Development of Protective Function of High-speed Wire Rod Production Line Automation System
Abstract
High-speed wire rod production line automation system is a process instrument used in metallurgical industry for automatic production. It plays an important role in modernizing the production process, improving production efficiency and realizing intelligent production. To ensure the normal operation and improve the protection of the production line, it is necessary to improve the protection function of the automatic system of the high-speed wire rod production line. The protection function of the high-speed wire rod production line automation system mainly includes overcurrent protection, phase failure protection, voltage protection, phase sequence protection, overload protection, ground-fault protection, single-element protection, system communication interruption protection and other functions. The selection principle of protective equipment for high-speed wire rod production line automation system is: complete protection function, simple operation and reliable performance.
1 Introduction
High-speed wire rod production line automation system is a kind of process instrument used in metallurgical production which realizes automatic control by using modern automatic control technology. Automation can reduce the labor intensity of workers, improve production efficiency and product quality, and play an important role in the modern metallurgical production process. Automatic control system of high-speed wire rod production line mainly includes distributed control system (DCS), programmable controller (PLC) and software simulator. The three parts can realize independent or combined operation. In the whole process of high-speed wire rod production line automation system, the choice and set of protection equipment is extremely important. The control system used should also be equipped with complete protective functions, so that it can work long-term and reliably.
2 Protective Function of High-speed Wire Rod Production Line Automation System
2.1 Overcurrent Protection
High-speed wire rod production line automation system uses a variety of electric energy sources such as motors, power supplies, inverters, PLCs and other devices, so the protection from overcurrent is necessary. Elements such as circuit breakers, moulded circuit breakers and air circuit breakers that can respond quickly to overcurrent signals can be selected for this purpose. When an excessive current is generated, the circuit breaker should be able to disconnect the power supply as soon as possible and prevent the hazards caused by the overcurrent, such as heat and insulation breakdown.
2.2 Phase Failure Protection
Phase failure protection is mainly used to detect the operation of four, three-phase systems and prevent mechanical equipment from being damaged due to incorrect connection or power failure of one of the three-phase system. In a high-speed wire rod production line automation system, when the voltage of one of the three-phase systems drops or loses connection, the circuit breaker should be able to quickly reset and reset the device, prevent mechanical equipment from burning. The AC contactor of the high-speed wire rod production line automation system should be equipped with an coil to monitor the phase failure. If a phase failure occurs, the circuit breaker can be reset by an external reset.
2.3 Voltage Protection
If the voltage of the power supply exceeds or is lower than the normal voltage value of the automatic system of the high-speed wire rod production line, the power supply should be immediately stopped to prevent the device from being damaged by the voltage instability. Different tolerances should be set for different sensitive devices in the high-speed wire rod production line automation system. The protector should be set on the main power line to control the voltage range of the power supply. The protector should quickly break the power supply when the voltage exceeds the tolerance and suspend the operation of the main power line until the voltage returns to the normal range.
2.4 Phase Sequence Protection
In the operation of high-speed wire rod production line automation system, the three-phase system should be connected in the correct order, or it may cause the rotor of the motor to reverse and affect the operation of the motor. A timer can be set at the output end of the power supply. When the output voltage is not in the correct order, the circuit breaker will trip and the device will be disconnected from the power supply.
2.5 Overload Protection
The protection system of the high-speed wire rod production line automation system should protect the motor system from overloading, which is usually caused by long-term overload or short-circuit of the motor current. The overload protection device should be able to quickly detect the overloading and disconnect the circuit. The electronic protector can monitor the current of the motor in real time and immediately trip when the current exceeds the max current.
2.6 Ground Fault Protection
Ground fault protection is used to monitor the ground fault of the high-speed wire rod production line automation system. Ground fault is caused by many factors, such as loose grounding, leakage of components and materials, incorrect grounding, etc. The ground fault protection device can detect the ground fault and quickly disconnect the power supply to prevent the grounding failure from causing serious accidents.
2.7 Single Element Protection
Single element protection includes overvoltage, undervoltage, short circuit, overload and other protections. The overvoltage protection device is used to control the voltage of the system. When the voltage is too high, the power supply will be interrupted. The undervoltage protection device is used to interrupt the power supply when the voltage is too low. The short circuit protection device is used to monitor the current and rapidly disconnect the circuit in case of a short circuit. The overload protection device is used to disconnect the power supply to protect the device from being damaged due to overloading.
2.8 System Communication Interruption Protection
The system communication interruption protection is used to protect the high-speed wire rod production line automation system from communication failures. A failure of the communication line will cause the system to run abnormally or even stop functioning, which will lead to serious production losses. The system communication interruption protection device should be able to monitor the communication line in real time and disconnect the power supply or reduce the power supply in case of communication failure.
3 Selection Principle of Protective Equipment for High-speed Wire Rod Production Line Automation System
When selecting the protective equipment of the high-speed wire rod production line automation system, the selection principle should be complete protection function and simple operation, reliable performance. The protection device should be able to detect overcurrent, phase failure, voltage and other conditions in real time and rapidly disconnect the power supply, so as to prevent accidents and protect the device from damage. The operation of the protection device should be simple and the performance should be reliable.
4 Conclusion
High-speed wire rod production line automation system is an important part of the metallurgical production process. To improve the protection of the system, the protective equipment should be selected carefully according to the operation conditions and the selection principle of complete protection function, simple operation and reliable performance.
Reference
[1] H. Lee, W. Kim, J. Lee and H. Yoon, Automation in Metallurgical Industry, Springer, 2017.
[2] H. Wang and H. Ma, PLC Design and Application, China machine press, 2012.
[3] X. Yang, Industrial Electrical Applications, Shanghai Jiao Tong University Press, 2018.
