An overload protection method and system for a JP cabinet, a terminal and a storage medium

Abstract

The application relates to an overload protection method and system of a JP cabinet, a terminal and a storage medium, and relates to the field of overload protection of a JP cabinet.The method comprises the following steps: identifying a day type label according to a current date and a calendar rule; obtaining maximum load currents of the JP cabinet in corresponding time periods of N same type day type labels from a historical database, and calculating an average value of the maximum load currents; calculating an overload protection threshold value of a current time period according to the average value and a preset safety margin coefficient; obtaining a total incoming line current value in real time and calculating a current change rate; if the current change rate exceeds a short-circuit threshold value within a preset time window, triggering a quick-break tripping signal after a first delay time; if the quick-break tripping signal is not triggered, triggering an overload tripping signal when the total incoming line current value exceeds the overload protection threshold value and reaches a second delay time; and updating the maximum load currents of each time period to the historical database.The application has the effects of improving power supply reliability and guaranteeing power supply continuity.

Description

Technical Field

[0001] This application relates to the field of overload protection for JP cabinets, and in particular to an overload protection method, system, terminal and storage medium for JP cabinets. Background Technology

[0002] In the power supply system, overload protection is a key technical support for improving power supply reliability and ensuring power supply continuity.

[0003] In related technologies, JP cabinets use fixed overcurrent thresholds for protection. Whether the load is abnormal depends on the experience and historical records of maintenance personnel for manual judgment, and cannot be adaptively adjusted.

[0004] The aforementioned technologies suffer from insufficient threshold adaptability and limited intelligence in overload protection, leading to inaccurate tripping judgments and failure to respond to overload conditions. Summary of the Invention

[0005] To improve power supply reliability and ensure power supply continuity, this application provides an overload protection method, system, terminal, and storage medium for a JP cabinet.

[0006] Firstly, this application provides an overload protection method for a JP cabinet, employing the following technical solution: An overload protection method for a JP cabinet includes: Based on the current date and calendar rules, identify the day type label, which includes at least one of the following: weekday, holiday, irrigation operation period, or Spring Festival peak electricity consumption period; Obtain the maximum load current of JP cabinets corresponding to N day type labels of the same type from the historical database, and calculate the average value of the maximum load current, where N≥5; Based on the average value and the preset safety margin coefficient, calculate the overload protection threshold for the current period. The overload protection threshold shall not exceed the safety limit allowed by the rated current of the main circuit breaker of the JP cabinet. Real-time acquisition of total incoming current value and calculation of current change rate; If the rate of change of current exceeds the short-circuit threshold within the preset time window, an instantaneous trip signal is triggered after the first delay time. If the total incoming current exceeds the overload protection threshold and reaches the second delay time without triggering the instantaneous trip signal, then the overload trip signal is triggered. The first delay time is less than the second delay time. Update the maximum load current for each time period to the historical database.

[0007] By adopting the above technical solution, the current power load characteristics are analyzed, and similar daily type tags are matched with historical load databases to calculate overload protection thresholds. Simultaneously, short-circuit faults are identified based on current change rate and interference criteria, and tiered tripping decisions are executed. This solution significantly improves the accuracy of tripping judgment, optimizes the adaptability of protection strategies, reduces false tripping and failure to operate, and significantly enhances power supply reliability and JP cabinet operational safety.

[0008] Optionally, the interference identification window can be activated, and the peak current, zero-sequence current amplitude, and three-phase current imbalance at the moment of current surge can be recorded. Determine whether the peak current decays to a first preset ratio in the first sub-period and exceeds a second preset ratio in the second sub-period, the first preset ratio is less than the second preset ratio, and both the first preset ratio and the second preset ratio are values ​​greater than 0 and less than 1. If so, determine whether the zero-sequence current amplitude is less than the preset ground fault threshold, whether the three-phase current imbalance is less than the preset symmetry threshold, and whether a voltage drop was not detected at the moment of current surge. If so, it is determined to be a non-fault interference, and the output of the instantaneous trip signal is suppressed; If not, it is determined to be a short circuit fault, and an instantaneous trip signal is triggered after the first delay time.

[0009] By employing the above technical solution, the peak current decay characteristics, zero-sequence current amplitude, and three-phase current imbalance at the moment of current surge are analyzed. Combined with voltage status and preset fault criteria, non-faulty interference and short-circuit faults are distinguished. When an interference is identified, the instantaneous trip signal is suppressed, and a tripping action is executed after a short circuit is confirmed. This solution significantly improves fault identification accuracy and reduces false tripping caused by transient interference such as motor starting or lightning strikes.

[0010] Optionally, start the monitoring window and acquire the total incoming current value at a fixed sampling period within the monitoring window; The actual thermal effect value is obtained by summing the product of the square of the total incoming current and the sampling period. Calculate the maximum theoretical energy value that can be passed through based on the impedance parameters and safe energy limits of the current power distribution circuit; Determine whether the actual thermal effect value reaches the maximum theoretical energy value before the end of the monitoring window; If so, a continuous fault is determined, and the JP cabinet is controlled to trigger an instantaneous trip signal; If not, the determination result of non-faulty interference is maintained.

[0011] By adopting the above technical solution, the thermal accumulation characteristics of the total incoming current within the monitoring window are analyzed. The maximum theoretical energy value is calculated by combining the distribution circuit impedance parameters and the safe energy limit, and compared with the actual thermal effect value to identify persistent faults. Simultaneously, normal operation is maintained after confirming that the interference is not due to a fault. This solution can promptly detect the risk of thermal accumulation caused by poor contact or insulation aging, reducing damage to the JP cabinet due to missed overheating risks.

[0012] Optionally, determine whether there are other JP cabinets operating in parallel within the same area as the JP cabinet; If so, the JP cabinet and the other JP cabinets exchange operating status data packets at a fixed period. The operating status data packets include local thermal effect values ​​and total incoming current values. Based on the operating status data packet, calculate the total heat effect value of the area and the proportion of the local heat effect value of each JP cabinet in the total heat effect value; If the total thermal effect value reaches the preset proportion of the theoretical energy limit of the corresponding transformer area, and the thermal effect proportion is lower than the preset abnormal threshold, the control JP cabinet sends a coordinated tripping request to the other JP cabinets. After sending the coordinated tripping request, wait to receive confirmation responses from the other JP cabinets and determine whether a majority of JP cabinets have tripped. If so, then initiate the collaborative delay timing; After the collaborative delay timer expires, the control JP cabinet triggers an instantaneous trip signal and records the trip event simultaneously.

[0013] By adopting the above technical solution, the local thermal effect value and total incoming current of the JP cabinet are analyzed. Combined with the operating status data of other parallel JP cabinets in the distribution area, the overall heat load level of the distribution area is assessed. When the total thermal effect approaches the safety limit and the contribution of this cabinet is abnormally low, a coordinated trip negotiation is initiated. At the same time, a unified trip decision is executed based on the response results of most JP cabinets. This solution significantly improves the coordinated response capability of the distribution area to thermal accumulation faults and reduces the risk of equipment burnout or fire caused by local overheating accumulation.

[0014] Optionally, a node query request can be initiated to the other JP cabinets, and valid response information can be collected within a preset response time. Based on the valid response information, construct an initial node list; Within each fixed period, each JP cabinet is controlled to send a running status data packet to the corresponding node in the initial node list, and the response status of each corresponding node is updated according to the running status data packet. The response status includes non-response status and response status. If the number of times any node is in an unresponsive state reaches the preset number of times it is considered to be out of contact, the node that has reached the preset number of times it is in an unresponsive state will be marked as out of contact, and the operating status data of the corresponding out-of-contact JP cabinet will not be used. If the disconnected JP cabinet resends the operating status data packet, it is determined whether the local thermal effect value of the disconnected JP cabinet is within the preset reasonable range. If so, then restore the lost JP cabinet as a valid node.

[0015] By adopting the above technical solution, a node query request is initiated to other JP cabinets within the distribution area to construct an initial node list. The response status of each node is updated by periodically exchanging operational status data packets. Abnormal data is excluded when consecutive node outages are detected. Furthermore, when an out-of-connection JP cabinet comes back online, its thermal effect value is verified to determine whether it is restored as a valid node. This solution significantly improves the reliability of multi-cabinet collaborative communication and reduces misjudgments caused by communication interruptions or interference from abnormal nodes.

[0016] Optionally, obtain the actual maximum load current during the preset observation period on the current date; From the historical database, query historical dates that have the same type label and belong to the same season as the current day, extract the maximum load current of the historical date in the same period of the current day, and calculate the historical average value; Determine whether the deviation between the actual maximum load current and the historical average value exceeds the preset tolerance threshold; If so, then the historical load level of the day type label is determined to be inconsistent with the current load level; If there is a discrepancy, match the historical date with the smallest difference from the current load level from the historical database and update the day type label.

[0017] By employing the above technical solution, the maximum load current of the current date within a preset observation period is obtained. This average value is calculated by combining historical load data from the same day type label and season in the historical database. Based on the deviation, it is determined whether the current label matches the actual electricity consumption level. If there is a discrepancy, the most similar historical date is matched, and the day type label is updated. This solution significantly improves the accuracy of day type identification and reduces false tripping caused by label misjudgment.

[0018] Optionally, a load-meteorological curve can be constructed based on the daily maximum load current and the corresponding meteorological data in the historical database. Based on the load-weather curve, the entire year is divided into multiple local seasonal intervals; Determine whether the meteorological data for the current date falls within the meteorological coverage area of ​​the load-meteorological curve; If not, the season will be determined according to calendar rules.

[0019] By employing the above technical solution, the maximum daily load current and its corresponding meteorological data within historical electricity consumption cycles are analyzed. Combined with the local load-meteorological correlation curve, local seasonal intervals reflecting actual electricity consumption characteristics are defined. When the current meteorological data exceeds the historical coverage range, the system automatically reverts to calendar rules to determine the season. This solution significantly improves the consistency between seasonal division and actual load patterns, reducing protection threshold deviations caused by mechanically dividing seasons by month.

[0020] Secondly, this application provides an overload protection system for a JP cabinet, which adopts the following technical solution: An overload protection system for a JP cabinet, comprising: The acquisition module is used to obtain the current date, calendar rules, and maximum load current; A memory for storing the program of the overload protection method for the JP cabinet; The processor and the program in the memory can be loaded and executed by the processor to implement the overload protection method of the JP cabinet.

[0021] By adopting the above technical solution, the acquisition module collects the current date, calendar rules and maximum load current in real time, the processor quickly executes the protection logic of overload identification and interference judgment, and the memory continuously updates historical load data and day type labels, realizing intelligent processing of the entire process from load perception to protection action. While ensuring the accuracy of tripping, it significantly improves response efficiency and provides an efficient and reliable solution for intelligent protection of JP cabinets.

[0022] Thirdly, this application provides a smart terminal, which adopts the following technical solution: A smart terminal includes a memory and a processor, wherein the memory stores a computer program that can be loaded by the processor and executed as described above.

[0023] Fourthly, this application provides a computer storage medium capable of storing corresponding programs, which facilitates improved power supply reliability and ensures power supply continuity, and adopts the following technical solution: A computer-readable storage medium storing a computer program that can be loaded by a processor and execute any of the above-described overload protection methods for a JP cabinet.

[0024] In summary, this application includes at least one of the following beneficial technical effects: 1. Analyze the current electricity load characteristics, match similar daily type tags with the historical load database, and calculate the overload protection threshold. Simultaneously, identify short-circuit faults based on current change rate and interference criteria, and execute tiered tripping decisions. This solution significantly improves the accuracy of tripping judgment, optimizes the adaptability of protection strategies, reduces false tripping and failure to operate, and significantly improves power supply reliability and JP cabinet operational safety. 2. Analyze the local thermal effect value and total incoming current of the JP cabinet, and combine this with the operating status data of other parallel JP cabinets in the distribution area to assess the overall heat load level of the distribution area. When the total thermal effect approaches the safety limit and the contribution of this cabinet is abnormally low, initiate coordinated trip negotiation, and simultaneously execute a unified trip decision based on the response results of the majority of JP cabinets. This scheme significantly improves the coordinated response capability of the distribution area to thermal accumulation faults and reduces the risk of equipment burnout or fire caused by local overheating accumulation. 3. Obtain the maximum load current for the current date within a preset observation period, calculate the average value by combining it with historical load data of the same day type label and season from the historical database, and determine whether the current label is consistent with the actual power consumption level based on the deviation. If inconsistent, match the historical date with the most similar load and update the day type label. This solution significantly improves the accuracy of day type identification and reduces false tripping caused by label misjudgment. Attached Figure Description

[0025] Figure 1 This is a flowchart illustrating an overload protection method for a JP cabinet provided in an embodiment of this application.

[0026] Figure 2 This is a flowchart illustrating a current disturbance identification method for a JP cabinet provided in an embodiment of this application.

[0027] Figure 3 This is a schematic flowchart of a JP cabinet thermal effect protection method provided in an embodiment of this application.

[0028] Figure 4 This is a flowchart illustrating a collaborative protection method for thermal accumulation in a JP cabinet provided in an embodiment of this application.

[0029] Figure 5 This is a flowchart illustrating a JP cabinet collaborative node maintenance method provided in an embodiment of this application.

[0030] Figure 6 This is a flowchart illustrating a method for calibrating a JP cabinet date type label according to an embodiment of this application.

[0031] Figure 7 This is a flowchart illustrating a method for seasonal division of JP cabinets provided in an embodiment of this application.

[0032] Figure 8 This is a structural schematic diagram of an overload protection system for a JP cabinet provided in an embodiment of this application. Detailed Implementation

[0033] To make the purpose, technical solution, and advantages of this application clearer, the following description is provided in conjunction with the appendix. Figures 1 to 8The present application will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the application.

[0034] This application discloses an overload protection method for a JP cabinet. (Refer to...) Figure 1 The method includes: Step 101: Identify the day type label based on the current date and calendar rules. The day type label includes at least one of the following: weekday, holiday, irrigation operation period, or Spring Festival peak electricity consumption period.

[0035] Calendar rules refer to pre-configured criteria for distinguishing dates of different electricity consumption behaviors. These include national statutory holiday schedules, irrigation schedules issued by local agricultural departments or village committees, and seasonal high-load periods such as the Spring Festival, determined based on historical electricity consumption data.

[0036] Daily type labels are classification identifiers for electricity consumption characteristics on different dates, used to reflect the differences in load patterns on different dates. Among them, weekdays refer to regular electricity consumption days, holidays refer to statutory rest days, irrigation operation periods refer to the concentrated water pumping period in agriculture, and the Spring Festival electricity consumption peak period refers to the lunar festival period when electricity consumption increases significantly due to people returning to their hometowns.

[0037] The system compares the current date with the calendar rules. If the date falls on a national statutory holiday, it is marked as a holiday. If it falls within the locally announced irrigation period, it is marked as an irrigation operation period. If it falls within the high load period around the Lunar New Year, it is marked as the peak electricity consumption period during the Lunar New Year. Other regular dates are marked as working days by default.

[0038] Step 102: Obtain the maximum load current of the JP cabinet corresponding to the time period of N days with the same type of label from the historical database, and calculate the average value of the maximum load current, N≥5.

[0039] Maximum load current refers to the highest effective value of the total incoming current of the JP cabinet within a specified time period. It is usually measured in 15-minute or 1-hour windows to represent the actual load level during that period. The time period is divided based on a 24-hour day, into multiple consecutive time periods at fixed intervals. Typically, each time period is 15 minutes, 30 minutes, or 1 hour. The specific interval is set according to the data acquisition capability of the JP cabinet and the load variation characteristics. The maximum load current for each time period is recorded and stored independently.

[0040] Step 103: Calculate the overload protection threshold for the current time period based on the average value and the preset safety margin coefficient. The overload protection threshold shall not exceed the safety limit allowed by the rated current of the main circuit breaker of the JP cabinet.

[0041] The overload protection threshold is a current threshold used to determine whether an overload has occurred in the JP cabinet. It is calculated by multiplying the average of the historical daily maximum load current of the same type by a safety margin factor less than 1, ensuring that it does not exceed the long-term safe operating limit allowed by the rated current of the main circuit breaker. The multiplication by the preset safety margin factor is to reserve a safety margin based on the historical average load, avoiding tripping due to normal load fluctuations or measurement deviations, and ensuring that the overload protection threshold is both close to the actual power consumption level and has the necessary reliability.

[0042] Step 104: Obtain the total incoming current value in real time and calculate the current change rate.

[0043] The rate of change of current refers to the increment of the total incoming current value per unit time. By continuously sampling the current value and calculating the rate of rise or fall of the current, it is used to reflect the degree of current change and is an important criterion for distinguishing between short-circuit faults and normal load fluctuations. For example, if the processor samples the total incoming current value every 10 milliseconds, and the current sampled value is 220 amps, and the previous sampled value was 120 amps, then the rate of change of current is (220−120)÷0.01=10,000A / s, or 10A / ms.

[0044] Step 105: If the rate of change of current exceeds the short-circuit threshold within the preset time window, trigger the instantaneous trip signal after the first delay time.

[0045] The first delay time refers to a short waiting period set after the current change rate exceeds the short-circuit threshold. During this period, interference judgment is performed. If it is confirmed to be a non-fault disturbance, the trip signal is not triggered. Only when it is determined to be a real short circuit will the instantaneous trip signal be output.

[0046] Step 106: If the total incoming current exceeds the overload protection threshold and reaches the second delay time without triggering the instantaneous trip signal, then the overload trip signal is triggered. The first delay time is less than the second delay time.

[0047] The second delay time refers to the waiting time set after the total incoming current value continuously exceeds the overload protection threshold. It is used to confirm the continuity of the overload state and avoid tripping due to short-term load fluctuations.

[0048] Short-circuit faults must be cleared quickly, and the circuit breaker should be tripped directly once the instantaneous tripping condition is met. Only when no short circuit has occurred is it necessary to determine whether the current has exceeded the overload threshold for an extended period of time, in order to prevent false tripping of normal short-term peak loads.

[0049] Step 107: Update the maximum load current for each time period to the historical database.

[0050] After the day's operation ends, the maximum load current recorded for each time period, along with the corresponding day type label, is stored in the historical database for load analysis and protection threshold calculation on subsequent similar dates, thereby achieving continuous accumulation and updating of historical data.

[0051] By adopting the above technical solution, the current power load characteristics are analyzed, and similar daily type tags are matched with historical load databases to calculate overload protection thresholds. Simultaneously, short-circuit faults are identified based on current change rate and interference criteria, and tiered tripping decisions are executed. This solution significantly improves the accuracy of tripping judgment, optimizes the adaptability of protection strategies, reduces false tripping and failure to operate, and significantly enhances power supply reliability and JP cabinet operational safety.

[0052] This application discloses a method for identifying current disturbances in a JP (Portable Switchgear) cabinet. (Refer to...) Figure 2 The method includes: Step 201: Start the interference identification window and record the peak current, zero-sequence current amplitude, and three-phase current imbalance at the moment of current surge.

[0053] The interference identification window is a short monitoring period that is activated after a sudden increase in current is detected. It is used to collect and analyze characteristic quantities such as peak current, zero-sequence current, and three-phase imbalance to determine whether the sudden increase is caused by non-fault interference.

[0054] Peak current refers to the maximum current value reached instantaneously during a current surge. It usually occurs in the initial stage of interference or fault occurrence and is used to indicate the intensity of the current surge.

[0055] Zero-sequence current amplitude refers to the effective value of the vector sum of three-phase currents, reflecting whether there is asymmetrical grounding or leakage. Under normal symmetrical operation, this value is close to zero, but it will increase significantly when a single-phase grounding fault occurs.

[0056] Three-phase current imbalance refers to the percentage of the difference between the maximum and minimum phase currents in the three-phase currents relative to the maximum phase current. It is used to measure the symmetry of a three-phase load, and this value will increase significantly when a single-phase load is too heavy.

[0057] Step 202: Determine whether the peak current decays to a first preset ratio in the first sub-period and exceeds a second preset ratio in the second sub-period, the first preset ratio is less than the second preset ratio, and both the first preset ratio and the second preset ratio are values ​​greater than 0 and less than 1.

[0058] The first sub-period refers to a short time interval, usually 10 to 30 milliseconds, starting from the moment of current surge. It is used to observe whether the peak current decays rapidly in order to make a preliminary judgment on whether it belongs to non-fault disturbances such as motor starting.

[0059] The first preset ratio refers to the relative level to which the peak current is allowed to decay within the first sub-period. It takes a value between 0 and 1 and is used to indicate whether the current drops rapidly. For example, 0.3 means that it decays to 30% of the original peak value.

[0060] The second sub-period refers to a monitoring period immediately following the first sub-period, typically 30 to 80 milliseconds. It is used to observe whether the current rises again after a brief decay, in order to identify non-fault disturbances with surge characteristics, such as motor starting.

[0061] The second preset ratio refers to the relative level reached by the peak current during the second sub-period. The value is between 0 and 1 and is greater than the first preset ratio. For example, 0.6 means that the peak current has risen to 60% of the original peak value. This is used to confirm whether the current exhibits the surge characteristics of non-fault disturbance.

[0062] The purpose of this judgment is to identify non-fault disturbances that exhibit a rapid initial decay followed by a partial recovery, such as the current waveform during motor startup. In contrast, short-circuit fault currents typically rise continuously without a significant decay and subsequent recovery process.

[0063] Step 203: If yes, determine whether the zero-sequence current amplitude is less than the preset ground fault threshold, whether the three-phase current imbalance is less than the preset symmetry threshold, and whether a voltage drop was not detected at the moment of current surge.

[0064] After the current waveform initially conforms to the characteristics of interference, the presence of a real grounding or short-circuit fault is further verified by three criteria: zero-sequence current, three-phase unbalance, and whether the voltage drops suddenly.

[0065] If the peak current does not decay to the first preset ratio within the first sub-period, or does not rise to the second preset ratio within the second sub-period, the current waveform is considered not to meet the typical characteristics of non-fault interference. Subsequent interference confirmation judgments regarding zero-sequence current, imbalance, and voltage drop are not performed, and the short-circuit fault judgment is directly entered.

[0066] Step 204: If so, it is determined to be a non-fault interference, and the output of the instantaneous trip signal is suppressed.

[0067] When all interference criteria are met, it is confirmed that the current surge is caused by non-fault factors. Therefore, no instantaneous trip signal is issued to avoid the JP cabinet from tripping due to normal disturbances such as motor starting and lightning strikes.

[0068] Step 205: If not, it is determined to be a short circuit fault, and an instantaneous trip signal is triggered after the first delay time.

[0069] If any interference criterion is not met, the sudden increase in current is determined to be caused by a short circuit fault. After confirmation by the first delay time, an instantaneous trip signal is output to quickly clear the fault and ensure the safety of equipment and lines.

[0070] By employing the above technical solution, the peak current decay characteristics, zero-sequence current amplitude, and three-phase current imbalance at the moment of current surge are analyzed. Combined with voltage status and preset fault criteria, non-faulty interference and short-circuit faults are distinguished. When an interference is identified, the instantaneous trip signal is suppressed, and a tripping action is executed after a short circuit is confirmed. This solution significantly improves fault identification accuracy and reduces false tripping caused by transient interference such as motor starting or lightning strikes.

[0071] This application discloses a method for thermal protection of a JP cabinet. (Refer to...) Figure 3 The method includes: Step 301: Start the monitoring window and obtain the total incoming current value within the monitoring window at a fixed sampling period.

[0072] The monitoring window is a fixed-duration observation interval that is opened after an abnormal current is detected. It is usually tens to hundreds of milliseconds and is used to collect the total incoming current value at fixed intervals during this period for subsequent thermal effect calculations.

[0073] Using a fixed sampling period is to ensure that the current data is evenly distributed on the time axis, which facilitates the accurate calculation of the integral of the square of the current over time, i.e., the thermal effect value, and avoids the distortion of energy accumulation calculation caused by uneven sampling intervals.

[0074] Step 302: Accumulate the product of the square of the total incoming current value and the sampling period to obtain the actual thermal effect value.

[0075] The actual thermal effect value is obtained by multiplying and summing the square of the total incoming current at each moment within the monitoring window with the sampling period, and is used to represent the degree of heat accumulation caused by the current within a time period.

[0076] Step 303: Calculate the maximum theoretical energy value that can be passed based on the impedance parameters and safe energy limits of the current power distribution circuit.

[0077] Impedance parameters refer to the equivalent resistance and reactance of transformers, cables, and connecting components in a power distribution circuit. They are used to calculate the short-circuit current level and thus determine the maximum energy allowed to pass within safe limits.

[0078] The safe energy limit refers to the maximum permissible value of the product of the square of the current and the time that a power distribution device can withstand without thermal damage.

[0079] The maximum theoretical energy value refers to the maximum allowable thermal effect value of the current that can pass through, calculated based on the impedance of the power distribution circuit and the safety energy limit of the equipment. Exceeding this value may cause the circuit breaker or line to overheat and be damaged.

[0080] The short-circuit current level is calculated based on the impedance parameters of the distribution circuit. Then, combined with the safe energy limit that the circuit breaker or cable can withstand, the maximum allowable thermal effect value after matching the two is taken as the maximum theoretical energy value. For example, if the equivalent total impedance of a 400V low-voltage distribution circuit is 0.08Ω, the short-circuit current is approximately 2875A. If the circuit breaker configured can withstand this current for 0.97s without thermal damage during type testing, its safe energy limit corresponds to the thermal effect generated by 2875A for 0.97s. Based on this, the maximum allowable theoretical energy value is calculated as the square of 2875A multiplied by 0.97s, resulting in approximately 8,000,000 A²·s.

[0081] Step 304: Determine whether the actual thermal effect value has reached the maximum theoretical energy value before the end of the monitoring window.

[0082] The purpose of this judgment is to promptly identify abnormal overcurrents within the monitoring window that, although not reaching the instantaneous overcurrent threshold, have accumulated dangerous heat due to their prolonged duration, in order to prevent safety accidents caused by thermal damage.

[0083] Step 305: If so, determine that a continuous fault has occurred and control the JP cabinet to trigger an instantaneous trip signal.

[0084] When the actual thermal effect value reaches the maximum theoretical energy value, it is confirmed that the fault is persistent and dangerous, and the JP cabinet is controlled to perform an instantaneous trip to cut off the power supply.

[0085] Step 306: If not, maintain the determination result of non-faulty interference.

[0086] When the actual thermal effect value does not reach the maximum theoretical energy value, the current abnormality is considered to be caused by a brief disturbance. Therefore, the judgment of non-fault interference is maintained to avoid false tripping.

[0087] By adopting the above technical solution, the thermal accumulation characteristics of the total incoming current within the monitoring window are analyzed. The maximum theoretical energy value is calculated by combining the distribution circuit impedance parameters and the safe energy limit, and compared with the actual thermal effect value to identify persistent faults. Simultaneously, normal operation is maintained after confirming that the interference is not due to a fault. This solution can promptly detect the risk of thermal accumulation caused by poor contact or insulation aging, reducing damage to the JP cabinet due to missed overheating risks.

[0088] This application discloses a method for coordinated protection against thermal accumulation in a JP cabinet. (Refer to...) Figure 4 The method includes: Step 401: Determine whether there are other JP cabinets operating in parallel within the area to which the JP cabinet belongs.

[0089] The purpose of this judgment is to determine whether the conditions for collaborative analysis of multiple JP cabinets are met. Only when other JP cabinets are operating in parallel will data be exchanged and a comprehensive judgment of the heat effect value of the distribution area be made.

[0090] Step 402: If yes, then control the JP cabinet and the other JP cabinets to exchange operating status data packets at a fixed period. The operating status data packets include local thermal effect values ​​and total incoming current values.

[0091] The operating status data packet refers to the data frame sent by each JP cabinet at a fixed period, where the local thermal effect value is the thermal effect value of each JP cabinet.

[0092] If there are no other JP cabinets operating in parallel in the same area as the JP cabinet, no data exchange will be performed, and subsequent fault diagnosis and tripping operations will be performed directly for a single JP cabinet.

[0093] Step 403: Based on the operating status data packet, calculate the total heat effect value of the area to which it belongs and the proportion of the local heat effect value of each JP cabinet in the total heat effect value.

[0094] The total heat effect value refers to the sum of the local heat effect values ​​of all JP cabinets within the same transformer area, and is used to reflect the current comprehensive heat energy level of the transformer area.

[0095] The heat effect ratio refers to the percentage of the local heat effect value of a certain JP cabinet to the total heat effect value of the area, and is used to determine whether the proportion of the JP cabinet in the overall heat generation is abnormal.

[0096] Step 404: If the total thermal effect value reaches the preset proportion of the theoretical energy limit of the corresponding transformer area, and the thermal effect proportion is lower than the preset abnormal threshold, then the control JP cabinet sends a coordinated tripping request to the other JP cabinets.

[0097] If the overall heat generation in the distribution area is close to a dangerous level, but the heat effect of a certain JP cabinet is relatively low, it indicates that the fault may be located on the common bus or external line rather than in the JP cabinet's own circuit. In this case, the JP cabinet should initiate a coordinated tripping request to prevent unnecessary tripping due to individual operation.

[0098] Step 405: After sending the coordinated tripping request, wait to receive confirmation responses from the remaining JP cabinets and determine whether a majority of JP cabinets have tripped.

[0099] A majority of JP cabinets refers to those JP cabinets that return trip confirmations among all JP cabinets participating in the response within their respective distribution area, which is more than half of the total number of JP cabinets.

[0100] By waiting for responses from other JP cabinets to the coordinated tripping request, it can be determined whether a majority of JP cabinets agree to trip, thus ensuring that the action is based on the joint judgment of most devices in the distribution area and avoiding misjudgment by a single JP cabinet.

[0101] Step 406: If so, start the collaborative delay timer.

[0102] The coordinated delay time refers to a short waiting period that starts after most JP cabinets agree to trip, in order to coordinate the synchronous execution of tripping actions by each JP cabinet and avoid inconsistencies in actions caused by differences in response timing.

[0103] After obtaining the consent of a majority of JP cabinets to trip, a short delay is initiated to ensure that the actions of each cabinet are synchronized and to prevent inconsistent tripping due to differences in processing timing.

[0104] If no tripping response is received from most JP cabinets, the collaborative delay timing will not be started, and each JP cabinet will continue to operate independently according to its own overload protection settings.

[0105] Step 407: After the collaborative delay timer ends, the control JP cabinet triggers an instantaneous trip signal and records the trip event simultaneously.

[0106] A tripping event refers to the key operational information recorded when the JP cabinet performs an instantaneous trip, including the tripping time, triggering reason, local thermal effect value, and area thermal effect value, which is used for subsequent fault verification and operation and maintenance analysis.

[0107] After the collaborative delay timer ends, a unified instantaneous trip signal is triggered to ensure that multiple JP cabinets disconnect synchronously and the trip event is recorded at the same time for future fault analysis.

[0108] By adopting the above technical solution, the local thermal effect value and total incoming current of the JP cabinet are analyzed. Combined with the operating status data of other parallel JP cabinets in the distribution area, the overall heat load level of the distribution area is assessed. When the total thermal effect approaches the safety limit and the contribution of this cabinet is abnormally low, a coordinated trip negotiation is initiated. At the same time, a unified trip decision is executed based on the response results of most JP cabinets. This solution significantly improves the coordinated response capability of the distribution area to thermal accumulation faults and reduces the risk of equipment burnout or fire caused by local overheating accumulation.

[0109] This application discloses a method for maintaining collaborative nodes in a JP cabinet. (Refer to...) Figure 5 The method includes: Step 501: Initiate node query requests to the other JP cabinets and collect valid response information within the preset response time.

[0110] A node query request is an inquiry signal sent to find out if there are other JP cabinets in the area.

[0111] A valid response message refers to the reply returned by other JP cabinets within the preset response time, which includes their own address and operating status.

[0112] Step 502: Construct an initial node list based on valid response information.

[0113] The initial node list refers to the set of all communicable JP cabinets within the transformer area generated based on valid response information, including all JP cabinets in the transformer area that have returned valid response information.

[0114] Extract the corresponding JP cabinet address from each valid response message. Each address corresponds to a node, and all JP cabinets in the corresponding area together form the initial node list.

[0115] Step 503: Within each fixed period, control each JP cabinet to send a running status data packet to the corresponding node in the initial node list, and update the response status of each corresponding node according to the running status data packet. The response status includes non-response status and response status.

[0116] By having each JP cabinet send a running status data packet to the corresponding node in the initial node list within each fixed period, and marking the response status of each corresponding node as responsive or unresponsive based on whether the running status data packet is received.

[0117] Step 504: If the number of times any node is in an unresponsive state reaches the preset number of disconnection judgments, the node whose number of unresponsive states reaches the preset number of disconnection judgments is marked as disconnected, and the operation status data of the disconnected JP cabinet corresponding to the disconnected node is not used.

[0118] The "out of contact" status refers to a situation where a JP cabinet fails to return operational status data multiple times in a row, and is therefore deemed to be temporarily unable to communicate normally.

[0119] When the number of consecutive unresponsive times of a node reaches a set threshold, its corresponding JP cabinet is removed from the nodes participating in collaborative computing.

[0120] Step 505: If the disconnected JP cabinet resends the operating status data packet, determine whether the local thermal effect value of the disconnected JP cabinet is within the preset reasonable range.

[0121] When the lost JP cabinet resends the operating status data packet, the local thermal effect value of the lost JP cabinet is verified to avoid the judgment being affected by data anomalies.

[0122] Step 506: If so, restore the lost JP cabinet as a valid node.

[0123] After confirming that the thermal effect value of the disconnected JP cabinet is normal, it is reinstated as a valid node and its participation in the exchange of operational status data packets is restored.

[0124] If the current local thermal effect value of the disconnected JP cabinet is not within the preset reasonable range, the disconnected status of the JP cabinet will be maintained and its data will continue to be excluded.

[0125] By adopting the above technical solution, a node query request is initiated to other JP cabinets within the distribution area to construct an initial node list. The response status of each node is updated by periodically exchanging operational status data packets. Abnormal data is excluded when consecutive node outages are detected. Furthermore, when an out-of-connection JP cabinet comes back online, its thermal effect value is verified to determine whether it is restored as a valid node. This solution significantly improves the reliability of multi-cabinet collaborative communication and reduces misjudgments caused by communication interruptions or interference from abnormal nodes.

[0126] This application discloses a method for calibrating JP cabinet date type labels. (Refer to...) Figure 6 The method includes: Step 601: Obtain the actual maximum load current during the preset observation period on the current date.

[0127] Record the maximum value of the total incoming current of the JP cabinet during the pre-defined power consumption period of the day.

[0128] Step 602: From the historical database, query historical dates that have the same type label and belong to the same season as the current day, extract the maximum load current of the historical date in the same period of the current day, and calculate the historical average value.

[0129] The historical average value refers to the arithmetic mean of the maximum load currents selected from multiple historical dates that are the same as the current day's type label and season and are in the same time period from the historical database. The historical dates may be one or multiple.

[0130] Electricity load is affected by both weekdays and holidays, as well as seasonal production and living habits. Only historical data that matches both of these conditions can truly reflect the normal load level under the current scenario.

[0131] Step 603: Determine whether the deviation between the actual maximum load current and the historical average value exceeds the preset tolerance threshold.

[0132] By comparing the difference between the current maximum load current and the historical average value to see if it exceeds the set tolerance range, it can be determined whether the current load has deviated significantly from the normal level.

[0133] Step 604: If yes, then determine that the historical load level of the day type label does not match the current load level.

[0134] When the current load level deviates significantly from the historical load level of the day type label, it is considered that the initially assigned day type label cannot accurately reflect the actual electricity consumption characteristics.

[0135] If the deviation between the maximum load current and the historical average value does not exceed the preset tolerance threshold, the current day type label will remain unchanged.

[0136] Step 605: In case of a mismatch, match the historical date with the smallest difference from the current load level from the historical database and update the day type label.

[0137] When the historical load level of the day type label does not match the current load level, find the historical date with the load level closest to the current value from the historical data, and use the day type label of that historical date as the updated label.

[0138] By employing the above technical solution, the maximum load current of the current date within a preset observation period is obtained. This average value is calculated by combining historical load data from the same day type label and season in the historical database. Based on the deviation, it is determined whether the current label matches the actual electricity consumption level. If there is a discrepancy, the most similar historical date is matched, and the day type label is updated. This solution significantly improves the accuracy of day type identification and reduces false tripping caused by label misjudgment.

[0139] This application discloses a method for seasonal division of JP cabinets. (Refer to...) Figure 7 The method includes: Step 701: Construct a load-meteorological curve based on the daily maximum load current and the corresponding meteorological data in the historical database.

[0140] Meteorological data refers to weather parameters such as temperature, rainfall, humidity, or sunshine duration recorded daily corresponding to the maximum load current, which affect electricity consumption behavior.

[0141] The load-meteorological curve is a curve that reflects the change of electricity load with weather, drawn based on the maximum daily load current and corresponding meteorological data of the local power distribution area throughout the year.

[0142] Step 702: Divide the entire year into multiple local seasonal intervals based on the load-weather curve;

[0143] Local seasonal intervals refer to time periods with similar load characteristics, defined based on the actual correlation between local electricity load and meteorological data, such as the spring irrigation period, the high-temperature air conditioning period, or the busy agricultural season with high load, and are not limited to the Gregorian calendar season.

[0144] Electricity load characteristics vary significantly under different meteorological conditions. Dividing the load into multiple local seasonal intervals can make the overload protection threshold more closely match the actual load patterns of each period. For example, spring irrigation usually begins in early April in the northern part of Province A, while it usually begins in late March in the southern part. If the overload threshold is uniformly set according to the Gregorian calendar spring, it will be difficult to match the actual peak electricity consumption for each region. Therefore, it is necessary to divide the load into multiple local seasonal intervals based on the local load-meteorological curve.

[0145] Step 703: Determine whether the meteorological data for the current date falls within the meteorological coverage area of ​​the load-meteorological curve.

[0146] It is essential to confirm whether the current meteorological data falls within the historical data range on which the local load-meteorological curve is based, in order to ensure that subsequent seasonal divisions and load forecasts have a practical basis.

[0147] Step 704: If not, determine the season according to the calendar rules.

[0148] When current meteorological data exceeds the historical coverage range, calendar rules are used to determine the season as a backup plan when local seasonal interval division fails.

[0149] If the current meteorological data is within the historical coverage area, the local seasonal intervals defined by the load-meteorological curve will continue to be used, without relying on calendar rules.

[0150] By employing the above technical solution, the maximum daily load current and its corresponding meteorological data within historical electricity consumption cycles are analyzed. Combined with the local load-meteorological correlation curve, local seasonal intervals reflecting actual electricity consumption characteristics are defined. When the current meteorological data exceeds the historical coverage range, the system automatically reverts to calendar rules to determine the season. This solution significantly improves the consistency between seasonal division and actual load patterns, reducing protection threshold deviations caused by mechanically dividing seasons by month.

[0151] Based on the same inventive concept, embodiments of this application provide an overload protection system for a JP cabinet, see reference. Figure 8 The system includes: The acquisition module is used to obtain the current date, calendar rules, and maximum load current; A memory for storing the program of the overload protection method for the JP cabinet; The processor and the program in the memory can be loaded and executed by the processor to implement the overload protection method of the JP cabinet.

[0152] By adopting the above technical solution, the acquisition module collects the current date, calendar rules and maximum load current in real time, the processor quickly executes the protection logic of overload identification and interference judgment, and the memory continuously updates historical load data and day type labels, realizing intelligent processing of the entire process from load perception to protection action. While ensuring the accuracy of tripping, it significantly improves response efficiency and provides an efficient and reliable solution for intelligent protection of JP cabinets.

[0153] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional modules is used as an example. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device, and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0154] This application provides a computer-readable storage medium storing a computer program that can be loaded by a processor and executed as an overload protection method for a JP cabinet.

[0155] Computer storage media include, for example, USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, optical disks, and other media that can store program code.

[0156] Based on the same inventive concept, embodiments of this application provide a smart terminal, including a memory and a processor, wherein the memory stores a computer program that can be loaded by the processor and executed as an overload protection method for a JP cabinet.

[0157] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional modules is used as an example. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device, and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0158] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Any feature disclosed in this specification (including the abstract and drawings) may be replaced by other equivalent or similar features unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is only one example of a series of equivalent or similar features.

Claims

1. A method of overload protection for a JP cabinet, characterized by, include: Based on the current date and calendar rules, identify the day type label, which includes at least one of the following: weekday, holiday, irrigation operation period, or Spring Festival peak electricity consumption period; Obtain the maximum load current of JP cabinets corresponding to N day type labels of the same type from the historical database, and calculate the average value of the maximum load current, where N≥5; Based on the average value and the preset safety margin coefficient, calculate the overload protection threshold for the current period. The overload protection threshold shall not exceed the safety limit allowed by the rated current of the main circuit breaker of the JP cabinet. Real-time acquisition of total incoming current value and calculation of current change rate; If the rate of change of current exceeds the short-circuit threshold within the preset time window, an instantaneous trip signal is triggered after the first delay time. If the total incoming current exceeds the overload protection threshold and reaches the second delay time without triggering the instantaneous trip signal, then the overload trip signal is triggered. The first delay time is less than the second delay time. Update the maximum load current for each time period to the historical database.

2. The overload protection method of a JP cabinet according to claim 1, wherein, After the rate of change of current exceeds the short-circuit threshold within a preset time window, the following applies: Start the interference identification window and record the peak current, zero-sequence current amplitude, and three-phase current imbalance at the moment of current surge; Determine whether the peak current decays to a first preset ratio in the first sub-period and exceeds a second preset ratio in the second sub-period, the first preset ratio is less than the second preset ratio, and both the first preset ratio and the second preset ratio are values ​​greater than 0 and less than 1. If so, determine whether the zero-sequence current amplitude is less than the preset ground fault threshold, whether the three-phase current imbalance is less than the preset symmetry threshold, and whether a voltage drop was not detected at the moment of current surge. If so, it is determined to be a non-fault interference, and the output of the instantaneous trip signal is suppressed; If not, it is determined to be a short circuit fault, and an instantaneous trip signal is triggered after the first delay time.

3. The overload protection method for a JP cabinet according to claim 2, wherein After determining that the interference is non-faulty and suppressing the output of the instantaneous trip signal, the following steps are taken: Start the monitoring window and acquire the total incoming current value within the monitoring window at a fixed sampling period; The actual thermal effect value is obtained by summing the product of the square of the total incoming current and the sampling period. Calculate the maximum theoretical energy value that can be passed through based on the impedance parameters and safe energy limits of the current power distribution circuit; Determine whether the actual thermal effect value reaches the maximum theoretical energy value before the end of the monitoring window; If so, a continuous fault is determined, and the JP cabinet is controlled to trigger an instantaneous trip signal; If not, the determination result of non-faulty interference is maintained.

4. The overload protection method for a JP cabinet according to claim 3, characterized in that, Following the determination of maintaining non-faulty interference, the following is included: Determine whether there are other JP cabinets operating in parallel within the same area as the JP cabinet; If so, the JP cabinet and the other JP cabinets exchange operating status data packets at a fixed period. The operating status data packets include local thermal effect values ​​and total incoming current values. Based on the operating status data packet, calculate the total heat effect value of the area and the proportion of the local heat effect value of each JP cabinet in the total heat effect value; If the total thermal effect value reaches the preset proportion of the theoretical energy limit of the corresponding transformer area, and the thermal effect proportion is lower than the preset abnormal threshold, the control JP cabinet sends a coordinated tripping request to the other JP cabinets. After sending the coordinated tripping request, wait to receive confirmation responses from the other JP cabinets and determine whether a majority of JP cabinets have tripped. If so, then initiate the collaborative delay timing; After the collaborative delay timer expires, the control JP cabinet triggers an instantaneous trip signal and records the trip event simultaneously.

5. The method of overload protection for a JP cabinet of claim 4, wherein, The control JP cabinet and the other JP cabinets exchange operating status data packets with each other at a fixed period, and also include: Initiate node query requests to other JP cabinets and collect valid response information within the preset response time; Based on the valid response information, construct an initial node list; Within each fixed period, each JP cabinet is controlled to send a running status data packet to the corresponding node in the initial node list, and the response status of each corresponding node is updated according to the running status data packet. The response status includes non-response status and response status. If the number of times any node is in an unresponsive state reaches the preset number of times it is considered to be out of contact, the node that has reached the preset number of times it is in an unresponsive state will be marked as out of contact, and the operating status data of the corresponding out-of-contact JP cabinet will not be used. If the disconnected JP cabinet resends the operating status data packet, it is determined whether the local thermal effect value of the disconnected JP cabinet is within the preset reasonable range. If so, then restore the lost JP cabinet as a valid node.

6. The method of overload protection for a JP cabinet of claim 1, wherein, After identifying the day type label based on the current date and calendar rules, the process includes: Obtain the actual maximum load current within the preset observation period on the current date; From the historical database, query historical dates that have the same type label and belong to the same season as the current day, extract the maximum load current of the historical date in the same period of the current day, and calculate the historical average value; Determine whether the deviation between the actual maximum load current and the historical average value exceeds the preset tolerance threshold; If so, then the historical load level of the day type label is determined to be inconsistent with the current load level; If there is a discrepancy, match the historical date with the smallest difference from the current load level from the historical database and update the day type label.

7. The method of overload protection for a JP cabinet of claim 6, wherein, The method further includes: Based on the daily maximum load current and the corresponding meteorological data in the historical database, a load-meteorological curve is constructed. Based on the load-weather curve, the entire year is divided into multiple local seasonal intervals; Determine whether the meteorological data for the current date falls within the meteorological coverage area of ​​the load-meteorological curve; If not, the season will be determined according to calendar rules.

8. An overload protection system for a JP cabinet, characterized by, The system is used to perform the overload protection method for the JP cabinet as described in any one of claims 1 to 7, including: The acquisition module is used to obtain the current date, calendar rules, and maximum load current; A memory for storing the program of the overload protection method for the JP cabinet; The processor and the program in the memory can be loaded and executed by the processor to implement the overload protection method of the JP cabinet.

9. A smart terminal, characterized by It includes a memory and a processor, wherein the memory stores a computer program that can be loaded by the processor and executed as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer program is stored that can be loaded by a processor and execute the method as described in any one of claims 1 to 7.

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