Multi-element thermal synergetic high-voltage cable degassing drying room and control method

Abstract

The invention discloses a multi-element heat synergistic high-voltage cable degassing drying room which comprises a drying room chamber, a conductor self-heating unit, a combined heat supply unit, a heat recovery unit and an automatic console. The conductor self-heating unit comprises an adjustable direct-current power supply arranged outside the drying room, and the adjustable direct-current power supply is used for supplying power to a conductor of a cable arranged in the drying room and heating the conductor; the combined heat supply unit comprises an air source heat pump, an air duct type electric heater and an air supply fan which are arranged outside the drying room chamber and are sequentially communicated in the airflow direction, an air outlet of the air supply fan is communicated with the drying room chamber, and the combined heat supply unit is used for heating the surface of the cable; the heat recovery unit is used for controlling an internal circulation mode or an exhaust and ventilation mode of air return of the drying room; and the automatic console is in electric signal connection with the air duct type electric heater, the air source heat pump, the adjustable direct-current power supply, the air supply fan and the heat recovery unit and controls the actions thereof. The cable degassing effect is improved through a multi-element heat synergistic heating mode, the degassing process period is shortened, and the annual heat efficiency of the high-voltage cable degassing drying room is greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of high-voltage cable degassing and drying oven heating technology, specifically relating to a multi-element heat-coordinated high-voltage cable degassing drying oven and its control method. Background Technology

[0002] In recent years, with the advancement of ultra-high voltage power transmission projects, the construction of urban rail transit, and the rapid development of the new energy industry, the domestic market demand for high-voltage cross-linked cables has ushered in a new growth point. However, during the cross-linking process of cable production, byproducts such as methane, acetophenone, and cumyl alcohol are generated. If the release of byproducts such as methane is incomplete during the cable production process, there are potential hazards such as partial discharge, damage to the mechanical properties of the cable, and spontaneous combustion of volatile gases during the subsequent use of the cable. Therefore, generally after the cross-linking reaction is completed and the insulation is extruded, and before the metal shielding layer is wrapped around the insulation layer, high-voltage cables need to undergo a degassing process in a specially constructed drying room under high temperature conditions.

[0003] Traditional high-voltage cable degassing ovens typically employ a single electric heating method, resulting in uneven heat distribution, insufficient heating of the inner cable layers, and prolonged time for the cable insulation to reach the predetermined temperature. Furthermore, when the methane concentration inside reaches a threshold, the high-temperature exhaust gas (approximately 70°C) is directly discharged outdoors. Therefore, these systems suffer from low thermal efficiency, long degassing cycles, high annual energy consumption, and wasted waste heat. Consequently, a more energy-efficient and effective system upgrade for traditional cable degassing ovens is of great practical significance. Summary of the Invention

[0004] The technical problem to be solved by this invention is: how to improve the annual thermal efficiency of the high-voltage cable degassing drying chamber, reduce energy consumption, shorten the degassing process cycle, and realize the automated and efficient operation of the high-voltage cable degassing drying chamber.

[0005] To solve the above-mentioned technical problems, the present invention provides a multi-element heat-coordinated high-voltage cable degassing drying chamber, including a drying chamber, a conductor self-heating unit, a combined heating unit, a heat recovery unit, and an automatic control console; The conductor self-heating unit includes an adjustable DC power supply located outside the drying chamber. The adjustable DC power supply is used to supply power and heat the conductor of the cable placed inside the drying chamber. The combined heating unit includes an air source heat pump, a duct-type electric heater, and a blower, which are located outside the drying chamber and connected sequentially along the airflow direction. The outlet of the blower is connected to the drying chamber. The combined heating unit is used to heat the surface of the cable. The heat recovery unit is used to control the internal circulation mode or the exhaust ventilation mode of the drying chamber. The automatic control console is electrically connected to and controls the operation of the duct-type electric heater, air source heat pump, adjustable DC power supply, air blower and heat recovery unit.

[0006] The aforementioned multi-element heat-coordinated high-voltage cable degassing drying chamber has an elevated structure with an elevated bottom layer. An array of perforated air vents is arranged on the upper side of the elevated layer and below each cable. An indoor air duct is provided on the upper side of the drying chamber, and the indoor air duct is equipped with a downward-facing return air inlet. The return air inlet is positioned corresponding to the perforated air vent array to receive the hot air delivered by the perforated air vent array and recover the gas inside the drying chamber.

[0007] In the aforementioned multi-element thermal synergistic high-voltage cable degassing oven, the adjustable DC power supply is connected in series with multiple cables to form a circuit via an electrical connector; the adjustable DC power supply is used to heat the cable insulation layer inside the cable.

[0008] The aforementioned multi-element thermal synergistic high-voltage cable degassing drying chamber also includes a thermocouple sensor, a thermistor sensor, and a methane concentration sensor; the thermocouple sensor is installed on the inner wall of the drying chamber to monitor the air temperature in the drying chamber; the thermistor sensor is installed in the interlayer of each cable to measure the temperature of the cable insulation layer; and the methane concentration sensor is installed on the upper part of the inner wall of the drying chamber to monitor the methane concentration in the drying chamber. The automatic control console receives signals from thermocouple sensors, thermistor sensors, and methane concentration sensors, and controls the operation of the combined heating unit, conductor self-heating unit, and heat recovery unit respectively based on these signals.

[0009] The aforementioned multi-element heat-coordinated high-voltage cable degassing oven has an air source heat pump with a two-layer chassis structure, the upper layer being a heat absorption box and the lower layer being a heat release box. The heat absorption box is divided into two chambers by a louvered air vent, with an evaporator installed in one chamber and an air inlet installed at the top of the other chamber. The heat release box has an air inlet and an air outlet at the front and back, respectively.

[0010] The aforementioned multi-element heat-coordinated high-voltage cable degassing drying chamber includes a heat recovery unit comprising a heat absorption box and a heat pipe heat exchanger, an outdoor air duct and a valve group; the heat pipe heat exchanger includes an evaporation end and a condensation end; one side of the outdoor air duct is connected to the indoor air duct, and the other side is divided into two branches via a three-way pipe; one branch is connected to the air inlet of the heat absorption box of the heat pump through the evaporation end for exhausting waste gas. Another branch is divided into branch two and branch three via a three-way pipe. Branch two is connected to the heat pump's heat release box inlet for airflow circulation and heating in the drying chamber. Branch three is connected to the outlet of the heat pipe heat exchanger's condenser end for introducing fresh air to the combined heating unit's air inlet.

[0011] In the aforementioned multi-element heat-coordinated high-voltage cable degassing drying chamber, the valve group consists of electric air valve one and electric air valve two; the pipe section between tee pipe one and tee pipe two is equipped with electric air valve one to control the internal air circulation; branch line three is equipped with electric air valve two to control the fresh air introduced from the outside to enter the combined heating unit.

[0012] In the aforementioned multi-element heat-coordinated high-voltage cable degassing drying chamber, the outer three sides of the chamber where the evaporator is located are provided with louvered air vents II. The opening and closing state of the louvered air vents II is opposite to that of the louvered air vents I. The louvered air vents I is used to control the passage of exhaust gas in the drying chamber into the evaporator, while the louvered air vents II are used to control the exhaust gas from mixing with the outdoor air when it is sent to the evaporator.

[0013] In the aforementioned multi-element heat-coordinated high-voltage cable degassing drying chamber, the automatic control console switches between the internal circulation mode and the exhaust ventilation mode of the drying chamber based on the methane concentration monitored by the methane concentration sensor. In the internal circulation mode, when the methane concentration does not exceed the threshold, electric air valve one and louvered air outlet two are opened, and electric air valve two and louvered air outlet one are closed. The return air inside the drying room enters the outdoor air duct through the indoor air duct, and the airflow then enters the air inlet of the combined heating unit through electric air valve one. The exhaust ventilation mode is as follows: when the methane concentration exceeds the threshold, electric air valve one and louvered air outlet two (406) are closed, and electric air valve two and louvered air outlet one are opened. The exhaust gas discharged from the drying room is sent to the evaporation end of the heat pipe heat exchanger through branch one for primary heat recovery of the exhaust gas. Then the exhaust gas is sent from the air outlet of the evaporation end to the evaporator of the heat absorption box for secondary heat recovery of the exhaust gas, and finally discharged to the outside. At the same time, the outdoor fresh air is preheated by exchanging heat with the exhaust gas flowing through the evaporation end through the condensation end of the heat pipe heat exchanger. The preheated fresh air enters the air inlet of the combined heating unit through electric air valve two and branch two.

[0014] The aforementioned multi-element heat-coordinated high-voltage cable degassing oven has an automatic control console that controls the start-up and shutdown of the air source heat pump and the duct-type electric heater, as well as their operating power, based on the temperature information monitored by the thermocouple sensor. This allows for automatic switching between three heating modes: single air source heat pump heating, single duct-type electric heater heating, and dual heat source heating.

[0015] The aforementioned multi-element heat-coordinated high-voltage cable degassing drying chamber provides a control method, including the following steps: Step 1: The automatic control console starts the adjustable DC power supply of the conductor self-heating unit, and the inside of the cable is heated; Step 2: The automatic control console starts the combined heating unit and the blower, and automatically switches the heating mode of the combined heating unit according to the temperature in the drying chamber. The heated air enters the drying chamber to externally heat the cables. Step 3: The automatic control console monitors the methane concentration inside the drying chamber in real time. When the monitored methane concentration does not exceed the threshold, the drying chamber maintains the internal circulation mode, and the return air inside the drying chamber returns to the combined heating unit through branch line 2 for reheating. Step 4: When the automatic control console detects that the methane concentration exceeds the threshold, the heat recovery unit switches to external circulation mode; the exhaust gas in the drying room is led to the evaporator end of the heat pipe heat exchanger through branch line 1 for primary waste heat recovery; the exhaust gas is introduced into the heat absorption box of the air source heat pump from the evaporator end outlet, flows through the evaporator, completes secondary waste heat recovery, and is discharged outdoors. Step 5: Outdoor fresh air is drawn into the condenser end and exchanges heat with the high-temperature exhaust gas. Then the gas enters the combined heating unit through branch line 2 for secondary heating and is finally sent into the drying chamber. When the methane concentration drops below the threshold, the automatic control console controls the heat recovery unit to automatically switch to the internal circulation mode described in step 3.

[0016] The beneficial effects achieved by this invention are as follows: The multi-element heat-synergistic high-voltage cable degassing drying chamber provided by this invention integrates a combined heating system consisting of a duct-type electric heater and an air source heat pump, and automatically switches between three heating modes—single heat pump, dual heat source, and single electric heating—according to operating conditions, significantly improving the annual thermal efficiency; by applying current to the cable conductor through an adjustable DC power supply to achieve conductor self-heating, the internal temperature of the cable insulation layer is uniformly and rapidly increased, greatly shortening the degassing cycle; the bottom of the drying chamber is equipped with an overhead air supply cavity and an array of perforated air vents, and the top is arranged with a return air duct. A uniform airflow organization with downward supply and upward return ensures even heating of the cable surfaces on each coil. A heat pipe heat exchanger performs primary heat recovery by exchanging heat between exhaust gas and fresh air, and the exhaust gas is further introduced into the heat pump evaporator for secondary heat recovery, achieving efficient cascade utilization of waste heat. By merging the return air vent and exhaust vent, interference with the original airflow organization is avoided. Furthermore, by controlling the coordinated opening and closing of the louvers inside and outside the heat pump heat absorption box, outside air is isolated in exhaust mode, while the heat pump fan also functions as an exhaust fan, improving the evaporator's heat absorption efficiency and reducing system power consumption. This invention significantly improves the annual thermal efficiency of the high-voltage cable degassing drying chamber, and the multi-element heat synergy heating method results in better cable degassing, with significant improvements in process cycle and operational adaptability. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the multi-element thermal synergistic high-voltage cable degassing drying chamber structure in Example 1; Figure 2 This is a front view of the structure of the multi-element thermal synergistic high-voltage cable degassing drying chamber in Example 1; Figure 3 This is an isometric view of the structure of the multi-element thermal synergistic high-voltage cable degassing drying chamber in Example 1; Figure 4 This is an exploded view of the combined heating unit in Example 1; Figure 5 This is a schematic diagram of the ventilation system inside the drying room in Example 1; Figure 6 This is a schematic diagram of the working state of the air source heat pump in the internal circulation mode in Example 1; Figure 7 This is a schematic diagram of the working state of the air source heat pump in the exhaust ventilation mode in Example 1; Figure 8 This is a top view of the conductor self-heating unit in Example 1; Figure 9 This is a partial enlarged view of the cable structure; Figure 10 This is a magnified view of a portion of the thermistor structure; Figure 11 This is a magnified view of a portion of the structure of the methane concentration sensor; Figure 12 This is a magnified view of a portion of the thermocouple sensor structure.

[0018] Markings in the diagram: 1. Drying chamber; 101. Elevated layer; 102. Perforated plate air vent array; 103. Air inlet one; 2. Cable; 201. Conductor; 202. Cable insulation layer; 203. Electrical connector; 3. Duct-type electric heater; 301. Air inlet two; 302. Air outlet two; 4. Air source heat pump; 401. Absorbing box; 402. Exothermic box; 403. Partition; 404. Evaporator; 405. Louvered air vent one; 406. Louvered air vent two; 407. Air inlet of the absorbing box; 408. Air inlet of the exothermic box; 409. Air outlet of the exothermic box. 410. Heat pump fan; 5. Heat pipe heat exchanger; 501. Evaporator end; 502. Condenser end; 6. Supply fan; 7. Adjustable DC power supply; 8. Automatic control console; 9a. Indoor air duct; 9b. Outdoor air duct; 901. Return air outlet; 902. Branch line two; 903. Branch line one; 904. Branch line three; 905. Exhaust duct; 10a. T-joint one; 10b. T-joint two; 11a. Electric air valve one; 11b. Electric air valve two; 12a. Thermocouple sensor; 12b. Thermistor sensor; 12c. Methane concentration sensor. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0020] Example 1

[0021] A multi-element heat-coordinated high-voltage cable degassing drying chamber includes a drying chamber 1, a conductor self-heating unit, a combined heating unit, a heat recovery unit, and an automatic control console 8. The upper side of the drying chamber 1 is provided with an indoor air duct 9a for recovering gas inside the drying chamber 1; The conductor self-heating unit includes an adjustable DC power supply 7 disposed outside the drying chamber 1. The adjustable DC power supply 7 is used to supply power and heat the conductor of the cable 2 placed inside the drying chamber 1. The combined heating unit includes an air source heat pump 4, a duct-type electric heater 3, and a blower 6 located outside the drying chamber 1 and connected sequentially in the airflow direction. The air outlet of the blower 6 is connected to the drying chamber 1. The combined heating unit is used to heat the surface of the cable 2. The heat recovery unit is used to control the internal circulation mode or exhaust ventilation mode of the return air in the drying chamber 1. The automatic control console 8 is electrically connected to and controls the operation of the duct-type electric heater 3, the air source heat pump 4, the adjustable DC power supply 7, the air blower 7, and the heat recovery unit.

[0022] The drying chamber 1 is an elevated structure with an elevated layer 101 at its bottom to maintain dryness and temperature stability within the chamber. Multiple perforated air vent arrays 102 are equidistantly arranged along the length of the drying chamber 1, above the elevated layer 101, to uniformly deliver hot air from the bottom of the drying chamber 1 upwards, forming a stable upward airflow. An indoor air duct 9a is located at the top of the drying chamber 1 along its length, with a closed end. The indoor air duct 9a has a downward-facing return air inlet 901, positioned corresponding to the perforated air vent array 102, to receive the hot air delivered by the perforated air vent array 102.

[0023] The drying chamber 1 is equipped with multiple cables 2. Each cable 2 is fixed above the perforated plate air outlet array 102 by a cable reel, so that the surface of the cable coil of the cable 2 is uniformly heated. The number of cables 2 is the same as the number of perforated plate air outlet array 102.

[0024] The conductor self-heating unit includes an adjustable DC power supply 7, a cable 2, and a thermistor sensor 12b.

[0025] An adjustable DC power supply 7 is located on the outside of the drying chamber 1. Each cable 2 is connected in series to form a loop via an electrical connector 203. The beginning and end of the loop are connected to the positive and negative terminals of the adjustable DC power supply 7, respectively. A thermistor sensor 12b is installed in the insulation layer of each cable 2 to measure the temperature of the cable insulation layer 202 and transmit the temperature signal to the automatic control console 8.

[0026] After the adjustable DC power supply 7 is turned on, the adjustable DC power supply 7 provides DC power to the multi-coil cable conductors 201 connected in series, and generates Joule heat through the cable conductors 201 to heat the cable insulation layer 202 from the inside of the cable 2; the resistance sensor 12b monitors the surface temperature of the cable insulation layer 202 in real time and transmits the temperature signal to the automatic control console 8.

[0027] The automatic control console 8 controls the heating power of the cable conductor 201 by precisely adjusting the power output voltage, so that the temperature of the cable insulation layer 202 rises quickly and evenly to close to the preset temperature value, and ensures that the temperature difference between its inner and outer layers is minimal.

[0028] The automatic control console 8 is located on the outer wall of the drying room 1 in the width direction.

[0029] In the conductor self-heating unit, the winding state of cable 2 on the coil does not affect its heating effect; the heating rate of cable 2 is only related to the voltage applied across the series circuit. Compared to traditional oven heating, under conductor self-heating, the temperature difference between the inner and outer layers of the cable insulation layer 202 is extremely small, approximately 1-2℃; the internal temperature of cable 2 is approximately uniformly distributed, and it can quickly reach the preset temperature in approximately 0.5-1.5 hours, significantly shortening the time required for degassing of high-voltage cables.

[0030] An air source heat pump 4, a duct-type electric heater 3, and a blower 6 are arranged along the length of the exterior side of the drying chamber 1. These components are sequentially connected in the direction of airflow within the drying chamber 1. The heat outlet 409 of the air source heat pump 4 is connected to the air inlet 301 of the duct-type electric heater 3. The air outlet 302 of the duct-type electric heater 3 is connected to the air inlet of the blower 6. The air outlet of the blower 6 is connected to the air inlet 103 of the drying chamber 1.

[0031] The heat dissipation box 402 of the air source heat pump 4 and the duct-type electric heater 3 form a combined heating unit. The automatic control console 8 controls the start-up and shutdown of the air source heat pump 4 and the duct-type electric heater 3, as well as their operating power, to achieve automatic switching between three heating modes: single electric heating, single heat pump heating, and dual heat source heating under different operating conditions.

[0032] The air source heat pump 4 is divided into an upper and lower two-layer chassis structure by a partition 403. The upper layer is the heat absorption box 401 and the lower layer is the heat release box 402.

[0033] The heat exchange chamber 402 houses a condenser, compressor, expansion valve, and other components used for the heating cycle; this is existing technology and will not be discussed further here. An air inlet 408 and an air outlet 409 are respectively located at the front and rear of the heat exchange chamber 402. A partition 403 has pre-drilled holes for the condenser pipes to pass through, providing a channel for the condenser pipes connecting the evaporator 404 and the condenser inside the heat exchange chamber 402.

[0034] Air heated by the combined heating unit enters the overhead layer 101 at the bottom of the drying chamber 1 through the blower 6. It forms a uniform and stable upward airflow through the perforated air vent array 102 on the floor, which heats the surface of the cable 2 uniformly. After the airflow rises to the top of the overhead layer 101, it is recovered by the return air vent 901 of the indoor air duct 9a. The recovered gas is led back to the combined heating system through the air duct loop for reheating, forming a cycle.

[0035] Thermocouple sensor 12a is installed at the reserved sensor interface on the inner side wall of the drying chamber 1. Its sensing head is suspended in the drying chamber 1 to monitor the temperature of the circulating air and transmit the temperature signal to the automatic control console 8. The automatic control console 8 makes intelligent decisions and drives the combined heating system to automatically switch between three modes: single electric heating, single heat pump heating, and dual heat source heating, based on the deviation between this temperature and the set target value and in combination with the real-time performance of the air source heat pump.

[0036] Among them, standalone heat pump heating means that in hot weather or at the beginning of the heating of drying room 1, the air source heat pump 4 has a strong heating capacity, and at this time, the heat load of drying room 1 can be met by using air source heat pump 4 alone; standalone electric heating means that in cold weather or at the end of the heating of drying room 1, the temperature of drying room 1 has exceeded the extreme heating limit temperature of air source heat pump 4, and air source heat pump 4 no longer has the heating capacity, at this time, the duct-type electric heater 3 is used alone; dual heat source heating means that in normal weather or at the middle of the heating of drying room 1, when the heating capacity of air source heat pump 4 decreases but still has the heating capacity, the duct-type electric heater 3 provides heat in conjunction.

[0037] The automatic control console 8 receives and monitors data from thermocouple sensor 12a and resistance sensor 12b in real time. By comparing the air temperature inside the drying chamber with the internal temperature of the cable insulation layer 202, it dynamically fine-tunes the heating power of the combined heating system. This ensures that the ambient temperature of the drying chamber 1 matches the surface temperature of the cable insulation layer 202, forming a thermal barrier and reducing heat loss caused by the temperature difference between the indoor and outdoor environments. This provides an efficient, uniform, stable, and energy-saving controllable thermal environment for the high-voltage cable degassing process, ensuring that the cable insulation layer quickly and safely removes impurity gases under optimal temperature conditions.

[0038] During the operation of the conductor self-heating unit, since the inner layer temperature of the cable insulation layer 202 is always higher than the outer layer temperature (approximately 1-2°C), a 3°C temperature margin is preset in the automatic control console 8 when setting the control program for the conductor self-heating unit to ensure process safety. When the thermistor sensor 12b detects that the surface temperature of the cable insulation layer 202 reaches 67°C, the automatic control console 8 shuts off the adjustable DC power supply 7. The minimal amount of heat required for the cable insulation layer 202 to continue rising to the predetermined final temperature is compensated by the combined heating unit.

[0039] The heat recovery unit includes: a heat absorption box 401, a heat pipe heat exchanger 5, and an outdoor air duct 9b.

[0040] The heat pipe heat exchanger 5 is located on the top of the outer side of the drying chamber 1, and includes an evaporator end 501 and a condenser end 502. The evaporator end 501 is used to treat the high-temperature exhaust gas discharged from the drying chamber 1; the condenser end 502 is used to introduce outdoor fresh air, and gas-heat exchange between exhaust gas and fresh air takes place inside the heat pipe heat exchanger 5 to achieve primary preheating and recovery.

[0041] The heat absorption box 401 is divided into two chambers by a louvered air vent 405. An evaporator 404 is installed in one chamber, and an air inlet 407 is installed at the top of the other chamber. A heat pump fan 410 is installed at the top of the heat absorption box 401 and on one side of the evaporator 404.

[0042] The outer three sides of the chamber containing the evaporator 404 on the heat absorption box 401 are provided with louvered air vents 406. The opening and closing state of louvered air vents 406 is opposite to that of the inner louvered air vents 405. Louvered air vents 405 are used to control the passage of exhaust gas from the drying chamber 1 into the evaporator 404, while louvered air vents 406 are used to prevent the exhaust gas from mixing with the outdoor air when it is sent to the evaporator 404.

[0043] On the other side of the indoor duct 9a is the outdoor duct 9b, which is located outside the drying chamber 1. After being led out from inside the drying chamber 1, the outdoor duct 9b is divided into two branches by a three-way pipe 10a. One branch is branch 903, which is connected to the air inlet of the evaporator end 501 of the heat pipe heat exchanger 5. The air outlet of the evaporator end 501 is connected to the air inlet 407 of the heat absorption box, forming the exhaust gas path.

[0044] Another branch is further divided into branch 2 (902) and branch 3 (904) via tee pipe 2 (10b). Branch 2 (902) is connected to the air inlet 408 of the heat release box of the air source heat pump 4, and is used to send return air to the air inlet of the combined heating unit for heating, forming the main air internal circulation route. Branch 3 (904) is connected to the air outlet of the condenser end 502 of the heat pipe heat exchanger 5, and is used to send fresh air introduced from the outside to the combined heating unit.

[0045] The pipe section between tee pipe 10a and tee pipe 2 10b is equipped with an electric air valve 11a to control the internal air circulation; branch pipe 3 904 is equipped with an electric air valve 2 11b to control the fresh air introduced from the outside to enter the combined heating unit.

[0046] The methane concentration sensor 12c is installed on the upper part of the inner wall of the drying chamber 1 to detect the methane concentration signal in the drying chamber 1 and transmit the methane concentration signal to the automatic control console 8. The automatic control console 8 controls the opening and closing of the electric air valve 11a, the electric air valve 21b, the louvered air outlet 1 405, and the louvered air outlet 2 406 according to this signal.

[0047] The heat recovery unit includes an internal circulation mode and an exhaust ventilation mode.

[0048] The internal circulation mode is as follows: when the methane concentration in the drying chamber 1 does not reach the threshold, the automatic control console 8 opens the electric air valve 11a and the louvered air outlet 406, and closes the electric air valve 11b and the louvered air outlet 405 inside the heat pump.

[0049] At this time, the airflow path is as follows: the airflow inside the drying chamber 1 enters the outdoor air duct 9b through the return air inlet 901 of the indoor air duct 9a, and then passes through the electric air valve 11a to reach the air inlet 408 of the heat release box, and enters the combined heating unit to start the next cycle.

[0050] The exhaust ventilation mode is as follows: when the methane concentration reaches the threshold, the automatic control console 8 closes the electric air valve 11a and the louvered air outlet 406, and opens the electric air valve 11b and the louvered air outlet 405 inside the heat pump.

[0051] At this point, the airflow path is divided into two paths: exhaust and exchange. The exhaust path is as follows: the exhaust gas discharged from the drying chamber 1 is sent to the evaporation end 501 of the heat pipe heat exchanger 5 through branch 903. Outdoor fresh air is drawn in and exchanges heat with the exhaust gas through the condenser end 502 to achieve primary heat recovery of the exhaust gas. Then the exhaust gas is sent from the air outlet of the evaporation end 502 to the evaporator 404 of the heat absorption box 401 for heat exchange to achieve secondary heat recovery of the exhaust gas. Finally, the exhaust gas is discharged to the outside through the heat pump fan 410. The ventilation path is as follows: outdoor fresh air passes through condenser end 502, and after being preheated by exhaust gas, it passes through electric air valve 11b, then through branch line 902 into the combined heating unit for secondary heating, and finally into drying room 1.

[0052] The closing of louvered vent 406 and the opening of louvered vent 405 allow the exhaust gas in the drying chamber 1 to pass through the evaporator 404 and be discharged outdoors. This prevents outdoor air from mixing with the exhaust gas when it is drawn into the heat absorption box 401, ensuring a high-quality heat source for the air source heat pump 4 and thus improving the coefficient of performance of the air source heat pump 4. When fresh air is introduced for ventilation, the automatic control panel 8 automatically adjusts the operating power of the air supply fan 6 according to the air volume required by the evaporator 404.

[0053] This exhaust process lasts for 1-2 minutes. After the exhaust is completed, the automatic control panel 8 restarts the internal circulation mode, opens the electric air valve 11a and the louvered air outlet 406, closes the electric air valve 11b and the inner louvered air outlet 405 of the heat pump, and automatically adjusts the heating power of the combined heating system unit and the operating power of the air supply fan 6, and repeats this process.

[0054] The automatic control console 8 is electrically connected to the conductor self-heating unit, the combined heating unit, and the heat recovery unit respectively, and receives signals from the thermocouple sensor 12a, the thermistor sensor 12b, and the methane concentration sensor 12c to control the operation of the conductor self-heating unit, the combined heating unit, and the heat recovery unit.

[0055] The automatic control console 8 adjusts and controls the heating mode and power of the air source heat pump 4 and the duct-type electric heater 3 in the combined heating unit based on the ambient temperature data of the drying chamber 1 provided by the thermocouple sensor 12a. The automatic control console 8 controls the on / off state and voltage level of the adjustable DC power supply 7 in the conductor self-heating unit based on the temperature of the cable insulation layer 202 provided by the thermistor sensor 12b. The automatic control console 8 controls the heat recovery unit to switch between internal circulation mode and external circulation mode based on the methane concentration data in the drying chamber 1 provided by the methane concentration sensor 12c.

[0056] Example 2

[0057] The multi-element thermal synergistic high-voltage cable degassing oven as described in Example 1 also includes insulation material and an exhaust duct 905.

[0058] The insulation material 13 is applied to the surfaces of the heat dissipation box 402, the duct-type electric heater box 3, the heat pipe heat exchanger box 5, and the outdoor air duct 9b to prevent excessive heat loss during the heating process and air flow.

[0059] The air inlet duct 905 is located at the air inlet of the condenser end 502 to improve the efficiency of outdoor fresh air introduction and ensure that fresh air is accurately introduced into the condenser end for heat exchange with the exhaust gas.

[0060] Example 3

[0061] This embodiment provides a control method for a high-voltage cable degassing drying chamber, including the following steps: Step 1: The automatic control console 8 starts the adjustable DC power supply 7 of the conductor self-heating unit, and the internal cable insulation layer 202 of the cable 2 is heated; Step 2: The automatic control console 8 starts the combined heating unit and the blower 6, and automatically switches the heating mode of the combined heating unit according to the temperature in the drying chamber 1. The heating modes include: single electric heating, single heat pump heating or dual heat source heating mode; the heated air enters the drying chamber 1 through the perforated plate air outlet array 102 to externally heat the cable 2. At the same time, the heating power of the combined heating unit is controlled to keep the internal temperature of the drying chamber 1 and the temperature of the cable insulation layer 202 consistent. Step 3: Automatic control console 8 monitors the methane concentration inside drying chamber 1 in real time. When the monitored methane concentration does not exceed the threshold, the heat recovery unit maintains the internal circulation mode; in this mode, automatic control console 8 controls electric air valve 11a to open and electric air valve 11b to close, and the return air in drying chamber 1 returns to the combined heating unit via branch 2 902 for reheating; Step 4: When the automatic control console 8 detects that the methane concentration exceeds the threshold, the heat recovery unit switches to external circulation mode; the automatic control console 8 controls the electric air valve 11a and the louvered air outlet 406 to close, and the electric air valve 11b and the louvered air outlet 405 to open. The exhaust gas in the drying chamber 1 is led to the condenser end 502 of the heat pipe heat exchanger 5 via branch 903 for primary waste heat recovery; the exhaust gas is introduced into the heat absorption box 401 of the air source heat pump 4, flows through the evaporator 404 to complete secondary waste heat recovery, and is then discharged from the heat pump fan 410. Step 5: Outdoor fresh air is drawn into the condenser end 502 of the heat pipe heat exchanger 5, where it exchanges heat with the high-temperature exhaust gas and is preheated. After being preheated, it enters the combined heating unit through branch 2 902 for secondary heating, and is finally sent to the drying chamber 1. When the methane concentration drops below the threshold, the automatic control console 8 controls the heat recovery unit to automatically switch to the internal circulation mode described in step 3.

[0062] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "up," "down," "front," "rear," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to explain the relative positional relationship and movement between components in a specific posture. If the specific posture changes, the directional indication will also change accordingly. These terms are used only for the convenience of describing the invention and for simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the invention.

[0063] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0064] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0065] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A multi-element thermal synergistic high-voltage cable degassing drying chamber, characterized in that, It includes a drying room (1), a conductor self-heating unit, a combined heating unit, a heat recovery unit, and an automatic control console (8); The conductor self-heating unit includes an adjustable DC power supply (7) located outside the drying chamber (1), which is used to supply power and heat the conductor of the cable (2) placed inside the drying chamber (1); The combined heating unit includes an air source heat pump (4), a duct-type electric heater (3), and a blower (6) located outside the drying chamber (1) and connected in sequence along the airflow direction. The outlet of the blower (6) is connected to the drying chamber (1). The combined heating unit is used to heat the surface of the cable (2). The heat recovery unit is used to control the internal circulation mode or the exhaust ventilation mode of the drying chamber (1); The automatic control console (8) is electrically connected to and controls the operation of the duct-type electric heater (3), the air source heat pump (4), the adjustable DC power supply (7), the air blower (6), and the heat recovery unit.

2. The multi-element thermal synergistic high-voltage cable degassing drying chamber as described in claim 1, characterized in that, The drying chamber (1) is an overhead structure with an overhead layer (101) at the bottom. An array of perforated air vents (102) is arranged on the upper side of the overhead layer (101) and below each cable (2). An indoor air duct (9a) is provided on the upper side of the interior of the drying chamber (1). The indoor air duct (9a) is provided with a return air inlet (901) with its opening facing downward. The return air inlet (901) is located opposite to the array of perforated air vents (102) and is used to receive the hot air sent out by the array of perforated air vents (102) and recover the gas in the drying chamber (1).

3. The multi-element thermal synergistic high-voltage cable degassing drying chamber as described in claim 2, characterized in that, The adjustable DC power supply (7) is connected in series with multiple cables (2) to form a circuit via an electrical connector (203); the adjustable DC power supply (7) is used to heat the cable insulation layer (202) inside the cable (2).

4. The multi-element thermal synergistic high-voltage cable degassing drying chamber as described in claim 3, characterized in that, It also includes a thermocouple sensor (12a), a thermistor sensor (12b), and a methane concentration sensor (12c); the thermocouple sensor (12a) is installed on the inner wall of the drying chamber (1) to monitor the air temperature in the drying chamber (1); the thermistor sensor (12b) is installed in the interlayer of each cable (2) to measure the temperature of the cable insulation layer (202); the methane concentration sensor (12c) is installed on the upper part of the inner wall of the drying chamber (1) to monitor the methane concentration in the drying chamber (1); The automatic control console (8) receives signals from the thermocouple sensor (12a), the thermistor sensor (12b), and the methane concentration sensor (12c) and controls the operation of the combined heating unit, the conductor self-heating unit, and the heat recovery unit respectively based on these signals.

5. The multi-element thermal synergistic high-voltage cable degassing drying chamber as described in claim 4, characterized in that, The air source heat pump (4) is divided into two-layer chassis structure, with the upper layer being the heat absorption box (401) and the lower layer being the heat release box (402). The heat absorption box (401) is divided into two chambers by a louvered air outlet (405). An evaporator (404) is installed in one chamber, and an air inlet (407) is installed at the top of the other chamber. The heat release box (402) is provided with a heat release box air inlet (408) and a heat release box air outlet (409) at the front and back, respectively.

6. The multi-element thermal synergistic high-voltage cable degassing oven as described in claim 5, characterized in that, The heat recovery unit includes a heat absorption box (401), a heat pipe heat exchanger (5), an outdoor air duct (9b), and a valve group; the heat pipe heat exchanger (5) includes an evaporation end (501) and a condensation end (502); one side of the outdoor air duct (9b) is connected to the indoor air duct (9a), and the other side is divided into two branches via a three-way pipe (10a); the branch (903) is connected to the heat absorption box air inlet (407) of the heat pump (4) through the evaporation end (501) for exhausting waste gas; Another branch is divided into branch two (902) and branch three (904) via three-way pipe two (10b). Branch two (902) is connected to the heat pump (4) heat dissipation box inlet (408) for airflow circulation and heating in the drying chamber (1). Branch three (904) is connected to the outlet of the heat pipe heat exchanger (5) condenser end (502) for introducing fresh air to the air inlet of the combined heating unit.

7. The multi-element thermal synergistic high-voltage cable degassing drying chamber as described in claim 6, characterized in that, The valve group consists of electric air valve one (11a) and electric air valve two (11b); the pipe section between tee pipe one (10a) and tee pipe two (10b) is equipped with electric air valve one (11a) to control the internal air circulation; branch three (904) is equipped with electric air valve two (11b) to control the fresh air introduced from the outside to enter the combined heating unit.

8. The multi-element thermal synergistic high-voltage cable degassing drying chamber as described in claim 7, characterized in that, The outer three sides of the chamber where the evaporator (404) is located are provided with louvered air vents two (406). The opening and closing state of the louvered air vents two (406) is opposite to that of the louvered air vents one (405). The louvered air vents one (405) is used to control the passage of exhaust gas in the drying chamber (1) into the evaporator (404), and the louvered air vents two (406) is used to control the exhaust gas from mixing with the outdoor air when it is sent to the evaporator (404).

9. The multi-element thermal synergistic high-voltage cable degassing drying chamber as described in claim 8, characterized in that, The automatic control console (8) switches the internal circulation mode or the exhaust ventilation mode of the drying chamber (1) according to the methane concentration monitored by the methane concentration sensor (12c). In the internal circulation mode, when the methane concentration does not exceed the threshold, the electric air valve one (11a) and the louvered air outlet two (406) are opened, and the electric air valve two (11b) and the louvered air outlet one (405) are closed. The return air inside the drying room (1) enters the outdoor air duct (9b) through the indoor air duct (9a), and the airflow then enters the air inlet of the combined heating unit through the electric air valve one (11a). The exhaust ventilation mode is as follows: when the methane concentration exceeds the threshold, the electric air valve one (11a) and the louvered air outlet two (406) are closed, and the electric air valve two (11b) and the louvered air outlet one (405) are opened. The exhaust gas discharged from the drying chamber (1) is sent to the evaporation end (501) of the heat pipe heat exchanger (5) through the branch line one (903) for primary heat recovery of the exhaust gas. Then the exhaust gas is sent from the air outlet of the evaporation end (501) to the evaporator (404) of the heat absorption box (401) for secondary heat recovery of the exhaust gas, and finally discharged to the outside. At the same time, the outdoor fresh air is preheated by exchanging heat with the exhaust gas flowing through the evaporation end (501) through the condensation end (502) of the heat pipe heat exchanger (5). The preheated fresh air enters the air inlet of the combined heating unit through the electric air valve two (11b) and the branch line two (902).

10. The multi-element thermal synergistic high-voltage cable degassing drying chamber as described in claim 4, characterized in that, The automatic control console (8) controls the opening and closing of the air source heat pump (4) and the duct-type electric heater (3) and their operating power respectively according to the temperature information monitored by the thermocouple sensor (12a), and is used to automatically switch between three heating modes: heating by the air source heat pump (4) alone, heating by the duct-type electric heater (3) alone, and heating by the dual heat source.

11. A control method for a multi-element thermal synergistic high-voltage cable degassing drying chamber based on claim 9, characterized in that, Includes the following steps: Step 1: The automatic control console (8) starts the adjustable DC power supply (7) of the conductor self-heating unit, and the inside of the cable (2) is heated; Step 2: The automatic control console (8) starts the combined heating unit and the blower (6), and automatically switches the heating mode of the combined heating unit according to the temperature in the drying chamber (1). The heated air enters the drying chamber (1) to externally heat the cable (2). Step 3: The automatic control console (8) monitors the methane concentration inside the drying chamber (1) in real time. When the monitored methane concentration does not exceed the threshold, the drying chamber (1) maintains the internal circulation mode, and the return air in the drying chamber (1) returns to the combined heating unit through branch line 2 (902) for reheating. Step 4: When the automatic control console (8) detects that the methane concentration exceeds the threshold, the heat recovery unit switches to external circulation mode; the exhaust gas in the drying chamber (1) is led to the evaporation end (501) of the heat pipe heat exchanger (5) through branch line (903) for primary waste heat recovery; the exhaust gas is introduced into the heat absorption box (401) of the air source heat pump (4) from the air outlet of the evaporation end (501), flows through the evaporator (404), completes the secondary waste heat recovery, and is discharged outdoors; Step 5: Outdoor fresh air is drawn into the condenser end (502) and exchanged heat with the high-temperature exhaust gas. Then the gas enters the combined heating unit through branch line 2 (902) for secondary heating and is finally sent into the drying room (1). When the methane concentration drops below the threshold, the automatic control console (8) controls the heat recovery unit to automatically switch to the internal circulation mode described in step 3.

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