Development history of circuit breaker
The early circuit breaker of China in the world was produced in 1885. It is a combination of knife head and over-current release.
In 1905, the air circuit breaker with free tripping device was born. Since 1930, with the progress of science and technology, the discovery of arc principle and the invention of various arc extinguishing devices have gradually formed a mechanism. At the end of the 1950s, due to the rise of electronic components, an electronic release came into being. Today, due to the popularity of SCM, an intelligent circuit breaker came out.
Common low voltage circuit breakers and vacuum breakers:
Low voltage circuit breaker is an electrical appliance used for making and breaking, controlling or protecting circuits with an AC voltage of 1200V and a DC voltage of 1500V. Low voltage circuit breaker is an important part of the electrical industry and a basic accessory in the mechanical industry. In the distribution system, the low-voltage complete switchgear is mainly composed of various low-voltage circuit breaker elements. The function and performance of low-voltage circuit breaker play a vital role in low-voltage complete switchgear. More than 80% of the electric energy generated by power generation equipment is distributed and used through low-voltage circuit breakers. Each additional 10000 kW power generation equipment requires about 20000 pieces of low-voltage circuit breakers. In the industrial automation system, various control panels, consoles, controllers and other products composed of low-voltage circuit breakers are also required. Since the afternoon of 1949, China's low-voltage circuit breaker industry has gradually developed into an industry capable of independent design and production on the basis of some simple electrical equipment repair and assembly plants. By 1979, there were more than 600 manufacturers. After two development peaks in 1985~1986 and 1990~1991, there were about 1500 manufacturers in the low-voltage circuit breaker industry in 1995.
China's low-voltage circuit breaker manufacturers are mainly concentrated in Beijing, Tianjin, Liaoning, Shanghai, Jiangsu, Zhejiang, Guangdong and other places. While promoting the development of the national economy, they also exposed many problems. It mainly includes the following two points:
1. The scale of enterprises is small and the number is too large. Among Chinese 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, most of which are small and medium-sized enterprises, resulting in the lack of economies of scale and competitiveness; Moreover, the number of low-voltage circuit breaker manufacturers in China has grown from the early days of the founding of the People's Republic of China to more than 1500 today. The number of enterprises is too large, resulting in excessive dispersion of economic resources and lack of overall innovation power, leading to low production efficiency, economic benefits and market competitiveness.
2. Regional structure convergence and serious duplication of construction. China's low-voltage electrical appliance industry has been blindly involved in projects and stalls, resulting in serious regional industrial convergence and low-level repetitive construction, resulting in excessive production, low utilization of energy and raw materials, low economic efficiency, regional protection, vicious competition and other consequences.
The progress of vacuum circuit breaker technology, the progress of vacuum circuit breaker technology is shown 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. It is reported that this technology can not only be used as a substitute for traditional motor technology, but also expand a wider 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 HVDC transmission network can not only save a lot of construction costs of converter stations, but also greatly reduce the transformation loss.
In the future, circuit breakers will develop towards the direction of type, multi-function, low overvoltage, intelligence, etc.
