A method and system for stripping a semi-conductive layer of a high voltage cable

Abstract

This invention discloses a method and system for stripping the semiconductive layer of a high-voltage cable, belonging to the field of high-voltage cable stripping. The method includes: obtaining reference parameters for the electrical characteristic difference between the semiconductive layer and the main insulation layer of the target high-voltage cable, and setting interface determination conditions; controlling the stripping tool to feed radially along the cable, and acquiring real-time AC impedance information at the contact position between the stripping tool and the cable stripping surface during the stripping process; comparing the real-time AC impedance information with the interface determination conditions, and determining the interface position between the stripping tool and the main insulation layer when the interface determination conditions are met; after reaching the interface position, generating a feedback signal based on the real-time AC impedance modulus and its rate of change, and adjusting the feed depth and / or feed speed of the stripping tool to make the stripping tool follow the interface position until stripping is completed. This invention improves the accuracy and consistency of semiconductive layer stripping.

Description

Technical Field

[0001] This invention relates to the field of high-voltage cable stripping, and specifically to a method and system for stripping the semiconductive layer of a high-voltage cable. Background Technology

[0002] High-voltage cable pretreatment is a critical process in cable line installation and maintenance. The quality of the semiconductive layer stripping affects the uniformity of the electric field distribution and long-term operational reliability of the cable terminals and intermediate joints. In the construction of cross-linked polyethylene insulated power cables with voltage levels of 110kV and above, the semiconductive layer at the cable ends must be stripped to a predetermined length to expose the main insulation layer and form a regular insulation interface.

[0003] The semiconductive layer is tightly bonded to the main insulation layer with no obvious visual boundary at the interface. Furthermore, due to the cable manufacturing process, the thickness of the semiconductive layer is uneven along both the circumferential and axial directions, resulting in an irregular spatial curved surface at the interface with the main insulation layer. In this scenario, accurately controlling the cutting depth of the tool is crucial when peeling the semiconductive layer, ensuring that the tool just removes the semiconductive layer without cutting into the main insulation layer.

[0004] Currently, the stripping of the semiconductive layer mainly employs manual stripping and mechanically assisted stripping methods. Mechanically assisted stripping involves using CNC stripping equipment or a conformal tool holder, driving the tool radially along the cable according to preset cutting parameters, and stripping the semiconductive layer according to a set cutting depth and feed rate. Some equipment is equipped with pressure sensors to monitor spring compression, or vision sensors to acquire color information of each layer of the cable structure, feeding the sensor signals back to the motor to adjust the tool's state. Motion control in mechanically assisted stripping is based on preset cutting parameters, running along a predetermined trajectory according to a set depth and feed rate. Pressure sensors are used to monitor spring compression to maintain stable contact pressure, and vision sensors are used to identify color differences between different structural layers to assist in positioning. However, the information obtained by the above-mentioned sensing methods is all indirect. The pressure sensor reflects the spring deformation state, and the vision sensor identifies the surface color characteristics. Both are indirect representations of the peeling state. When the thickness of the semiconductive layer fluctuates due to process deviations, or when there is insulation layer eccentricity in the cable, the control system cannot know the true position of the tool relative to the interface. The tool will continue to advance according to the preset depth. If the actual thickness of the semiconductive layer is less than the preset value, the tool will cut into the main insulation layer, leaving a scratch on the surface of the main insulation. If the actual thickness of the semiconductive layer is greater than the preset value, the semiconductive layer remains. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a method and system for stripping the semiconductive layer of a high-voltage cable. The method converts the electrical characteristic difference between the semiconductive layer and the main insulation layer into a real-time quantitative detection signal of the interface position, thereby enabling the tool to perform adaptive conformal stripping along the interface. This eliminates stripping errors caused by uneven semiconductive layer thickness and irregular interface morphology, improving the accuracy and consistency of semiconductive layer stripping.

[0006] In a first aspect, the present invention provides a method for stripping the semiconductive layer of a high-voltage cable, comprising the following steps: Obtain the reference parameters for the electrical characteristic difference between the semiconducting layer and the main insulation layer of the target high-voltage cable. The reference parameters for the electrical characteristic difference include at least the first AC impedance characteristic value of the semiconducting layer and the second AC impedance characteristic value of the main insulation layer. Set the interface determination conditions based on the first AC impedance characteristic value and the second AC impedance characteristic value. The stripping tool is controlled to feed radially along the cable to strip the semiconductive layer, and real-time AC impedance information of the contact position between the stripping tool and the cable stripping surface is obtained during the stripping process; The real-time AC impedance information is compared with the interface judgment condition. When the real-time AC impedance information meets the interface judgment condition, it is determined that the stripping tool has reached the interface position between the semiconductive layer and the main insulating layer. After determining the arrival position at the interface, a feedback signal is generated based on the real-time AC impedance modulus and its rate of change. The feed depth and / or feed speed of the peeling tool are adjusted so that the peeling tool moves along the interface position until the peeling of the semiconductive layer is completed.

[0007] Secondly, the technical solution of the present invention provides a high-voltage cable semiconductive layer stripping system, comprising: The judgment condition setting module is used to obtain the electrical characteristic difference benchmark parameters between the semiconductive layer and the main insulation layer of the target high-voltage cable. The electrical characteristic difference benchmark parameters include at least the first AC impedance characteristic value of the semiconductive layer and the second AC impedance characteristic value of the main insulation layer, and set the interface judgment conditions based on the first AC impedance characteristic value and the second AC impedance characteristic value. The impedance acquisition module is used to control the stripping tool to feed radially along the cable, strip the semiconductive layer, and acquire real-time AC impedance information of the contact position between the stripping tool and the cable stripping surface during the stripping process. The interface determination module is used to compare the real-time AC impedance information with the interface determination conditions. When the real-time AC impedance information meets the interface determination conditions, it determines the interface position between the stripping tool and the main insulating layer. The fine peeling control module is used to generate a feedback signal based on the real-time AC impedance modulus and its rate of change after determining the arrival position of the interface, and adjust the feed depth and / or feed speed of the peeling tool so that the peeling tool moves along the interface position until the peeling of the semiconductive layer is completed.

[0008] As can be seen from the above technical solutions, this application has the following advantages: By utilizing the inherent electrical characteristic difference between the semiconductive layer and the main insulating layer as the physical basis for interface identification, the control system can directly obtain the spatial relationship information between the tool and the interface during the peeling process. Using AC impedance information as a direct representation of the interface position, the control system obtains a quantitative basis for judging whether the tool has reached the interface, thus transforming the peeling control from relying on indirect inference to being based on direct interface measurement, thereby improving the peeling accuracy. By comparing real-time AC impedance information with preset interface judgment conditions to trigger interface arrival judgment, the tool can be promptly identified when it reaches the interface between the semiconductive layer and the main insulation layer. When the actual semiconductive layer thickness is less than the preset value, the tool arrives at the interface earlier than the time corresponding to the preset depth. The control system can trigger the interface arrival judgment and adjust the tool state before the tool cuts into the main insulation layer. When the actual semiconductive layer thickness is greater than the preset value, the control system continues to advance according to impedance feedback until the interface is reached after the preset depth is reached. This makes the cutting endpoint of the tool independent of the consistency between the preset value and the actual value of the semiconductive layer thickness, avoiding incomplete peeling or damage to the main insulation layer caused by the deviation of the semiconductive layer thickness. By generating a feedback signal based on the AC impedance modulus and its rate of change upon reaching the interface, and adjusting the tool's depth of feed and / or feed rate, the cutting parameters of the tool can be adaptively adjusted in real time according to changes in the interface position. The control system dynamically corrects the tool's depth of feed and feed rate, allowing the tool to follow the interface shape, avoiding machining errors caused by mismatch between preset parameters and the actual interface shape. This ensures that the fracture boundary of the semiconductive layer after peeling is consistent with the interface morphology, reducing the risk of electric field distortion and partial discharge caused by semiconductive layer residue or scratches on the main insulating layer. Attached Figure Description

[0009] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a schematic flowchart of a method for stripping the semiconductive layer of a high-voltage cable, provided in an embodiment of the present invention.

[0011] Figure 2This is a schematic block diagram of a high-voltage cable semiconductive layer stripping system provided in an embodiment of the present invention. Detailed Implementation

[0012] To make the purpose, features, and advantages of this application more apparent and understandable, specific embodiments and accompanying drawings will be used to clearly and completely describe the technical solution protected by this application. Obviously, the embodiments described below are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0013] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this application and in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0014] Figure 1 This is a schematic flowchart illustrating a method for stripping the semiconductive layer of a high-voltage cable according to an embodiment of the present invention. Figure 1 The executing entity can be a high-voltage cable semiconducting layer stripping system. The high-voltage cable semiconducting layer stripping method provided in this embodiment is executed by a computer device; correspondingly, the high-voltage cable semiconducting layer stripping system runs within the computer device. Depending on different requirements, the order of the steps in this flowchart can be changed, and some steps can be omitted.

[0015] like Figure 1 As shown, the method includes the following steps.

[0016] S1, obtain the electrical characteristic difference reference parameters between the semiconducting layer and the main insulation layer of the target high-voltage cable. The electrical characteristic difference reference parameters include at least the first AC impedance characteristic value of the semiconducting layer and the second AC impedance characteristic value of the main insulation layer, and set the interface judgment conditions based on the first AC impedance characteristic value and the second AC impedance characteristic value.

[0017] S2 controls the stripping tool to feed radially along the cable to strip the semiconductive layer, and obtains real-time AC impedance information of the contact position between the stripping tool and the cable stripping surface during the stripping process.

[0018] S3 compares the real-time AC impedance information with the interface determination conditions. When the real-time AC impedance information meets the interface determination conditions, it determines the position of the stripping tool at the interface between the semiconductive layer and the main insulating layer.

[0019] S4, after determining the arrival at the interface position, generates a feedback signal based on the real-time AC impedance modulus and its rate of change, adjusts the feed depth and / or feed speed of the peeling tool, so that the peeling tool moves along the interface position until the peeling of the semiconductive layer is completed.

[0020] The stripping of the semiconductive layer of high-voltage cables is typically carried out at the cable termination or intermediate joint fabrication site. The cable to be processed is clamped and fixed on an electrically operated platform equipped with clamping devices, linear guides, and auxiliary supports. The cable passes through the center of a turntable, which drives the cutting tool to rotate circumferentially around the cable to achieve circumferential cutting. Simultaneously, the linear guides drive the cutting tool to move axially along the cable to achieve longitudinal cutting and axial feed.

[0021] The clamping fixture holds and fixes the cable to be processed, ensuring its axis is parallel to the movement direction of the linear guide rail. The linear guide rail is fed by a ball screw driven by a servo motor, which in turn drives the tool holder assembly to move axially along the cable. Auxiliary supports are located on both sides of the clamping fixture to support the cable and adjust its height, preventing processing deviation caused by cable sagging. The tool holder assembly is mounted on the linear guide rail and can move axially along the cable. The tool holder assembly includes a tool holder body, a feed module, and a stripping tool. The feed module includes a servo motor and a ball screw feed assembly, used to drive the stripping tool to feed radially along the cable and retract.

[0022] In this embodiment, the impedance measurement probe can be mounted on the tool holder assembly via an elastic floating connector, moving axially synchronously with the stripping tool. An electrode structure is provided at the front end of the impedance measurement probe. The elastic floating connector applies an elastic biasing force towards the cable stripping surface to the impedance measurement probe, ensuring that the electrode structure maintains elastic contact with the cable stripping surface throughout the stripping tool's feed process. When radial runout occurs on the cable stripping surface due to roundness errors or uneven semiconductive layer thickness, the elastic floating connector absorbs the runout through expansion and contraction, maintaining stable contact between the electrode structure and the cable stripping surface. The impedance measurement probe is electrically connected to the signal processing unit of the control system via a signal cable.

[0023] In this embodiment, the control system applies a constant low-voltage AC excitation signal to the cable stripping surface through an impedance measurement probe and collects AC voltage and current signals at the contact point between the electrode structure and the cable stripping surface. The signal processing unit calculates the real-time AC impedance magnitude |Z(t)| based on the amplitude ratio of the AC voltage and current signals, and calculates the real-time phase angle θ(t) based on the phase difference between the AC voltage and current signals. The control system compares the real-time AC impedance magnitude |Z(t)| and the real-time phase angle θ(t) with preset interface determination conditions. After determining that the interface position has been reached, the control system uses the real-time AC impedance magnitude |Z(t)| and its rate of change d|Z| / dt as feedback signals to output speed and direction control commands to the servo motor driver of the feed module. By controlling the rotation angle and speed of the servo motor, the ball screw feed assembly is driven, thereby dynamically adjusting the radial feed depth and feed speed of the stripping tool. This allows the stripping tool to follow the interface position after reaching the interface until the stripping of the semiconductive layer is completed, ensuring that the stripping endpoint is consistent with the actual position of the interface.

[0024] As a refinement and extension of the specific implementation of the above embodiments, in order to fully explain the specific implementation process of this embodiment, the following will provide possible embodiments to describe the specific implementation of the above steps in a non-limiting manner.

[0025] In this embodiment, step S1 involves obtaining the reference parameters for the electrical characteristic difference between the semiconductive layer and the main insulation layer of the target high-voltage cable, specifically including the following steps S1.1 to S1.3.

[0026] S1.1, cut semiconductive layer samples and main insulation layer samples from cable samples of the same specifications and models as the cable to be processed.

[0027] Obtain a cable sample of the same specification and model as the cable to be processed, and cut semiconducting layer and main insulation layer samples from the sample. The same specification and model includes the same voltage rating, the same cross-section, and the same insulation material formula.

[0028] S1.2, an impedance analyzer is used to apply multi-band AC excitation signals to the semiconducting layer sample and the main insulating layer sample respectively.

[0029] An impedance analyzer or equivalent impedance measuring device is used to apply multi-band AC excitation signals to both the semiconductive layer sample and the main insulating layer sample. The multi-band AC signals include at least three frequency ranges: power frequency (50Hz / 60Hz), intermediate frequency (100Hz–1kHz), and high frequency (1kHz–100kHz). At each frequency point, the AC impedance magnitude |Z| and phase angle θ of the sample are collected.

[0030] S1.3, Collect the AC impedance modulus of the semiconducting layer sample at each frequency point. and phase angle As the first characteristic value of AC impedance, the AC impedance modulus of the main insulation layer sample was collected at each frequency point. and phase angle As the second AC impedance characteristic value.

[0031] For each frequency point, an interface determination threshold is set based on the difference between the first AC impedance characteristic value and the second AC impedance characteristic value. The interface determination threshold includes an impedance magnitude threshold. and phase angle threshold Specifically, the interface determination conditions are set based on the first AC impedance characteristic value and the second AC impedance characteristic value, including the following steps S1.4 to S1.10.

[0032] S1.4, Determine the impedance modulus range of the semiconductive layer based on the AC impedance modulus of the semiconductive layer sample at each frequency point. .

[0033] S1.5, Determine the impedance modulus range of the main insulation layer based on the AC impedance modulus of the main insulation layer sample at each frequency point. ,in .

[0034] It should be noted that the resistivity of the semiconductive layer and the main insulating layer differs by orders of magnitude, and the upper limit of the impedance modulus range of the semiconductive layer is... Significantly lower than the lower limit of the impedance modulus range of the main insulating layer .

[0035] S1.6 Determine the impedance magnitude threshold at the corresponding frequency point based on the impedance magnitude range of the semiconductive layer and the impedance magnitude range of the main insulating layer.

[0036] The impedance magnitude threshold at the corresponding frequency point is calculated using the following formula. :

[0037] in, This is a proportionality coefficient used to control the relative position of the impedance magnitude threshold between two intervals.

[0038] Due to the order-of-magnitude difference in resistivity between the semiconducting layer and the main insulating layer, a distinct transition band forms between their impedance modulus ranges. This formula applies to the upper limit of the impedance modulus range of the semiconducting layer. The lower limit of the impedance modulus range of the main insulation layer Within the transition zone, through the scaling factor Determine a dividing point. The smaller the value, the closer it is to the threshold. (On the semiconductive side), the more sensitive the interface determination, the greater the risk of misjudging the semiconductive layer as an insulating layer. The larger the value, the closer it is to the threshold. (On the insulation side), the more conservative the judgment, the greater the risk of missed judgment.

[0039] S1.7, Determine the phase angle range of the semiconductive layer based on the phase angle of the semiconductive layer sample at each frequency point. .

[0040] S1.8, Determine the phase angle range of the main insulation layer based on the phase angle of the main insulation layer sample at each frequency point. .

[0041] S1.9, determine the phase angle threshold at the corresponding frequency point based on the phase angle range of the semiconductive layer and the phase angle range of the main insulating layer.

[0042] The phase angle threshold is calculated using the following formula:

[0043] in, This is the proportionality coefficient.

[0044] In the semiconductive layer, conductive fillers such as carbon black form a conductive network, with charge carriers primarily transported by electrons, exhibiting resistive characteristics and an AC phase angle close to 0°. The main insulating layer is cross-linked polyethylene, which has a long polarization relaxation time. Under an AC electric field, its polarization response lags behind the change in electric field, exhibiting capacitive characteristics, with a negative phase angle and an absolute value close to 90°. This formula, within the region between the lower limit of the phase angle interval of the semiconductive layer (the side with the smaller absolute value) and the upper limit of the phase angle interval of the main insulating layer (the side with the larger absolute value), uses a proportionality coefficient... Determine the phase angle threshold. Similar to the impedance magnitude threshold, By controlling the relative position of the threshold within the transition zone, the sensitivity and reliability of the criterion can be adjusted.

[0045] S1.10, the setting interface judgment condition is: the real-time AC impedance magnitude is greater than or equal to the impedance magnitude threshold, and the real-time phase angle is less than or equal to the phase angle threshold.

[0046] This criterion is based on the fundamental difference in electrical properties between the semiconductive layer and the main insulating layer. When the stripping tool is inside the semiconductive layer, the electrode structure is in contact with the semiconductive material, and the measured impedance modulus is in the low resistance range. The phase angle is close to 0°. When the cutting tool penetrates the semiconductive layer and reaches the interface, the medium in contact with the electrode structure gradually switches from the semiconductive layer to the main insulating layer, and the impedance modulus undergoes a sharp jump of several orders of magnitude, crossing the impedance modulus threshold. At the same time, the phase angle changes from resistive to capacitive characteristics, crossing the phase angle threshold ( ).

[0047] Impedance modulus condition ( Ensure that the impedance amplitude has entered the characteristic range of the insulating layer to avoid misinterpreting normal fluctuations within the semiconductive layer as an interface; phase angle condition ( This ensures that the phase characteristics of the impedance exhibit the capacitive response of the insulation layer, eliminating abnormal changes in impedance magnitude caused by non-interface factors such as poor contact between the electrode and the cable surface, the presence of water film or impurities on the surface. The system only triggers the interface arrival signal when the tool actually reaches the material interface between the semiconductive layer and the main insulation layer, that is, when both the impedance magnitude jump and the phase angle change are satisfied, effectively reducing the false alarm rate.

[0048] In this embodiment, step S2, which involves acquiring real-time AC impedance information at the contact position between the stripping tool and the cable stripping surface during the stripping process, specifically includes: applying a constant low-voltage AC excitation signal to the cable stripping surface through an impedance measurement probe; acquiring AC voltage and current signals at the contact point between the electrode structure of the impedance measurement probe and the cable stripping surface; calculating the real-time AC impedance modulus based on the amplitude ratio of the AC voltage and current signals; and calculating the real-time phase angle based on the phase difference between the AC voltage and current signals.

[0049] Specifically, the cable to be processed is fixed to the clamping device of the electric operating platform, and leveled using an auxiliary bracket to keep the cable axis parallel to the moving direction of the linear guide rail. The control system controls the linear guide rail to move the tool holder assembly, equipped with the stripping tool and impedance measurement probe, along the cable axis to the preset stripping starting position. The control system sends a feed command to the servo drive module, driving the radial feed assembly to move the stripping tool along the radial direction of the cable, so that the cutting edge of the stripping tool cuts into the semiconductive layer. During the feed process, the control system controls the operating parameters of the stripping tool according to the preset initial feed speed and initial feed depth. While the stripping tool is feeding radially, it rotates circumferentially along the cable under the drive of the control system to perform circumferential stripping of the semiconductive layer; after completing the circumferential stripping, the stripping tool moves along the cable axis to perform axial longitudinal stripping of the semiconductive layer. The circumferential and longitudinal stripping work together to complete the coarse stripping removal of the semiconductive layer.

[0050] During the stripping process of the semiconductive layer by the stripping blade, an impedance measurement probe mounted on the blade holder of the stripping blade moves synchronously with the stripping blade via an elastic floating connector. The front end of the impedance measurement probe is equipped with an electrode structure, which maintains elastic contact with the cable stripping surface throughout the feeding process of the stripping blade.

[0051] With the electrode structure of the impedance measurement probe in contact with the cable stripping surface, the signal processing unit applies a constant low-voltage AC excitation signal (the frequency of which is a selected frequency from the reference database established during the pre-calibration phase) to the cable stripping surface through the impedance measurement probe. The signal processing unit acquires the AC voltage and current signals flowing through the contact point between the electrode structure and the cable stripping surface, and calculates the real-time AC impedance modulus based on the amplitude ratio of the AC voltage and current signals. Real-time phase angle is calculated based on the phase difference between AC voltage and current signals. .

[0052] The control system will With impedance magnitude threshold Compare, and at the same time With phase angle threshold Comparison. When and This indicates that the impedance amplitude at the current measuring point has jumped from the low-resistance range of the semiconducting layer to the high-resistance range of the insulating layer, and the phase characteristic has changed from the resistive characteristic of the semiconducting layer to the capacitive characteristic of the insulating layer. Both of these characteristics indicate that the medium in contact with the electrode structure has switched from the semiconducting layer to the main insulating layer. Furthermore, the control system determines that the stripping tool has reached the interface between the semiconducting layer and the main insulating layer.

[0053] In this embodiment, after determining the arrival at the interface position, step S4 generates a feedback signal based on the real-time AC impedance modulus and its rate of change, and adjusts the feed depth and / or feed speed of the peeling tool so that the peeling tool moves along the interface position until the peeling of the semiconductive layer is completed. Specifically, it includes the following steps S4.1 to S4.6.

[0054] S4.1, Fine-stripping mode startup and status parameter initialization.

[0055] When step S3 determines that the stripping tool has reached the interface between the semiconductive layer and the main insulating layer, the control system automatically switches from coarse stripping mode to fine stripping mode. In fine stripping mode, the control system records the real-time AC impedance modulus value at the current moment. Real-time impedance change rate and current feed depth and feed rate , which serves as the initial state parameter for the stripping stage.

[0056] S4.2 Calculate the deviation and rate of change to generate a feedback signal.

[0057] The control system continuously acquires the real-time AC impedance modulus at a preset sampling period Δt. And calculate the feedback components, including impedance magnitude deviation and impedance change rate.

[0058] Impedance magnitude deviation :

[0059] when When the impedance modulus at the current measuring point exceeds the interface threshold, the stripping tool has entered the main insulation layer area, and a tool retraction action should be performed to protect the insulation layer; when When the impedance modulus at the current measuring point has not yet reached the interface threshold, the peeling tool is still in the semi-conductive layer region, and the cutting action can continue; when When the cutting tool is exactly at the interface position, it indicates that the cutting tool is exactly at the interface position.

[0060] Impedance change rate :

[0061] Impedance change rate This characterizes the rate of change of the real-time AC impedance modulus per unit time, i.e., the rate at which the peeling tool traverses the interface region. When A large positive value indicates that the stripping tool is cutting into the main insulating layer region from the semiconductive layer region at a relatively high speed, which will soon lead to overcutting risk; when Approaching zero and Stable at greater than When the range is within a certain range, it indicates that the peeling tool has moved stably along the interface position and no significant adjustment is required.

[0062] S4.3, adjust the feed rate.

[0063] The control system is based on the impedance change rate Within the specified numerical range, the radial feed rate of the peeling tool is adjusted according to a segmented control strategy. .

[0064] (1) Safe stripping interval: when When the peeling tool is determined to be moving normally along the interface, the feed speed of the peeling tool is dynamically adjusted according to the impedance change rate, and the feed speed decreases as the impedance change rate increases.

[0065] In one specific embodiment, the feed rate is dynamically calculated according to the following formula. :

[0066] in, This is the baseline feed rate when entering the fine stripping mode. This is the speed adjustment coefficient.

[0067] This indicates the relative position of the rate of change of impedance within the effective range. (Molecular) This indicates the current rate of change relative to the lower boundary. Overshoot, denominator This represents the width of the entire effective range. The ratio of the two represents the current rate of change of impedance. to The normalized position within the interval, when the rate of change is close to When the rate of change approaches 0, the ratio approaches 0; when the rate of change approaches 0... When this ratio approaches 1.

[0068] The attenuation factor that constitutes the velocity. When the rate of change of impedance is at a low level (close to...) The decay factor approaches 0. near The tool maintains a high feed efficiency; when the impedance change rate increases, the attenuation factor increases, and the feed rate decreases proportionally; when the impedance change rate approaches... When the decay factor approaches The feed rate is reduced to a minimum, at which point the tool approaches the interface at an extremely low speed to allow sufficient response time for possible tool retraction.

[0069] The rate of change of impedance is a direct representation of the speed at which the tool crosses the interface region. A higher rate of change indicates that the tool is rapidly approaching or cutting into the main insulation layer, posing a higher risk. The control system continuously reduces the feed rate, slowing the tool in advance when the risk increases. This minimizes the kinetic energy and inertial impact of the tool, avoiding mechanical shocks caused by sudden speed changes and providing time margin for subsequent tool retraction or fine-tuning. Consequently, the feed rate can be smoothly adjusted according to real-time changes in the interface risk level, ensuring a smooth transition from rapid peeling to low-speed fine-tuning.

[0070] (2) Stable tracking interval: when the impedance change rate At this point, it is determined that the peeling tool has stabilized at the interface position and the impedance modulus no longer changes significantly. At this time, the peeling tool is controlled to maintain a preset third feed rate. Running, third feed rate Less than the reference feed rate and dynamically calculated feed rate exist Any value under the given conditions is used to move along the interface at a low speed, ensuring that neither the insulating layer is damaged nor any semiconductive layer residue is missed.

[0071] (3) Emergency protection interval: when the impedance change rate When it is determined that the stripping tool is rapidly cutting into the main insulation layer, the control system immediately performs an emergency protection action: reducing the feed speed to zero and triggering the radial retraction command in step S4.4. The feed is automatically resumed after the impedance change rate falls back to the safe fine stripping range.

[0072] S4.4, Proportional-Derivative (PD) Closed-Loop Adjustment of Feed Depth.

[0073] The control system dynamically adjusts the radial feed depth of the peeling tool based on the impedance magnitude deviation e(t) according to the PD control law. The expression for the PD control law is:

[0074] in, The feed depth adjustment is calculated using the following proportional-derivative control law formula:

[0075] in, This is the proportional gain coefficient, used to determine the magnitude of depth adjustment based on the current impedance deviation; It is the differential gain coefficient, used to predict future trends based on the changing trend of impedance deviation and suppress overshoot in advance.

[0076] Then the current feed depth Updated to With feed depth adjustment sum.

[0077] Proportional Term The tool is adjusted to retract or advance by a certain amount. When e(t) > 0 (the tool has entered the main insulating layer), the value is positive, driving the tool to retract. When e(t) < 0 (the tool is still in the semi-conductive layer), the value is negative, driving the tool to advance. The magnitude of the retraction or advance is proportional to the absolute value of e(t), meaning the further away from the interface, the greater the adjustment.

[0078] Differential term This item determines which direction the adjustment should take in the future. With the rate of change of impedance The product of these factors is used to predict the movement trend of the tool. When the tool is rapidly approaching the interface ( (If the value is relatively large and positive), the differential term generates an early retraction pre-adjustment amount, which can effectively prevent overcutting caused by system inertia.

[0079] It should be noted that the radial retraction command has a higher priority than the radial feed command. When e(t) > 0, regardless of the current speed, the control system will prioritize the retraction action. Once e(t) falls back to the range ≤ 0, normal feed control will resume.

[0080] S4.5, Three-dimensional path collaborative control of the stress cone transition zone.

[0081] This embodiment includes three-dimensional path coordination control of the stress cone transition zone during the contour-following movement of the peeling tool along the interface. In the stress cone transition zone, the control system calls a preset stress cone slope model and simultaneously adjusts the radial feed depth, radial feed speed, and axial feed speed of the peeling tool to achieve a smooth transition between the peeling surface and the main insulation layer.

[0082] The stress cone slope model describes the target peeling radius. axial distance Specifically, based on the main insulation layer radius, the semiconducting layer outer radius, the preset axial length of the stress cone transition zone, and the preset slope shape parameters, the model generates the axial position of the cable at time t. Target peeling radius at the location , is represented as:

[0083] in, The radius of the main insulation layer is determined by the cable specifications. The outer radius of the semiconductive layer is determined by the cable specifications. This is the preset axial length of the stress cone transition zone; It is a slope shape index used to control the curvature of transition curves.

[0084] It should be noted that stress cones are structures used in high-voltage cable terminations and intermediate joints to uniformly distribute the electric field. Their function is to gradually disperse the concentrated electric field region at the semiconductive layer fracture along the axial direction, ensuring a uniform transition of the electric field gradient. Specifically, the stress cone forms a smooth, conical transition zone from the semiconductive layer fracture to the surface of the main insulation layer, causing the electric field, originally concentrated at the fracture edge, to be distributed axially along the conical surface. This effectively disperses the electric field, reduces the maximum field strength, and thus prevents partial discharge and insulation breakdown.

[0085] The above model formula describes the target profile curve of the stress cone transition region. hour, That is, the target peeling radius at the beginning of the stress cone is equal to the outer radius of the semiconductive layer, and the taper change has not yet begun. When hour, That is, the target peeling radius at the end of the stress cone is equal to the radius of the main insulation layer, and the taper change is completed. Increase from 0 to During the process, the target peeling radius from Continuously and smoothly decrease to , a tapered profile that gradually shrinks along the axis is formed. n controls the bending shape of the curve. When n = 1, the radius changes linearly and the conical surface is a straight cone; when 0 < n < 1, the curve shows a shape that is steep at first and then gentle, with a fast change at the starting end and a slow change at the ending end; when n > 1, the curve shows a shape that is gentle at first and then steep, with a slow change at the starting end and a fast change at the ending end. By adjusting the value of n, the requirements for the shape of the transition curve can be adapted to different cable models and different stress cone design specifications. In this embodiment, a power function curve is used as the transition profile to obtain a gentle curvature change and avoid stress concentration.

[0086] During the forming process of the stress cone transition area, the control system uses the real-time AC impedance modulus as the interface tracking signal, and maps the real-time AC impedance modulus to the real-time stripping radius at the current stripping position , which is expressed as:

[0087] where is the radius mapping coefficient, which is obtained through experimental calibration.

[0088] Calculate the radius deviation between the real-time stripping radius and the target stripping radius .

[0089] Based on the radius deviation , the control system corrects the radial feed depth and radial feed speed of the stripping tool to make the actual stripping profile approximate the preset stress cone slope model; at the same time, the control system adjusts the axial feed speed of the stripping tool according to the positive and negative of the radius deviation : when is positive (the stripping radius is too large), increase the radial retraction amount and reduce the axial feed speed to increase the cutting time at this position; when is negative (the stripping radius is insufficient), reduce the radial retraction amount and increase the axial feed speed to reduce the cutting time at this position; when the absolute value of the radius deviation is less than the preset tolerance, maintain the current motion parameters. Through the coordinated adjustment of the radial parameters and axial parameters, until the absolute value of the radius deviation is less than the preset tolerance, the forming of the stress cone transition area is completed.

[0090] In a preferred embodiment, the increase amount of the radial retraction amount is calculated according to the following formula:

[0091] where is the radial adjustment coefficient, which is used to convert the radius deviation into the correction amount of the radial feed depth.

[0092] Axial feed rate Adjust as follows:

[0093] in, As the reference axial feed rate, This is the axial reduction coefficient.

[0094] when When the value is positive (the peeling radius is too large, i.e., the cut is too deep), A positive value (increases the retraction amount), and at the same time Decrease; when When the value is negative (the peeling radius is insufficient, i.e., the cut is too shallow), A negative value (reducing the retraction amount or increasing the feed amount), at the same time Increase.

[0095] During the forming process of the stress cone transition zone, when the real-time AC impedance modulus... Exceeding the impedance magnitude threshold If the duration exceeds a preset time threshold, a radial retraction action is performed first to protect the main insulation layer, and then the radial deviation is considered. Readjust the toolpath, prioritizing avoiding damage to the insulation layer.

[0096] S4.6, Determine the end point of the peeling process.

[0097] Monitoring the real-time AC impedance modulus during the stripping process Impedance change rate Cumulative radial feed of the peeling tool The semiconductive layer stripping is considered complete when all three conditions A, B, and C are met simultaneously: Condition A: And the real-time AC impedance modulus remains within a preset stable duration threshold. Fluctuation range within ,in This is the preset stable fluctuation threshold.

[0098] This condition requires that the impedance magnitude has reached or exceeded the interface threshold. This indicates that the tool has crossed the semiconductive layer region and entered the main insulating layer interface region. Simultaneously, the impedance modulus is required to be within [specific range]. The internal stability is maintained, with fluctuations not exceeding [a certain value]. This is to confirm that this is not a momentary signal spike or accidental fluctuation, but rather that the tool has indeed remained stably on the interface of the insulating layer.

[0099] Condition B: ,in This is the preset lower limit threshold for the rate of change.

[0100] This condition requires that the rate of change of impedance be less than or equal to the second rate of change threshold. . This reflects the rate of change of the impedance modulus over time. When the tool moves steadily along the interface, the impedance modulus no longer experiences a significant jump, and the rate of change falls back to a low value range close to zero. This condition confirms that the impedance has stabilized, further demonstrating that the tool is moving smoothly along the interface, rather than in a risky state of cutting into the insulation layer.

[0101] Condition C: ,in This is the preset total feed rate for peeling. The preset feed rate completion tolerance.

[0102] This condition requires that the cumulative radial feed amount has reached the allowable deviation range of the preset total peeling feed amount. It is the theoretical total feed rate preset before the stripping begins, based on the cable specifications and process requirements. This is the allowable completion tolerance. This condition ensures that the tool has advanced to a sufficient depth in the radial direction, preventing premature stopping of the tool before the semiconductive layer has been completely removed due to abnormal impedance signals.

[0103] The three conditions—stable impedance modulus, zero rate of change, and satisfactory cumulative feed rate—verify the authenticity of the stripping process. Failure to meet any of these conditions will not trigger the endpoint determination, effectively avoiding misjudgments caused by sensor noise, poor contact, or cable surface abnormalities, thus improving the reliability of endpoint determination.

[0104] The above text provides a detailed description of an embodiment of a high-voltage cable semi-conductive layer stripping method. Based on the high-voltage cable semi-conductive layer stripping method described in the above embodiment, this invention also provides a high-voltage cable semi-conductive layer stripping system corresponding to the method.

[0105] Figure 2 This is a schematic block diagram of a high-voltage cable semiconducting layer stripping system provided in an embodiment of the present invention. In this embodiment, the high-voltage cable semiconducting layer stripping system can be divided into multiple functional modules according to its function. A module, as referred to in this invention, is a series of computer program segments that can be executed by at least one processor and perform a fixed function, and is stored in memory.

[0106] The judgment condition setting module is used to obtain the electrical characteristic difference benchmark parameters between the semiconductive layer and the main insulation layer of the target high-voltage cable. The electrical characteristic difference benchmark parameters include at least the first AC impedance characteristic value of the semiconductive layer and the second AC impedance characteristic value of the main insulation layer, and set the interface judgment conditions based on the first AC impedance characteristic value and the second AC impedance characteristic value.

[0107] The impedance acquisition module is used to control the stripping tool to feed radially along the cable, strip the semiconductive layer, and acquire real-time AC impedance information of the contact position between the stripping tool and the cable stripping surface during the stripping process.

[0108] The interface determination module is used to compare the real-time AC impedance information with the interface determination conditions. When the real-time AC impedance information meets the interface determination conditions, it determines the interface position between the stripping tool and the main insulating layer.

[0109] The fine peeling control module is used to generate a feedback signal based on the real-time AC impedance modulus and its rate of change after determining the arrival position of the interface, and adjust the feed depth and / or feed speed of the peeling tool so that the peeling tool moves along the interface position until the peeling of the semiconductive layer is completed.

[0110] The high-voltage cable semi-conductive layer stripping system of this embodiment is used to implement the aforementioned high-voltage cable semi-conductive layer stripping method. Therefore, the specific implementation of this system can be found in the embodiment section of the high-voltage cable semi-conductive layer stripping method above. Thus, the specific implementation can be referred to the description of the corresponding embodiments, and will not be elaborated here.

[0111] Furthermore, since the high-voltage cable semiconductive layer stripping system of this embodiment is used to implement the aforementioned high-voltage cable semiconductive layer stripping method, its function corresponds to the function of the above method, and will not be repeated here.

[0112] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of stripping and shearing a semi-conductive layer of a high voltage cable, characterized in that, Includes the following steps: Obtain the reference parameters for the electrical characteristic difference between the semiconducting layer and the main insulation layer of the target high-voltage cable. The reference parameters for the electrical characteristic difference include at least the first AC impedance characteristic value of the semiconducting layer and the second AC impedance characteristic value of the main insulation layer. Set the interface determination conditions based on the first AC impedance characteristic value and the second AC impedance characteristic value. The stripping tool is controlled to feed radially along the cable to strip the semiconductive layer, and real-time AC impedance information of the contact position between the stripping tool and the cable stripping surface is obtained during the stripping process; The real-time AC impedance information is compared with the interface judgment condition. When the real-time AC impedance information meets the interface judgment condition, it is determined that the stripping tool has reached the interface position between the semiconductive layer and the main insulating layer. After determining the arrival position at the interface, a feedback signal is generated based on the real-time AC impedance modulus and its rate of change. The feed depth and / or feed speed of the peeling tool are adjusted so that the peeling tool moves along the interface position until the peeling of the semiconductive layer is completed.

2. The high voltage cable semiconductive layer stripping method according to claim 1, characterized in that, Obtain the baseline parameters for the electrical characteristic difference between the semiconductive layer and the main insulation layer of the target high-voltage cable, specifically including: Semiconductor layer samples and main insulation layer samples were cut from cable samples of the same specifications and models as the cable to be processed. An impedance analyzer was used to apply multi-band AC excitation signals to the semiconducting layer sample and the main insulating layer sample, respectively. The complex impedance modulus of the semiconductive layer sample at each frequency point is collected and the phase angle The complex impedance modulus of the main insulation layer sample at each frequency point is collected and the phase angle as the first complex impedance characteristic value.

3. The method for stripping the semiconductive layer of a high-voltage cable according to claim 2, characterized in that, The interface determination conditions are set based on the first AC impedance characteristic value and the second AC impedance characteristic value, specifically including: The impedance modulus range of the semiconducting layer is determined based on the AC impedance modulus of the semiconducting layer sample at each frequency point. ; The impedance modulus range of the main insulation layer is determined based on the AC impedance modulus of the main insulation layer sample at each frequency point. ,in ; The impedance magnitude threshold at the corresponding frequency point is determined based on the impedance magnitude range of the semiconducting layer and the impedance magnitude range of the main insulating layer. The phase angle range of the semiconducting layer is determined based on the phase angle of the semiconducting layer sample at each frequency point. ; The phase angle range of the main insulation layer is determined based on the phase angle of the main insulation layer sample at each frequency point. ; The phase angle threshold at the corresponding frequency point is determined based on the phase angle range of the semiconductive layer and the phase angle range of the main insulating layer. The setting interface determines the following conditions: the real-time AC impedance magnitude is greater than or equal to the impedance magnitude threshold, and the real-time phase angle is less than or equal to the phase angle threshold.

4. The method for stripping the semiconductive layer of a high-voltage cable according to claim 3, characterized in that, The impedance magnitude threshold at a given frequency point is determined based on the impedance magnitude ranges of the semiconductive layer and the main insulating layer. Specifically, this involves calculating the impedance magnitude threshold at the corresponding frequency point using the following formula. : in, This is the proportionality coefficient; The phase angle threshold at the corresponding frequency point is determined based on the phase angle range of the semiconductive layer and the phase angle range of the main insulating layer, specifically by calculating the phase angle threshold using the following formula: in, This is the proportionality coefficient.

5. The method for stripping the semiconductive layer of a high-voltage cable according to claim 3, characterized in that, During the stripping process, real-time AC impedance information at the contact position between the stripping tool and the cable stripping surface is obtained, specifically including: A constant low-voltage AC excitation signal is applied to the cable stripping surface using an impedance measurement probe; Acquire AC voltage and current signals at the contact point between the electrode structure of the impedance measurement probe and the cable stripping surface; The real-time AC impedance magnitude is calculated based on the amplitude ratio of the AC voltage signal and the current signal, and the real-time phase angle is calculated based on the phase difference between the AC voltage signal and the current signal.

6. The method for stripping the semiconductive layer of a high-voltage cable according to claim 3, characterized in that, Adjusting the feed speed of the peeling tool specifically includes: When the rate of change of impedance satisfy When the peeling tool is determined to be moving normally along the interface, the feed rate of the peeling tool is dynamically adjusted according to the impedance change rate, and the feed rate decreases as the impedance change rate increases; among which, The first rate of change threshold, The second rate of change threshold; When the rate of change of impedance At that time, control the peeling tool to feed at the third feed rate. Operation, the third feed rate Less than the reference feed rate and dynamically calculated feed rate exist Any value under the given conditions; When the rate of change of impedance When the cutting tool is detected to be cutting into the main insulation layer, a protective action is executed.

7. The method for stripping the semiconductive layer of a high-voltage cable according to claim 6, characterized in that, Adjusting the feed depth of the peeling tool specifically includes: Calculate the impedance magnitude deviation ; Based on impedance magnitude deviation The feed depth adjustment is calculated according to the following proportional-derivative control law. : in, This is the proportional gain coefficient. The differential gain coefficient; feed depth at the current moment Updated to With feed depth adjustment sum.

8. The method for stripping the semiconductive layer of a high-voltage cable according to claim 7, characterized in that, The peeling tool moves contour-followingly along the interface, and the three-dimensional path coordination control of the stress cone transition zone also includes: In the stress cone transition zone, a preset stress cone slope model is used to calculate the target stripping radius. This stress cone slope model generates the axial position along the cable based on the radius of the main insulation layer, the outer radius of the semiconductive layer, the preset axial length of the stress cone transition zone, and the preset slope shape parameters. Target peeling radius at the location ; Real-time AC impedance modulus Mapped to the real-time peeling radius of the current peeling position It also calculates the radius deviation between the real-time peeling radius and the target peeling radius. ; Based on radius deviation Correct the radial feed depth, radial feed speed, and axial feed speed of the peeling tool: when When the value is positive, increase the radial retraction amount and decrease the axial feed rate; when When the value is negative, decrease the radial retraction amount and increase the axial feed rate; when the radius deviation... When the absolute value is less than the preset tolerance, maintain the current motion parameters; During the forming process of the stress cone transition zone, when the real-time AC impedance modulus... Exceeding the impedance magnitude threshold If the duration exceeds a preset time threshold, a radial retraction action is performed first to protect the main insulation layer, and then the radial deviation is considered. Readjust the toolpath.

9. The method for stripping the semiconductive layer of a high-voltage cable according to claim 1, characterized in that, Until the stripping of the semiconductive layer is completed, specifically including: Monitoring the real-time AC impedance modulus during the stripping process Impedance change rate Cumulative radial feed of the peeling tool ; The semiconductive layer stripping is considered complete when the following conditions are met simultaneously: Condition A: And the real-time AC impedance modulus remains within a preset stable duration threshold. Fluctuation range within ,in The preset stable fluctuation threshold; Condition B: ,in The lower limit threshold of the rate of change is preset; Condition C: ,in This is the preset total feed rate for peeling. The preset feed rate completion tolerance.

10. A high-voltage cable semiconductive layer stripping system, characterized in that, include: The judgment condition setting module is used to obtain the electrical characteristic difference benchmark parameters between the semiconductive layer and the main insulation layer of the target high-voltage cable. The electrical characteristic difference benchmark parameters include at least the first AC impedance characteristic value of the semiconductive layer and the second AC impedance characteristic value of the main insulation layer, and set the interface judgment conditions based on the first AC impedance characteristic value and the second AC impedance characteristic value. The impedance acquisition module is used to control the stripping tool to feed radially along the cable, strip the semiconductive layer, and acquire real-time AC impedance information of the contact position between the stripping tool and the cable stripping surface during the stripping process. The interface determination module is used to compare the real-time AC impedance information with the interface determination conditions. When the real-time AC impedance information meets the interface determination conditions, it determines the interface position between the stripping tool and the main insulating layer. The fine peeling control module is used to generate a feedback signal based on the real-time AC impedance modulus and its rate of change after determining the arrival position of the interface, and adjust the feed depth and / or feed speed of the peeling tool so that the peeling tool moves along the interface position until the peeling of the semiconductive layer is completed.

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