Anatomy platform and quantitative analysis method for failed cable terminations

Abstract

The application discloses a kind of dissection platform and quantitative analysis method of fault cable terminal, and its quantitative analysis method includes the following steps: placing fault cable terminal on dissection platform;Observe the appearance of fault cable terminal and carry out dissection, determine fault feature vector;Using fault feature vector and correlation matrix, calculate fault type judgment characteristic quantity;Establish the corresponding relationship between the size of different fault type judgment characteristic quantity and cable fault type, as fault type discrimination basis, according to the size of the obtained fault type judgment characteristic quantity, determine cable fault type.The dissection platform and quantitative analysis method of fault cable terminal provided by the application can reduce the difficulty of cable terminal fault analysis, obtain accurate fault reason, lay the foundation for further proposing prevention and rectification measures and reducing cable failure rate, and effectively improve the reliability of cable line.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fault cable terminal measurement test, in particular to a fault cable terminal dissection platform and a quantitative analysis method. BACKGROUND

[0002] With the development of economic society, cable lines are applied more and more widely in power transmission network due to the advantages of low land occupation rate. The fault rate of cable lines directly affects the reliability of the entire power transmission network. Statistics show that the number of faults of cable terminals is much higher than that of cable bodies and intermediate joints. Cable terminals are mainly divided into oil-filled terminals, dry-type flexible terminals and GIS terminals, and the fault rate of dry-type flexible terminals is much higher than that of the other two types of terminals. In order to prevent the repeated occurrence of similar faults, it is necessary to dissect the fault dry-type flexible cable terminal, analyze the fault causes, and propose effective detection and prevention methods. Dry-type flexible cable terminal faults can be divided into seven types according to their causes: A-surface discharge, B-cable insulation mechanical damage, C-stress cone and cable interface air gap discharge, D-stress cone and cable interface overlap misplacement, E-cable insulation deterioration, and F-cable insulation quality problem.

[0003] However, there is currently a lack of special dissection platform, scientific dissection process and effective analysis method for fault cable terminals:

[0004] 1) Lack of special dissection platform. Fault cable terminals are often not straight, but present a certain curved state, which makes it impossible to maintain the ideal dissection position upward during the dissection and observation, measurement of the cable terminal, increases the dissection difficulty, and reduces the dissection efficiency. Therefore, it is urgent to develop a special dissection platform for cable terminals to ensure that the posture of the cable terminal can be adjusted according to the needs of dissection and observation, measurement.

[0005] 2) Lack of scientific dissection process. There is no clear understanding of how to dissect the terminal and what the specific steps are in the industry. Blind dissection by dissection personnel leads to damage to the fault phenomenon, changes the relative position of the cable terminal main body and the cable body, makes it difficult to observe the complete fault phenomenon, makes it difficult to review the installation size, and hinders the analysis of the fault cause.

[0006] 3) Lack of effective and quantitative analysis method. There is a lack of scientific guidance on how to obtain the fault cause from the complex fault phenomenon. It is urgent to find the correlation between the fault phenomenon and the fault cause, reduce the difficulty of fault analysis, and clearly identify the fault cause, so as to propose targeted prevention and improvement measures and reduce the cable fault rate. SUMMARY

[0007] In order to solve the problems in the prior art, the present application provides a dissection platform and a quantitative analysis method for a fault cable terminal, which can reduce the difficulty of analyzing the fault cable terminal, obtain accurate fault causes, lay a foundation for further proposing prevention and rectification measures and reducing the cable fault rate, and effectively improve the reliability of the cable line.

[0008] The present application adopts the following technical solutions.

[0009] In a first aspect, the present application provides a quantitative analysis method for a fault cable terminal, comprising the following steps: placing the fault cable terminal on a dissection platform; observing the appearance of the fault cable terminal and dissecting it to determine the values of the top sealing part appearance characteristic quantity a, the tail sealing part appearance characteristic quantity b, the top sealing part internal moisture characteristic quantity c, the tail sealing part internal moisture characteristic quantity d, the metal sheath fracture internal insulation shielding damage mark characteristic quantity e, the stress cone lap misalignment characteristic quantity f, the breakdown channel characteristic quantity g, the cable insulation shielding fracture processing condition characteristic quantity h, the cable bending degree characteristic quantity i, the slice electric tree branch growth direction characteristic quantity j, the cable body insulation quality problem characteristic quantity k, and the physicochemical property test result characteristic quantity m.

[0010] Calculating a fault type judgment characteristic quantity V = | nP |, wherein n = [a bc d e f g h j k m],

[0011] Establishing a corresponding relationship between the sizes of different fault type judgment characteristic quantities and the cable fault types as a fault type discrimination basis, and determining the cable fault type according to the size of the obtained fault type judgment characteristic quantity.

[0012] Preferably, the step of placing the fault cable terminal on the dissection platform comprises the following steps: cutting the cable terminal at a first distance below the lower edge of the heat shrink tube at the lower end of the fault cable terminal; placing the two ends of the cut cable terminal on the two cable holders of the dissection platform, respectively, and placing the end of the cable terminal with the outgoing fitting on the cable holder with the locking wheel; aligning the pressing block of the locking wheel at a second distance above the pressing part of the outgoing fitting and the cable core; rotating the fault cable terminal so that the breakdown position faces upward, and locking the locking wheel.

[0013] Preferably, the first distance is 20-200mm, and the second distance is 5mm-10mm.

[0014] Preferably, the values of the top seal appearance feature a and the tail seal appearance feature b are determined by the following steps: after fixing the fault cable terminal on the dissection platform, observing the top seal and the tail seal of the cable terminal; if the top seal has a tear phenomenon, a = 1, if not, a = 0; if the terminal tail is separated from the tail seal or the tail seal has a bulge phenomenon, b = 1, if the terminal tail is not separated from the tail seal and the tail seal has no bulge phenomenon, b = 0.

[0015] Preferably, the values of the top seal internal moisture feature c, the tail seal internal moisture feature d, and the metal sheath fracture internal insulation shield damage feature e are determined by the following steps: after determining the values of the top seal appearance feature a and the tail seal appearance feature b, rotating the cable terminal by 90° so that the fault breakdown position faces the left or right side, and re-securing the fault cable terminal; removing the top seal and the tail seal, and observing whether there are moisture traces inside the top seal and the tail seal; if there are moisture traces inside the top seal, c = 1, otherwise, c = 0; if there are moisture traces inside the tail seal, d = 1, otherwise, d = 0; checking whether the cable body metal sheath fracture internal insulation shield has a knife mark scratch or is damaged by metal sheath burr, if the metal sheath fracture internal insulation shield has a knife mark scratch or is damaged by metal sheath burr, e = 1; otherwise, e = 0.

[0016] Preferably, the value of the stress cone lap misalignment feature f is determined by the following steps: after determining the values of the top seal internal moisture feature c, the tail seal internal moisture feature d, and the metal sheath fracture internal insulation shield damage feature e, vertically cutting the cable terminal body from the top to the tail along a straight line perpendicular to the cable, first measuring the cable insulation shield and the terminal internal stress cone semi-conductive portion lap depth L d ; rotating the cable terminal by 180°, and again cutting the cable terminal body from the top to the tail along a straight line perpendicular to the cable, removing the two parts of the cable terminal to expose the cable body; if the first measurement cannot obtain L d , then the second measurement L d ; measuring the stress cone internal semi-conductive buffer segment length L s ; if L d ≤ 0 or L d ≥ L s -5 mm, f = 1, if 0 < L d < L s -5 mm, f = 0.

[0017] Preferably, the value of the breakdown channel characteristic g is determined by the following steps: after the value of the stress cone lap misalignment characteristic f is determined, it is checked whether there is a surface discharge channel between the insulation shield break and the top end wire or a radial breakdown hole, and the distance between the center of the breakdown hole and the cable insulation shield break; if there is a surface discharge channel between the insulation shield break and the top end wire, g = 0; if there is a radial breakdown hole, it is divided into the following three cases: if the breakdown hole is located at the position of the metal sheath break, g = 1; if the center of the breakdown hole is at the position of the insulation shield break, g = 4; if the center of the breakdown hole is between the position above the insulation shield break and the upper edge of the semi-conductive buffer segment inside the stress cone, g = 3; if the breakdown hole is located at other positions except the above-mentioned positions, and there is obvious color abnormality or impurities in the insulation at the breakdown position, g = 6.

[0018] Preferably, the value of the cable insulation shield break processing condition characteristic h is determined by the following steps: after the value of the stress cone lap misalignment characteristic f is determined, it is checked whether there are pits, burrs and steps at the cable insulation shield break; if there are no pits, burrs and steps, h = 0; otherwise, h = 1.

[0019] Preferably, the value of the cable bending degree characteristic i is determined by the following steps: after the value of the stress cone lap misalignment characteristic f is determined, the cable bending degree θ is measured; when θ < 30°, i = 0; when θ ≥ 30°, i = 1.

[0020] Preferably, the values of the slice electrical tree growth direction characteristic j and the cable body insulation quality problem characteristic k are determined by the following steps: the cable is cut along the cable axial direction by a cable stripping knife to obtain a cable slice, the cable is cut within a third distance range on both sides of the breakdown position, wherein the third distance is less than or equal to 100 mm; it is observed whether there is a radial electrical tree in the cable slice and the growth direction of the electrical tree; if the electrical tree grows from the outside to the inside, j = -1; if the electrical tree grows from the inside to the outside, j = 1; if there is no electrical tree, j = 0; it is observed whether there are impurities or micro-holes in the cable slice; if there are no impurities and micro-holes, k = 0; if there are impurities or micro-holes, k = 1.

[0021] Preferably, the value of the physicochemical property test result characteristic m is determined by the following steps: after the values of the slice electrical tree growth direction characteristic j and the cable body insulation quality problem characteristic k are determined, it is observed whether there is color abnormality in the cable insulation; if there is color abnormality, the cable slice of the color abnormality section is cut; the cable slice of the color abnormality section is subjected to physicochemical property test to test whether the insulation is deteriorated; if there is no insulation deterioration, m = 0; if there is insulation deterioration, m = 1.

[0022] Preferably, the correspondence between the characteristic values of different fault types and the cable fault types is as follows:

[0023] If 0≤V≤1.8, the cable fault type is A - surface discharge;

[0024] If 1.8

[0025] If 4.8≤V≤8.0, the cable fault type is C - stress cone and cable interface air gap discharge;

[0026] If 8.0

[0027] If 11.5

[0028] If V>11.7, the cable fault type is F - cable insulation quality problem.

[0029] In a second aspect, the present application provides an anatomical platform for a fault cable terminal, which is used for the anatomical dissection of the fault cable terminal in the quantitative analysis method of the fault cable terminal described above. The anatomical platform comprises a support, locking wheels, support rods and cable holders. The cable holders are arranged on opposite sides of the support, and each cable holder is provided with a holding groove for holding the fault cable terminal. The centers of the holding grooves of the two cable holders are on the same horizontal straight line. The locking wheels are arranged on one side of the support, and three locking wheels are arranged on the upper side, the left side and the right side of one cable holder, respectively. The support rod is a telescopic rod, and the lower end of the telescopic rod is fixedly connected with the bottom of the support perpendicularly. The other end of the telescopic rod is between the two cable holders, and a holder ring is arranged on the other end of the telescopic rod.

[0030] Preferably, the support comprises a first support frame, a second support frame and an extension frame. The first support frame and the second support frame are symmetrically arranged, and the top of the first support frame and the top of the second support frame are connected by a connecting rod. The bottom of the first support frame and the bottom of the second support frame are connected by a first connecting seat. The extension frame is arranged on the side of the second support frame away from the first support frame, and the extension frame is used for supporting the extension of the tail of the cable. The bottom of the extension frame and the bottom of the second support frame are connected by a second connecting seat, and the second connecting seat is provided with a tool box for storing anatomical tools. Cable holders are fixedly installed at the same height of the first support frame, the second support frame and the extension frame, and the centers of the holding grooves of the three cable holders are on the same horizontal straight line. Two universal brake wheels are symmetrically arranged on the two sides of the bottom of the first support frame, the second support frame and the extension frame.

[0031] Preferably, the cable holder comprises: a bracket, a roller, a bearing and a bolt; the bottom of the bracket is fixedly connected with the cross bar on the support, the top of the bracket is symmetrically provided with two groups of steps, each group of steps is gradually inclined downward from outside to inside, the table surfaces at the lowest positions of the two groups of steps are connected, and a bracket groove for placing a fault cable terminal is formed at the center of the top surface of the bracket; a notch for installing the roller is formed downward on the top of the bracket; the roller is rotatably installed at the corner of each step surface of the top of the bracket through the bearing, and the bearing and the step are fixedly connected through the bolt.

[0032] Preferably, the locking wheel is installed on the support through a fixing rod, both ends of the fixing rod are fixedly connected with the support; a moving rod is vertically installed at the center of the locking wheel, the moving rod vertically penetrates through the fixing rod through threaded connection, and a pressing block is arranged at the end of the moving rod away from the locking wheel, the pressing block is used for contacting the surface of the cable terminal and applying a pressing force to the cable terminal.

[0033] Compared with the prior art, the present application has the beneficial effects that: the present application introduces top sealing element appearance characteristic quantity a, tail sealing element appearance characteristic quantity b, top sealing element internal moisture characteristic quantity c, tail sealing element internal moisture characteristic quantity d, metal sheath fracture internal insulation shielding damage characteristic quantity e, stress cone lap misplacement characteristic quantity f, breakdown channel characteristic quantity g, cable insulation shielding fracture processing condition characteristic quantity h, cable bending degree determination cable bending degree characteristic quantity i, slice electric tree branch growth direction characteristic quantity j, cable body insulation quality problem characteristic quantity k, and physicochemical property test result characteristic quantity m. These fault characteristic quantities are obtained by observing and dissecting the appearance of the fault cable terminal, and constitute a fault feature vector. Then, the fault type judgment characteristic quantity is obtained through quantitative analysis of the fault feature vector and the correlation matrix. The correlation between the fault type judgment characteristic quantity and the cable fault type is established, so that the cable fault type is obtained. The difficulty of fault analysis is reduced, the accurate fault cause is obtained, the foundation for further proposing prevention and rectification measures and reducing the cable fault rate is laid, and the reliability of the cable line is effectively improved.

[0034] In addition, the present application provides a complete cable dissection process when the fault feature vector is obtained, and provides scientific and clear cable dissection steps for dissection of the fault cable.

[0035] Furthermore, the present application also provides a dissection platform for the fault cable terminal, which can make the fault cable terminal present in a straight line through the setting of the cable holder and the telescopic support rod, so that an ideal dissection posture is obtained, the dissection difficulty is reduced, the dissection efficiency is improved, and the dissection, observation and measurement of the cable terminal are facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is a structure schematic diagram of the dissection platform for the fault cable terminal in the present application.

[0037] Figure 2 is a structural diagram of a cable holder in the present application Figure 1 ;

[0038] Figure 3 is a structural diagram of a cable holder in the present application Figure 2 ;

[0039] Figure 4 is a structural diagram of a support rod in the present application

[0040] Figure 5 is a flowchart of a dissection process of a fault cable terminal in the present application

[0041] Figure 6 is a flowchart of a dissection process of a cable system in the present application

[0042] Figure 7 is a mind map for obtaining fault characteristic quantities from a fault phenomenon and generating a correlation matrix by using a quantitative analysis method of a fault cable terminal in the present application.

[0043] Reference numerals in the drawings:

[0044] 1, support; 2, locking wheel; 3, support rod; 301, holder ring; 4, cable terminal; 5, cable holder; 501, bracket; 502, roller; 503, bearing; 504, bolt; 6, cable fixing clamp; 7, extension rod; 8, tool box; 9, universal brake wheel. DETAILED DESCRIPTION

[0045] In order to make the objectives, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. The embodiments described in the present application are only a part of the embodiments of the present application, but not all the embodiments. All other embodiments obtained by those skilled in the art without creative labor on the basis of the spirit of the present application are within the protection scope of the present application.

[0046] As shown in Figure 1 , embodiment 1 of the present application provides a dissection platform of a fault cable terminal, which comprises a support 1, a locking wheel 2, a support rod 3, a cable terminal 4, a cable holder 5, a cable fixing clamp 6, an extension rod 7, a tool box 8 and a universal brake wheel 9.

[0047] The support 1 comprises a first support frame, a second support frame and an extension frame, the first support frame and the second support frame are symmetrically arranged, the top of the two is connected through a connecting rod, and the bottom is connected through a first connecting seat. The extension frame is arranged on the side of the second support frame away from the first support frame, the bottom of the extension frame is connected with the bottom of the second support frame through a second connecting seat, and the extension frame is used for supporting the tail end of the cable when the length of the cable to be cut is relatively long, preferably more than 2 m, so as to avoid that the tail of the cable lacks support and falls and injures people. Two universal brake wheels 9 are symmetrically arranged on the bottom of the first support frame, the second support frame and the extension frame. In the preferred but non-limiting embodiment of the application, the first connecting seat and the second connecting seat can be combined into one connecting seat or two separate connecting seats.

[0048] The tool box 8 is placed on the top of the second connecting seat and is used for placing cable dissection tools.

[0049] A cable support 5 is fixedly installed at the same height of the first support frame, the second support frame and the extension frame, and the center of the support groove of the three cable supports is on the same horizontal straight line, so that the cable terminal is kept in a straight line and uniformly stressed, and the cable terminal is easy to dissect and observe.

[0050] As shown in Figure 2 , Figure 3 In the preferred but non-limiting embodiment of the application, the cable support 5 comprises a bracket 501, a roller 502, a bearing 503 and a bolt 504. The bottom of the bracket 501 is fixedly connected with the support 1, the top of the bracket 501 is symmetrically provided with two groups of steps, each group of steps is gradually inclined downward from outside to inside, and the lowest surfaces of the two groups of steps are connected, so that a support groove for placing the fault cable terminal is formed at the center of the top surface of the bracket 501. A notch for installing the roller is formed in the top of the bracket 501. The roller 502 is rotatably installed at the corner of each step surface of the top of the bracket 501 through the bearing 503, the bearing 503 is fixed between the step and the bracket 503 through the bolt 504, and the bolt 504 is preferably a stainless steel bolt.

[0051] The first support frame is provided with a locking wheel 2 corresponding to the left side, the right side and the upper side of the cable support 5, which is used for exerting a locking force on the cable terminal from the upper side, the left side and the right side of the cable terminal after the cable terminal is placed on the top of the cable support 5, so as to fix the cable terminal.

[0052] In the preferred but non-limiting embodiment of the application, each locking wheel 2 is installed on the first support frame through a fixed rod, and the two ends of the fixed rod are fixedly connected with the first support frame. A moving rod is vertically installed at the center of the locking wheel 2, the moving rod vertically penetrates the fixed rod through threaded connection, and a pressing block is arranged at the end of the moving rod away from the locking wheel 2, and the pressing block is used for contacting the surface of the cable terminal and exerting a pressing force on the cable terminal.

[0053] As shown in Figure 1 , Figure 4 , the support rod 3 is vertically installed at the top center of the connecting seat between the first support frame and the second support frame, the support rod 3 is a telescopic rod, and one end of the support rod 3 is fixedly connected with the connecting seat, and the other end is provided with a supporting ring 301 for supporting the middle part of the cable terminal. The supporting ring 301 is a semicircular ring with an opening upward, and the center of the semicircular ring is located on the same horizontal straight line as the center of the cable support, so that the cable terminal is in a straight line, avoiding the bending of the middle part of the cable terminal, affecting the dissection and measurement.

[0054] When the fault cable terminal is placed on the first support frame, the support rod and the second support frame, and needs to be rotated, a cable fixing clamp 6 can be installed at one end of the fault cable terminal close to the second support frame, the cable fixing clamp 6 is a clamp structure commonly used for fixing cables in the prior art, and an extension rod 7 is provided on one side of the cable fixing clamp 6, the extension rod 7 is used to increase the force arm to facilitate the rotation of the fault cable terminal.

[0055] As shown in Figure 5 , the embodiment 2 of the present application provides a quantitative analysis method for the fault cable terminal, comprising the following steps:

[0056] Step S1, cutting the cable terminal at a first distance below the lower edge of the heat shrink tube at the lower end of the fault cable terminal.

[0057] In the preferred but non-limiting embodiment of the present application, the first distance is 20-200mm, which can avoid cutting too short to verify whether the cable outer sheath, metal sheath stripping length and terminal tail sealing are correct.

[0058] Step S2, fixing the fault cable terminal to be dissected on the dissection platform of the fault cable terminal in embodiment 1. Step S2 specifically comprises the following steps:

[0059] Step S2.1, placing one end of the fault cable terminal with the outgoing fitting on the cable support 5 of the first support frame, placing the other end on the cable support 5 of the second support frame, and placing the middle part on the upper end supporting ring 301 of the support rod 3.

[0060] Step S2.2, aligning the outgoing fitting at the top of the fault cable terminal with the pressing block of the locking wheel 2 at a second distance above the cable core pressure contact part.

[0061] In the preferred but non-limiting embodiment of the present application, the second distance is 5mm-10mm.

[0062] Step S2.3, rotate the fault cable terminal so that the breakdown position faces upward, and lock the three locking wheels to fix the cable terminal.

[0063] Step S3, after fixing the fault cable terminal on the dissection platform, observe the top seal and the tail seal of the cable terminal to determine whether the cable terminal body is misaligned with the cable.

[0064] Let the top seal appearance characteristic quantity be a, if there is a tearing phenomenon, take a = 1, if there is no tearing phenomenon, take a = 0; let the tail seal appearance characteristic quantity be b, if the terminal tail is separated from the seal or the seal has a bulging phenomenon, take b = 1, if the terminal tail is not separated from the seal and the seal has no bulging phenomenon, take b = 0.

[0065] Step S4, dissection of the cable terminal is carried out in a room with a room temperature not lower than 20℃, so as to ensure that the terminal body and the cable are not too hard, which makes it difficult to dissection, and also avoids pollution of the terminal body and the cable after dissection caused by bad weather outdoors. As shown in Figure 6 Step S4.1, remove the top seal and the tail seal of the terminal cable.

[0066] Step S4.1, remove the top seal and the tail seal of the terminal cable.

[0067] Specifically, loosen the three side locking wheels, rotate the cable terminal by 90°, so that the fault breakdown position faces the left side or the right side, lock the three side locking wheels. Remove the current collector ring at the tail of the cable terminal, and peel off the top and tail seals, and observe and obtain the following characteristic quantities:

[0068] ①Observe whether there is moisture trace inside, let the top seal inside moisture characteristic quantity be c, if there is moisture trace, take c = 1, if there is no moisture trace, take c = 0; let the tail seal inside moisture characteristic quantity be d, if there is moisture trace, take d = 1, if there is no moisture trace, take d = 0;

[0069] ②Check whether there is a scratch or a scratch mark on the metal sheath of the cable body, let the metal sheath of the cable body be e, if there is a scratch or a scratch mark on the metal sheath of the cable body, take e = 1; if there is no scratch or scratch mark on the metal sheath of the cable body, take e = 0.

[0070] Step S4.2, vertically cut the cable terminal body from the top to the tail along a straight line, and pay attention not to scratch the internal cable body.

[0071] Measure the overlap depth of the cable insulation shield and the terminal internal stress cone semi-conductive part, that is, the distance L between the cable insulation shield fracture and the lower edge of the stress cone internal semi-conductive buffer segmentd .

[0072] Further, if the fault causes the cable insulation shield breakage to be unclear, a glass sheet can be used to gently scrape the nearby cable body, if white leaks out, it proves that this position is the cable insulation, if black leaks out, it proves that this position is the insulation shield layer. If the fault causes the cable insulation shield breakage to be incomplete, this step does not measure the overlap depth L of the cable insulation shield and the semi-conductive part of the internal stress cone of the terminal d . The lower edge position of the semi-conductive buffer segment inside the stress cone is marked on the cable insulation shield with a white marker, and the distance from the marked position to the cable insulation shield is measured as the overlap depth L in the subsequent step d . If the conditions are met, try to complete the measurement of the overlap depth at this step, because the measurement after marking may cause the measurement error to increase.

[0073] Step S4.3, rotate the terminal by 180°, and again cut the cable terminal body vertically along a straight line from the top to the tail of the cable, taking care not to scratch the internal cable body, and then mark the lower edge position of the semi-conductive buffer segment inside the stress cone on the cable insulation shield in the cut seam. At this time, the entire cable terminal body has been divided into two halves.

[0074] If the overlap depth cannot be measured in step S4.2, the overlap depth is measured in this step, and the specific method is: the two halves of the terminal body are removed, if the cable insulation shield breakage is incomplete, the breakage position is determined according to the mark formed by the insulation shield on the insulation layer and the highest point around the breakage, and the distance from the breakage to the previously marked lower edge position of the semi-conductive buffer segment inside the stress cone is measured as the overlap depth L of the cable insulation shield and the semi-conductive part of the internal stress cone of the terminal d . If the breakage is below the previously marked lower edge position of the semi-conductive buffer segment inside the stress cone, L d is negative, the length L s of the semi-conductive buffer segment inside the stress cone is measured, and the stress cone overlap misalignment characteristic quantity f is set to 1 if L d ≤ 0 or L d ≥ L s -5 mm, the stress cone overlap misalignment characteristic quantity f is set to 1 if 0 < L d < L s -5 mm, the stress cone overlap misalignment characteristic quantity f is set to 0.

[0075] Step S4.4, cable body inspection. As shown in Figure 3 , step S4.4 specifically includes the following steps:

[0076] Step S4.4.1, check whether there is a surface discharge channel between the insulation shield break and the top end wire core or a radial breakdown hole, and the distance between the center of the breakdown hole and the insulation shield break of the cable.

[0077] Let g be the breakdown channel characteristic quantity, if there is a surface discharge channel between the insulation shield break and the top end wire core, take g = 0; if there is a radial breakdown hole, it is divided into the following three cases: if the breakdown hole is located at the position of the metal sheath break, take g = 1; if the center of the breakdown hole is at the position of the insulation shield break, take g = 4; if the center of the breakdown hole is between the position above the insulation shield break and the upper edge of the semi-conductive buffer segment inside the stress cone, take g = 3. If the breakdown hole is located at other positions except the above-mentioned positions, and there is obvious color abnormality or impurity in the insulation at the breakdown position, take g = 6.

[0078] Step S4.4.2, check whether the cable insulation shield break is smooth transition, whether there are pits, burrs, steps, let h be the cable insulation shield break processing condition characteristic quantity, if there are no pits, burrs and steps, take h = 0; if there are pits, burrs or steps, take h = 1.

[0079] Step S4.4.3, measure the cable bending degree. The cable terminal may be bent due to the problem of fixing method, and the end is roughly a straight line. Take the cable body off the dissection platform and place it on a neat plane, align the end of the cable (the end without the crimped terminal fitting) from the outside of the cable bend with the 1000mm scale of a long ruler, let the ruler close to the end of the cable, and then overlap a short ruler on the 0 scale line of the long ruler to measure the distance h between the 0 scale line of the ruler and the cable. The cable bending degree. The cable bending degree characteristic quantity i is i = 0 when θ < 30°, and i = 1 when θ ≥ 30°.

[0080] Step S5, local dissection.

[0081] Use the cable stripping knife to strip the cable in the range of the third distance on both sides of the breakdown position along the cable axis to form a 1mm thick slice, and observe whether there is a radial tree branch and the growth direction of the tree branch. The third distance is less than or equal to 100mm. Let j be the slice tree branch growth direction characteristic quantity, if the tree branch grows from outside to inside, take j = -1; if the tree branch grows from inside to outside, take j = 1; if there is no tree branch, take j = 0.

[0082] Observe whether there is impurity or micropore, and the cable body insulation quality problem characteristic quantity k, if there is no impurity and micropore, take k = 0; if there is impurity or micropore, take k = 1.

[0083] Step S6, sample extraction.

[0084] If the color of the cable insulation is found to be abnormal, the cable is cut at the abnormal color section.

[0085] S1-S6 full video recording.

[0086] Step S7, test detection.

[0087] The cable cut obtained in step S6 is subjected to physicochemical property test to test whether the insulation is aged. Let the physicochemical property test result feature quantity be m, if there is no insulation deterioration, take m=0, if there is insulation deterioration, take m=1.

[0088] Step S8, fault cause judgment. Specifically, the following steps are included:

[0089] Step S8.1, calculate the fault type judgment feature quantity V=|nP|, n is the fault feature vector, the mind map is as shown in Figure 7 , P is the correlation matrix, n=[a b c d e f g h i j k m],

[0090]

[0091] Step S8.2, establish the corresponding table of fault type judgment feature quantity and cable fault type relationship, as shown in Table 1 below; wherein, the common cable terminal fault causes are divided into: A-surface discharge, B-cable insulation mechanical damage, C-stress cone and cable interface air gap discharge, D-stress cone and cable interface lap misplacement, E-cable insulation deterioration, F-cable insulation quality problem.

[0092] Table 1, corresponding table of fault type judgment feature quantity and cable fault type relationship

[0093] Diagnosis basis Fault type 0≤V≤1.8 A 1.8＜V≤4.8 B 4.8≤V≤8.0 C 8.0＜V≤11.5 D 11.5＜V≤11.7 E V＞11.7 F

[0094] Step S8.3, according to the calculated fault type judgment feature quantity, look up Table 1 to get the cable fault type.

[0095] The beneficial effects of the present application are that, compared with the prior art, the present application introduces top seal appearance characteristic quantity a, tail seal appearance characteristic quantity b, top seal internal moisture characteristic quantity c, tail seal internal moisture characteristic quantity d, metal sheath fracture internal insulation shielding scratch characteristic quantity e, stress cone lap misplacement characteristic quantity f, breakdown channel characteristic quantity g, cable insulation shielding fracture processing condition characteristic quantity h, cable bending degree determination cable bending degree characteristic quantity i, slice electric tree branch growth direction characteristic quantity j, cable body insulation quality problem characteristic quantity k, physicochemical property test result characteristic quantity m, these fault characteristic quantities, by observing the appearance of the fault cable terminal and dissecting, the above fault characteristic quantities can be calculated to form a fault feature vector, and then the fault feature vector and the correlation matrix are subjected to quantitative analysis to obtain a fault type judgment characteristic quantity. By establishing the correlation between the fault type judgment characteristic quantity and the cable fault type, the cable fault type can be obtained, the difficulty of fault analysis can be reduced, the accurate fault reason can be obtained, the foundation for further proposing prevention and rectification measures and reducing the cable fault rate is laid, and the reliability of the cable line is effectively improved.

[0096] In addition, when the fault feature vector is calculated, the present application provides a complete cable dissection process, which provides scientific and clear cable dissection steps for dissection of the fault cable.

[0097] Furthermore, the present application also provides a dissection platform for the fault cable terminal, which can make the fault cable terminal present a straight line by setting a cable support and a telescopic support rod, so that an ideal dissection posture is obtained, the dissection difficulty is reduced, the dissection efficiency is improved, and the dissection and observation and measurement of the cable terminal are facilitated.

[0098] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit it, although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that the specific embodiments of the present application can be modified or replaced equivalently without departing from the spirit and scope of the present application, and any modification or equivalent replacement without departing from the spirit and scope of the present application should be covered in the protection scope of the claims of the present application.

Claims

1. A quantitative analysis method for faulty cable terminals, characterized in that, Includes the following steps: Place the faulty cable terminal on the dissection platform; The dissection platform includes: a bracket (1), a locking wheel (2), a support rod (3), and a cable tray (5); the cable tray (5) is located on opposite sides of the bracket (1), and has a tray for holding faulty cable terminals; the center of the trays of the two cable trays (5) is on the same horizontal line; the locking wheel (2) is located on one side of the bracket (1), and there are three locking wheels (2), located on the upper, left and right sides of one cable tray (5) respectively; the support rod (3) is a telescopic rod, the lower end of which is vertically fixed to the bottom of the bracket (1), and the other end is located between the two cable trays (5), and is provided with a support ring (301). Observe the appearance of the faulty cable terminal and dissect it to determine the values ​​of the following characteristics: a) top seal appearance characteristics b) tail seal internal moisture characteristics c) tail seal internal moisture characteristics d) metal sheath fracture internal insulation shielding damage characteristics e) stress cone lap misalignment characteristics f) breakdown path characteristics g) cable insulation shielding fracture treatment characteristics h) cable bending characteristics i) slice electrical tree growth direction characteristics j) cable body insulation quality problems characteristics k) and physical and chemical property test results characteristics m. The determination of the values ​​of the top seal appearance characteristic 'a' and the tail seal appearance characteristic 'b' includes the following steps: After fixing the faulty cable terminal on the dissection platform, observe the top and tail seals of the cable terminal; if the top seal is torn, take a=1; if there is no tear, take a=0; if the tail of the terminal is detached from the tail seal or the tail seal is bulging, take b=1; if the tail of the terminal is not detached from the tail seal and the tail seal is not bulging, take b=0. The determination of the values ​​of the moisture characteristic quantity c inside the top seal, the moisture characteristic quantity d inside the tail seal, and the insulation shielding damage characteristic quantity e inside the metal sheath break point includes the following steps: After determining the values ​​of the appearance characteristic quantity a of the top seal and the appearance characteristic quantity b of the tail seal, rotate the cable terminal 90° so that the fault breakdown position faces the left or right side, and re-tighten the faulty cable terminal; remove the top and tail seals and observe whether there are moisture marks inside the top and tail seals; if there are moisture marks inside the top seal, take c=1, otherwise, take c=0; if there are moisture marks inside the tail seal, take d=1, otherwise, take d=0; check whether there are knife marks, scratches, or puncture marks from metal sheath burrs inside the cable body's metal sheath break point on the insulation shielding; if there are puncture marks or knife marks from metal sheath burrs or scratches inside the metal sheath break point on the insulation shielding, take e=1; otherwise, take e=0. Determining the value of the stress cone lap misalignment characteristic quantity f includes the following steps: After determining the values ​​of the moisture characteristic quantity c inside the top seal, the moisture characteristic quantity d inside the tail seal, and the insulation shielding scratch characteristic quantity e inside the metal sheath fracture, the cable terminal body is cut perpendicularly along a straight line from top to tail. The first measurement is the lap depth L between the cable insulation shielding and the semi-conductive part of the stress cone inside the terminal. d Rotate the cable terminal 180°, and then cut the cable terminal body perpendicular to the cable from top to bottom in a straight line. Remove the two parts of the cable terminal to expose the cable body. If the L cannot be obtained from the first measurement... d Then the second measurement L d ; Measure the length L of the semi-conductive buffer section inside the stress cone s If L d ≤0 or L d ≥L s -5mm, then f is 1, if 0 <L d <L s If the value is -5mm, then f is 0; Determining the value of the breakdown path characteristic quantity g includes the following steps: After determining the value of the stress cone lap misalignment characteristic quantity f, check whether there is a surface discharge path from the insulation shield break to the top conductor or a radial breakdown hole on the cable body, and the distance from the center of the breakdown hole to the cable insulation shield break; if there is a surface discharge path from the insulation shield break to the top conductor, take g=0; if there is a radial breakdown hole, there are three cases: if the breakdown hole is located at the metal sheath break, take g=1; if the center of the breakdown hole is at the insulation shield break, take g=4; if the center of the breakdown hole is above the insulation shield break to the upper edge of the semi-conductive buffer section inside the stress cone, take g=3; if the breakdown hole is located at other locations besides the above-mentioned locations, and the insulation at the breakdown location has obvious color abnormalities or impurities, take g=6. Calculate the characteristic quantity for fault type determination ;in, , ; Establish a correspondence between the magnitude of different fault type judgment characteristic quantities and cable fault types, as a basis for fault type discrimination; The magnitude of the characteristic quantity is determined based on the obtained fault type to identify the cable fault type.

2. The quantitative analysis method for faulty cable terminals according to claim 1, characterized in that: Placing the faulty cable termination on the dissection platform includes the following steps: Cut the cable terminal at a first distance below the lower edge of the heat shrink tubing at the lower end of the faulty cable terminal; Place the two ends of the cut cable terminal on the two cable trays (5) of the dissection platform respectively, and place the end of the cable terminal with the wire exit hardware on the cable tray (5) with the locking wheel (2); Align the second distance above the upper edge of the crimping part between the outgoing fitting and the cable core with the pressure block of the locking wheel (2); Rotate the faulty cable terminal so that the breakdown position faces upward, and lock the locking wheel (2).

3. The quantitative analysis method for faulty cable terminals according to claim 2, characterized in that: The first distance is 20-200mm; the second distance is 5mm-10mm.

4. The quantitative analysis method for faulty cable terminals according to claim 1, characterized in that: Determining the value of the characteristic quantity h for the cable insulation shield break treatment includes the following steps: After determining the value of the characteristic quantity f of the stress cone lap misalignment, check whether there are pits, burrs, or steps at the cable insulation shield break. If there are no pits, burrs, or steps, take h=0; otherwise, take h=1.

5. The quantitative analysis method for faulty cable terminals according to claim 1, characterized in that: Determining the cable bending degree involves the following steps: After determining the value of the characteristic quantity f of the stress cone lap misalignment, the cable bending degree θ is measured; When θ<30°, i=0; when θ≥30°, i=1.

6. The quantitative analysis method for faulty cable terminals according to any one of claims 1-5, characterized in that: Determining the values ​​of the characteristic quantity j of the growth direction of electrical tree branches in the cable slice and the characteristic quantity k of the insulation quality problem of the cable body includes the following steps: The cable is cut along the axial direction of the cable by a cable stripper within a third distance range on both sides of the puncture position to obtain cable slices, wherein the third distance is less than or equal to 100mm. Observe whether there are radial electrical trees on the cable slice and the growth direction of the electrical trees. If the electrical trees grow from the outside to the inside, take j=-1; if the electrical trees grow from the inside to the outside, take j=1; if there are no electrical trees, take j=0. Observe the cable slice for impurities or micropores. If there are no impurities or micropores, take k=0; if there are impurities or micropores, take k=1.

7. The quantitative analysis method for faulty cable terminals according to claim 6, characterized in that: Determining the value of the characteristic quantity m of the physicochemical property test results includes the following steps: After determining the values ​​of the characteristic quantity j of the growth direction of electrical tree branches in the slice and the characteristic quantity k of the insulation quality problem of the cable body, observe whether there is a color abnormality in the cable insulation. If there is a color abnormality, slice the cable in the section with the color abnormality. Perform physical and chemical property tests on the cable slices with abnormal color to test whether the insulation has deteriorated. If there is no insulation deterioration, take m=0; if there is insulation deterioration, take m=1.

8. The quantitative analysis method for faulty cable terminals according to claim 1, characterized in that: The correspondence between the magnitude of different fault type identification characteristic quantities and the cable fault type is as follows: like The cable fault type is then classified as A-surface discharge; like Then the cable fault type is B - mechanical damage to cable insulation; like The cable fault type is C-stress cone and cable interface air gap discharge; like The cable fault type is D-stress cone and cable interface misalignment. like The cable fault type is E - cable insulation deterioration; like If so, the cable fault type is F - cable insulation quality problem.

9. The quantitative analysis method for faulty cable terminals according to claim 1, characterized in that: The bracket (1) includes: a first support frame, a second support frame, and an extension frame; The first support frame and the second support frame are symmetrically arranged, and their tops are connected by a connecting rod, and their bottoms are connected by a first connecting seat; The extension frame is located on the side of the second support frame away from the first support frame. The extension frame is used to extend and support the cable tail. The bottom of the extension frame is connected to the bottom of the second support frame through a second connecting seat. The second connecting seat is equipped with a toolbox (8) for storing dissecting tools. Cable trays (5) are fixedly installed at the same height of the first support frame, the second support frame and the extension frame, and the center of the tray of the three cable trays is on the same horizontal straight line; Two universal brake wheels (9) are symmetrically arranged on both sides of the bottom of the first support frame, the second support frame, and the extension frame.

10. The quantitative analysis method for faulty cable terminals according to claim 1, characterized in that: The cable tray (5) includes: a bracket (501), a roller (502), a bearing (503), and a bolt (504). The bottom of the bracket (501) is fixedly connected to the crossbar on the support (1). The top of the bracket (501) is symmetrically provided with two sets of steps. Each set of steps gradually slopes downward from the outside to the inside. The lowest platform of the two sets of steps is connected, and a groove for placing faulty cable terminals is formed at the center of the top surface of the bracket (501). The bracket (501) has a slot for mounting rollers (502) at the top. The rollers (502) are rotatably mounted at the corner of each step surface at the top of the bracket (501) via bearings (503). The bearings (503) are fixedly connected to the steps by bolts (504).

11. The quantitative analysis method for faulty cable terminals according to claim 1, characterized in that: The locking wheel (2) is mounted on the bracket (1) by a fixing rod, and both ends of the fixing rod are fixedly connected to the bracket (1); a moving rod is vertically installed at the center of the locking wheel (2), and the moving rod passes vertically through the fixing rod by a threaded connection. A pressure block is provided at the end of the moving rod away from the locking wheel (2), and the pressure block is used to contact the surface of the cable terminal and apply a clamping force to it.

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