity causes the insulation performance of the line to deteriorate and cause leakage. If the line load is also high at this time, this situation will be further aggravated. When the ambient temperature is too high and the line load is large, the line temperature may be too high due to poor heat dissipation, accelerating insulation aging, and then causing line failure.

[0055] In one embodiment, Figure 6As shown, in step S110, after the step in which the leakage protector detects the current residual current, the power distribution protection method further includes:

[0056] Step S410, obtaining historical current data.

[0057] Specifically, the distribution control system will record and store the residual current data detected by the leakage protector and use it as historical current data. The historical current data covers the residual current conditions in different time periods and different power usage scenarios, including small residual current fluctuations during normal power usage, as well as abnormal residual current records when minor leakage faults occur. Through long-term accumulation, the historical current data can reflect the changing patterns and trends of the residual current in the substation.

[0058] Step S420, determining the current fault type based on the historical current data and the current residual current.

[0059] Specifically, when determining the current fault type, the amplitude and change trend of the current residual current can be compared and analyzed based on the historical current data to determine the current fault type. For example, if the current residual current amplitude is far beyond the historical normal range, and is close to or exceeds the residual current amplitude when tripping due to leakage faults in history, it means that a more serious leakage fault has occurred; on the contrary, if the current residual current amplitude is only slightly higher than the historical normal range, it may be a minor fault caused by slight moisture in the line, slight aging of equipment insulation, etc. If the current residual current shows a continuous upward trend, and similar trends in historical data are often accompanied by aggravated equipment aging or gradual development of faults, then it can be determined that there may be a problem of aggravated equipment aging or potential faults are worsening. If the current residual current changes suddenly and significantly, similar to the sudden change in residual current caused by instantaneous interference such as lightning strikes and load switching in history, it may be subject to similar external interference.

[0060] Step S430: adjusting the state of the leakage protector based on the current fault type.

[0061] Specifically, after determining the current fault type, the state of the leakage protector is adjusted again. The state adjustment includes: adjusting the leakage protection value, alarm slow trip control, and controlling the leakage protection closing. For example, if it is determined that the current fault is a slight leakage caused by the aging of the line insulation, resulting in the residual current slightly exceeding the normal range but not reaching the dangerous level, the leakage protection value can be appropriately increased, so as to avoid frequent tripping due to the slight leakage caused by the normal aging of the line, and ensure the continuity of power supply. When it is determined that the current fault may have potential risks but will not pose a serious threat to personnel and equipment for the time being, the alarm slow trip control is used to delay the tripping time and leave time for the operation and maintenance personnel to troubleshoot and handle the fault. During the slow tripping period, the residual current changes are continuously monitored. If the residual current rises sharply or reaches the dangerous threshold, it will trip immediately. If it is determined that the current fault has been eliminated, for example, after the operation and maintenance personnel have inspected the line or equipment, it is determined that the residual current has returned to the normal range based on the historical current data and the current residual current, and the leakage protection closing can be controlled to restore power supply. In some cases, when the residual current is temporarily abnormal, which may be caused by momentary interference, and the residual current returns to normal after the interference disappears, the leakage protection circuit breaker can also be automatically controlled to close, reducing power outage time and improving power supply reliability.

[0062] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0063] Based on the same inventive concept, the embodiment of the present application also provides a power distribution protection device for implementing the power distribution protection method of the low-voltage substation involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more power distribution protection device embodiments provided below can refer to the limitations on the power distribution protection method above, and will not be repeated here.

[0064] In one embodiment, Figure 7 As shown, a power distribution protection device is provided, including: a type determination module 510 and a leakage protection control module 520, wherein:

[0065] The type determination module 510 is used to determine the current type based on the change of the current residual current when the residual current protector detects the current residual current; wherein the current type includes: slowly changing residual current and suddenly changing residual current;

[0066] The leakage protection control module 520 is used to control the leakage protector to trip when the current type is a slowly changing residual current; when the current type is a sudden changing residual current, if no locking signal is detected, the leakage protector is controlled to trip after a first preset delay time, and the leakage protector is controlled to reclose after a second preset delay time.

[0067] In one embodiment, the leakage protection control module 520 is further used to control the leakage protector to lock and trip if a sudden change in the current residual current is detected within the first preset time.

[0068] In one embodiment, the power distribution protection device further includes: a circuit breaker control module, which is used to obtain the unbalanced current and phase current of the low-voltage magnetically controlled circuit breaker; and control the low-voltage magnetically controlled circuit breaker based on the changes in the unbalanced current and the phase current.

[0069] In one embodiment, the circuit breaker control module is further configured to control the low voltage magnetically controlled circuit breaker based on the change of the phase current if both the unbalanced current and the phase current are sudden change currents.

[0070] In one embodiment, the circuit breaker control module is also used to control the low-voltage magnetically controlled circuit breaker not to trip if the change in phase current meets the first preset change characteristic; wherein the first preset change characteristic is the change characteristic of the phase current during lightning strike or load switching; if the change in phase current meets the second preset change characteristic, the low-voltage magnetically controlled circuit breaker is controlled to trip and reclose after a delay of a third preset time; wherein the second preset change characteristic is the change characteristic of the phase current during electric shock or grounding.

[0071] In one embodiment, the power distribution protection device further includes: an abnormality analysis module, which is used to obtain line status information and current environmental information; wherein the line status information includes: line load, three-phase imbalance, and line operation time, and the current environmental information includes: temperature and humidity information; the cause of the line abnormality is determined based on the line status information and the current environmental information.

[0072] In one embodiment, the power distribution protection device further includes: a state adjustment module for obtaining historical current data; wherein the historical current data includes: multiple residual currents detected by the leakage protector; determining the current fault type based on the historical current data and the current residual current; adjusting the state of the leakage protector based on the current fault type; wherein the state adjustment includes: adjusting the leakage protector setting value, alarm slow trip control, and controlling the leakage protector closing.

[0073] Each module in the above-mentioned power distribution protection device can be implemented in whole or in part by software, hardware and a combination thereof. Each of the above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory in the computer device in the form of software, so that the processor can call and execute the corresponding operations of each of the above modules.

[0074] In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Figure 8 As shown. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface, the display unit and the input device are connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and the external device. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be realized through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a power distribution protection method for a low-voltage station area is realized. The display unit of the computer device is used to form a visually visible picture, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse.

[0075] Those skilled in the art will understand that Figure 8 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0076] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0077] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the processor executes the computer program, the steps in the above-mentioned method embodiments are implemented.

[0078] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0079] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0080] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A power distribution protection method for a low voltage area, characterized in that: The method comprises: When the leakage protector detects the current residual current, the current type is determined based on the change of the current residual current; wherein the current type includes: slowly changing residual current and suddenly changing residual current; When the current type is the slowly varying residual current, controlling the leakage protector to trip; When the current type is the sudden residual current, if the locking signal is not detected, the leakage protector is controlled to trip after a first preset delay time, and is controlled to reclose after a second preset delay time.

2. The power distribution protection method for low voltage substations according to claim 1, characterized in that: After the step of when the current type is the sudden residual current, the method further includes: If a sudden change in the current residual current is detected within the first preset time, the leakage protector is controlled to lock and trip.

3. The power distribution protection method for low voltage substations according to claim 1, characterized in that: The method further comprises: Obtain unbalanced current and phase current of low voltage magnetic circuit breaker; The low-voltage magnetically controlled circuit breaker is controlled based on changes in the unbalanced current and the phase current.

4. The power distribution protection method for low voltage substations according to claim 3 is characterized in that: The step of controlling the low-voltage magnetically controlled circuit breaker based on the change of the unbalanced current and the phase current comprises: If the unbalanced current and the phase current are both sudden currents, the low-voltage magnetically controlled circuit breaker is controlled based on the change of the phase current.

5. The power distribution protection method for low voltage substations according to claim 4 is characterized in that: The step of controlling the low voltage magnetically controlled circuit breaker based on the change of the phase current comprises: If the change of the phase current meets the first preset change characteristic, the low-voltage magnetically controlled circuit breaker is controlled not to trip; wherein the first preset change characteristic is the change characteristic of the phase current when lightning strikes or load switching; If the change of the phase current meets the second preset change characteristic, the low-voltage magnetically controlled circuit breaker is controlled to trip and reclose after a delay of a third preset time; wherein the second preset change characteristic is the change characteristic of the phase current when electric shock or grounding occurs.

6. The power distribution protection method for low voltage substations according to claim 1, characterized in that: After the step of detecting the current residual current by the leakage protector, the method further comprises: Acquire line status information and current environment information; wherein the line status information includes: line load, three-phase imbalance, and line operation time, and the current environment information includes: temperature and humidity information; The cause of the line abnormality is determined based on the line status information and the current environment information.

7. The power distribution protection method for low voltage substations according to claim 1, characterized in that: After the step of detecting the current residual current by the leakage protector, the method further comprises: Acquire historical current data; wherein the historical current data includes: a plurality of residual currents detected by the leakage protector; Determine a current fault type based on the historical current data and the current residual current; The state of the leakage protector is adjusted based on the current fault type; wherein the state adjustment includes: adjusting the leakage protector setting value, alarm slow tripping control, and controlling the leakage protector closing.

8. A power distribution protection device for a low voltage area, characterized in that: The device comprises: A type determination module, used for determining the current type based on the change of the current residual current when the residual current is detected by the leakage protector; wherein the current type includes: slowly changing residual current and suddenly changing residual current; The leakage protection control module is used to control the leakage protector to trip when the current type is the slowly changing residual current; when the current type is the sudden changing residual current, if no locking signal is detected, the leakage protector is controlled to trip after a first preset delay time, and the leakage protector is controlled to reclose after a second preset delay time.

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

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

Images