A 10kV drop-out fuse fuse temperature real-time early warning method

Abstract

This invention provides a real-time early warning method for the temperature of a 10kV drop-out fuse, belonging to the field of power distribution network equipment monitoring technology. The method includes: collecting fuse body temperature, ambient temperature, and line current data; dynamically calculating a baseline value for the normal operating temperature of the fuse based on the ambient temperature and line current data; calculating the cumulative temperature rise of the fuse body relative to the baseline value within a set time window, where the cumulative temperature rise is the integral area of ​​the difference between the fuse body temperature and the baseline value within the time window; comparing the cumulative temperature rise with a preset cumulative temperature rise warning threshold, and determining that the fuse has entered a critical melting state and issuing a high-temperature warning signal when the threshold is exceeded; and executing one or more response operations after receiving the warning signal. This invention achieves critical early warning before fuse melting by using a dynamic baseline and an integral criterion of cumulative temperature rise, reducing the false alarm rate and missed alarm rate under different operating conditions.

Description

Technical Field

[0001] This invention relates to the field of power distribution network equipment monitoring technology, and in particular to a real-time early warning method for the fuse temperature of a 10kV drop-out fuse. Background Technology

[0002] Drop-out fuses are the most commonly used short-circuit protection switches for 10kV distribution line branches and distribution transformers, widely used for primary side protection of lines and equipment. Traditional drop-out fuses only have the function of interrupting current after a fault occurs; that is, when a short circuit or overload occurs in the line, the fuse wire melts and the fuse tube drops to cut off the fault current. However, they lack the ability to monitor the fuse status in real time and provide early warning. Maintenance personnel often only know that a fault has occurred after the fuse has blown and the line has been de-energized, making it impossible to take preventive or emergency measures in the critical stage before the fuse blows. This seriously affects the reliability of power supply.

[0003] In recent years, with the development of intelligent power distribution networks, several online monitoring technologies for drop-out fuses have been proposed. For example, temperature sensors are installed outside the fuse tube to monitor the fuse temperature, or data such as current and temperature are collected to analyze the fuse status and issue alarms. However, most of these existing technologies adopt a post-diagnosis mode or a fixed threshold judgment method, that is, setting a fixed temperature or current limit, and issuing an alarm when the measured value exceeds the limit. Because the operating environment of drop-out fuses is complex, with ambient temperatures varying drastically throughout the year (from -10℃ to above 40℃), and line load current fluctuating significantly with electrical load, the normal heating reference of the fuse varies greatly under different operating conditions. Using a fixed threshold inevitably leads to a high rate of false alarms or missed alarms.

[0004] Furthermore, the process from abnormal temperature rise to eventual fuse failure is a continuous accumulation of heat, and comparing a single-point temperature value with a fixed threshold cannot reflect the effect of heat accumulation over time. The intermittent temperature rise caused by periodic load fluctuations and the cumulative temperature rise caused by continuous overload have completely different impacts on fuse failure risk, and existing technologies struggle to effectively distinguish between these two scenarios. Simultaneously, temperature sensors in existing solutions are mostly located on the outer surface of the fuse tube or at the moving contact, resulting in significant deviations between the measured temperature and the actual temperature of the fuse body, thus limiting the accuracy and timeliness of early warnings. The power supply issue for sensors is also unresolved; drop-out fuses are suspended from 10kV lines, making it difficult to provide external power, and battery-powered solutions have limited lifespans, hindering long-term maintenance-free operation. Therefore, accurately identifying the critical state before fuse failure under dynamically changing operating conditions and issuing early warnings is a pressing technical problem in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a real-time early warning method for the fuse temperature of a 10kV drop-out fuse, in order to solve the technical problems in the prior art, such as the high false alarm or missed alarm rate under different operating conditions due to the use of a fixed temperature threshold, the inability to provide critical early warning before the fuse blows, and the inability to distinguish between heat accumulation effect and instantaneous temperature rise.

[0006] To achieve the above objectives, the present invention provides a real-time early warning method for the fuse temperature of a 10kV drop-out fuse, comprising the following steps: Step S1: Collect fuse body temperature, ambient temperature, and line current data; Step S2: Based on the ambient temperature and line current data collected in step S1, dynamically calculate the baseline value of the normal operating temperature of the fuse. Step S3: Using a set time window as the unit, calculate the cumulative temperature rise of the fuse body temperature collected in step S1 relative to the baseline value calculated in step S2. Step S4: Compare the accumulated temperature rise calculated in step S3 with the preset accumulated temperature rise warning threshold. When the accumulated temperature rise exceeds the accumulated temperature rise warning threshold, determine that the fuse has entered the critical state of melting and issue a high temperature warning signal. Step S5: After receiving the high temperature warning signal issued in step S4, perform one or more response operations.

[0007] Preferably, in step S1, the temperature data of the fuse body is collected by a miniature temperature sensor set on the surface of the fuse body. The miniature temperature sensor adopts a self-powered power supply method, obtains electrical energy from the line current through a current inductance energy harvesting coil, and sets a supercapacitor as a backup energy storage unit.

[0008] Preferably, the specific method for dynamically calculating the baseline value in step S2 includes: Calculate the preliminary baseline value ,in Indicates the ambient temperature at which the data was collected. This indicates the collected line current. Indicates the line current The calculated rate of change of current, and The weighting coefficient is determined by the thermal property coefficient of the fuse material. This is the inherent thermal equilibrium constant of the equipment; Calculate the impact of current fluctuations on indicators ,in This is the preset current fluctuation influence coefficient. For the line current The absolute value of the calculated rate of change of current; Calculate the influence index of ambient temperature ,in For reference to ambient temperature, The preset influence coefficient of ambient temperature change. Indicated by ambient temperature The calculated rate of change of ambient temperature; Calculation of thermal fatigue index of fuse ,in This is the cumulative temperature rise calculated in the previous time window, and for the first time window, The value is 0; The cumulative temperature rise warning threshold; According to the thermal fatigue index of the fuse The numerical range is used to determine the correction strategy: At that time, only the influence of current fluctuations was corrected to obtain the index. And the environmental temperature influence index remains unchanged. ,in, The corrected current fluctuation impact index. The corrected environmental temperature influence index; when At that time, only the influence index of ambient temperature was corrected to obtain Furthermore, the impact of current fluctuations on the indicators remains unchanged. ; when At the same time, the influence of current fluctuation and the influence of ambient temperature were corrected to obtain the following results. and ; Calculate the overall correction factor ; Correct the baseline value using a comprehensive correction factor: ; This is the final output baseline value.

[0009] Preferably, the cumulative temperature rise in step S3 is calculated as follows: Cumulative temperature rise It equals the integral area of ​​the difference between the fuse body temperature and the reference baseline value within a set time window, i.e.: ; in, The starting time of integration, To set a time window, This is a function of the fuse body temperature changing with time. It is a function of the baseline value changing over time.

[0010] Preferably, the set time window in step S3 Adaptive adjustment based on the rate of change of current: ; in, Used as the base time window; This is the sensitivity adjustment coefficient.

[0011] Preferably, the set time window in step S3 It is also adjusted a second time based on the ratio of the fuse body temperature to the critical melting temperature: when When it exceeds 0.7, the time window will be adjusted. Forced to shorten to 0.5 seconds, of which Indicates the temperature of the fuse body. This indicates the critical temperature at which the fuse breaks.

[0012] Preferably, the integration start time Rate of change of current The time when the preset start-up threshold is exceeded is the rate of change of the line current corresponding to an increase from the rated value to 1.2 times the rated value within 1 second; or the time when the fuse body temperature collected in step S1 first exceeds the baseline value calculated in step S2. At that moment.

[0013] Preferably, the preset cumulative temperature rise warning threshold in step S4 Determined by the material properties of the fuse and the fusing time-current characteristic curve: ; in, This is the theoretical time from the start of heating of the fuse to its melting point, which can be obtained from the fuse's ampere-second characteristic curve; Indicates the critical temperature at which the fuse melts; This indicates the initial ambient temperature at which the fuse begins to heat up.

[0014] Preferably, the high-temperature warning signal issued in step S4 includes warning level information, and the warning level is based on the cumulative temperature rise calculated in step S3. Exceeding the cumulative temperature rise warning threshold The relative degree is divided into three levels: when At that time, it was determined to be a Level 1 warning; when At that time, it was determined to be a Level II warning; when At that time, it was determined to be a Level III warning; The warning information for a Level 1 warning is sent once every 60 seconds, and the response priority is the lowest; the warning information for a Level 2 warning is sent once every 10 seconds, and the response priority is medium; the warning information for a Level 3 warning is sent once per second, and the response priority is the highest, requiring immediate tripping.

[0015] Preferably, one or more response operations in step S5 include: sending a warning message to the remote maintenance terminal, activating the local audible and visual alarm device, triggering the preparatory action of the drop actuator, and sending a trip command to the circuit breaker; wherein the warning message sent to the remote maintenance terminal includes the fuse number, location coordinates, the real-time temperature value collected in step S1, the cumulative temperature rise calculated in step S3, and the estimated remaining fuse time, the estimated remaining fuse time being based on the current temperature rise rate. and remaining threshold Calculations show that This represents the cumulative temperature rise corresponding to the theoretical melting point of the fuse, and its value is... .

[0016] Therefore, the present invention employs the above-mentioned method for real-time early warning of fuse temperature in a 10kV drop-out fuse, and the beneficial technical effects are as follows: (1) This invention directly acquires the actual temperature change of the fuse by placing a miniature temperature sensor close to the surface of the fuse body, and uses the cumulative temperature rise within a set time window (i.e., the integral area of ​​the difference between the fuse temperature and the dynamic baseline) as the early warning criterion, overcoming the limitation of the prior art that only relies on the comparison of a single point temperature value with a fixed threshold. When the cumulative temperature rise exceeds the preset threshold, it is determined that the fuse has entered the critical state of melting and an early warning is issued. At this time, the fuse material has not completely melted, which buys maintenance personnel emergency handling time, so that measures such as transferring load, starting backup power supply or notifying maintenance personnel can be taken, significantly reducing unplanned power outage time.

[0017] (2) This invention abandons the traditional fixed temperature threshold judgment method. It dynamically calculates the baseline value of the fuse's normal operating temperature based on ambient temperature, line current, and current change rate. A multi-index correction mechanism is constructed using current fluctuation impact index, ambient temperature impact index, and fuse thermal fatigue degree index. This correction mechanism adaptively selects to correct only the impact of current fluctuation, only the impact of ambient temperature, or both, depending on the different numerical ranges of the fuse thermal fatigue degree index. Finally, a weighted comprehensive correction coefficient is obtained and used to correct the baseline value. This allows the early warning judgment to adapt to the wide-ranging changes in ambient temperature throughout the year and the drastic fluctuations in load current. Compared with existing fixed threshold methods, both the false alarm rate and the missed alarm rate are significantly reduced.

[0018] (3) This invention uses an integral method of accumulated temperature rise to quantify the thermal state of the fuse. The short-term intermittent temperature rise caused by periodic load fluctuations has a limited integral area within the time window, which is insufficient to trigger an early warning. However, the cumulative temperature rise caused by continuous overload or fault current will cause the integral area to continue to grow and eventually exceed the early warning threshold. This evaluation method based on energy accumulation truly reflects the physical nature of fuse blowing, avoids false alarms caused by short-term load spikes, and ensures accurate identification of continuous overheating faults that truly threaten line safety, thereby improving the reliability and practicality of the early warning system. Attached Figure Description

[0019] Figure 1 This is a flowchart of a real-time early warning method for the fuse wire temperature of a 10kV drop-out fuse according to the present invention; Figure 2 Flowchart for calculating dynamic baseline values; Figure 3 This is a curve comparing the fuse body temperature with the dynamic baseline. Figure 4 This is a graph showing the cumulative temperature rise over time. Detailed Implementation

[0020] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0022] Example 1 This embodiment provides a real-time early warning method for the fuse wire temperature of a 10kV drop-out fuse, applied to a drop-out fuse in a 10kV distribution line. The fuse has a rated current of 100A, the fuse wire material is copper, and the critical melting temperature of the fuse wire is... Take 700℃. The following is combined with... Figure 1 The process will be described in detail in this embodiment.

[0023] Step S1: Collect data on fuse body temperature, ambient temperature, and line current.

[0024] A miniature PT100 platinum resistance temperature sensor is mounted closely to the fuse body surface inside the fuse tube, with thermally conductive silicone grease filling the space between the sensor and the fuse to ensure good thermal contact. An ambient temperature sensor (model DS18B20) is installed outside the fuse tube to collect ambient temperature data. A current inductor coil is wound around the outside of the fuse tube, serving a dual function of power supply and current measurement: providing operating power to the system and collecting line current data. A supercapacitor is also included as a backup energy storage unit to ensure the system can continue operating for more than one second when the line current momentarily drops, guaranteeing reliable transmission of warning signals.

[0025] The sampling frequency is set to once per second. Let's assume the following data is collected at a certain moment: the temperature of the fuse body. =85℃, ambient temperature =28℃, line current =120A.

[0026] Step S2: Based on the ambient temperature and line current data collected in step S1, dynamically calculate the baseline value of the normal operating temperature of the fuse.

[0027] Step S2 dynamically calculates the normal heating baseline of the fuse under the current operating conditions based on ambient temperature and line current. Since the line current and ambient temperature change in real time, the normal operating temperature of the fuse also changes accordingly. Therefore, using a dynamic baseline can adaptively reflect the expected heating under different operating conditions. Figure 2 As shown, this step first calculates the preliminary baseline value, and then performs adaptive correction using three influencing indicators.

[0028] (1) Calculate the preliminary baseline value.

[0029] Preliminary baseline value Calculate using the following formula: ,in Indicates the ambient temperature at which the data was collected. This indicates the collected line current. Indicates the line current The calculated rate of change of current, =0.01℃ / A 2 and =0.08℃·s / A is a weighting coefficient determined by the thermal characteristic coefficient of the fuse material. =20℃ is the inherent thermal balance constant of the equipment.

[0030] (2) Calculate the three influencing indicators.

[0031] 1) Calculate the impact index of current fluctuation ,in The preset current fluctuation influence coefficient has a value of 0.05 to 0.15, and is set to 0.1 in this embodiment.

[0032] 2) Calculate the environmental temperature influence index ,in With an ambient temperature of 25℃ as a reference, The preset influence coefficient of ambient temperature change ranges from 0.1 to 0.3; in this embodiment, it is set to 0.2. Indicated by ambient temperature The calculated rate of change in ambient temperature.

[0033] 3) Calculate the thermal fatigue index of the fuse wire ,in This is the cumulative temperature rise calculated in the previous time window, and for the first time window, The value is 0; This is the cumulative temperature rise warning threshold.

[0034] According to the thermal fatigue index of the fuse The numerical range is used to determine the correction strategy: At that time, only the influence of current fluctuations was corrected to obtain the index. And the environmental temperature influence index remains unchanged. ,in, The corrected current fluctuation impact index. The corrected environmental temperature influence index; when At that time, only the influence index of ambient temperature was corrected to obtain Furthermore, the impact of current fluctuations on the indicators remains unchanged. ; when At the same time, the influence of current fluctuation and the influence of ambient temperature were corrected to obtain the following results. and .

[0035] In this embodiment =0 (<0.3), which belongs to the initial aging stage, so only the current fluctuation effect index is corrected: =14400, =3.

[0036] To obtain a reasonable comprehensive correction factor, both indicators need to be normalized. Using the standard value of 100 amperes at rated current as 10000, the corrected indicator value of 14400 is divided by 10000, resulting in a normalized value of 1.44. For the environmental temperature influence indicator, normalization is performed: using the standard value of 25 degrees Celsius as reference environmental temperature as 1, the corrected indicator value of 3 is divided by 1, resulting in a normalized value of 3.0.

[0037] Calculate the overall correction factor ; Correct the baseline value using a comprehensive correction factor: =382℃; This is the final output baseline value. This value indicates that under the current load and environmental conditions, the fuse's normal operating temperature should be around 382℃ if it continues to heat up. (Actual measurement...) =85℃, which is far below the benchmark, indicating that the fuse is still in a safe state.

[0038] By introducing indicators of current fluctuation impact, ambient temperature impact, and fuse thermal fatigue degree, this invention can dynamically adjust the baseline value based on the actual aging degree of the fuse and the current operating conditions. For example, when there is a sudden increase in current or a drastic change in ambient temperature, the baseline will be raised or lowered accordingly, thereby avoiding false alarms caused by fixed thresholds in high-temperature environments and missed alarms in low-temperature environments. At the same time, considering the degree of thermal fatigue makes the correction strategy more refined, further improving the accuracy of the early warning.

[0039] Step S3: Using a set time window as the unit, calculate the cumulative temperature rise of the fuse body temperature collected in step S1 relative to the baseline value calculated in step S2.

[0040] Cumulative temperature rise It equals the integral area of ​​the difference between the fuse body temperature and the reference baseline value within a set time window, i.e.: ; in, The starting time of integration, To set the time window, the initial value is set to 2 seconds. The value is a function of the change in fuse body temperature over time, as collected in step S1. It is a function of the baseline value calculated in step S2 changing over time.

[0041] Set time window Adaptive adjustment based on the rate of change of current: ; in, The base time window is set to 2 seconds. This is the sensitivity adjustment factor, with a value of 0.5; The line current collected in step S1 The absolute value of the calculated rate of change of current.

[0042] Second adjustment of the time window: Set time window It is also adjusted a second time based on the ratio of the fuse body temperature to the critical melting temperature: when When it exceeds 0.7, the time window will be adjusted. Forced to shorten to 0.5 seconds, of which This indicates the temperature of the fuse body collected in step S1. This indicates the critical temperature at which the fuse breaks; for copper fuses, this value is 700℃.

[0043] Determining the starting time of integration: Integral start time The moment when one of the following two conditions is satisfied: (1) Rate of change of current The time when the preset start-up threshold is exceeded is the rate of change of the line current corresponding to the current changing from the rated value to 1.2 times the rated value within 1 second. (2) The fuse body temperature collected in step S1 exceeds the baseline value calculated in step S2 for the first time. At that moment.

[0044] Step S4: Compare the cumulative temperature rise calculated in step S3 with the preset cumulative temperature rise warning threshold. When the cumulative temperature rise exceeds the cumulative temperature rise warning threshold, determine that the fuse has entered the critical state of melting and issue a high temperature warning signal.

[0045] Preset cumulative temperature rise warning threshold Determined by the material properties of the fuse and the fusing time-current characteristic curve: ; in, This is the theoretical time from the start of heating of the fuse to its complete melting, obtained from the fuse's ampere-second characteristic curve. At a current of 150A, ≈15 seconds; This indicates the critical temperature at which the fuse breaks; for copper fuses, the value is 700℃. =28℃ represents the initial ambient temperature when the fuse begins to heat up, which is collected in step S1 at the start-up time. Calculated... =5040℃·s. When the actual integral area Q reaches 5040℃·s, the fuse is determined to have entered the critical state of melting and a high-temperature warning signal is issued. The warning signal includes level information, and the levels are divided as follows: when At that time, it was determined to be a Level 1 warning; when At that time, it was determined to be a Level II warning; when At that time, it was determined to be a Level III warning; The warning information for a Level 1 warning is sent once every 60 seconds, and the response priority is the lowest; the warning information for a Level 2 warning is sent once every 10 seconds, and the response priority is medium; the warning information for a Level 3 warning is sent once per second, and the response priority is the highest, requiring immediate tripping.

[0046] Step S5: After receiving the high temperature warning signal issued in step S4, perform one or more response operations.

[0047] Step S5 includes one or more of the following response operations: sending a warning message to the remote maintenance terminal, activating the local audible and visual alarm device, triggering the preparatory action of the drop-out actuator, and sending a trip command to the circuit breaker; wherein the warning message sent to the remote maintenance terminal includes the fuse number, location coordinates, the real-time temperature value collected in step S1, the cumulative temperature rise calculated in step S3, and the estimated remaining fuse time, the estimated remaining fuse time being based on the current temperature rise rate. and remaining threshold Calculations show that This represents the cumulative temperature rise corresponding to the theoretical melting point of the fuse, and its value is... .

[0048] To more intuitively demonstrate the effect of the method proposed in this invention, a typical overload condition is used as an example to plot the temperature curve and the cumulative temperature rise curve. Under this condition, the line current jumps from 100A to 150A in 5 seconds, the ambient temperature is maintained at 28℃, and the other parameters are the same as above.

[0049] Figure 3 This is a comparison curve of the fuse body temperature and the dynamic baseline. From Figure 3 As can be seen, before the current step (0-5 seconds), the fuse body temperature stabilizes at around 42℃, and the dynamic reference baseline remains at 155℃. After the current step, the dynamic reference baseline immediately adjusts to 382℃, and slightly increases with the secondary thermal effect caused by the increase in fuse temperature. After thermal inertia delay, the fuse body temperature exceeds the reference baseline at 10 seconds, after which the temperature difference gradually decreases. This curve proves that the dynamic reference baseline can follow the changes in operating conditions in real time, providing an accurate adaptive reference for calculating the cumulative temperature rise.

[0050] Figure 4 The curve shows the cumulative temperature rise over time, with the integration starting at the 10th second. From... Figure 4It can be seen that the cumulative temperature rise initially increased slowly, but accelerated as the temperature difference widened, reaching the preset cumulative temperature rise warning threshold of 5040℃·s at 17.6 seconds, at which point the system issued a warning. The cumulative temperature rise continued to increase thereafter, reaching the theoretical melting point of 10080℃·s at 20 seconds, corresponding to the actual melting of the fuse. Figure 4 There is a time window of about 2.4 seconds between the warning point (17.6 seconds) and the circuit breaker point (20.0 seconds). This window gives maintenance personnel time to take measures such as transferring load, starting backup power, or notifying maintenance personnel.

[0051] It is worth noting that all contents not described in detail in this invention are existing technologies and are well known to those skilled in the art.

[0052] Therefore, the present invention adopts the above-mentioned real-time early warning method for the temperature of a 10kV drop-out fuse. By constructing a dynamic baseline and introducing a multi-index correction mechanism, the cumulative temperature rise of the fuse body relative to the baseline is calculated. The heat accumulation integral is used as the early warning criterion to realize the early identification of the critical state of fuse melting. At the same time, the impact of changes in ambient temperature and load current on the accuracy of early warning is reduced, and the reliability of power distribution network operation is improved.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for real-time early warning of fuse wire temperature in a 10kV drop-out fuse, characterized in that, Includes the following steps: Step S1: Collect fuse body temperature, ambient temperature, and line current data; Step S2: Based on the ambient temperature and line current data collected in step S1, dynamically calculate the baseline value of the normal operating temperature of the fuse. Step S3: Using a set time window as the unit, calculate the cumulative temperature rise of the fuse body temperature collected in step S1 relative to the baseline value calculated in step S2. Step S4: Compare the accumulated temperature rise calculated in step S3 with the preset accumulated temperature rise warning threshold. When the accumulated temperature rise exceeds the accumulated temperature rise warning threshold, determine that the fuse has entered the critical state of melting and issue a high temperature warning signal. Step S5: After receiving the high temperature warning signal issued in step S4, perform one or more response operations.

2. The method for real-time early warning of fuse wire temperature for a 10kV drop-out fuse according to claim 1, characterized in that, In step S1, the temperature data of the fuse body is collected by a miniature temperature sensor set on the surface of the fuse body. The miniature temperature sensor adopts a self-powered power supply method, which obtains electrical energy from the line current through a current inductance energy harvesting coil, and sets a supercapacitor as a backup energy storage unit.

3. The method for real-time early warning of fuse wire temperature for a 10kV drop-out fuse according to claim 1, characterized in that, The specific methods for dynamically calculating the baseline value in step S2 include: Calculate the preliminary baseline value ,in Indicates the ambient temperature at which the data was collected. This indicates the collected line current. Indicates the line current The calculated rate of change of current, and The weighting coefficient is determined by the thermal property coefficient of the fuse material. This is the inherent thermal equilibrium constant of the equipment; Calculate the impact of current fluctuations on indicators ,in This is the preset current fluctuation influence coefficient. For the line current The absolute value of the calculated rate of change of current; Calculate the influence index of ambient temperature ,in For reference to ambient temperature, The preset influence coefficient of ambient temperature change. Indicates the ambient temperature The calculated rate of change of ambient temperature; Calculation of thermal fatigue index of fuse ,in This is the cumulative temperature rise calculated in the previous time window, and for the first time window, The value is 0; The cumulative temperature rise warning threshold; According to the thermal fatigue index of the fuse The numerical range is used to determine the correction strategy: At that time, only the influence of current fluctuations was corrected to obtain the index. And the environmental temperature influence index remains unchanged. ,in, The corrected current fluctuation impact index. The corrected environmental temperature influence index; when At that time, only the influence index of ambient temperature was corrected to obtain Furthermore, the impact of current fluctuations on the indicators remains unchanged. ; when At the same time, the influence of current fluctuation and the influence of ambient temperature were corrected to obtain the following results. and ; Calculate the overall correction factor ; Correct the baseline value using a comprehensive correction factor: ; This is the final output baseline value.

4. The method for real-time early warning of fuse wire temperature for a 10kV drop-out fuse according to claim 3, characterized in that, The calculation method for the cumulative temperature rise in step S3 is as follows: Cumulative temperature rise It equals the integral area of ​​the difference between the fuse body temperature and the reference baseline value within a set time window, i.e.: ； in, The starting time of integration, To set a time window, This is a function of the fuse body temperature changing with time. It is a function of the baseline value changing over time.

5. The method for real-time early warning of fuse wire temperature for a 10kV drop-out fuse according to claim 4, characterized in that, Setting the time window in step S3 Adaptive adjustment based on the rate of change of current: ； in, Used as the base time window; This is the sensitivity adjustment coefficient.

6. The method for real-time early warning of fuse wire temperature for a 10kV drop-out fuse according to claim 5, characterized in that, Setting the time window in step S3 It is also adjusted a second time based on the ratio of the fuse body temperature to the critical melting temperature: when When it exceeds 0.7, the time window will be adjusted. Forced to shorten to 0.5 seconds, of which Indicates the temperature of the fuse body. This indicates the critical temperature at which the fuse melts.

7. The method for real-time early warning of fuse wire temperature for a 10kV drop-out fuse according to claim 6, characterized in that, Integral start time Rate of change of current The time when the preset start-up threshold is exceeded is the rate of change of the line current corresponding to an increase from the rated value to 1.2 times the rated value within 1 second; or the time when the fuse body temperature collected in step S1 first exceeds the baseline value calculated in step S2. At that moment.

8. The method for real-time early warning of fuse wire temperature for a 10kV drop-out fuse according to claim 7, characterized in that, The preset cumulative temperature rise warning threshold in step S4 Determined by the material properties of the fuse and the fusing time-current characteristic curve: ； in, This is the theoretical time from the start of heating of the fuse to its melting point, which can be obtained from the fuse's ampere-second characteristic curve; Indicates the critical temperature at which the fuse melts; This indicates the initial ambient temperature at which the fuse begins to heat up.

9. A method for real-time early warning of fuse wire temperature for a 10kV drop-out fuse according to claim 8, characterized in that, The high-temperature warning signal issued in step S4 includes warning level information, which is based on the cumulative temperature rise calculated in step S3. Exceeding the cumulative temperature rise warning threshold The relative degree is divided into three levels: when At that time, it was determined to be a Level 1 warning; when At that time, it was determined to be a Level II warning; when At that time, it was determined to be a Level III warning; The warning information for a Level 1 warning is sent once every 60 seconds, and the response priority is the lowest; the warning information for a Level 2 warning is sent once every 10 seconds, and the response priority is medium; the warning information for a Level 3 warning is sent once per second, and the response priority is the highest, requiring immediate tripping.

10. A method for real-time early warning of fuse wire temperature for a 10kV drop-out fuse according to claim 9, characterized in that, Step S5 includes one or more of the following response operations: sending a warning message to the remote maintenance terminal, activating the local audible and visual alarm device, triggering the preparatory action of the drop-out actuator, and sending a trip command to the circuit breaker; wherein the warning message sent to the remote maintenance terminal includes the fuse number, location coordinates, the real-time temperature value collected in step S1, the cumulative temperature rise calculated in step S3, and the estimated remaining fuse time, the estimated remaining fuse time being based on the current temperature rise rate. and remaining threshold Calculations show that This represents the cumulative temperature rise corresponding to the theoretical melting point of the fuse, and its value is... .

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