After years of development, mine explosion-proof electrical products have made many advancements. Automation products such as coal mine electrical automation technology and coal mine safety production monitoring system have reached a certain level. Mechanical and electrical integration technology and power electronic speed control technology have been used in coal mines. Underground transportation machinery, lifting machinery and coal mining machinery have begun to be widely used. It should be said that after years of development, a complete manufacturing system of explosion-proof electrical products has been formed, which basically meets the current needs of power supply and distribution, downhole mechanization, and control and protection of coal mines.

　　In recent years, mine explosion-proof electrical products have been expanded in style and specifications, such as mine explosion-proof high and low voltage soft starters, mining explosion-proof frequency converters, mine explosion-proof high and low voltage combination switches, and a number of new technologies. It has also begun to be widely used in coal mines. Due to the continuous and stable demand, China's mining electrical product production has formed a large manufacturing industry, and peer competition is also becoming increasingly fierce. How to avoid price competition, avoid low-level repeated production, and develop enterprises through technological innovation has become a problem for each of our mining electrical product producers and operators. Where is the route for the successful development of an enterprise? Only technological innovation is the only way to win the market through the development of high-tech, high-value-added mining electrical products. At the same time, in terms of social benefits, it is only through the development of technological innovation that coal mining mechanization, electrification, and automation can promote the establishment of a true modern, intrinsically safe mine.

　　Technological innovation is an important indicator for measuring whether an enterprise is advanced, whether it has market competitiveness, and whether it can keep ahead of competitors. With the rapid development of China's mining electrical appliance market, the related core production technology application and R&D will surely become the focus of attention in the industry. It is critical to understand the trend of research and development, technology and equipment, technology applications, and trends in core technologies for domestic and international mining electrical appliances to improve product specifications and improve market competitiveness. Although the development of new products such as high and low voltage soft starters, high and low voltage combination switches, and variable frequency speed control devices, these products are still subject to many restrictions in their development. The core components of many explosion-proof electrical products still rely on foreign technologies. The production level of these core components still has a big gap with similar foreign products. From initial research and development to maturity, technological innovation generally goes through three stages: introduction, growth, and maturity. In the introduction period, the development of technology is very slow, and it often takes quite a long time before it can be broken. For example, about 50% of mine explosion-proof companies at this stage use direct purchases of foreign movements to assemble; 40 % of companies use domestic technology to absorb and use, and only about 10% of companies can achieve independent development and production. At the same time, the study of the EMC performance of the inverter is still in its infancy, but this stage challenges us. How to overcome the influence of the output harmonics of the inverter on the power supply and monitoring equipment of the grid has become the target that many companies have overcome. Harmonic control of downhole power grids It will also become the next stage development goal. When the technological innovation is in the growth stage, the technology develops rapidly and the technical performance rapidly improves; for example, the current phase of the frequency traction shearer, the use of variable frequency constant power speed regulation and PLC centralized control features, the application of shearer Mature, improved the working efficiency and reliability of the shearer, basically replaced the hydraulic traction technology; another example is the hydraulic winch collecting electricity, oil, gas three energy as one, the operation is complex, backward, noise, maintenance workload is also large After the explosion-proof inverter technology was adopted, the production process was completely changed and it was approved by users of coal enterprises. When technological innovation enters a mature period, the technology is relatively stable and there is no longer any major change. Technological progress is reflected as a partial improvement. For example, the high-low voltage combination switch at the present stage is close to the existing foreign level. The application of electronic technologies such as PLC, DSP, and field bus provides technical support for the stable operation of the combination switch, and the related cable introduction device has also basically reached localization. The unit structure of the combination switch has also made great progress. Recognizing the three development processes of technological innovation can accurately position our product development ideas.

　　Many companies also recognize the necessity of technological innovation, but are still unable to find a breakthrough. What are our technological innovation goals for the current product situation? Actually, the conventional starters, feed switches, and electronic control boxes are mainly protected by discrete component circuits, which have the disadvantages of unstable components and large drift. The application of single chip technology to protectors brings convenience and performance. The advantages of stability; the application of man-machine interface to make the operation more clear, fault memory function, provides a basis for the analysis of coal mining companies. Technological innovation is also focused on the continuous improvement of the performance of its own products. For example, a company's GM series shearer isolating switch used in the market has reached more than 90% of the market share, the stability of the performance has been recognized by the same industry; a company's miniaturized flameproof and intrinsically safe water level control starter also get the industry And the approval of coal enterprise users. Many companies' successful cases are worth learning and learning from. Enterprises should change their minds to blindly follow the trend and look for products on the whole. They only consider the coverage of the product and neglect the improvement of the product performance of their own expertise. Technological innovation, with its own intellectual property rights, is also a guarantee for the development of our mining explosion-proof enterprises.

　　Grasping the development trend of the product, it also grasps the market. According to the development trend of mining products, the following three points are put forward for mine explosion-proof electrical appliances:

　　First, the basic performance of electrical appliances

　　In the early 1980s, vacuum tubes were used in China. Mine explosion-proof vacuum switches have been widely used underground. The use of vacuum tubes plays a very important role in the safe supply of underground coal mines. For example, the mine explosion-proof vacuum electromagnetic starter products have strong limit breaking capacity and are suitable for frequent start-up of mine motor and low maintenance; mine explosion-proof The full-breaking time of the vacuum feed switch is small, and it cooperates with fast leakage protection to improve the safety of protection against electric shock and gas explosion. The demand for vacuum contactors and vacuum circuit breakers is very large. However, on the market today, the quality of vacuum tubes is uneven. Many production processes still remain on the basis of the early 1980s, and they are still relatively large compared with foreign technologies. gap. In the application of vacuum tubes, there is also the problem of operating overvoltage, and the problem of vacuum degree assurance. The decrease of vacuum degree makes it easy to cause leakage accidents in the downhole, which will affect production and cause accidents. Some companies have also begun to work on vacuum tube electrical appliances, and Research on gas leakage protection has made progress in gas leakage protection and vacuum tube adhesion protection, which provides guarantee for the safe operation of underground electric appliances in the future. With the continuous development of electronic technology, the use of power electronic devices instead of vacuum tubes to achieve the start and stop of the motor control, will be the direction of development, has been used in the comprehensive control of coal-fired drills, such as SCR non-contact shut down Control, increase the service life, safe and reliable. The use of high-power thyristors on starters also changes the performance of conventional starters. Power electronic devices are used to provide new vitality to the performance and reliability of explosion-proof electrical products. At the same time, they also bring new issues to the explosion-proof and safety technical requirements of products.

　　Second, selective leakage of low-voltage feed switch

　　Leakage protection is one of the three major protections of coal mine underground electric appliances, and the reliability of its protection affects the safety production of coal mines. The current principle of selective leakage protection for low-voltage feed switches is still based on the zero-sequence voltage and zero-sequence current protection methods. In addition, external DC is used to continuously monitor the insulation of the power supply network. Due to the lengthening of the power supply network and the application of shielded cables and the application of power electronic devices such as inverters, the downhole power supply network is complicated, and there are many spurious and selective capacitance leakage uncertainties in the selective leakage protection. There is a requirement for leakage protection. The use of advanced digital acquisition technology, how to analyze the distribution of underground capacitance, to achieve accurate selective tripping fault trips without affecting other work branches, to ensure reliable and safe underground power supply is also a new subject in urgent need of research.

　　Third, the development of mining AC inverter products

　　Due to the continuous advancement and development of science and technology, high-power electronic appliances are rapidly developed in downhole applications. Among them, AC frequency converters have the advantages of high efficiency, low failure rate, and good control performance, which can significantly improve the production process. Due to the attention of the coal mining industry, the mine frequency conversion speed control device was mainly used for the speed adjustment of about 100 kW for coal mining and electro-magnetic traction components. Generally, there is a dedicated transformer for power supply in the front stage, which has little impact on the grid. However, with the continuous development of frequency converter technology, the successful operation of electric traction shearers began in the 1980s. Frequency conversion technology was used in coal mine production equipment such as ventilators, winches, hoists, and air compressors. Not only changes in the traditional production process, but also mainly reflected in energy efficiency. For example, the selection of the main fan of the mine is based on the maximum air flow requirement for the production and service period of the mine. From the time of well construction to production until the mine is scrapped, the amount of air to be used in each period is different. The difference is very large. The use of mechanical adjustment of the air volume results in a large amount of electrical energy wasted. Fans use energy-saving converter technology to save energy is very considerable, and if the local exhaust ventilator work surface is installed in many places, long running time, is a large energy consumer, as coal mining continues to extend, the amount of air required in a long time is far less than the ventilation The aircraft's air supply capacity, in response to the current situation of the large horse-drawn car, the use of variable frequency speed control technology is also very obvious energy-saving effect, due to the high efficiency of the inverter, speed control performance, can implement electric braking and stepless speed regulation to save energy, It is an inevitable trend to use frequency conversion technology more widely in coal mines. However, at present, both product development and detection technologies cannot keep pace with the needs of production development.

　　According to the application experience of the ground frequency conversion speed control device, we must make good use of the frequency conversion speed control device, we must take the power supply, inverter motor, production machinery combined production process as a system to study, and take appropriate suppression measures on the harmonic of the power grid. In order to adapt to the development of variable-frequency electrical technology in coal mines, study the technical problems of the performance of high-power frequency conversion equipment for mines, the EMC research of frequency converters and the effect of wave suppression measures, and provide a technologically advanced technology for mining inverter technology research, design and production. The test platform is imminent.

　　How to carry out EMC testing, making the mine frequency converter can be used in the coal mine "green", reduce the harm to the coal mine production has become an important issue in the next stage of the detection department.

　　China is the world’s largest coal producing country, and coal is China’s largest energy source. In light of the above three development trends, it is of great significance to develop coal mining mechanization and electrification through technological innovation and accelerate coal mine modernization. In order to meet the requirements of technological innovation and development of enterprises, our testing organizations will continue to improve their capabilities and provide advanced detection methods and test methods. The National Safe Production Testing Center of Shanghai Mining Equipment has responded to the needs of technological development, and has continuously improved its own inspection capabilities and level. Large-scale explosion proof test tanks, such as the 3.4m, have been included in the plan to accommodate the detection of large-scale mining electrical equipment. Needs; mine explosion-proof inverter's inspection capability will be upgraded to the level of 1000kW to meet the test needs of large-capacity high-voltage motors and high-voltage inverters. Our inspection department will use advanced inspection technology support as a means to strengthen the exchanges and cooperation with enterprises, and provide technical support for the technical innovation and safety management of mining explosion-proof electrical products.