Relays, which originated in the mid-to-late 1960s, were researched at the initiative of some scholars in the UK, Australia and the US.
In the mid-1960s, some people proposed the idea of using a small computer to realize relay protection, but because the computer was expensive at that time and could not meet the technical requirements of high-speed relay protection, it did not have practical application in protection, but it began. A large number of studies on the theoretical calculation method and program structure of computer relay protection have laid a theoretical foundation for the subsequent development of relay protection.
In the early and mid-1970s, major breakthroughs occurred in computer technology, and the rapid development of large-scale integrated circuit technology brought microprocessors and microcomputers into a practical stage. The sharp drop in price and the sharp increase in reliability and computing speed have led to rubbish in the study of computer relay protection. In the late 1970s, a relatively complete microcomputer protection prototype appeared and was put into trial operation in the power system.
In the 1980s, microcomputer protection became more and more mature in terms of hardware structure and software technology, and has been popularized and applied in some countries.
In the 1990s, the power system relay protection technology developed into the era of microcomputer protection, which is the fourth generation in the history of the development of relay protection technology.
my country's microcomputer protection research started in the late 1970s and early 1980s. Although it started late, it has made rapid progress due to the efforts of my country's relay protection workers.
After about 10 years of struggle, by the end of the 1980s, computer relay protection, especially the microcomputer protection of transmission lines, has reached a large number of practical levels. In the research process of computer relay protection in my country, colleges and research institutes play a leading role.
From the perspective of relay application fields in my country, communications and industrial control, home appliances and automobiles are still the largest relay markets. According to the relay market survey report, the largest demand is for general-purpose relays, especially high-sensitivity, small, ultra-small PCB relays, and low-power relays. Judging from the market situation, relays are a competitive industry with large volume, wide service coverage, low technical content, meager profits and large market potential.
Although my country's relay industry has experienced decades of development, there is still a big gap between the overall level of products and the world's advanced level, mainly as follows:
1) The design level is low, the variety of military products is small, the environmental adaptability is poor, and the reliability level is low, which cannot fully meet the requirements of weapons and equipment and high-tech operations. General relays have poor quality consistency, slow variety replacement, and low market share of high-end products, which cannot meet the needs of domestic and international markets, nor can they completely replace imports.
2) Low ability of independent development and innovation: The research on common technologies is not deep or wide, the technical force has not been fully exerted, and the supporting technology is weak, which are the main reasons that affect the speed of new product development.
3) The production technology is backward, the automation level is low, and the ability of process control means is worse, which seriously affects the consistency and reliability of product quality and increases the service cost.
4) The management level is low, the overall quality of the management personnel is low, and the business model is outdated, especially the slow change of management thinking, which is not compatible with the technological development.
5) CAD is still in low-level application, CAM and CAT are in their infancy, and the product development cycle is long, which does not meet the requirements of rapid replacement of the whole machine. The application of materials cannot keep up with the development requirements of relay technology.
6) The physical analysis of material failure is not extensive or deep; there are few domestic materials, and there are no manufacturers of key materials, such as flame-retardant thin plastic installation lines and pressure-sensitive tapes, which still need to be imported; the material modification equipment to meet the requirements of relays is even more backward and incomplete , especially the material rolling. Testing technology and means need to be improved and perfected.