Application of PLC-based Flameproof Feed Switch Control System in Mine
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Second, the system configuration and function to achieve 1, KBZ630Z control system hardware configuration display: protection level to IP65 4 lines of Chinese characters text display,
Programmable controller: UN200 series CPU224QUN214-1AF23-0XB0 an expansion module: three-phase AC and leakage monitoring module UN231-0BH22-0XA0 (Note: KBZ800Z type requires two three-phase AC and leakage monitoring module)
2. System Architecture The system consists of a control system consisting of a UniMAT PLC+ text screen and an execution system consisting of a vacuum circuit breaker. as the picture shows. Among them, the CPU performs some logic control. The mining module mainly collects AC voltage, current and leakage resistance signals, thereby realizing system monitoring and monitoring and completing protection functions such as leakage blocking, overload, short circuit, phase failure, undervoltage and overvoltage. High intelligence, stable performance, reliable operation and other advantages. 
3. System Difficulties The system is mainly to ensure that leakage protection action time is less than 50ms and short-circuit protection action time is less than 100ms, so to ensure that the CPU's acquisition and processing speed is very fast, UniMATPLC adopts high-frequency microprocessor and the command processing speed is faster than ordinary PLC. 3-10 times increase, using UniMATUN200PLC acquisition and control cycle time is 12ms, plus the peripheral device time 30ms, a total of 42ms, to meet the standard equipment requirements.
4. Monitor function design adopts text display screen, cooperates with UniMATUN200 series small-scale PLC, realizes the display and memory of working status, parameters and fault type of the feed switch, and can modify and adjust specific parameters. The friendly user interface has good Man-machine conversation function can greatly improve the efficiency of judging faults and troubleshooting.
All analog signals are processed as digital signals, with strong anti-interference ability, simple wiring, large amount of information, and reliable and accurate control.
With complete self-test, self-diagnosis and fault simulation experiments, it is easy to check whether the protection and control system is normal or not.
5. System Function The feed switch fully considers the underground coal mine working environment, integrates machinery manufacturing, automation, measurement and control technology and instrumentation, computer application science and technology, etc. The main technical indicators are as follows:
Voltage level: 1140V/660V; frequency: 50HZ;
The total rated current: 800A, 1200A, a single working current can reach 400A;
Leakage blocking protection: additional DC detection, 1140V-40K Europe, 660V-22K Europe;
Leakage protection action: 1140V-20K Europe, 660V-11K Europe;
Short circuit protection: 3-10 times of the rated current;
Overvoltage and undervoltage protection: 0.75Ue
Over-temperature protection and over-limit protection;
Switchgear has leakage test and overcurrent test button, which can detect feed switch protection function at any time; 
At present, most domestic feed-in switches use the Siemens+transmitter+leakage protector control scheme. Although this scheme can meet the system requirements, it has a very limited control function. After adopting this scheme instead of the above scheme, the parameters of the whole feed switch such as current, voltage and other parameters can be detected online. The cost of the customer is reduced, the stability of the process conditions is ensured, and the response speed of the product is improved. With the text display screen, the alarm information reflected by the display screen makes it easy for staff to troubleshoot. Increased production efficiency.
6. System Highlights The three-phase AC and leakage monitoring module UN231-0BH22-0XA0 used by the system is a major highlight. The module can achieve the collection of AC information through the AC transformer, and it can be realized through the calculation and control of the CPU. Pressure, undervoltage, overload, short circuit, leakage, three-phase unbalanced protection and other functions; able to monitor the insulation resistance of the grid; with zero-sequence voltage and zero-sequence current acquisition. This product is an expansion module of UN200PLC. Please refer to the following figure and wiring diagram for details: 
The module technical indicators are as follows: 
The module can also be applied to a variety of power monitoring and control products, such as various electrical control of power distribution system monitoring, monitoring systems of small substations and other combination switches.
Third, the use of effects analysis The control system in the feed switch system to achieve the desired purpose, according to the importance of the feed switch system in practical choice of Shenzhen billion peacekeeping automation UN200 series PLC and three-phase AC and leakage monitoring module, improved The system stability meets the system's response requirements, simplifies the wiring construction, and reduces the difficulty of maintenance. Because the series PLC is fully compatible with the Siemens S7-200 PLC, it reduces the difficulty of engineers' development and saves the system cost to some extent. . The system is in good condition after being put into operation, and it is also applied to power screen monitoring of multiple automatic control systems, which has a good prospect of application in the industry.