Rapid testing methods and equipment for insulation performance of medium and low voltage power boxes

Abstract

This invention relates to the field of insulation testing technology for medium and low voltage power boxes, specifically to a rapid insulation performance testing method and equipment for medium and low voltage power boxes. The method includes: acquiring current-resistance data of the medium and low voltage power box using a megohmmeter; obtaining absorption effect saturation data of the insulation material at each acquisition time based on the current-resistance data; obtaining the insulation information level at each acquisition time based on the absorption effect saturation data, and then determining an optional detection stop time; determining the corresponding stable state access level based on the insulation information level before the optional detection stop time; obtaining the absorption process cutoff level based on the stable state access level and its corresponding insulation information level, and then determining the detection stop time; and officially starting the insulation test of the medium and low voltage power box after the detection stop time. Using this invention enhances the reliability of insulation testing of medium and low voltage power boxes and significantly improves testing efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of insulation testing of medium and low voltage power boxes, and particularly relates to a method and device for rapid testing of insulation performance of medium and low voltage power boxes. BACKGROUND

[0002] Medium and low voltage power boxes are usually installed in densely populated areas, such as residential areas, work parks, etc., for power conversion and distribution to meet the needs of users for stable power supply and ensure the normal operation of various electrical equipment. To protect the safety of users, maintenance personnel need to regularly perform routine inspections on power boxes. Since medium and low voltage power boxes are large equipment with high electrical energy, to avoid electric shock accidents during operation, the existing technology usually strengthens their insulation performance to prevent electric leakage. Therefore, when performing regular inspections, maintenance personnel also need to test the insulation performance of the power boxes. The test needs to be performed under the condition that the power box is powered off, and considering the high demand of users for power supply continuity, the test process must be completed quickly. Currently, insulation testing is generally implemented using a megohmmeter (insulation meter), which is connected to the line of the device to be tested to form a closed loop, and the megohmmeter provides a test current and displays the corresponding reading to complete the evaluation of insulation performance.

[0003] The commonly used megohmmeter currently mainly includes a hand-cranking type and a digital type, among which the digital megohmmeter is widely used because it does not need to be manually cranked. As a large equipment, the insulation material of the medium and low voltage power box will have an absorption effect after the voltage is applied, which is manifested as the insulation resistance value gradually rising with the extension of the applied voltage time, and finally tending to be stable, at which time the insulation test can be formally performed. The existing operation usually presets an experience stable time of 1 minute, but since the external environment and the types and quantities of internal elements of the power box differ, the stable time of the absorption effect may be longer or shorter than the experience value, thereby leading to a decrease in the reliability of the insulation test results and affecting the overall detection efficiency. SUMMARY

[0004] In order to solve the technical problem that in the existing insulation test of medium and low voltage power boxes, the stable time of the absorption effect of the insulation material is affected by the environment and internal elements, and fixedly using an experience value of 1 minute may lead to a decrease in the reliability of the test results and affect the detection efficiency, the purpose of the present application is to provide a method for rapid testing of insulation performance of medium and low voltage power boxes, and the technical solution adopted is as follows:

[0005] The current resistance data of the medium and low voltage power box is collected by the megohmmeter, and based on the current resistance data, absorption effect saturation data of the insulation material of the medium and low voltage power box at each collection time is obtained.

[0006] Based on the absorption effect saturation data, the insulation information level at each acquisition time is obtained, and the optional detection stop time is determined according to the insulation information level.

[0007] The degree of stable state access is determined based on the degree of insulation information before the optional detection stop time, and the degree of absorption process cutoff is obtained based on the degree of stable state access and the degree of insulation information.

[0008] The stopping time for detection is determined based on the degree of cutoff of the absorption process, and the megohmmeter officially starts the insulation test of the medium and low voltage power box after the stopping time.

[0009] Furthermore, the process of obtaining the absorption effect saturation data includes:

[0010] Obtain voltage level anomaly data based on the current and resistance data at the current acquisition time;

[0011] The absorption correlation performance data is obtained by measuring the changes in current and resistance data at adjacent acquisition times before the current acquisition time.

[0012] The absorption effect saturation data at the current acquisition time are obtained based on the voltage level anomaly data and the absorption correlation performance data.

[0013] Furthermore, the process of obtaining the insulation information level includes:

[0014] The absorption effect saturation data prior to the current acquisition time are subjected to curve fitting to obtain the absorption effect saturation curve, and the slopes corresponding to each acquisition time in the absorption effect saturation curve are subjected to curve fitting to obtain the absorption effect saturation change rate curve.

[0015] Map the data in the absorption effect saturation curve and the absorption effect saturation change rate curve to the corresponding data ranges, and place the two mapped curves in the same horizontal coordinate space;

[0016] Determine whether there is an intersection between the absorption effect saturation curve and the absorption effect saturation change rate curve. If not, use the first acquisition method to obtain the insulation information level corresponding to the current acquisition time. If yes, use the second acquisition method to obtain the insulation information level corresponding to the current acquisition time.

[0017] Furthermore, the step of acquiring the insulation information level corresponding to the current acquisition time using the first acquisition method includes:

[0018] Acquire the absorption effect saturation data of the absorption effect saturation curve at the current acquisition time and the absorption effect saturation rate of change data of the absorption effect saturation rate curve at the current acquisition time;

[0019] Calculate the difference between the absorption effect saturation data and the absorption effect saturation change rate data;

[0020] The insulation information level corresponding to the current acquisition time is calculated based on the difference and the number of acquisition times before the current acquisition time.

[0021] Furthermore, the step of acquiring the insulation information level corresponding to the current acquisition time using the second acquisition method includes:

[0022] Obtain the number of intersection points between the absorption effect saturation curve and the absorption effect saturation rate of change curve before the current acquisition time;

[0023] Between the first and last intersection points before the current acquisition time, obtain the mean value of the data difference between the absorption effect saturation curve and the absorption effect saturation change rate curve;

[0024] The insulation information level corresponding to the current acquisition time is calculated based on the number of intersections and the average value.

[0025] Furthermore, determining the optional detection stop time based on the insulation information level includes:

[0026] When the insulation information level is greater than the first preset value, each acquisition time after the acquisition time corresponding to the insulation information level can be used as the optional detection stop time.

[0027] Furthermore, the process of obtaining the stable state access level includes:

[0028] The difference in the degree of insulation information between the current optional detection stop time and the previous optional detection stop time is obtained as the real-time insulation information degree increment.

[0029] Before the current optional detection stop time, the difference in the degree of insulation information between adjacent optional detection stop times is obtained, and the average value of the difference in the degree of insulation information is calculated as the average increase in the degree of insulation information in history.

[0030] The inverse proportional value of the absolute value of the difference between the real-time increase in insulation information level and the historical average increase in insulation information level is used as the stable state access level at the current optional detection stop time.

[0031] Furthermore, the process of obtaining the cutoff level of the absorption process includes:

[0032] The normalized value obtained by multiplying the stable state access level by the corresponding insulation information level is used as the absorption process cutoff level.

[0033] Furthermore, determining the detection stop time based on the degree of cutoff in the absorption process includes:

[0034] Determine whether the cutoff degree of the absorption process is greater than a second preset value. If so, take the acquisition time corresponding to the cutoff degree of the absorption process as the stop detection time.

[0035] This invention also provides a rapid insulation performance testing device for medium and low voltage power boxes. The device includes a memory and a processor, wherein the memory is used to store program code; and the processor is used to read the program code stored in the memory and execute the aforementioned rapid insulation performance testing method for medium and low voltage power boxes.

[0036] The present invention has the following beneficial effects:

[0037] The current and resistance data of the medium and low voltage power box are collected by a megohmmeter. Based on the current and resistance data, the absorption effect saturation data of the insulation material of the medium and low voltage power box at each collection time are obtained. The larger the value of the absorption effect saturation data, the slower the rate at which the insulation material absorbs electrical energy at the current collection time, and the closer the absorption effect of the insulation material is to completion.

[0038] Based on the absorption effect saturation data, the insulation information level at each acquisition time is obtained, and the optional detection stop time is determined according to the insulation information level; the greater the insulation information level, the closer the process of the insulating material absorbing electrical energy is to saturation, and the more it meets the conditions for stopping the test.

[0039] The stable state access level is determined based on the insulation information level before the optional detection stop time, and the absorption process cutoff level is obtained based on the stable state access level and the corresponding insulation information level; the absorption process cutoff level is a quantitative indicator used to determine when the detection should stop, and the larger the value, the more suitable it is to stop the test.

[0040] The stopping time for testing is determined based on the degree of cutoff in the absorption process. After this stopping time, the megohmmeter formally begins the insulation test of the medium- and low-voltage power box. After the stopping time, the resistance of the insulating material has stabilized and is accurate, thus the insulation test of the medium- and low-voltage power box can be formally initiated.

[0041] In summary, this invention analyzes the testing delay caused by the absorption effect of insulating materials before rapid insulation performance testing of medium and low voltage power boxes using digital megohmmeters. Considering the urgency of actual power demand, it introduces a dynamic index, "absorption process cutoff degree," to quantify the threshold for stopping the absorption effect detection in real time. This invention can more rationally terminate the absorption effect detection stage without significantly affecting subsequent insulation performance test results, thereby optimizing the timing of insulation performance testing and improving overall testing efficiency. Attached Figure Description

[0042] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a flowchart of a rapid insulation performance testing method for medium and low voltage power boxes provided in the first embodiment of the present invention;

[0044] Figure 2 This is a flowchart illustrating the process of obtaining absorption effect saturation data provided in the second embodiment of the present invention;

[0045] Figure 3 A flowchart illustrating the process of obtaining insulation information level according to the third embodiment of the present invention;

[0046] Figure 4 This is a flowchart of the fourth embodiment of the present invention, which describes the process of obtaining the insulation information level corresponding to the current acquisition time using a first acquisition method.

[0047] Figure 5 This is a flowchart of the fifth embodiment of the present invention, which describes the process of obtaining the insulation information level corresponding to the current acquisition time using a second acquisition method.

[0048] Figure 6 This is a flowchart illustrating the process of obtaining the stable access level provided in the sixth embodiment of the present invention. Detailed Implementation

[0049] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of the rapid insulation performance testing method and equipment for medium and low voltage power boxes proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0051] The specific scheme of the rapid insulation performance testing method for medium and low voltage power boxes provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0052] Please see Figure 1 The diagram illustrates a flowchart of a rapid insulation performance testing method for medium and low voltage power boxes provided in the first embodiment of the present invention, the method comprising:

[0053] S101. Collect current and resistance data of the medium and low voltage power box using a megohmmeter, and obtain absorption effect saturation data of the insulation material of the medium and low voltage power box at each collection time based on the current and resistance data.

[0054] Before using a megohmmeter to collect current and resistance data from medium and low voltage power boxes, the following steps must be followed:

[0055] a. Completely disconnect the power supply: Completely disconnect all power supply circuits of the low-voltage power box under test.

[0056] b. Discharge and grounding: Fully discharge any residual charge from equipment such as power capacitors and long cables inside the box, and reliably ground the grounding terminal.

[0057] c. Isolate low-voltage equipment: Physically disconnect the wiring terminals of low-voltage electronic equipment such as frequency converters, PLCs, smart meters, and surge protectors to prevent damage caused by high voltage output from megohmmeters.

[0058] d. Meter Selection and Wiring: Select a megohmmeter of appropriate specifications based on the voltage level of the power box, correctly connect it to the circuit under test, and record the current and resistance data at a frequency of twice per second. Refer to the table below for the relationship between equipment voltage level and megohmmeter selection based on the voltage level of the power box.

[0059]

[0060] Under normal testing conditions, when a megohmmeter is connected to a medium- or low-voltage power supply box, its built-in lithium battery begins to apply voltage to the line and continuously supplies power. At this time, the insulation material inside the box will experience a typical "absorption effect": initially absorbing a large amount of current, then the absorption rate gradually decreases until it almost stops. Correspondingly, the measured insulation resistance value will show a trend of first rising rapidly and then gradually stabilizing.

[0061] Based on the above process, both current and resistance data will change systematically as the absorption effect develops. Therefore, by simultaneously analyzing current and resistance data, the degree of energy absorption by the insulating material can be assessed. Absorption saturation is used to characterize the degree to which the absorption behavior of the insulating material approaches saturation at a specific moment, thereby quantifying the progress of the absorption effect.

[0062] The process of obtaining the absorption effect saturation data will be described in detail in the second embodiment, and will not be repeated here.

[0063] S102. Based on the absorption effect saturation data, obtain the insulation information level at each acquisition time, and determine the optional detection stop time according to the insulation information level.

[0064] In practical applications, medium and low voltage power distribution boxes are often deployed in areas with high electricity demand. Therefore, when testing their insulation performance, not only is accurate result required, but the testing process must also be completed as quickly as possible. To balance efficiency and reliability, based on the absorption effect saturation, the energy absorption process that the insulation material has undergone can be further analyzed in real time, and the "absorption process cutoff degree" at the current moment can be calculated accordingly. The specific logic is as follows:

[0065] Under the premise of a fixed voltage applied by the megohmmeter, the absorption effect of insulating materials on electrical energy is characterized by the index of "absorption effect saturation". Therefore, the cumulative change trend of absorption effect saturation over time can directly reflect the insulation performance of different electrical boxes. Based on this, the actual insulation effect of the electrical box's insulating material can be analyzed according to the cumulative change of absorption effect saturation before the current acquisition time, and then the "degree of insulation information" contained in the megohmmeter test data at the current acquisition time can be calculated, providing a quantitative basis for determining whether it is appropriate to consider stopping the test.

[0066] The process of obtaining the insulation information level will be described in detail in the third embodiment, and will not be repeated here.

[0067] Furthermore, determining the optional detection stop time based on the insulation information level includes:

[0068] When the insulation information level is greater than the first preset value, each acquisition time after the acquisition time corresponding to the insulation information level can be used as the optional detection stop time.

[0069] The first preset value can be set independently, preferably 0.5. If the insulation information level exceeds the first preset value for the first time, it indicates that the absorption effect of the insulation material has entered a critical period of transition from the initial stage to the saturated and stable stage. At this time, the acquisition time corresponding to the first time the insulation information level exceeds the first preset value and all subsequent acquisition times can be marked as the optional detection stop time.

[0070] S103. Determine the corresponding stable state access degree based on the insulation information degree before the optional detection stop time, and obtain the absorption process cutoff degree based on the stable state access degree and the corresponding insulation information degree.

[0071] In standard procedures, it is generally assumed that the absorption effect of insulating materials should stabilize and persist for a period of time before the rapid insulation performance test of medium and low voltage power boxes can be formally conducted. However, in practical applications, due to environmental factors and the size of the power box model, the absorption effect of insulating materials often meets the requirements for terminating the test as soon as it enters the stable stage (i.e., the transition from rapid absorption of electrical energy to a state of basically no absorption of electrical energy).

[0072] To balance testing efficiency and reliability, based on the level of insulation information, the performance intensity of the insulation material during the transition to a stable state can be further analyzed, and the degree of stable state access, i.e. the degree to which the absorption effect of the insulation material transitions into a stable state, can be calculated in real time, thereby achieving a more accurate quantitative judgment on the timing of the termination of the absorption effect.

[0073] The process of obtaining the stable state access level will be described in detail in the sixth embodiment, and will not be repeated here.

[0074] Furthermore, the process of obtaining the cutoff level of the absorption process includes:

[0075] The normalized value obtained by multiplying the stable state access level by the corresponding insulation information level is used as the absorption process cutoff level.

[0076] The degree of cutoff in the absorption process can be expressed by the following formula:

[0077] ;

[0078] Among them, the The degree of cutoff in the absorption process at the time of acquisition is indicated. The degree of stable state access at the time of data acquisition, the The degree of insulation information at the time of acquisition, the This represents a normalization function, such as the range normalization function.

[0079] The larger the value of the absorption process cutoff, the more sufficient the absorption effect of the insulating material has become at the corresponding optional detection stop time, and the less need there is for further detection. This value directly reflects the appropriateness of stopping the detection at this point in the megohmmeter's operation.

[0080] S104. Determine the stop detection time based on the degree of cutoff of the absorption process, and the megohmmeter officially starts the insulation test of the medium and low voltage power box after the stop detection time.

[0081] Furthermore, determining the detection stop time based on the degree of cutoff in the absorption process includes:

[0082] Determine whether the cutoff degree of the absorption process is greater than a second preset value. If so, take the acquisition time corresponding to the cutoff degree of the absorption process as the stop detection time.

[0083] The second preset value can be set independently, preferably 0.65. When the absorption process cutoff level first exceeds the second preset value, the corresponding optional detection stop time is determined as the detection stop time. At this time, the megohmmeter stops monitoring and interference elimination of the insulation material absorption effect and immediately switches to the rapid testing phase of the insulation performance of the medium and low voltage power box. If the absorption process cutoff level is less than or equal to the second preset value, the corresponding stable state access level can be preset to 0. At this time, the detection stop time has not yet arrived, and the testing should continue.

[0084] Figure 2 This is a flowchart of the process for obtaining absorption effect saturation data provided in the second embodiment of the present invention. The process for obtaining absorption effect saturation data includes:

[0085] S201. Obtain voltage level anomaly data based on the current and resistance data at the current acquisition time.

[0086] Since the voltage level given by the megohmmeter is fixed, it is determined by the existing Ohm's law ( As can be seen, under normal circumstances, regardless of how the current and voltage data change at the current moment, the voltage level expressed by their combination should be consistent with the voltage level given by the megohmmeter.

[0087] The voltage level anomaly data can be expressed by the following formula:

[0088] ;

[0089] Among them, the This indicates the fixed voltage level provided by the megohmmeter's built-in power supply. The current data at the time of acquisition is described in the following text. The resistance data at the time of acquisition, the This indicates the voltage level anomaly data at the time of data acquisition.

[0090] The larger the value of the voltage level anomaly data, the more obvious the instability of the insulating material when absorbing electrical energy, which further indicates that the absorption effect of the insulating material is faster, reflecting the greater the impact of the electromagnetic interference generated by the absorption effect of the insulating material on the detection of current resistance data.

[0091] S202. Obtain absorption correlation performance data based on the changes in current and resistance data at adjacent acquisition times before the current acquisition time.

[0092] The sequences of current and resistance data prior to the current acquisition time are used as the historical current data sequence and historical resistance data sequence for the current acquisition time, respectively.

[0093] In the historical current data sequence, the change in current data at adjacent acquisition times is calculated, i.e., the change in current data. In the historical resistance data sequence, the change in resistance data at adjacent acquisition times is calculated, i.e., the change in resistance data. Both the change in current data and the change in resistance data are non-negative numbers.

[0094] The absorption-related expressiveness data can be expressed by the following formula: Wherein, N represents the number of acquisition times prior to the current acquisition time, and the... This represents the absolute value of the difference between the current data at acquisition time n and the current data at acquisition time n+1. This represents the absolute value of the difference between the resistance data at acquisition time n and the resistance data at acquisition time n+1. K is a preset standard value, which can be set independently, preferably 1. The data representing the absorption correlation expressiveness at the time of acquisition.

[0095] If the above occurs In the case where it equals 0, then the... The value can be set independently according to the actual situation, such as 0 or Numbers, etc.

[0096] The larger the value of the absorption correlation performance data, the more the changes in current and resistance of the insulating material follow Ohm's law during the process of absorbing electrical energy, reflecting the greater the degree to which the changes in current and resistance can characterize the absorption progress.

[0097] S203. Based on the voltage level anomaly data and the absorption correlation performance data, obtain the absorption effect saturation data at the current acquisition time.

[0098] The absorption effect saturation data at the current acquisition time is obtained by dividing the voltage level anomaly data at the current acquisition time by the absorption correlation performance data at the current acquisition time.

[0099] The absorption effect saturation data can be expressed by the following formula:

[0100] ;

[0101] Among them, the This represents the absorption effect saturation data at the time of data collection.

[0102] If the above occurs In the case where it equals 0, then the... It can be replaced with The The value can be set independently according to the actual situation, such as setting it to .

[0103] The larger the value of the absorption effect saturation data, the lower the absorption rate of the insulating material. The change trends of its current and resistance together characterize the degree of completion of the absorption progress, reflecting that the absorption effect of the insulating material has tended to saturate.

[0104] Figure 3 The flowchart illustrates the process of obtaining insulation information level according to the third embodiment of the present invention. The process of obtaining insulation information level includes:

[0105] S301. Perform curve fitting on the absorption effect saturation data prior to the current acquisition time to obtain the absorption effect saturation curve, and perform curve fitting on the slope corresponding to each acquisition time in the absorption effect saturation curve to obtain the absorption effect saturation change rate curve.

[0106] The absorption effect saturation curve Curve fitting is performed using the absorption effect saturation data prior to the current acquisition time.

[0107] The absorption effect saturation change rate curve The absorption effect saturation curve The slopes at each acquisition time point were obtained by curve fitting.

[0108] S302. Map the data in the absorption effect saturation curve and the absorption effect saturation change rate curve to the corresponding data range, and place the two mapped curves in the same horizontal coordinate space.

[0109] The absorption effect saturation curve and the absorption effect saturation change rate curve All can be mapped to a certain data range using a normalization function, which can be a range normalization function, and the absorption effect saturation curve. and the absorption effect saturation change rate curve After mapping, they correspond to the absorption effect saturation curves respectively. and the saturation rate of change curve of absorption effect .

[0110] The absorption effect saturation curve and the absorption effect saturation change rate curve Placed within the same horizontal coordinate space.

[0111] S303. Determine whether there is an intersection between the absorption effect saturation curve and the absorption effect saturation change rate curve. If not, use the first acquisition method to obtain the insulation information degree corresponding to the current acquisition time. If yes, use the second acquisition method to obtain the insulation information degree corresponding to the current acquisition time.

[0112] If there is no intersection, it means that when the megohmmeter detects the current data acquisition time, the insulating material is still in the stage of rapidly absorbing electrical energy. Because of this strong absorption effect, the insulation performance of the insulating material will be temporarily suppressed, making the insulation effect the least obvious stage. However, during this stage, the two curves gradually converge.

[0113] If an intersection point exists, it indicates that during the rapid energy absorption phase, the insulating material does not have a suitable moment to stop the energy absorption process. When the megohmmeter detects the current acquisition time, the insulating material has already entered the stage of overall energy stability, at which point the insulation effect of the insulating material will be maximized.

[0114] If there is no intersection, the insulation information level corresponding to the current acquisition time is obtained using the first acquisition method. The method of obtaining the insulation information level corresponding to the current acquisition time using the first acquisition method will be described in detail in the fourth embodiment, and will not be repeated here.

[0115] If an intersection exists, the insulation information level corresponding to the current acquisition time is obtained using the second acquisition method. The method of obtaining the insulation information level corresponding to the current acquisition time using the second acquisition method will be described in detail in the fifth embodiment, and will not be repeated here.

[0116] Figure 4This is a flowchart of the fourth embodiment of the present invention, which describes the process of obtaining the insulation information level corresponding to the current acquisition time using a first acquisition method. The process of obtaining the insulation information level corresponding to the current acquisition time using the first acquisition method includes:

[0117] S401. Obtain the absorption effect saturation data of the absorption effect saturation curve at the current acquisition time and the absorption effect saturation change rate data of the absorption effect saturation change rate curve at the current acquisition time.

[0118] The absorption effect saturation data The absorption effect saturation curve represents the absorption effect saturation curve. The data at the current acquisition time, the data on the saturation rate of change of the absorption effect. The curve representing the saturation rate of change of the absorption effect Data at the current acquisition time.

[0119] S402. Calculate the difference between the absorption effect saturation data and the absorption effect saturation change rate data.

[0120] The difference can be expressed as: Wherein, the difference is a non-negative number, the It represents the absolute value.

[0121] S403. Calculate the insulation information level corresponding to the current acquisition time based on the difference and the number of acquisition times before the current acquisition time.

[0122] The degree of insulation information can be expressed by the following formula:

[0123] ;

[0124] Among them, the This indicates the number of data collection times prior to the current data collection time. This represents a normalization function, preferably a range normalization function. This indicates the degree of insulation information corresponding to the current acquisition time.

[0125] It should be noted that when the current acquisition time is the first acquisition time, because the number of acquisition times before the first acquisition time is 0, it will lead to... Since the denominator is meaningless, the formula for obtaining the insulation information level can be transformed into: The The value can be set independently according to the actual situation, such as setting it to 1.

[0126] The higher the value of the insulation information level, the more the actual insulation information of the insulation material at the current acquisition time can meet the conditions for the absorption process to stop, even though the absorption effect of the insulation material has not reached a completely stable state at the current acquisition time. This is because the actual insulation information of the insulation material at the current acquisition time is limited by the differences in its actual structure in different medium and low voltage power boxes.

[0127] Figure 5 This is a flowchart of the fifth embodiment of the present invention, which describes the process of obtaining the insulation information level corresponding to the current acquisition time using a second acquisition method. The process of obtaining the insulation information level corresponding to the current acquisition time using the second acquisition method includes:

[0128] S501. Obtain the number of intersection points between the absorption effect saturation curve and the absorption effect saturation rate of change curve before the current acquisition time.

[0129] The absorption effect saturation curve mentioned before the current acquisition time The curve of the rate of change of the saturation of the absorption effect The number of intersections between them can be used To express.

[0130] S502. Between the first and last intersection points before the current acquisition time, obtain the mean value of the data difference between the absorption effect saturation curve and the absorption effect saturation change rate curve.

[0131] The mean value between the first and last intersection points before the current acquisition time. The absorption effect saturation curve represents the absorption effect saturation curve. The curve of the rate of change of the saturation of the absorption effect The average of the absolute values ​​of the data differences between corresponding acquisition times.

[0132] S503. Calculate the insulation information level corresponding to the current acquisition time based on the number of intersections and the average value.

[0133] The degree of insulation information can be expressed by the following formula:

[0134] ;

[0135] Among them, the This represents a normalization function, preferably a range normalization function. This indicates the degree of insulation information corresponding to the current acquisition time.

[0136] The higher the value of the insulation information level, the more obvious it is that the state of the insulation material absorbing electrical energy is in a generally stable stage at the current acquisition time, and the more the actual insulation information of the insulation material at the current acquisition time can meet the conditions for the absorption process to stop.

[0137] Figure 6 The flowchart below illustrates the process for obtaining the stable state access level according to the sixth embodiment of the present invention. The process for obtaining the stable state access level includes:

[0138] S601. Obtain the difference in insulation information level between the current optional detection stop time and the previous optional detection stop time as the real-time insulation information level increment.

[0139] The It can represent the absolute value of the difference in the degree of insulation information between the current optional detection stop time and the previous optional detection stop time.

[0140] S602. Before the current optional detection stop time, obtain the difference in the degree of insulation information between adjacent optional detection stop times, and calculate the average value of the difference as the average increase in the degree of insulation information in history.

[0141] The average increase in the historical insulation information level can be expressed as: .

[0142] S603. The inverse proportional value of the absolute value of the difference between the real-time increase in insulation information level and the historical average increase in insulation information level is used as the stable state access level at the current optional detection stop time.

[0143] The degree of stable state access can be expressed by the formula:

[0144] ;

[0145] Among them, the This indicates the degree of stable access. This is a preset constant; to ensure the denominator is not zero, it can be set to 10. -6 .

[0146] This invention also provides a rapid insulation performance testing device for medium and low voltage power boxes. The device includes a memory and a processor, wherein the memory is used to store program code; and the processor is used to read the program code stored in the memory and execute the aforementioned rapid insulation performance testing method for medium and low voltage power boxes.

[0147] The technical features and effects of the rapid insulation performance testing equipment for medium and low voltage power boxes proposed in this embodiment of the invention are the same as those of the method proposed in this embodiment of the invention, and will not be repeated here.

[0148] The present invention has the following beneficial effects:

[0149] The current and resistance data of the medium and low voltage power box are collected by a megohmmeter. Based on the current and resistance data, the absorption effect saturation data of the insulation material of the medium and low voltage power box at each collection time are obtained. The larger the value of the absorption effect saturation data, the slower the rate at which the insulation material absorbs electrical energy at the current collection time, and the closer the absorption effect of the insulation material is to completion.

[0150] Based on the absorption effect saturation data, the insulation information level at each acquisition time is obtained, and the optional detection stop time is determined according to the insulation information level; the greater the insulation information level, the closer the process of the insulating material absorbing electrical energy is to saturation, and the more it meets the conditions for stopping the test.

[0151] The stable state access level is determined based on the insulation information level before the optional detection stop time, and the absorption process cutoff level is obtained based on the stable state access level and the corresponding insulation information level; the absorption process cutoff level is a quantitative indicator used to determine when the detection should stop, and the larger the value, the more suitable it is to stop the test.

[0152] The stopping time for testing is determined based on the degree of cutoff in the absorption process. After this stopping time, the megohmmeter formally begins the insulation test of the medium- and low-voltage power box. After the stopping time, the resistance of the insulating material has stabilized and is accurate, thus the insulation test of the medium- and low-voltage power box can be formally initiated.

[0153] In summary, this invention analyzes the testing delay caused by the absorption effect of insulating materials before rapid insulation performance testing of medium and low voltage power boxes using digital megohmmeters. Considering the urgency of actual power demand, it introduces a dynamic index, "absorption process cutoff degree," to quantify the threshold for stopping the absorption effect detection in real time. This invention can more rationally terminate the absorption effect detection stage without significantly affecting subsequent insulation performance test results, thereby optimizing the timing of insulation performance testing and improving overall testing efficiency.

[0154] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0155] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A method for rapid testing of insulation performance of low and medium voltage power boxes, characterized in that, The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises:

2. The method for testing the insulation performance of a medium-low voltage power box according to claim 1, characterized in that, The method comprises: The method comprises: The method comprises: The method comprises:

3. The method for testing the insulation performance of a medium-low voltage power box according to claim 1, wherein, The method comprises: The method comprises: The method comprises: The method comprises:

4. 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The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: The method comprises: acquire the absorption effect saturation data of the absorption effect saturation curve and the absorption effect saturation change rate data of the absorption effect saturation change rate curve at the current acquisition time point; calculate the difference between the absorption effect saturation data and the absorption effect saturation change rate data; calculate the insulation information degree corresponding to the current acquisition time point according to the difference and the number of acquisition time points before the current acquisition time point.

5. The method for testing the insulation performance of a medium-low voltage power box according to claim 3, wherein, The method for acquiring the insulation information degree corresponding to the current acquisition time point by using the second acquisition method comprises: acquire the number of intersection points between the absorption effect saturation curve and the absorption effect saturation change rate curve before the current acquisition time point; acquire the average of the data difference between the absorption effect saturation curve and the absorption effect saturation change rate curve between the first intersection point and the last intersection point before the current acquisition time point; calculate the insulation information degree corresponding to the current acquisition time point according to the number of intersection points and the average.

6. The method for testing the insulation performance of a medium-low voltage power box according to claim 1, wherein, The method for determining the optional detection stop time point according to the insulation information degree comprises: when the insulation information degree is greater than a first preset value, each acquisition time point after the acquisition time point corresponding to the insulation information degree can be used as the optional detection stop time point.

7. The method for testing the insulation performance of a medium-low voltage power box according to claim 1, wherein, The method for determining the detection stop time point according to the absorption process cutoff degree comprises: determine whether the absorption process cutoff degree is greater than a second preset value, and if yes, use the acquisition time point corresponding to the absorption process cutoff degree as the detection stop time point.

8. The insulation performance rapid test equipment for low and medium voltage power box, characterized in that, The device comprises a memory and a processor, wherein: the memory is used to store program code; the processor is used to read the program code stored in the memory and execute the method for testing the insulation performance of a medium-low voltage power box according to any one of claims 1 to 7. The device comprises a memory and a processor, wherein: the memory is used to store program code; the processor is used to read the program code stored in the memory and execute the method for testing the insulation performance of a medium-low voltage power box according to any one of claims 1 to 7.

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