Circuit breaker development status

The earliest circuit breaker in the world was produced in 1885. It is a combination of a knife opening and an overcurrent release. In 1905, an air circuit breaker with a free release device was born. Since 1930, with the advancement of science and technology, the discovery of the arc principle and the invention of various arc extinguishing devices have gradually formed a mechanism. In the late 1950s, due to the rise of electronic components, electronic releases were produced. Today, due to the popularity of single-chip microcomputers, intelligent circuit breakers have come into being.
Common ones are low-voltage circuit breakers and vacuum breakers:
Low-voltage circuit breakers are electrical appliances used for switching, control or protection in circuits with AC voltage of 1200V and DC voltage of 1500V. Low-voltage circuit breakers are an important part of the electrical industry and a basic accessory in the machinery industry. In the power distribution system, low-voltage complete switchgear is mainly composed of various low-voltage circuit breaker components. The function and performance of low-voltage circuit breakers play a vital role in low-voltage complete switchgear. More than 80% of the electrical energy generated by power generation equipment is distributed and used through low-voltage circuit breakers. For every additional 10,000 kW of power generation equipment, about 20,000 various low-voltage circuit breakers are required to match it. In industrial automation systems, various control panels, consoles, controllers and other products composed of low-voltage circuit breakers are also needed. Since 1949, China's low-voltage circuit breaker industry has gradually developed into an industry that can independently design and produce on the basis of some factories that repair and assemble simple electrical appliances. By 1979, there were more than 600 production companies. After two development peaks in 1985-1986 and 1990-1991, there were about 1,500 production companies in the low-voltage circuit breaker industry in 1995.
China's low-voltage circuit breaker manufacturing companies are mainly concentrated in Beijing, Tianjin, Liaoning, Shanghai, Jiangsu, Zhejiang, Guangdong and other places. While promoting the development of the national economy, they have also exposed many problems. There are mainly the following two points:
1. The scale of enterprises is small and the number is too large. Among China's low-voltage circuit breaker manufacturers, there are only 2 to 4 large enterprises with annual sales revenue and total assets of more than 500 million yuan, and the vast majority are small and medium-sized enterprises, resulting in a lack of economies of scale and competitiveness; and China's low-voltage circuit breaker manufacturers have grown from the early days of the founding of the People's Republic of China to more than 1,500 today. The excessive number of enterprises has led to excessive dispersion of economic resources, lack of overall innovation motivation, and low production efficiency, economic benefits and market competitiveness.
2. Regional structural convergence and serious duplication of construction. Due to blindly launching projects and spreading stalls, China's low-voltage electrical industry has serious regional industrial convergence and low-level duplication of construction, resulting in overproduction of products, low utilization of energy and raw materials, low economic benefits, and regional protection and vicious competition.
The progress of vacuum circuit breaker technology is reflected in large capacity, low overvoltage, intelligence and miniaturization. This progress is the result of the development of vacuum technology, arc extinguishing chamber technology and the adoption of new processes, new materials and new operating technologies. According to the inventor, in addition to being a substitute for traditional motor technology, this technology will also expand the development and application space for DC motors. For example, developing large-capacity DC motors to replace the AC synchronous generators and converter station equipment powered by the high-voltage DC transmission network can not only save a lot of converter station construction costs, but also significantly reduce substation losses.