A method and system for evaluating latent insulation faults of power distribution equipment

Abstract

The present invention relates to the technical field of distribution equipment, and specifically discloses a method and system for evaluating latent insulation faults of distribution equipment. A megohmmeter is used to measure the insulation resistance value of the external insulator material of the distribution equipment, and the absorption ratio of the insulator material is calculated and obtained; an insulation abnormality signal of the distribution equipment is obtained; the discharge detection area on the surface of the distribution equipment is subjected to discharge detection, and the discharge coefficient ratio of the discharge detection area is calculated and obtained; and a regional abnormality signal is obtained, and then the extreme value of the discharge amount risk fluctuation performance of the i-th discharge detection area is calculated and obtained; a discharge warning signal is obtained, the temperature of the discharge detection area is detected by an infrared thermal imaging sensor, a thermal abnormality signal or a thermal stability signal is obtained, and fault evaluation is carried out from aspects such as the insulation state, discharge amount and operating temperature of the external insulation material of the distribution equipment, so as to discover and solve the insulation faults of the distribution equipment in advance and ensure the stable and normal operation of the equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of power distribution equipment, and in particular to a method and system for evaluating latent insulation faults of power distribution equipment. Background Art

[0002] At present, for commonly used power distribution network equipment in the open-air environment, insulation damage faults often occur. At the same time, a large number of equipment have latent insulation hidden dangers and faults. Most of the insulation detection means for power distribution line equipment faults in the power distribution network are discharge detection;

[0003] During the detection process, on the one hand, the detection personnel make judgments and evaluations based on the manual detection results. There is no accurate evaluation and judgment standard, and at the same time, it is affected by subjectivity more; on the other hand, the general partial discharge test is measured under a voltage higher than the normal operating voltage of the equipment. If under the normal operating voltage, latent faults are difficult to find. At this time, manual detection may bring certain safety hazards and the measurement results are inaccurate. Summary of the Invention

[0004] The purpose of the present invention is to provide a method and system for evaluating latent insulation faults of power distribution equipment to solve the problems in the above background.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A method for evaluating latent insulation faults of power distribution equipment includes:

[0007] Measure the insulation resistance value of the external insulator material of the power distribution equipment using a megohmmeter, and calculate and obtain the absorption ratio JK of the insulator material based on the measured insulation resistance value; and compare it with the absorption ratio threshold JKyz; obtain the power distribution equipment insulation stable signal or the power distribution equipment insulation abnormal signal;

[0008] Based on the power distribution equipment insulation abnormal signal, divide the surface of the power distribution equipment into several discharge detection areas, and mark the discharge detection areas as i, where i is 1, 2, 3...; perform discharge detection on the discharge detection areas on the surface of the power distribution equipment, and calculate the discharge coefficient ratio FIB of the discharge detection areas i ; and compare it with the preset discharge coefficient ratio FIBin; obtain the area stable signal or the area abnormal signal;

[0009] Based on the area abnormal signal, obtain the area current change curve Q of the discharge detection area on the surface of the power distribution equipment （i） ;

[0010] By Calculate and obtain the discharge amount GDF of the discharge detection area i i ;

[0011] Then by Calculate and obtain the extreme value QI of the discharge amount risk fluctuation performance in the discharge detection area i i ; Then compare the extreme value QI of the discharge amount risk fluctuation performance i with the discharge amount safety value Qan; Obtain a discharge risk signal or a discharge warning signal;

[0012] Based on the discharge warning signal, use an infrared thermal imaging sensor to detect the temperature in the discharge detection area i, and obtain the temperature distribution image of the discharge detection area i; Calculate the temperature foreign ratio SB in the discharge detection area i i ; Then compare it with the extreme value SBJ of the temperature foreign ratio; Obtain a thermal anomaly signal or a thermal stability signal.

[0013] As a further solution of the present invention: The calculation process of the absorption ratio JK is as follows:

[0014] A11: Connect a DC voltage with a voltage value of KU to the insulating material of the power distribution equipment, and then use a megohmmeter to perform periodic insulation resistance detection on the power distribution equipment;

[0015] A12: Obtain the detection current value at each detection time point n within the insulation resistance detection period T, and mark it as JI n ;

[0016] A13: Through Calculate and obtain the insulation resistance value JR of the power distribution equipment at each detection time point n n ;

[0017] A14: Obtain the insulation resistance values at the initial state time point ct and the final state time point wt within the insulation resistance detection period T, and mark them as the initial state resistance value JR ct and the final state resistance value JR wt ;

[0018] Through Calculate and obtain the absorption ratio JK of the insulating material.

[0019] As a further solution of the present invention: The process of the periodic insulation resistance detection is to connect the DC voltage of the power distribution equipment to the starting moment 0, use the unit time t as the detection time interval, divide the insulation resistance detection period RT into several detection time points, and mark them as n respectively, where n is 1, 2, 3...

[0020] As a further solution of the present invention: Compare the absorption ratio JK of the insulating material of the power distribution equipment with the absorption ratio threshold JKyz:

[0021] If the absorption ratio JK of the insulating material of the power distribution equipment is greater than or equal to the absorption ratio threshold JKyz, generate an insulation stability signal for the power distribution equipment;

[0022] If the absorption ratio JK of the insulating material of the power distribution equipment is less than the absorption ratio threshold JKyz, an abnormal insulation signal of the power distribution equipment is generated.

[0023] As a further solution of the present invention: the discharge coefficient ratio FIB i is obtained by:

[0024] B1: Detect the discharge current in the discharge detection area i on the surface of the power distribution equipment to obtain the area discharge detection current value I of the discharge detection area within the discharge detection cycle duration FT （FT） ; Then, taking the area discharge detection current value as the ordinate and the discharge detection time as the abscissa, establish a rectangular coordinate to obtain the area current change curve from the detection initial time FTz to the detection end time FTm within the discharge detection cycle duration FT, and denote it as Q （i） ;

[0025] B2: Based on the area current change curve Q within the discharge detection area （i） ; Obtain the number value of the current wave bands in the area current change curve, and mark them as j in sequence, where j is a non-negative integer; at the same time, obtain the duration of each current wave band based on the area current change curve and mark it as BT （i，j） ;

[0026] At the same time, obtain the maximum value of the wave band current in each current wave band and mark it as Imax （i，j） ;

[0027] B3: Compare the maximum value of the wave band current Imax in each current wave band of the discharge detection area i within the discharge detection cycle duration FT （i，j） with the detection current extreme value threshold Isa respectively;

[0028] Obtain the number value of the wave band current whose maximum value of the wave band current Imax in the discharge detection area i within the discharge detection cycle duration FT （i，j） is greater than the detection current extreme value threshold Isa, and mark it as m;

[0029] B4: Calculate to obtain the discharge coefficient ratio FIB of the discharge detection area i through i .

[0030] As a further solution of the present invention: Compare the discharge coefficient ratio FIB i with the preset discharge coefficient ratio FIBin:

[0031] If the discharge coefficient ratio FIB i is less than or equal to the preset discharge coefficient ratio FIBin, generate an area stability signal;

[0032] If the discharge coefficient ratio FIB iGenerate an area anomaly signal when it is greater than the preset ratio FIBin of the discharge coefficient.

[0033] As a further solution of the present invention: Compare the extreme value QI of the discharge amount risk fluctuation performance i with the discharge amount safety value Qan:

[0034] If the extreme value QI of the discharge amount risk fluctuation performance i is greater than or equal to the discharge amount safety value Qan; generate a discharge risk signal;

[0035] If the extreme value QI of the discharge amount risk fluctuation performance i is less than the discharge amount safety value Qan; generate a discharge warning signal.

[0036] As a further solution of the present invention: The acquisition method of the temperature anomaly area ratio SB i is as follows:

[0037] Step C1: Divide the temperature distribution image of the discharge detection area i into grids with a length of kXk and label them as f; where f is 1, 2, 3...; Obtain the initial temperature value at the initial detection moment FTz;

[0038] C2: After the discharge detection cycle duration FT, obtain the vertex temperature value of each grid at the end detection moment FTm. By subtracting the initial temperature value of each grid at the end detection moment FTm from the initial temperature value at the initial detection moment FTz, obtain the vertex temperature change value of each grid;

[0039] C3: Compare the vertex temperature change value of each grid with the temperature change threshold; Obtain the number of vertex temperature change values of each grid that are greater than the temperature change threshold and label it as WY f ;

[0040] Through calculate to obtain the temperature anomaly area value Swy of the grid f in the discharge detection area i f ;

[0041] C4: Then, through calculate to obtain the temperature foreign ratio SB of the discharge detection area i i .

[0042] As a further solution of the present invention: Compare the temperature foreign ratio SB i with the extreme value SBJ of the temperature foreign ratio:

[0043] If the temperature foreign ratio SB i is greater than or equal to the extreme value SBJ of the temperature foreign ratio, generate a thermal anomaly signal;

[0044] If the temperature foreign ratio SB iGenerate a thermally stable signal when less than the extreme value SBJ of the temperature foreign region ratio.

[0045] As a further solution of the present invention: A distribution equipment insulation latent fault evaluation system includes:

[0046] Data acquisition module: Used to measure the insulation resistance value of the external insulator material of the distribution equipment by using a megohmmeter, calculate and obtain the absorption ratio JK of the insulator material based on the measured insulation resistance value; compare it with the absorption ratio threshold JKyz; obtain the distribution equipment insulation stable signal or the distribution equipment insulation abnormal signal;

[0047] Insulation treatment module: Based on the distribution equipment insulation abnormal signal, divide the surface of the distribution equipment into several discharge detection areas, and mark the discharge detection areas as i, where i is 1, 2, 3...; perform discharge detection on the discharge detection areas on the surface of the distribution equipment, and calculate the discharge coefficient ratio FIB of the discharge detection areas i ; compare it with the preset discharge coefficient ratio FIBin; obtain the area stable signal or the area abnormal signal;

[0048] Discharge evaluation module: Based on the area abnormal signal, obtain the area current change curve Q of the discharge detection area on the surface of the distribution equipment （i） ;

[0049] Through Calculate and obtain the discharge amount GDF of the discharge detection area i i ;

[0050] Then through Calculate and obtain the extreme value QI of the discharge amount risk fluctuation performance of the discharge detection area i i ; then compare the extreme value QI of the discharge amount risk fluctuation performance i with the discharge amount safety value Qan; obtain the discharge risk signal or the discharge warning signal;

[0051] Temperature evaluation module: Based on the discharge warning signal, detect the temperature of the discharge detection area i through an infrared thermal imaging sensor to obtain the temperature distribution image of the discharge detection area i; calculate the temperature foreign region ratio SB in the discharge detection area i i ; then compare it with the extreme value SBJ of the temperature foreign region ratio; obtain the thermal abnormal signal or the thermal stable signal.

[0052] Advantages of the present invention:

[0053] In the present invention, by dividing the discharge detection areas on the surface of the insulating material of the power distribution equipment, detecting the pulse current in each discharge detection area, detecting the change in the current on the insulating material during the discharge detection cycle duration, and based on the area discharge detection current on the surface of the insulating material and the change in the current band, the discharge insulation performance of the insulating material is judged. At the same time, based on the discharge coefficient ratio and the discharge amount in the discharge detection area, the current band of the insulating material in the discharge detection area is calculated continuously, and the maximum discharge amount of the insulating material in the discharge detection area is obtained, and then it is judged whether it is safe outside the discharge detection area;

[0054] Under the discharge warning signal of the discharge detection area, the temperature of the discharge detection area is detected, and the temperature change state of the insulating material in the discharge detection area during the discharge detection process is detected, so as to detect whether the temperature change of the insulating material is abnormal when the external insulating equipment has a discharge current fluctuation during the operation of the power distribution equipment, so as to avoid the safety risk caused by the heating of the insulating material and the discharge of the power distribution equipment. When evaluating and calculating the insulation of the power distribution equipment during operation, a fault assessment is carried out from aspects such as the insulation state, discharge amount, and operating temperature of the external insulating material of the power distribution equipment, so as to discover and solve the insulation faults of the power distribution equipment in advance, ensure the stable and normal operation of the equipment, and at the same time, avoid the problem of inaccurate detection caused by manual detection and evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The present invention will be further described below with reference to the accompanying drawings.

[0056] Figure 1 is a schematic flow chart of the method of the present invention;

[0057] Figure 2 is a system block diagram of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0058] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work shall fall within the protection scope of the present invention. Embodiment 1

[0059] Please refer to Figure 1 shown, the present invention is a method for evaluating the latent insulation fault of a power distribution equipment, including:

[0060] Step 1: Measure the insulation resistance value of the external insulator material of the power distribution equipment with a megohmmeter, and calculate and obtain the absorption ratio JK of the insulator material based on the measured insulation resistance value;

[0061] The calculation process of the absorption ratio JK is as follows:

[0062] A11: Apply a DC voltage with a value of KU to the insulating material of the power distribution equipment, and then use a megohmmeter to perform periodic insulation resistance detection on the power distribution equipment;

[0063] Specifically: The process of periodic insulation resistance detection is to set the external DC voltage of the power distribution equipment as the starting moment 0, use the unit time t as the detection time interval, divide the insulation resistance detection period RT into several detection time points, and mark them as n respectively, where n is 1, 2, 3...;

[0064] A12: Obtain the detection current value at each detection time point n within the insulation resistance detection period T, and mark it as JI n ;

[0065] A13: Calculate and obtain the insulation resistance value JR of the power distribution equipment at each detection time point n through ; n ;

[0066] A14: Obtain the insulation resistance values at the initial state time point ct and the final state time point wt within the insulation resistance detection period T, and mark them as the initial state resistance value JR ct and the final state resistance value JR wt ; It should be noted that the initial state time point and the final state time point are usually two relatively accurate time points during the insulation resistance value detection process, such as the two time points at the 10th second and the 50th second. The specific time points are determined based on the working environment and application scenarios of the power distribution equipment. Usually, the absorption ratio calculated from these two time points can measure the insulation stability of the insulating material during the operation of the power distribution equipment;

[0067] Calculate and obtain the absorption ratio JK of the insulating material through ;

[0068] Step 2: Compare the absorption ratio JK of the insulating material of the power distribution equipment with the absorption ratio threshold JKyz;

[0069] If the absorption ratio JK of the insulating material of the power distribution equipment is greater than or equal to the absorption ratio threshold JKyz, generate a power distribution equipment insulation stability signal;

[0070] If the absorption ratio of the insulating material on the power distribution equipment is relatively large, it indicates that the insulation effect of the insulating material is good, and the insulation resistance can be quickly increased during the operation of the power distribution equipment, ensuring the stable operation of the power distribution equipment;

[0071] If the absorption ratio JK of the insulating material of the power distribution equipment is less than the absorption ratio threshold JKyz, an abnormal insulation signal of the power distribution equipment is generated; at this time, it indicates that the insulating material of the power distribution equipment is abnormal during operation, so that the insulating material cannot meet the insulation requirements during the operation of the power distribution equipment, and it is necessary to further detect the abnormality of the insulating material;

[0072] Step 3: Based on the abnormal insulation signal of the power distribution equipment, divide the surface of the power distribution equipment into several discharge detection areas, and mark the discharge detection areas as i, where i is 1, 2, 3...; perform discharge detection on the discharge detection areas on the surface of the power distribution equipment, and during the discharge detection process, use a high-frequency current sensor to perform pulsed current detection with a detection period duration of FT on the discharge detection areas on the surface of the power distribution equipment; calculate the discharge coefficient ratio FIB of the discharge detection area i ;

[0073] Specifically, it includes the following steps:

[0074] B1: Perform discharge current detection on the discharge detection area i on the surface of the power distribution equipment to obtain the regional discharge detection current value I of the discharge detection area within the detection period duration FT （FT） ; Then, establish a rectangular coordinate system with the regional discharge detection current value as the ordinate and the discharge detection time as the abscissa to obtain the regional current change curve from the detection start time FTz to the detection end time FTm within the detection period duration FT, and record it as Q （i） ;

[0075] B2: Based on the regional current change curve Q within the discharge detection area （i） ; Obtain the number of current wavebands in the regional current change curve, and mark them as j in turn, where j is a non-negative integer; at the same time, obtain the duration of each current waveband based on the regional current change curve and mark it as BT （i，j） ;

[0076] At the same time, obtain the maximum waveband current value in each current waveband and mark it as Imax （i，j） ;

[0077] It should be noted that: the current waveband refers to the change curve in which the regional current in the discharge detection area rises from zero and then drops to zero between the detection start time FTz and the detection end time FTm;

[0078] B3: Compare the maximum waveband current value Imax in each current waveband of the discharge detection area i within the detection period duration FT （i，j） with the detection current extreme value threshold Isa respectively;

[0079] Obtain the maximum waveband current value Imax of the discharge detection area i within the detection period duration FT（i，j） The number of band currents greater than the detection current extreme value threshold Isa is marked as m;

[0080] B4: Pass Calculate the discharge coefficient ratio FIB of the discharge detection area i i ;

[0081] By dividing the insulating material on the surface of the distribution equipment into discharge detection areas, pulse current detection is performed on each discharge detection area, and the current change on the insulating material during the discharge detection cycle is detected. Based on the regional discharge detection current and current band change on the surface of the insulating material, the discharge coefficient ratio is calculated and obtained. This can be used to determine the proportion of discharge time of the insulating material during the working time of the distribution equipment during the staged working process of the distribution equipment;

[0082] Step 4: Compare the discharge coefficient to FIB i Compare with the preset discharge coefficient ratio FIBin;

[0083] If the discharge coefficient is greater than FIB i Less than or equal to the preset discharge coefficient ratio FIBin, a regional stability signal is generated; this indicates that the proportion of discharge time and discharge fluctuation on the surface of the insulating material during the discharge detection test are small, that is, the insulating material in the discharge detection area is relatively stable;

[0084] If the discharge coefficient is greater than FIB i If the discharge coefficient is greater than the preset ratio FIBin, a regional abnormality signal is generated; this indicates that the insulation effect of the insulating material in the region is poor during the discharge detection process, and more discharge current fluctuations occur. At this time, it indicates that material abnormalities occur in the discharge detection region of the insulating material, which may be manifested as aging or cracking of the insulating material;

[0085] Step 5: Based on the regional abnormal signal, obtain the regional current change curve Q of the surface discharge detection area of ​​the distribution equipment （i） ;

[0086] pass Calculate the discharge amount GDF of the discharge detection area i i ;

[0087] Then through Calculate and obtain the discharge amount risk fluctuation extreme value QI of the discharge detection area i i ;

[0088] Based on the discharge coefficient ratio and the discharge amount in the discharge detection area, the current band of the insulating material in the discharge detection area is calculated to be continuous, the maximum discharge amount of the insulating material in the discharge detection area is calculated, and then it is determined whether it is safe outside the discharge detection area;

[0089] It should be noted that the calculation method of the extreme value of the power risk fluctuation performance is to make a continuous assumption about the current fluctuation on the insulating material during the discharge current detection process, so as to calculate the maximum discharge amount that may occur in the discharge detection area; to ensure that there is no discharge risk in the discharge detection area to the greatest extent;

[0090] Then, the extreme value QI of the discharge amount risk fluctuation performance i is compared with the discharge amount safety value Qan;

[0091] If the extreme value QI of the discharge amount risk fluctuation performance i is greater than or equal to the discharge amount safety value Qan; a discharge risk signal is generated; at this time, it indicates that continuous discharge may occur in the discharge detection area, resulting in an excessive discharge amount, and thus a risk hidden danger appears;

[0092] If the extreme value QI of the discharge amount risk fluctuation performance i is less than the discharge amount safety value Qan; a discharge warning signal is generated; at this time, a discharge warning is given to the discharge detection area, and the insulating material in the discharge detection area is inspected;

[0093] Step Six: Based on the discharge warning signal, use an infrared thermal imaging sensor to detect the temperature of the discharge detection area i, and obtain the temperature distribution image of the discharge detection area i; and calculate the temperature abnormal ratio SB in the discharge detection area i based on the temperature distribution image i ;

[0094] Specifically, the acquisition method of the temperature abnormal area ratio SB i is as follows:

[0095] Step C1: Divide the temperature distribution image of the discharge detection area i into grids with a length of kXk and mark them as f; where f is 1, 2, 3...; obtain the initial temperature value at the initial detection moment FTz;

[0096] C2: After the discharge detection cycle duration FT, obtain the vertex temperature values of each grid at the end detection moment FTm. By subtracting the initial temperature value at the initial detection moment FTz from the vertex temperature values of each grid at the end detection moment FTm, obtain the vertex temperature change values of each grid;

[0097] C3: Compare the vertex temperature change value of each grid with the temperature change threshold; obtain the number of vertex temperature change values of each grid that are greater than the temperature change threshold, and mark it as WY f ;

[0098] Through calculate and obtain the temperature abnormal area value Swy of the grid f in the discharge detection area if ;

[0099] C4: Then, again, through calculate to obtain the temperature difference ratio SB of the discharge detection area i i ;

[0100] Step Seven: Compare the temperature difference ratio SB i with the extreme value SBJ of the temperature difference ratio;

[0101] If the temperature difference ratio SB i is greater than or equal to the extreme value SBJ of the temperature difference ratio, generate a thermal anomaly signal;

[0102] If the temperature difference ratio SB i is less than the extreme value SBJ of the temperature difference ratio, generate a thermal stability signal.

[0103] Under the discharge warning signal of the discharge detection area, perform temperature detection on the discharge detection area to detect the temperature change state of the insulating material in the discharge detection area during the discharge detection process, so as to detect whether there is an abnormality in the temperature change of the insulating material when there is a discharge current fluctuation in the external insulating equipment during the operation of the distribution equipment, so as to avoid safety risks caused by the heating of the insulating material and the discharge of the distribution equipment. When evaluating and calculating the insulation of the distribution equipment during operation, perform fault evaluation from aspects such as the insulation state, discharge amount, and operating temperature of the external insulating material of the distribution equipment, so as to detect and solve the insulation faults of the distribution equipment in advance, ensure the stable and normal operation of the equipment, and at the same time, avoid the problem of inaccurate detection caused by manual detection and evaluation. Embodiment Two

[0104] Refer to Figure 2 as shown, a distribution equipment insulation latent fault evaluation system includes:

[0105] Data acquisition module: used to measure the insulation resistance value of the external insulator material of the distribution equipment using a megohmmeter, and calculate and obtain the absorption ratio JK of the insulator material based on the measured insulation resistance value; and compare it with the absorption ratio threshold JKyz; obtain the distribution equipment insulation stability signal or the distribution equipment insulation anomaly signal;

[0106] Insulation processing module: Based on the distribution equipment insulation anomaly signal, divide the surface of the distribution equipment into several discharge detection areas, and mark the discharge detection areas as i, where i is 1, 2, 3...; perform discharge detection on the discharge detection areas on the surface of the distribution equipment, and calculate the discharge coefficient ratio FIB of the discharge detection area i ; and compare it with the preset discharge coefficient ratio FIBin; obtain the area stability signal or the area anomaly signal;

[0107] Discharge evaluation module: Based on the regional abnormal signal, obtain the regional current change curve Q of the surface discharge detection area of the power distribution equipment （i） ;

[0108] Through Calculate to obtain the discharge amount GDF of the discharge detection area i i ;

[0109] Then through Calculate to obtain the extreme value QI of the discharge amount risk fluctuation performance of the discharge detection area i i ; Then compare the extreme value QI of the discharge amount risk fluctuation performance i with the discharge amount safety value Qan; Obtain a discharge risk signal or a discharge warning signal;

[0110] Temperature evaluation module: Based on the discharge warning signal, use an infrared thermal imaging sensor to detect the temperature of the discharge detection area i, and obtain the temperature distribution image of the discharge detection area i; Calculate the temperature foreign region ratio SB in the discharge detection area i i ; Then compare it with the extreme value SBJ of the temperature foreign region ratio; Obtain a thermal anomaly signal or a thermal stability signal.

[0111] Under the discharge warning signal of the discharge detection area, detect the temperature of the discharge detection area, and detect the temperature change state of the insulating material in the discharge detection area during the discharge detection process, so as to detect whether the temperature change of the insulating material is abnormal when the external insulating equipment has discharge current fluctuations during the operation of the power distribution equipment, so as to avoid safety risks caused by the heating of the insulating material and the discharge of the power distribution equipment. When evaluating and calculating the insulation of the power distribution equipment during operation, fault evaluation is carried out from aspects such as the insulation state, discharge amount and operating temperature of the external insulating material of the power distribution equipment, so as to detect and solve the insulation faults of the power distribution equipment in advance and ensure the stable and normal operation of the equipment.

[0112] The above has described an embodiment of the present invention in detail, but the content described is only a preferred embodiment of the present invention and cannot be considered as limiting the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of the present invention application shall still fall within the scope covered by the patent of the present invention.

Claims

1. A method for evaluating latent insulation faults of power distribution equipment, characterized in that: include: The insulation resistance value of the external insulation material of the power distribution equipment is measured by using a megohmmeter, and the absorption ratio JK of the insulation material is calculated based on the measured insulation resistance value; And compare it with the absorption ratio threshold JKyz to obtain the insulation stability signal of the distribution equipment or the insulation abnormality signal of the distribution equipment; Based on the insulation abnormality signal of the distribution equipment, the surface of the distribution equipment is divided into several discharge detection areas, and the discharge detection areas are marked as i, where i is 1, 2, 3...; discharge detection is performed on the discharge detection areas on the surface of the distribution equipment, and the discharge coefficient ratio FIB of the discharge detection area is calculated. i ; and compare with the preset discharge coefficient ratio FIBin; obtain regional stability signal or regional abnormal signal; The discharge coefficient is higher than FIB i The way to obtain is: B1: Perform discharge current detection on the discharge detection area i on the surface of the power distribution equipment to obtain the regional discharge detection current value I of the discharge detection area within the discharge detection cycle time FT （FT） Then, a rectangular coordinate system is established with the regional discharge detection current value as the ordinate and the discharge detection time as the abscissa to obtain the regional current change curve from the detection initial time FTz to the detection end time FTm within the discharge detection cycle FT, and recorded as Q （i） ; B2: Based on the regional current variation curve Q in the discharge detection area （i） ; Get the current band values ​​in the regional current change curve and mark them as j in turn, where j is a non-negative integer; at the same time, get the duration of each current band based on the regional current change curve and mark it as BT （i，j） ; At the same time, the maximum current value in each current band is obtained and marked as Imax （i，j） ; B3: The maximum current Imax in each current band of the discharge detection area i within the discharge detection cycle FT （i，j） Compare with the detection current extreme value threshold Isa respectively; Get the maximum current Imax of the discharge detection area i in the discharge detection cycle FT （i，j） The number of band currents greater than the detection current extreme value threshold Isa is marked as m; B4: Pass Calculate the discharge coefficient ratio FIB of the discharge detection area i i ; Based on the regional abnormal signal, obtain the regional current change curve Q of the surface discharge detection area of ​​the distribution equipment （i） ; pass Calculate the discharge amount GDF of the discharge detection area i i ; Then through Calculate and obtain the discharge amount risk fluctuation extreme value QI of the discharge detection area i i ; Then the discharge risk fluctuation performance extreme value QI i Compare with the discharge amount safety value Qan; obtain a discharge risk signal or a discharge warning signal; Based on the discharge warning signal, the temperature of the discharge detection area i is detected by an infrared thermal imaging sensor to obtain the temperature distribution image of the discharge detection area i; the temperature heterogeneity ratio SB in the discharge detection area i is calculated. i ; Then compare it with the extreme value SBJ of temperature heterogeneity ratio; obtain thermal anomaly signal or thermal stability signal; The temperature isotropic ratio SB i The way to obtain is: Step C1: Divide the temperature distribution image of the discharge detection area i into grids of length kXk and mark them as f; where f is 1, 2, 3, ...; obtain the initial temperature value at the initial detection time FTz; C2: After the discharge detection cycle FT, the vertex temperature value of each grid at the detection end time FTm is obtained, and the vertex temperature change value of each grid is obtained by subtracting the vertex temperature value of each grid at the detection end time FTm from the initial temperature value at the detection initial time FTz; C3: Compare the vertex temperature change value of each mesh with the temperature change threshold; obtain the number of vertex temperature change values ​​of each mesh that are greater than the temperature change threshold and mark them as WY f ; pass Calculate and obtain the temperature anomaly area value Swy of the grid f in the discharge detection area i f ; C4: Then, through Calculate the temperature difference ratio SB of the discharge detection area i i .

2. A method for evaluating latent insulation faults of power distribution equipment according to claim 1, characterized in that: The calculation process of the absorption ratio JK is: A11: Connect a DC voltage with a voltage value of KU to the insulation material of the power distribution equipment, and then use a megohmmeter to perform periodic insulation resistance testing on the power distribution equipment; A12: Get the detection current value at each detection time point n within the insulation resistance detection cycle T and mark it as JI n ; A13: Pass Calculate and obtain the insulation resistance value JR of the power distribution equipment at each detection time point n n ; A14: Obtain the insulation resistance values ​​at the initial state time point ct and the final state time point wt within the insulation resistance detection period T, and mark them as initial state resistance values ​​JR ct and final resistance JR wt ; pass Calculate the absorption ratio JK of the insulating material.

3. A method for evaluating latent insulation faults of power distribution equipment according to claim 2, characterized in that: The process of the periodic insulation resistance detection is to take the external DC voltage of the distribution equipment as the starting time 0, the unit time t as the detection time interval, and divide the insulation resistance detection period RT into several detection time points, which are marked as n respectively, where n is 1, 2, 3...

4. A method for evaluating latent insulation faults of power distribution equipment according to claim 3, characterized in that: Compare the absorption ratio JK of the insulation material of the power distribution equipment with the absorption ratio threshold JKyz: If the absorption ratio JK of the insulation material of the power distribution equipment is greater than or equal to the absorption ratio threshold JKyz, a power distribution equipment insulation stability signal is generated; If the absorption ratio JK of the insulation material of the power distribution equipment is less than the absorption ratio threshold JKyz, an insulation abnormality signal of the power distribution equipment is generated.

5. A method for evaluating latent insulation faults of power distribution equipment according to claim 1, characterized in that: The discharge coefficient is compared to FIB i Compare with the preset discharge coefficient ratio FIBin: If the discharge coefficient is greater than FIB i Less than or equal to the preset discharge coefficient ratio FIBin, generating a regional stability signal; If the discharge coefficient is greater than FIB i If it is greater than the preset discharge coefficient ratio FIBin, a regional abnormality signal is generated.

6. A method for evaluating latent insulation faults of power distribution equipment according to claim 1, characterized in that: The discharge risk fluctuation shows the extreme value QI i Compared with the discharge safety value Qan: If the discharge risk fluctuation shows extreme value QI i Greater than or equal to the discharge safety value Qan; generating a discharge risk signal; If the discharge risk fluctuation shows extreme value QI i Less than the discharge safety value Qan; a discharge warning signal is generated.

7. A method for evaluating latent insulation faults of power distribution equipment according to claim 6, characterized in that: Compare the temperature to SB i Compared with the extreme value SBJ of temperature heterogeneity ratio: If the temperature is different than SB i If it is greater than or equal to the extreme value of the temperature heterogeneity ratio SBJ, a thermal anomaly signal is generated; If the temperature is different than SB i When the temperature is less than the extreme value SBJ of the temperature heterogeneity ratio, a thermal stability signal is generated.

8. A system for evaluating latent insulation faults of power distribution equipment, characterized in that: The system is used to perform the evaluation method as described in any one of claims 1 to 7, comprising: Data acquisition module: used to measure the insulation resistance value of the external insulation material of the power distribution equipment with a megohmmeter, and calculate the absorption ratio JK of the insulation material based on the measured insulation resistance value; and compare it with the absorption ratio threshold JKyz; obtain the insulation stability signal of the power distribution equipment or the insulation abnormality signal of the power distribution equipment; Insulation processing module: Based on the insulation abnormality signal of the distribution equipment, the surface of the distribution equipment is divided into several discharge detection areas, and the discharge detection areas are marked as i, where i is 1, 2, 3...; discharge detection is performed on the discharge detection areas on the surface of the distribution equipment, and the discharge coefficient ratio FIB of the discharge detection areas is calculated. i ; and compare with the preset discharge coefficient ratio FIBin; obtain regional stability signal or regional abnormal signal; Discharge assessment module: Based on regional abnormal signals, obtain the regional current change curve Q of the surface discharge detection area of ​​the distribution equipment （i） ; pass Calculate the discharge amount GDF of the discharge detection area i i ; Then through Calculate and obtain the discharge amount risk fluctuation extreme value QI of the discharge detection area i i ; Then the discharge risk fluctuation performance extreme value QI i Compare with the discharge amount safety value Qan; obtain a discharge risk signal or a discharge warning signal; Temperature evaluation module: Based on the discharge warning signal, the temperature of the discharge detection area i is detected by the infrared thermal imaging sensor to obtain the temperature distribution image of the discharge detection area i; the temperature heterogeneity ratio SB in the discharge detection area i is calculated i ; Then compare it with the temperature heterogeneity ratio extreme value SBJ; obtain thermal anomaly signal or thermal stability signal.

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