Development Status Of Circuit Breakers

The world's earliest circuit breaker was produced in 1885. It was a combination of a knife opening and an overcurrent release. In 1905, the air circuit breaker with a free tripping 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, an organization has gradually formed. In the late 1950s, due to the rise of electronic components, electronic trippers were produced. Today, due to the popularity of single-chip microcomputers, intelligent circuit breakers have been produced.
Common ones include low-voltage circuit breakers and vacuum breakers:
Low-voltage circuit breaker is an electrical appliance used for switching, controlling or protecting circuits with AC voltage of 1200V and DC voltage of 1500V. Low-voltage circuit breakers are an important part of the electrical industry and are basic accessories in the machinery industry. In power distribution systems, low-voltage complete sets of switchgear are mainly composed of various low-voltage circuit breaker components. The functions and performance of low-voltage circuit breakers are crucial to low-voltage complete sets of switches. Equipment plays a vital role. More than 80% of the electric energy generated by power generation equipment is distributed and used through low-voltage circuit breakers. For every additional 10,000 kW power generation equipment, approximately 20,000 pieces of various types of low-voltage circuit breakers are needed 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 capable of independent design and production based on some simple electrical appliance factories that repaired and assembled. By 1979, there were more than 600 manufacturing companies. After 1985-1986, 1990- There were two development peaks in 1991. In 1995, there were about 1,500 manufacturing companies in the low-voltage circuit breaker industry.
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 two points:
1. The scale of enterprises is too small and there are too many. Among China's low-voltage circuit breaker manufacturers, there are only 2 to 4 large-scale enterprises with annual sales revenue and total assets of more than 500 million yuan. The vast majority are small and medium-sized enterprises, resulting in the lack of economies of scale and competitiveness; and China's low-voltage circuit breakers The number of appliance manufacturing enterprises has 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 over-dispersion of economic resources and a lack of overall innovation power, resulting in low production efficiency, economic benefits and market competitiveness.
2. The regional structure is convergent and there is serious duplication of construction. China's low-voltage electrical appliance industry has blindly embarked on projects and paved the way, resulting in 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, regional protection, vicious competition and other consequences.
The progress of vacuum circuit breaker technology is reflected in large capacity, low overvoltage, intelligence and miniaturization. This progress is due to 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 replacement for traditional motor technology, this technology will also expand a broader development and application space for DC motors. For example, the development of large-capacity DC motors to replace AC synchronous generators and converter station equipment powered by high-voltage DC transmission grids can not only save a large amount of construction costs for converter stations, but also significantly reduce transformation losses.