A method for optimizing the preparation process of the insulation protective layer of a solar thermal energy storage cable

Abstract

The present application relates to the technical field of preparation of cross-linked polyethylene power cable insulation layers, and specifically to a method for optimizing the preparation process of an insulation protective layer of a solar thermal energy storage cable, the method comprising: mixing a certain weight of polyethylene, a peroxide cross-linking agent, and an antioxidant to obtain a polyethylene mixture; using a three-layer co-extrusion device to wrap the cable core with the polyethylene mixture and a semi-conductive shielding material to obtain a pre-treated cable; cross-linking and cooling the pre-treated cable in a cross-linking tube and a cooling tube by controlling the winding speed of the lower traction device; and after processing, obtaining a solar thermal energy storage cable with cross-linked polyethylene as an insulation protective layer. The present application aims to suppress the oscillation phenomenon of the cable core during the cross-linking process and improve the production efficiency and quality of solar thermal energy storage cables with cross-linked polyethylene as an insulation protective layer.

Description

Technical Field

[0001] The present application relates to the technical field of preparation of cross-linked polyethylene power cable insulation layers, and specifically to a method for optimizing the preparation process of an insulation protective layer of a solar thermal energy storage cable. Background Art

[0002] Solar thermal energy storage cables are a type of cable specifically designed for use in solar thermal energy storage systems. These systems place high demands on the insulation layer of the cable, as both high and low temperatures can affect the insulation. Therefore, cross-linked polyethylene (XLPE) insulation is used as the insulation layer for the cable core. This material exhibits high-temperature and chemical corrosion resistance, as well as excellent mechanical strength and insulation properties. It can adapt to the high-temperature and chemical media environments found in solar thermal energy storage systems, thereby ensuring stable power transmission and efficient system operation.

[0003] During the production process of solar thermal energy storage cables wrapped with a cross-linked polyethylene insulation protective layer, the tension of the cable core is affected by the different thermal expansion of the cable core at different positions in the cross-linked tube due to different temperatures, the influence of pressure in the tube, and the influence of cooling water. This can cause the cable core to oscillate or even hit the wall in the cross-linked tube. These situations can cause the produced cables to become waste or even damage the tube, thus affecting the normal production of the cable. Therefore, it is necessary to control the tension of the cable core in the solar thermal energy storage cable production line with cross-linked polyethylene as the insulation protective layer to ensure that the cable core can be stably suspended in the center of the cross-linked tube.

[0004] At present, a suspension controller is usually used to control the cable tension. This method uses the offset of the cable core from the center position of the cross-linked tube to perform feedback adjustment compensation to achieve cable tension control. However, in the actual production process of solar thermal energy storage cables with cross-linked polyethylene as the insulating protective layer, the change in the winding radius of the cable core during its winding process and the fluctuation of the parameters of the auxiliary device of the cable production line will cause the upper and lower pulling speeds of the cable core to differ. This difference will cause the tension of the cable core to change, and then cause the cable core to oscillate. The feedback adjustment compensation has a lag, making it difficult for the traditional cable tension control method to respond to the cable core oscillation in time, thereby reducing the production efficiency and quality of solar thermal energy storage cables with cross-linked polyethylene as the insulating protective layer. Summary of the Invention

[0005] In order to solve the above technical problems, the present application provides a method for optimizing the preparation process of the insulation protective layer of a solar thermal energy storage cable to solve the existing problems.

[0006] The present invention provides a method for optimizing the preparation process of the insulation protective layer of a solar thermal energy storage cable using the following technical solutions:

[0007] One embodiment of the present application provides a method for optimizing a process for preparing an insulating protective layer of a solar thermal energy storage cable, the method comprising the following steps:

[0008] S1, mixing a certain weight of polyethylene, a peroxide crosslinking agent and an antioxidant to obtain a polyethylene mixture;

[0009] S2, using a three-layer co-extrusion device to wrap the cable core with the polyethylene mixture and the semi-conductive shielding material to obtain a pretreated cable;

[0010] S3, by controlling the winding speed of the lower traction device, cross-linking and cooling the pretreated cable in the cross-linking tube and the cooling tube. The process of controlling the winding speed of the lower traction device includes:

[0011] S301: Acquire the exit speed data of the upper traction device, the winding speed data of the lower traction device, and the position offset data of the cable in the cross-linked tube at the current moment and all the acquisition moments before the preset time period;

[0012] S302: The difference between the winding speed data and the outlet speed data at each acquisition moment is recorded as the speed deviation data at each acquisition moment; a time series decomposition algorithm is used to obtain a trend item sequence of all speed deviation data, and the first oscillation coefficient at the current moment is obtained by analyzing the change trend of all elements in the trend item sequence;

[0013] S303: Determine a second oscillation coefficient at the current moment by measuring the correlation of the periodic characteristics between all winding speed data and all outlet speed data before the current moment, and respectively evaluating the average distribution of all winding speed data and all outlet speed data. Combined with the first oscillation coefficient, determine an oscillation response coefficient at the current moment.

[0014] S304: Analyze the change trend and average distribution of all position offset data, and determine the response adjustment coefficient at the current moment in combination with the oscillation response coefficient to control the winding speed data of the lower traction device;

[0015] S4, after the processing is completed, a solar thermal energy storage cable with cross-linked polyethylene as the insulating protective layer is obtained.

[0016] Preferably, the weight of the peroxide crosslinking agent accounts for 1.5% to 2.5% of the total weight of the polyethylene, and the weight of the antioxidant accounts for 0.5% to 0.6% of the total weight of the polyethylene.

[0017] Preferably, the polyethylene is one of high-density polyethylene or linear low-density polyethylene, the peroxide crosslinking agent is one of ethylene peroxide or diisopropylbenzene peroxide, and the antioxidant is one of polyphenol antioxidant 1010, polyphenol antioxidant 1076 or thiobisphenol antioxidant 300.

[0018] Preferably, the extrusion temperature of the three-layer co-extrusion device is 110-130°C.

[0019] Preferably, the method for determining the first oscillation coefficient at the current moment is:

[0020] The speed deviation data at the current moment and all previous acquisition moments are fitted to obtain a fitting straight line, and the first oscillation coefficient at the current moment is the absolute value of the slope of the fitting straight line.

[0021] Preferably, the method for determining the second oscillation coefficient at the current moment is:

[0022] The time series decomposition algorithm is used to obtain the seasonal item series of all winding speed data and all exit speed data at the current moment and before respectively;

[0023] The expression of the second oscillation coefficient s at the current moment is: s = p × (q + g); where p represents the correlation coefficient of the seasonal term sequence between all winding speed data at the current moment and before and all outlet speed data; q represents the mean of all winding speed data at the current moment and before; g represents the mean of all outlet speed data at the current moment and before.

[0024] Preferably, the oscillation response coefficient at the current moment is the average of the first oscillation coefficient and the second oscillation coefficient at the current moment.

[0025] Preferably, the method for determining the response adjustment coefficient at the current moment is:

[0026] A time series decomposition algorithm is used to obtain a trend item sequence of all position offset data at and before the current moment, recorded as a position offset trend item sequence, and all elements in the position offset trend item sequence are fitted to obtain a position offset fitting line;

[0027] The product of the mean of all position offset data at the current moment and before and the slope of the position offset fitting line is taken as the position offset response coefficient at the current moment;

[0028] The response adjustment coefficient at the current moment is the average of the oscillation response coefficient and the position offset response coefficient at the current moment.

[0029] Preferably, the controlling of the winding speed data of the lower traction device includes:

[0030] The expression of the optimized proportional coefficient P at the current moment is: P = P1 + round[norm(H) × P2]; where P1 and P2 represent the initial proportional coefficient and initial integral coefficient of the PID control algorithm in the drape controller obtained by trial and error; H represents the response adjustment coefficient at the current moment; norm() represents the normalization function; round[] represents the rounding function;

[0031] The optimized proportional coefficient at the current moment is used as the proportional coefficient in the lower suspension controller at the current moment to obtain an improved suspension controller, and the position offset data of the lower cable at the current moment is used as the input of the improved suspension controller to output a speed control signal to control the winding speed data of the lower traction device at the current moment.

[0032] Preferably, in S3, the running speed of the pretreated cable is 1.4-1.6 m / min; the pressure in the cross-linked tube is 14-16 bar, and the temperature is 270-330°C.

[0033] This application has at least the following beneficial effects:

[0034] This application constructs a response adjustment coefficient by analyzing the changing trends and changing rules of the relevant speed data of the upper and lower traction devices. It can accurately evaluate the oscillation of the cable core during the cross-linking process, thereby accurately controlling the speed data of the lower traction device, suppressing the oscillation of the cable core, and improving the production efficiency and quality of the solar thermal energy storage cable with cross-linked polyethylene as the insulating protective layer; further, based on the response adjustment coefficient, the proportional coefficient of the PID control algorithm in the suspension controller is optimized to improve the accuracy of the speed data control of the lower traction device during the production process of the solar thermal energy storage cable, thereby improving the accuracy of the cable core tension control, thereby improving the production efficiency and quality of the solar thermal energy storage cable with cross-linked polyethylene as the insulating protective layer. This application synchronizes the relevant speed data of the upper and lower traction devices through the suspension controller, suppresses the oscillation phenomenon of the cable core during the cross-linking process, and improves the production efficiency and quality of the solar thermal energy storage cable with cross-linked polyethylene as the insulating protective layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present application or the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0036] Figure 1 A flowchart of a method for optimizing a process for preparing an insulating protective layer of a solar thermal energy storage cable provided in one embodiment of the present application;

[0037] Figure 2 A schematic diagram of a solar thermal energy storage cable production line device using cross-linked polyethylene as an insulating protective layer, provided in one embodiment of the present application;

[0038] Figure 3 A flow chart of a method for controlling a lower traction device according to an embodiment of the present application;

[0039] Figure 4 A flow chart of the process for preparing a solar thermal energy storage cable with cross-linked polyethylene as the insulating protective layer provided in one embodiment of the present application. DETAILED DESCRIPTION

[0040] To further illustrate the technical means and effects adopted by this application to achieve the intended invention objectives, the following, in conjunction with the accompanying drawings and preferred embodiments, describes in detail the method for optimizing the preparation process of the insulation protective layer of a solar thermal energy storage cable proposed in this application, its specific implementation, structure, features, and effects. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable form.

[0041] Unless otherwise defined, terms such as "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a circuit structure, article or device comprising a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the article or device comprising the element. In addition, the term "and\or" used herein includes any and all combinations of one or more related listed items. All technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs.

[0042] The following describes in detail a specific method for optimizing the preparation process of the insulation protective layer of a solar thermal energy storage cable provided in this application with reference to the accompanying drawings.

[0043] Example 1

[0044] Example 1 provides an optimization method for preparing the insulation protective layer of a solar thermal energy storage cable. For details, please refer to Figure 1 , the method comprises the following steps:

[0045] S1, mixing a certain weight of polyethylene, a peroxide crosslinking agent and an antioxidant to obtain a polyethylene mixture.

[0046] A polyethylene mixture is uniformly mixed with a peroxide crosslinking agent and an antioxidant in parts by weight to form a polyethylene mixture. In this embodiment, the weight of the peroxide crosslinking agent accounts for 1.5% of the total weight of the polyethylene, and the weight of the antioxidant accounts for 0.5% of the total weight of the polyethylene. In this embodiment, the polyethylene is high-density polyethylene, the peroxide crosslinking agent is ethylene peroxide, and the antioxidant is polyphenol antioxidant 1010.

[0047] S2, using a three-layer co-extrusion device, the polyethylene mixture and the semi-conductive shielding material are used to wrap the cable core to obtain a pretreated cable.

[0048] The polyethylene mixture obtained in S1 and a commercially available ±525kV semi-conductive shielding material are placed into an extruder unit of a three-layer co-extrusion device. The die head of the three-layer co-extrusion device is further responsible for separating the materials in the extruder unit into a conductor shielding layer, an insulation layer, and an insulation shielding layer, which are then wrapped around the cable core. In this embodiment, the polyethylene mixture is used as the insulation layer material, and the ±525kV semi-conductive shielding material is used as the shielding layer material to wrap the cable core to obtain a pretreated cable. The base temperature of the three-layer co-extrusion device is 110°C.

[0049] S3, by controlling the winding speed of the lower traction device, the pretreated cable is cross-linked and cooled in the cross-linking tube and the cooling tube.

[0050] During the preparation of cross-linked polyethylene insulated cables, the pretreated cables obtained in S2 are input into a cross-linking tube for cross-linking, so that the insulation layer materials of the cable cores undergo cross-linking in the cross-linking tube to generate cross-linked polyethylene. During the cross-linking process, the pressure in the cross-linking tube is 14 bar and the temperature is 270°C. Furthermore, the cables that have undergone cross-linking in the cross-linking tube are transported to a cooling tube for cooling, and the temperature of the cables is cooled to below a preset temperature, so that the cables can be cooled and shaped in time to obtain cooled cables.

[0051] It should be noted that the value of the preset temperature is manually set. In this embodiment, the value of the preset temperature is 50° C. The implementer can also set it by himself according to the specific situation. This embodiment does not impose any special restrictions.

[0052] Preferably, the schematic diagram of the solar thermal energy storage cable production line device provided in this embodiment using cross-linked polyethylene as the insulating protective layer is as follows Figure 2 As shown, Figure 2 In the middle, serial number 1 is the pay-off device 1, serial number 2 is the wire storage device, serial number 3 is the upper traction equipment, serial number 4 is the three-layer co-extrusion device, serial number 5 is the upper closer, serial number 6 is the cross-linking tube, serial number 7 is the suspension controller, serial number 8 is the cooling tube, serial number 9 is the lower closer, serial number 10 is the wire arrangement device, serial number 11 is the traction auxiliary device, and serial number 12 is the lower traction equipment.

[0053] In the production process of cross-linked polyethylene insulated cables, to improve the stability of cable tension, the motor speed of the upper traction device is usually kept constant, that is, the cable outlet speed is kept constant. The cable tension is controlled in real time by adjusting the motor speed of the lower traction device through a suspension controller. However, when the cable is wound using the lower traction device, the cable winding radius gradually increases over time. In this case, if the motor speed of the lower traction device is kept constant, the winding speed of the lower traction device will increase over time, while the outlet speed of the upper traction device remains unchanged. At this time, the difference between the force generated by the lower traction device when pulling the cable in the forward direction and the reaction force generated by the upper traction device when pulling the cable core in the reverse direction also increases over time. This will increase the tension of the cable core and cause oscillation of the cable core.

[0054] Therefore, in order to improve the stability of cable tension, the winding speed of the lower traction device is controlled. The specific control process includes:

[0055] S301: Acquire the exit speed data of the upper traction device at the current moment and all acquisition moments before the preset time, the winding speed data of the lower traction device, and the position offset data of the cable in the cross-linked tube.

[0056] The speed sensor is used to collect the exit speed data of the upper traction device and the winding speed data of the lower traction device at the current moment and all the collection moments before the preset time, and the suspension controller is used to collect the position offset data of the cable in the cross-linked tube, where the data collection frequency is set to f.

[0057] It should be noted that the values ​​of the preset duration and data acquisition frequency are both manually set. In this embodiment, the preset duration is 10s and the data acquisition frequency f is 20Hz. The implementer can also set them according to the specific situation. This embodiment does not impose any special restrictions.

[0058] Furthermore, in order to eliminate the influence of data dimension on the calculation results, all collected data are normalized. There are many commonly used normalization methods. In this embodiment, the maximum and minimum value normalization method is adopted. As other implementation methods, the implementer may also adopt other normalization methods such as the z-score normalization method. This embodiment does not impose any special restrictions on the selection of normalization method.

[0059] S302: The difference between the winding speed data and the outlet speed data at each collection moment is recorded as the speed deviation data at each collection moment; a time series decomposition algorithm is used to obtain a trend item sequence of all speed deviation data, and the first oscillation coefficient at the current moment is obtained by analyzing the change trend of all elements in the trend item sequence.

[0060] During the production process of solar thermal energy storage cables with cross-linked polyethylene as the insulating protective layer, if the motor speed of the lower traction device is not controlled in a timely manner, and the difference between the cable winding speed at the lower traction device and the outlet speed at the upper traction device shows a trend of single change over time, the tension on the cable core will cause an increase or decrease. This change in tension will affect the stability of cable production and increase the risk of cable core oscillation.

[0061] Therefore, in order to suppress the oscillation of the cable core, the first oscillation coefficient is determined by analyzing the change characteristics of the winding speed data and the outlet speed data, so as to judge the oscillation of the cable core and reduce the oscillation risk, thereby improving the stability of the cable tension. Specifically:

[0062] The difference between the winding speed data and the outlet speed data at each collection moment, that is, the absolute value of the difference between the winding speed data and the outlet speed data at each collection moment, is recorded as the speed deviation data at each collection moment;

[0063] Furthermore, the speed deviation data of all collected moments before the current moment is used as the input of the time series decomposition algorithm, and a trend item sequence is output. All elements in the trend item sequence are fitted to obtain a fitting straight line, and the first oscillation coefficient at the current moment is the absolute value of the slope of the fitting straight line.

[0064] It should be noted that there are many commonly used time series decomposition algorithms. In this embodiment, the STL time series decomposition algorithm is used to obtain the trend item sequence of speed deviation data. In actual applications, as another implementation method, the implementer may also use the SEATS decomposition algorithm to obtain the trend item sequence.

[0065] In addition, it should be understood that there are many commonly used fitting methods. In this embodiment, the least squares fitting method is used to fit all elements in the trend item sequence. In actual application, as other implementation methods, the implementer may also use other fitting methods such as polynomial fitting.

[0066] Among them, the STL time series decomposition algorithm and the least square fitting method are both well-known technologies, and their specific principles are not described in detail here.

[0067] According to the first oscillation coefficient at the current moment, it can be understood that the first oscillation coefficient is used to characterize the possibility of oscillation in the cable core when the cable core speed deviation data shows a single change trend. If the absolute value of the slope of the fitting straight line is larger, it means that the possibility of a single change trend in the speed deviation data is greater, the possibility of inducing linear oscillation of the cable is greater, and the obtained first oscillation coefficient is larger; conversely, if the absolute value of the slope of the fitting straight line is smaller, it means that the possibility of a single change trend in the speed deviation data is smaller, the possibility of inducing linear oscillation of the cable is smaller, and the obtained first oscillation coefficient is smaller.

[0068] S303: By measuring the correlation between the periodic characteristics of all winding speed data and all outlet speed data before the current moment, and evaluating the average distribution of all winding speed data and all outlet speed data respectively, the second oscillation coefficient at the current moment is determined, and combined with the first oscillation coefficient, the oscillation response coefficient at the current moment is determined.

[0069] During the production process of solar thermal energy storage cables with cross-linked polyethylene as the insulating protective layer, fluctuations in the parameters of production line auxiliary devices such as the three-layer co-extrusion device, cooling device, sealing device, and traction device will have a certain impact on the winding speed and outlet speed of the cable core, thereby causing fluctuations in the data of the winding speed and outlet speed of the cable core. When the data fluctuations of the winding speed and outlet speed of the cable core have the same change pattern, it is usually easier to cause oscillation of the cable core. This is because when the winding speed and outlet speed have the same fluctuation pattern, the speed deviation data will also fluctuate accordingly. If this fluctuation cannot be adjusted and controlled in time, it may cause unstable tension in the cable core, thereby causing oscillation.

[0070] Therefore, in order to suppress the cable core oscillation phenomenon caused by the fluctuation of the auxiliary device parameters of the cable production line, the second oscillation coefficient is determined by measuring the correlation between the periodic characteristics of all winding speed data and all outlet speed data before the current moment, and evaluating the average distribution of all winding speed data and all outlet speed data respectively. In combination with the first oscillation coefficient, the oscillation response coefficient is determined to improve the stability of the cable tension and suppress the cable core oscillation phenomenon. Specifically,

[0071] The STL time series decomposition algorithm is used to obtain the seasonal item series of all winding speed data and all exit speed data at the current moment and before respectively.

[0072] Among them, the method of using the STL time series decomposition algorithm to obtain the seasonal term series is a well-known technology, and its specific acquisition process will not be repeated here.

[0073] The expression of the second oscillation coefficient s at the current moment is: s = p × (q + g); where p represents the correlation coefficient of the seasonal term sequence between all winding speed data at the current moment and before and all outlet speed data; q represents the mean of all winding speed data at the current moment and before; g represents the mean of all outlet speed data at the current moment and before.

[0074] It should be noted that there are many commonly used methods for measuring the correlation between sequences. In this embodiment, the absolute value of the Pearson correlation coefficient between the seasonal item sequence of all winding speed data and the seasonal item sequence of all outlet speed data is calculated to measure the correlation of the periodic characteristics between the winding speed data and the outlet speed data. In actual application, as its implementation method, the implementer may also use the Spearman correlation coefficient or the Kendall rank correlation coefficient.

[0075] The calculation method of the Pearson correlation coefficient is a well-known technique, and the specific calculation process will not be described in detail.

[0076] According to the second oscillation coefficient at the current moment, it can be understood that if the fluctuation change law between the winding speed and the outlet speed is more similar, that is, the correlation coefficient between the seasonal item sequence of the winding data and the seasonal item sequence of the outlet data is larger, and the fluctuation degree of the winding speed data and the outlet speed data is greater, that is, the larger the mean of the winding speed data and the larger the mean of the outlet speed, then the second oscillation coefficient at the current moment is larger, indicating that the possibility of oscillation of the cable core at the current moment is greater; conversely, if the difference in the fluctuation change law between the winding speed and the outlet speed is greater, that is, the correlation coefficient between the seasonal item sequence of the winding data and the seasonal item sequence of the outlet data is smaller, and the fluctuation degree of the winding speed data and the outlet speed data is smaller, that is, the smaller the mean of the winding speed data and the smaller the mean of the outlet speed, then the second oscillation coefficient at the current moment is smaller, indicating that the possibility of oscillation of the cable core at the current moment is smaller.

[0077] Furthermore, the first oscillation coefficient and the second oscillation coefficient are combined to determine the oscillation response coefficient, specifically:

[0078] The average of the first oscillation coefficient and the second oscillation coefficient at the current moment is used as the oscillation response coefficient at the current moment.

[0079] According to the oscillation response coefficient at the current moment, it can be understood that if the first oscillation coefficient and the second oscillation coefficient are larger, the obtained oscillation response coefficient is larger, indicating that the possibility of linear oscillation of the cable at the current moment is greater; conversely, if the first oscillation coefficient and the second oscillation coefficient are smaller, the obtained oscillation response coefficient is smaller, indicating that the possibility of linear oscillation of the cable at the current moment is smaller.

[0080] S304: Analyze the change trend and average distribution of all position offset data, and determine the response adjustment coefficient at the current moment in combination with the oscillation response coefficient to control the winding speed data of the lower traction device.

[0081] When the cable core deviates from the central axis of the cross-linked pipe, in order to maintain the cable core stably suspended at the central axis of the cross-linked pipe as quickly as possible, the winding speed data of the lower traction equipment needs to be controlled. The specific control process is as follows:

[0082] First, based on the changing trend and average distribution of the position offset data and combined with the oscillation response coefficient, the response adjustment coefficient at the current moment is determined, specifically:

[0083] A time series decomposition algorithm is used to obtain a trend item sequence of all position offset data at and before the current moment, recorded as a position offset trend item sequence, and all elements in the position offset trend item sequence are fitted to obtain a position offset fitting line;

[0084] The product of the mean of all position offset data at the current moment and before and the slope of the position offset fitting line is taken as the position offset response coefficient at the current moment;

[0085] The response adjustment coefficient at the current moment is the average of the oscillation response coefficient and the position offset response coefficient at the current moment.

[0086] According to the response adjustment coefficient at the current moment, it can be understood that the response adjustment coefficient is used to evaluate the adjustment of the response speed when the cable oscillates. If the oscillation response coefficient is larger and the position offset response coefficient is larger, it means that the possibility of the cable oscillating in the cross-linked tube at the current moment is greater. Therefore, in order to be able to suppress the cable oscillation in time, the response adjustment coefficient should also be larger; conversely, if the oscillation response coefficient is smaller and the position offset response coefficient is smaller, it means that the possibility of the cable oscillating in the cross-linked tube at the current moment is smaller, and the response adjustment coefficient can be appropriately reduced.

[0087] Secondly, the optimization scale coefficient at the current moment is optimized based on the response adjustment coefficient, specifically:

[0088] The expression of the optimized proportional coefficient P at the current moment is: P = P1 + round[norm(H) × P2]; where P1 and P2 respectively represent the initial proportional coefficient and initial integral coefficient in the PID control algorithm in the drape controller obtained by trial and error; H represents the response adjustment coefficient at the current moment; norm() represents the normalization function; and round[] represents the rounding function.

[0089] Among them, the use of trial and error method to obtain the initial proportional coefficient and initial integral coefficient in the PID control algorithm in the suspension controller is a well-known technology, and its specific acquisition process is not repeated here.

[0090] According to the optimized proportional coefficient at the current moment, it can be understood that the larger the response adjustment coefficient at the current moment, in order to suppress the oscillation of the cable core and the phenomenon that the cable core deviates from the central axis of the cross-linked tube, the proportional coefficient in the suspension controller should be appropriately increased, thereby improving the suppression speed of the cable oscillation.

[0091] Furthermore, the optimized proportional coefficient at the current moment is used as the proportional coefficient in the lower suspension controller at the current moment to obtain an improved suspension controller, and the position offset data of the lower cable at the current moment is used as the input of the improved suspension controller to output a speed control signal to control the winding speed data of the lower traction device at the current moment.

[0092] Preferably, the flow chart of the lower traction device control method provided in this embodiment is as follows: Figure 3 shown.

[0093] S4, after the processing is completed, a solar thermal energy storage cable with cross-linked polyethylene as the insulating protective layer is obtained.

[0094] After the pretreated cable is cross-linked and cooled in the cross-linking tube and the cooling tube, the cooled cable is sheathed and inspected after the sheath extrusion. The inspected cable is wound onto a cable drum for packaging, thereby completing the preparation of the solar thermal energy storage cable with cross-linked polyethylene as the insulating protective layer.

[0095] Preferably, the process flow chart for preparing a solar thermal energy storage cable with cross-linked polyethylene as an insulating protective layer provided in this embodiment is as follows: Figure 4 shown.

[0096] Example 2

[0097] Example 2 provides an optimization method for preparing the insulation protective layer of a solar thermal energy storage cable. For details, please refer to Figure 1 , the method comprises the following steps:

[0098] S1, mixing a certain weight of polyethylene, a peroxide crosslinking agent and an antioxidant to obtain a polyethylene mixture.

[0099] A polyethylene mixture is uniformly mixed with a peroxide crosslinker and an antioxidant in parts by weight to form a polyethylene mixture. In this embodiment, the weight of the peroxide crosslinker accounts for 2% of the total weight of the polyethylene, and the weight of the antioxidant accounts for 0.55% of the total weight of the polyethylene. In this embodiment, the polyethylene is low-density polyethylene, the peroxide crosslinker is dicumyl peroxide, and the antioxidant is polyphenol antioxidant 1076.

[0100] S2, using a three-layer co-extrusion device to wrap the polyethylene mixture and the semi-conductive shielding material for the cable core to obtain a pretreated cable, wherein the base temperature of the three-layer co-extrusion device is 120°C, and the operation of wrapping the cable core with the polyethylene mixture and the semi-conductive shielding material is the same as in Example 1.

[0101] S3, by controlling the winding speed of the lower traction device, the pretreated cable is cross-linked and cooled in the cross-linking tube and the cooling tube. In this embodiment, the pressure in the cross-linking tube during the cross-linking process is 15 bar and the temperature is 300°C; the value of the preset temperature during the cooling process, the operation of the cross-linking process and the cooling process, and the operation of controlling the winding speed of the lower traction device are the same as in Example 1.

[0102] S4, the operation of obtaining a solar thermal energy storage cable with cross-linked polyethylene as an insulating protective layer after processing is the same as in Example 1.

[0103] Example 3

[0104] Example 3 provides an optimization method for preparing the insulation protective layer of a solar thermal energy storage cable. For details, please refer to Figure 1 , the method comprises the following steps:

[0105] S1, mixing a certain weight of polyethylene, a peroxide crosslinking agent and an antioxidant to obtain a polyethylene mixture.

[0106] A polyethylene mixture is uniformly mixed with a peroxide crosslinker and an antioxidant in parts by weight to form a polyethylene mixture. In this embodiment, the weight of the peroxide crosslinker accounts for 2.5% of the total weight of the polyethylene, and the weight of the antioxidant accounts for 0.6% of the total weight of the polyethylene. In this embodiment, the polyethylene is high-density polyethylene, the peroxide crosslinker is ethylene peroxide, and the antioxidant is thiobisphenol antioxidant 300.

[0107] S2, using a three-layer co-extrusion device to wrap the cable core with the polyethylene mixture and the semi-conductive shielding material to obtain a pretreated cable, wherein the base temperature of the three-layer co-extrusion device is 130°C, and the operation of wrapping the cable core with the polyethylene mixture and the semi-conductive shielding material is the same as in Example 1.

[0108] S3, by controlling the winding speed of the lower traction device, the pretreated cable is cross-linked and cooled in the cross-linking tube and the cooling tube. In this embodiment, the pressure in the cross-linking tube during the cross-linking process is 16 bar and the temperature is 330°C; the value of the preset temperature during the cooling process, the operation of the cross-linking process and the cooling process, and the operation of controlling the winding speed of the lower traction device are the same as in Example 1.

[0109] S4, the operation of obtaining a solar thermal energy storage cable with cross-linked polyethylene as an insulating protective layer after processing is the same as in Example 1.

[0110] It is understood that references to "one embodiment" or "some embodiments" in the present specification mean that one or more embodiments of the present application include a particular feature, structure, or characteristic described in conjunction with that embodiment. Thus, if "in one embodiment," "in some embodiments," "in other embodiments," or "in other embodiments" appear in different places in this specification, they do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and their variations all mean "including but not limited to," unless otherwise specifically emphasized.

[0111] It should be noted that the above-mentioned sequence of the embodiments of the present application is for description only and does not represent the advantages and disadvantages of the embodiments. The above description is of a specific embodiment of this specification. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multi-tasking and parallel processing are also possible or may be advantageous. At the same time, the size of the sequence number of each step in the embodiment does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments in this specification.

[0112] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A method for optimizing the preparation process of the insulation protective layer of a solar thermal energy storage cable, characterized in that: The method comprises the following steps: S1, mixing a certain weight of polyethylene, a peroxide crosslinking agent and an antioxidant to obtain a polyethylene mixture; S2, using a three-layer co-extrusion device to wrap the cable core with the polyethylene mixture and the semi-conductive shielding material to obtain a pretreated cable; S3, by controlling the winding speed of the lower traction device, cross-linking and cooling the pretreated cable in the cross-linking tube and the cooling tube. The process of controlling the winding speed of the lower traction device includes: S301: Acquire the exit speed data of the upper traction device, the winding speed data of the lower traction device, and the position offset data of the cable in the cross-linked tube at the current moment and all the acquisition moments before the preset time period; S302: The difference between the winding speed data and the outlet speed data at each acquisition moment is recorded as the speed deviation data at each acquisition moment; a time series decomposition algorithm is used to obtain a trend item sequence of all speed deviation data, and the first oscillation coefficient at the current moment is obtained by analyzing the change trend of all elements in the trend item sequence; S303: Determine a second oscillation coefficient at the current moment by measuring the correlation of the periodic characteristics between all winding speed data and all outlet speed data before the current moment, and respectively evaluating the average distribution of all winding speed data and all outlet speed data. Combined with the first oscillation coefficient, determine an oscillation response coefficient at the current moment. S304: Analyze the change trend and average distribution of all position offset data, and determine the response adjustment coefficient at the current moment in combination with the oscillation response coefficient to control the winding speed data of the lower traction device; S4, after the processing is completed, a solar thermal energy storage cable with cross-linked polyethylene as the insulating protective layer is obtained.

2. The method for optimizing the preparation process of the insulation protective layer of a solar thermal energy storage cable according to claim 1, characterized in that: The weight of the peroxide crosslinking agent accounts for 1.5% to 2.5% of the total weight of the polyethylene, and the weight of the antioxidant accounts for 0.5% to 0.6% of the total weight of the polyethylene.

3. The method for optimizing the preparation process of the insulation protective layer of a solar thermal energy storage cable according to claim 1, characterized in that: The polyethylene is one of high-density polyethylene or linear low-density polyethylene, the peroxide crosslinking agent is one of ethylene peroxide or dicumyl peroxide, and the antioxidant is one of polyphenol antioxidant 1010, polyphenol antioxidant 1076 or thiobisphenol antioxidant 300.

4. The method for optimizing the preparation process of the insulation protective layer of a solar thermal energy storage cable according to claim 1, characterized in that: The extrusion temperature of the three-layer co-extrusion device is 110-130°C.

5. The method for optimizing the preparation process of the insulation protective layer of a solar thermal energy storage cable according to claim 1, characterized in that: The method for determining the first oscillation coefficient at the current moment is: The speed deviation data at the current moment and all previous acquisition moments are fitted to obtain a fitting straight line, and the first oscillation coefficient at the current moment is the absolute value of the slope of the fitting straight line.

6. The method for optimizing the preparation process of the insulation protective layer of a solar thermal energy storage cable according to claim 1, characterized in that: The method for determining the second oscillation coefficient at the current moment is: The time series decomposition algorithm is used to obtain the seasonal item series of all winding speed data and all exit speed data at the current moment and before respectively; The second oscillation coefficient at the current moment The expression is: Where, It represents the correlation coefficient of the seasonal term series between all winding speed data and all outlet speed data at the current moment and before; represents the mean of all winding speed data at the current moment and before; g represents the mean of all outlet speed data at the current moment and before.

7. The method for optimizing the preparation process of the insulation protective layer of a solar thermal energy storage cable according to claim 1, characterized in that: The oscillation response coefficient at the current moment is an average of the first oscillation coefficient and the second oscillation coefficient at the current moment.

8. The method for optimizing the preparation process of the insulation protective layer of a solar thermal energy storage cable according to claim 7, characterized in that: The method for determining the response adjustment coefficient at the current moment is: A time series decomposition algorithm is used to obtain a trend item sequence of all position offset data at and before the current moment, recorded as a position offset trend item sequence, and all elements in the position offset trend item sequence are fitted to obtain a position offset fitting line; The product of the mean of all position offset data at the current moment and before and the slope of the position offset fitting line is taken as the position offset response coefficient at the current moment; The response adjustment coefficient at the current moment is the average of the oscillation response coefficient and the position offset response coefficient at the current moment.

9. The method for optimizing the preparation process of the insulation protective layer of a solar thermal energy storage cable according to claim 1, characterized in that: The controlling of the winding speed data of the lower traction device includes: The optimized scaling factor at the current moment The expression is: Where, , P2 represent the initial proportional coefficient and initial integral coefficient of the PID control algorithm in the drape controller obtained by trial and error respectively; Indicates the response adjustment coefficient at the current moment; represents the normalization function; Represents the rounding function; The optimized proportional coefficient at the current moment is used as the proportional coefficient in the lower suspension controller at the current moment to obtain an improved suspension controller, and the position offset data of the lower cable at the current moment is used as the input of the improved suspension controller to output a speed control signal to control the winding speed data of the lower traction device at the current moment.

10. The method for optimizing the preparation process of the insulation protective layer of a solar thermal energy storage cable according to claim 1, wherein: In the above-mentioned S3, the running speed of the pretreated cable is 1.4-1.6 m / min; the pressure in the cross-linked tube is 14-16 bar, and the temperature is 270-330°C.

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