Self-adaptive precise intelligent temperature control feedback system during operation of enclosed bus

Abstract

The invention discloses a self-adaptive precise intelligent temperature control feedback system during operation of an enclosed bus, and relates to the technical field of power system equipment. The system is composed of a plurality of high-precision sensors, an intelligent central controller and an execution mechanism, wherein the high-precision sensors are distributed at key parts of an enclosed bus. The sensor collects multi-dimensional data such as bus temperature, environment temperature and current magnitude in real time and transmits the data to the central controller. The intelligent central controller uses an advanced algorithm to accurately analyze the current heating state of the bus according to the data, and then adaptively adjusts the execution mechanism. The system has adaptive capability, can automatically optimize a temperature control strategy according to the dynamic change of the working load of the bus, and always ensures that the bus runs in the optimal temperature interval. Compared with a traditional temperature control system, the temperature control precision is remarkably improved, the risk of faults caused by overheating of the bus is effectively reduced, the stability and reliability of power transmission are guaranteed, and the system has wide application prospects in the power industry.

Description

Technical Field

[0001] The present invention relates to the technical field of power system equipment, and in particular to an adaptive, precise, intelligent temperature control feedback system for a closed busbar in operation. Background Art

[0002] In modern power systems, enclosed busbars, as key equipment for power transmission, are widely used in substations, power plants, and other scenarios. As power systems evolve toward higher voltages and higher currents, the safe and stable operation of enclosed busbars is crucial. Accurate temperature monitoring, efficient heat dissipation, and reliable temperature control strategies are key elements in ensuring the proper operation of enclosed busbars. However, current technologies still have limitations.

[0003] Existing closed busbar temperature control technology has numerous drawbacks. Regarding monitoring technology, contact sensors have insufficient coverage, are susceptible to electromagnetic interference, and have low reliability. Non-contact monitoring has a limited detection range and poor environmental adaptability. Regarding heat dissipation technology, air cooling has insufficient heat dissipation capacity, introduces environmental risks, and has low equipment reliability. Liquid cooling carries the risk of leakage and is difficult to adapt to different operating conditions. Temperature control strategies lack adaptability to complex operating conditions, and there is a lack of coordinated optimization across various links. Summary of the Invention

[0004] To solve the above-mentioned problems, the present invention is implemented through the following technical solutions: an adaptive, precise, intelligent temperature control feedback system for a closed busbar during operation, characterized in that it includes a sensing layer comprising a plurality of temperature sensors arranged at key locations of the closed busbar, a current sensor arranged at the incoming end of the busbar, and an environmental sensor located in the environment in which the busbar is located;

[0005] The control layer receives data from the perception layer, analyzes and processes the data using adaptive control algorithms, predictive control algorithms, and fuzzy logic control algorithms, and generates control instructions based on the analysis results;

[0006] The execution layer controls the cooling fan speed control system, the coolant circulation control system, and the optional heating device according to the instructions issued by the control layer to adjust the temperature of the closed busbar;

[0007] It also includes a fault diagnosis module, which has an average fault diagnosis time of less than 30 seconds and is used to monitor the working status of each sensor, actuator and communication network in the system in real time, and diagnose the fault type and location through data analysis and fault model matching;

[0008] It also has a fault-tolerant mechanism. When a sensor or actuator in the system fails, the system can automatically switch to the backup device or adopt a fault-tolerant control strategy within 1.5 seconds to ensure that the basic functions of the temperature control feedback system are not affected.

[0009] Furthermore, the temperature sensor is a thermocouple or thermistor temperature sensor with an accuracy of ±0.2°C and a response time of less than 300ms, and is arranged at intervals of 0.8 meters at the conductor connection, insulator position and shell surface of the closed busbar.

[0010] Furthermore, the current sensor is a Hall effect current sensor with a measurement range of 0-8000A and a measurement accuracy of ±0.8%.

[0011] Furthermore, the environmental sensors include a temperature and humidity sensor with a measurement accuracy of ±0.3°C for temperature and ±3% for humidity, and an air pressure sensor with an accuracy of ±1hPa.

[0012] Furthermore, the adaptive control algorithm can automatically adjust the cooling fan speed to increase by 200 rpm or increase the coolant flow by 5 L / min within 1.2 seconds when the bus current increases by 1000 A in a short period of time.

[0013] Furthermore, the predictive control algorithm can predict busbar temperature changes 4 minutes in advance, with the prediction error controlled within ±0.6°C;

[0014] Furthermore, the fuzzy logic control algorithm can control the busbar temperature fluctuation range within ±1.2°C under complex working conditions; in simulation tests of complex working conditions including sudden changes in ambient temperature and drastic changes in busbar load.

[0015] Furthermore, the speed regulation range of the cooling fan speed regulation system is 500-2000 rpm, and the speed regulation accuracy can reach ±50 rpm.

[0016] Furthermore, the flow control valve opening adjustment range in the coolant circulation regulation system is 0-100%, the adjustment accuracy can reach ±2%, and the water pump speed adjustment range is 1000-3000 rpm, which can accurately control the coolant flow rate within 0-50L / min.

[0017] Furthermore, the power of the heating device can be adjusted within 1-5kW, and the busbar temperature can be raised to the set preheating temperature within 12 minutes.

[0018] (3) Beneficial effects

[0019] The present invention has the following beneficial effects:

[0020] Reduced power loss: When enclosed busbars transmit high currents, their resistance generates Joule heating, causing the temperature to rise. This temperature increase further increases the busbar resistance, creating a vicious cycle that results in significant energy loss as heat. A precise intelligent temperature control feedback system effectively and timely lowers the busbar temperature, maintaining low busbar resistance. This significantly reduces excess power loss caused by temperature and improves power transmission efficiency. Actual testing has shown that, under the same load conditions, power loss can be reduced by approximately 15%.

[0021] Extending Equipment Life: Excessively high temperatures accelerate insulation aging and mechanical degradation of enclosed busbars and their associated equipment. Prolonged exposure to high temperatures degrades the insulation of insulators, potentially leading to faults such as leakage and short circuits. Thermal expansion and contraction of busbar conductors can also loosen connections, affecting conductivity. This patented technology stabilizes busbar temperature within an appropriate range, slowing equipment aging and significantly extending the service life of enclosed busbars and associated equipment. Based on experimental data and actual operating experience, equipment service life can be extended by more than five years.

[0022] Improve operational safety: Excessive temperature of the enclosed busbar is a major safety hazard in the operation of the power system. Once the temperature exceeds the limit, it may cause a fire or even a large-scale power outage, seriously affecting social production and life. This patent ensures that the busbar temperature is always below the safety threshold through real-time monitoring and adaptive regulation, effectively avoiding various safety accidents caused by excessive temperature, ensuring the stable and reliable operation of the power system, and providing a solid guarantee for the safety of power supply. Since the pilot project using this patented technology was put into operation, no safety accidents caused by excessive busbar temperature have occurred.

[0023] Reduced maintenance costs: Frequent equipment failures and aging require extensive maintenance, including regular inspections, troubleshooting, and repairs, which undoubtedly increases manpower, material, and financial costs. This patented technology reduces equipment failure rates, reduces maintenance frequency, and reduces repair workload, thereby effectively lowering the overall maintenance cost of the enclosed busbar system. Statistics show that the use of this patented technology can reduce annual maintenance costs by approximately 20%.

[0024] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the process flow of the present invention. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] In the description of the present invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inside", "around" and the like indicating orientation or positional relationship are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0028] See also Figure 1 The embodiment of the present invention provides a technical solution: an adaptive, precise, intelligent temperature control feedback system for a closed busbar during operation, comprising a sensing layer comprising a plurality of temperature sensors arranged at key locations of the closed busbar, a current sensor arranged at the incoming end of the busbar, and an environmental sensor located in the environment in which the busbar is located;

[0029] Used to collect real-time temperature data, operating current data, and ambient temperature, humidity, and air pressure data of the closed busbar; for a closed busbar system with a rated voltage of 66kV-1100kV and a rated current of 2kA-63kA, there are no less than 30 temperature sensors to ensure full coverage of the key heating areas of the busbar; the range of the current sensor is set to 0-65kA according to the current load range of the closed busbar.

[0030] The control layer receives data from the perception layer, analyzes and processes the data using adaptive control algorithms, predictive control algorithms, and fuzzy logic control algorithms, and generates control instructions based on the analysis results;

[0031] The data processing capability of the control layer must be able to complete the initial screening and integration of the perception layer data within 15ms to adapt to the rapidly changing operating conditions in the rated voltage 66kV-1100kV system.

[0032] The execution layer controls the cooling fan speed control system, coolant circulation control system, and optional heating device according to the instructions issued by the control layer to adjust the closed bus temperature;

[0033] This system adopts a layered and distributed system architecture, dividing the entire temperature control feedback system into a perception layer, a control layer, and an execution layer. The perception layer is responsible for collecting various types of data, the control layer performs data processing and decision-making, and the execution layer performs corresponding temperature control operations according to control instructions. This architecture makes the system scalable and reliable, and easy to maintain and upgrade. Taking a medium-sized closed bus system as an example, it can support at least 50 sensor nodes connected to the perception layer. The control layer can complete the initial processing of large amounts of data within 10ms, and the response time of the execution layer is less than 20ms, ensuring the efficient operation of the entire system.

[0034] Establish a high-speed, stable communication network between each layer, such as industrial Ethernet or wireless communication modules. This ensures that data collected by the perception layer is transmitted to the control layer in real time and accurately, and that instructions from the control layer are quickly transmitted to the execution layer. The communication network features data encryption and verification to prevent data loss and errors during data transmission. Industrial Ethernet communication rates can reach over 100 Mbps, and wireless communication modules, when used in industrial environments, have data transmission delays of less than 30 ms and data transmission accuracy exceeding 99.9%.

[0035] The cooling fan speed control system must respond to speed adjustments within 250ms after receiving a command, and the coolant circulation control system must complete flow control within 400ms to ensure timely control of busbar temperature under different rated parameters.

[0036] The cooling fan speed control system utilizes a variable-speed cooling fan equipped with an intelligent speed controller. Based on commands from the control layer, the controller adjusts the fan motor's voltage or frequency to precisely control the fan speed, thereby adjusting the cooling intensity. The cooling fan speed range is 600-1800 rpm, with an accuracy of ±80 rpm. It responds quickly to control commands and allows for flexible adjustment of cooling intensity.

[0037] Coolant Circulation Control System: A flow control valve and water pump speed control device are installed in the coolant circulation line. Control commands are used to adjust the flow control valve opening and the water pump speed, precisely controlling the coolant flow and circulation speed, achieving precise regulation of liquid cooling. The flow control valve opening range is 0-100%, with an adjustment accuracy of ±3%. The water pump speed range is 1200-2800 rpm, accurately controlling the coolant flow rate within 0-40 L / min.

[0038] It also includes a fault diagnosis module with an average fault diagnosis time of less than 30 seconds. It is used to monitor the working status of each sensor, actuator and communication network in the system in real time, and diagnose the fault type and location through data analysis and fault model matching;

[0039] In a series of 150 simulated fault tests of various types, the fault diagnosis module accurately identified the fault type and location no fewer than 147 times, ensuring the stable operation of the temperature control system for the 66kV-1100kV enclosed busbar system with high accuracy.

[0040] The fault diagnosis module was developed to monitor the operating status of each sensor, actuator, and communication network in the system in real time. Through data analysis and fault model matching, it can quickly and accurately diagnose the type and location of any faults in the system. The module's average fault diagnosis time is less than 40 seconds, with an accuracy rate exceeding 95%.

[0041] It also has a fault-tolerant mechanism. When a sensor or actuator in the system fails, the system can automatically switch to a backup device or adopt a fault-tolerant control strategy within 1.5 seconds to ensure that the basic functions of the temperature control feedback system are not affected.

[0042] During the switching of backup equipment, the busbar temperature fluctuation range is controlled within ±1.5℃, ensuring that the operation of the closed busbar system with a rated current of 2kA-63kA is not excessively disturbed by equipment failures.

[0043] Among them, a fault-tolerant mechanism is designed. If a sensor or actuator in the system fails, the system automatically switches to a backup device or adopts a fault-tolerant control strategy, ensuring that the basic functions of the temperature control feedback system are not affected and that the closed busbar operates safely. Simultaneously, the system issues a fault alarm, prompting maintenance personnel to perform repairs promptly. The backup device switchover time is less than 2 seconds, ensuring stable system operation in the event of a fault.

[0044] Specifically, the temperature sensor is a thermocouple or thermistor temperature sensor with an accuracy of up to ±0.2°C and a response time of less than 300ms, and is arranged at intervals of 0.8 meters at the conductor connection, insulator position and casing surface of the closed busbar.

[0045] In this implementation scheme, actual testing has shown that at this layout density, the busbar temperature changes can be accurately captured, and the temperature monitoring blind area is less than 0.08 square meters, meeting the high-precision temperature monitoring requirements of the closed busbar system with a rated voltage of 66kV-1100kV.

[0046] Specifically, the current sensor is a Hall effect current sensor with a measurement range of 0-8000A and a measurement accuracy of ±0.8%.

[0047] In this implementation, a Hall-effect current sensor is installed at the busbar incoming line end to monitor the busbar operating current in real time. Current data is crucial for determining the busbar load condition and heating trend, providing a key basis for formulating temperature control strategies. The Hall-effect current sensor has a measurable range of 0-8000A and a measurement accuracy of ±0.8%, enabling it to quickly capture current changes and transmit data in a timely manner. Even under conditions where the busbar current fluctuation range is ±12%, the sensor can still stably and accurately output current data. This fluctuation range is consistent with the current fluctuations during normal operation of a closed busbar system with a rated current of 2kA-63kA.

[0048] Specifically, the environmental sensors include a temperature and humidity sensor with a measurement accuracy of ±0.3°C for temperature and ±3% for humidity, and an air pressure sensor with an accuracy of up to ±1hPa.

[0049] In this implementation scheme, temperature and humidity sensors and air pressure sensors are arranged in the environment where the closed bus is located to collect ambient temperature, humidity and air pressure data. Environmental factors have a significant impact on the heat dissipation effect of the bus, and these data help the system adjust the temperature control strategy according to environmental changes. The measurement accuracy of the temperature and humidity sensors is ±0.3°C for temperature and ±3% for humidity, and the accuracy of the air pressure sensor can reach ±1hPa, which can reflect changes in environmental parameters in real time. It can work stably and measure accurately within the ambient temperature range of -25°C-55°C, the humidity range of 12%-85%, and the air pressure range of 940hPa-1060hPa. These environmental parameter ranges cover the common operating environments of closed bus systems with rated voltages of 66kV-1100kV.

[0050] Specifically, the adaptive control algorithm can automatically adjust the cooling fan speed by 200 rpm or increase the coolant flow by 5 L / min within 1.2 seconds when the bus current increases by 1000 A in a short period of time.

[0051] In this implementation, an adaptive control algorithm is used to enable the system to automatically adjust control parameters based on the busbar operating status and environmental changes. For example, when the busbar load current suddenly increases, causing the temperature to rise, the system can automatically increase the speed of the cooling fan or increase the coolant flow rate to enhance the heat dissipation effect. In actual application, when the busbar current increases by 800A in a short period of time, the system can increase the cooling fan speed by 150 rpm or increase the coolant flow rate by 4L / min within 1.5s. After multiple simulation tests, under the condition of sudden busbar load changes, the algorithm can stabilize the busbar temperature to the normal range within 4 minutes, and is optimized for the load change characteristics of the closed busbar system with a rated current of 2kA-63kA.

[0052] Specifically, the predictive control algorithm can predict bus temperature changes 4 minutes in advance, and the prediction error is controlled within ±0.6℃.

[0053] This implementation incorporates a predictive control algorithm, which uses currently collected data and historical operating data to predict busbar temperature changes over time. This allows for proactive adjustment of temperature control equipment parameters, improving both the accuracy and timeliness of temperature control. Trained with extensive historical data, the predictive control algorithm can predict busbar temperature changes up to three minutes in advance, with a prediction error within ±0.8°C. Through training and optimization based on historical operating data, the prediction accuracy exceeds 95%. This long-term accumulation of operating data allows for temperature prediction in closed busbar systems with varying rated parameters.

[0054] Specifically, the fuzzy logic control algorithm can control the busbar temperature fluctuation range within ±1.2°C under complex working conditions; in simulation tests of complex working conditions including sudden changes in ambient temperature and drastic changes in busbar load.

[0055] In this implementation scheme, a fuzzy logic control algorithm is used to handle complex multivariable and nonlinear temperature control problems. Temperature, current, environment and other factors are used as fuzzy inputs, and the control output is obtained through fuzzy reasoning, thereby achieving precise control of the actuator. The fuzzy logic control algorithm can effectively deal with uncertainties and interference factors in the system. After actual testing, under complex working conditions, the fuzzy logic control algorithm can control the busbar temperature fluctuation range to within ±1.5°C. This algorithm reduces the number of busbar temperature fluctuations by 40% compared to traditional control algorithms, effectively improving the temperature control stability of the closed busbar system with a rated voltage of 66kV-1100kV.

[0056] Specifically, the speed regulation range of the cooling fan speed regulation system is 500-2000 rpm, and the speed regulation accuracy can reach ±50 rpm.

[0057] In this implementation, under different ambient temperature and busbar temperature combinations, the fan speed regulation response time is less than 350ms, meeting the fast response requirements of cooling fan speed regulation for closed busbar systems with different rated parameters.

[0058] Specifically, the flow control valve opening adjustment range in the coolant circulation regulation system is 0-100%, the adjustment accuracy can reach ±2%, and the water pump speed adjustment range is 1000-3000 rpm, which can accurately control the coolant flow rate within 0-50L / min.

[0059] In this embodiment, during system startup and operation, the stabilization time of coolant flow regulation is less than 1.5 seconds, ensuring the high efficiency of coolant circulation regulation when the closed busbar system with rated voltage of 66kV-1100kV and rated current of 2kA-63kA is running.

[0060] Specifically, the heating device power can be adjusted within 1-5kW, and can raise the busbar temperature to the set preheating temperature within 12 minutes;

[0061] In this implementation scheme, when the ambient temperature is -15°C, the preheating task can still be completed within the specified time, adapting to the startup requirements of closed busbar systems with different rated parameters in low temperature environments.

[0062] Practical applications of this system:

[0063] A 500kV substation: The rated current of the enclosed bus within the station reaches 31.5kA. Before the implementation of this system, the temperature monitoring coverage rate of key busbar parts was only 60%. Due to electromagnetic interference, the temperature measurement error reached ±3°C. In addition, due to insufficient heat dissipation, the busbar temperature often exceeded 80°C during high loads in the summer, seriously affecting the busbar lifespan. After the introduction of this system, contact sensors were arranged at 1-meter intervals, and the coverage rate jumped to 98%, and the impact of electromagnetic interference was reduced to within ±0.5°C. Efficient air cooling and intelligent liquid cooling work together to stabilize the busbar temperature below 60°C, reduce equipment failure rate by 50%, significantly improve the power supply stability of the substation, and ensure reliable power supply in the region.

[0064] Power Plant: A 1000MW power plant has an enclosed busbar with a rated voltage of 110kV and a rated current of 20kA. Previously, air cooling was ineffective, resulting in large busbar temperature fluctuations and frequent overheating and loosening of some electrical connections. With this system, the new axial fan and heat sink fins tripled the heat dissipation capacity, while the air filtration and dehumidification device improved the internal busbar environment and stabilized insulation performance. Furthermore, a multimodal algorithm precisely controlled the cooling equipment, keeping busbar temperature fluctuations within ±2°C. The equipment maintenance cycle was extended from quarterly to annually, reducing operation and maintenance costs and improving the power plant's efficiency.

[0065] New Energy Converter Station: A new energy converter station, with its enclosed busbars operating in a complex electromagnetic environment and rated at 800kV and 40kA, faced difficulties in accurately monitoring the busbar's operating status, and the cooling system was unable to meet the busbar's cooling requirements under varying operating conditions. After the system went into operation, its infrared imaging and ultrasonic composite monitoring technology achieved 75% coverage of potential internal busbar faults. The double-sealed liquid cooling system reduced the risk of leakage to near zero, and the collaborative optimization platform improved cooling efficiency by 35%. This ensured stable operation of the converter station and guaranteed the efficient and safe integration of new energy power into the grid.

[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above-disclosed technical content to modify or modify the present invention into equivalent embodiments. However, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical content of the present invention and are based on the technical essence of the present invention remain within the scope of protection of the present invention.

Claims

1. The adaptive precise intelligent temperature control feedback system during closed busbar operation is characterized by: It includes a sensing layer, which includes a plurality of temperature sensors arranged at key positions of the closed busbar, a current sensor arranged at the incoming end of the busbar, and an environmental sensor located in the environment where the busbar is located; The control layer receives data from the perception layer, analyzes and processes the data using adaptive control algorithms, predictive control algorithms, and fuzzy logic control algorithms, and generates control instructions based on the analysis results; The execution layer controls the cooling fan speed control system, the coolant circulation control system, and the optional heating device according to the instructions issued by the control layer to adjust the temperature of the closed busbar; It also includes a fault diagnosis module, which has an average fault diagnosis time of less than 30 seconds and is used to monitor the working status of each sensor, actuator and communication network in the system in real time, and diagnose the fault type and location through data analysis and fault model matching; It also has a fault-tolerant mechanism. When a sensor or actuator in the system fails, the system can automatically switch to the backup device or adopt a fault-tolerant control strategy within 1.5 seconds to ensure that the basic functions of the temperature control feedback system are not affected.

2. The adaptive, precise, intelligent temperature control feedback system for closed busbar operation according to claim 1, characterized in that: The temperature sensor is a thermocouple or thermistor temperature sensor with an accuracy of ±0.2°C and a response time of less than 300ms, and is arranged at intervals of 0.8 meters at the conductor connection, insulator position and shell surface of the closed busbar.

3. The adaptive, precise, intelligent temperature control feedback system for closed busbar operation according to claim 1, characterized in that: The current sensor is a Hall effect current sensor with a measurement range of 0-8000A and a measurement accuracy of ±0.8%.

4. The adaptive, precise, intelligent temperature control feedback system for closed busbar operation according to claim 1 is characterized by: The environmental sensors include a temperature and humidity sensor with a measurement accuracy of ±0.3°C for temperature and ±3% for humidity, and an air pressure sensor with an accuracy of ±1hPa.

5. The adaptive, precise, intelligent temperature control feedback system for closed busbar operation according to claim 1 is characterized by: The adaptive control algorithm can automatically adjust the cooling fan speed by 200 rpm or increase the coolant flow by 5 L / min within 1.2 seconds when the bus current increases by 1000 A in a short period of time.

6. The adaptive, precise, intelligent temperature control feedback system for closed busbar operation according to claim 1 is characterized by: The predictive control algorithm can predict busbar temperature changes 4 minutes in advance, and the prediction error is controlled within ±0.6°C.

7. The adaptive, precise, intelligent temperature control feedback system for closed busbar operation according to claim 1 is characterized by: The fuzzy logic control algorithm can control the busbar temperature fluctuation range within ±1.2°C under complex working conditions; in simulation tests of complex working conditions including sudden changes in ambient temperature and drastic changes in busbar load.

8. The adaptive, precise, intelligent temperature control feedback system for closed busbar operation according to claim 1 is characterized by: The speed regulation range of the cooling fan speed regulation system is 500-2000 rpm, and the speed regulation accuracy can reach ±50 rpm.

9. The adaptive, precise, intelligent temperature control feedback system for closed busbar operation according to claim 1, characterized in that: The flow regulating valve opening adjustment range in the coolant circulation regulation system is 0-100%, the adjustment accuracy can reach ±2%, and the water pump speed adjustment range is 1000-3000 rpm, which can accurately control the coolant flow rate within 0-50L / min.

10. The adaptive, precise, intelligent temperature control feedback system for closed busbar operation according to claim 1, characterized in that: The power of the heating device can be adjusted within 1-5kW, and the busbar temperature can be raised to the set preheating temperature within 12 minutes.

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