Small circuit breaker with selective protection for domestic use

Abstract: with the improvement of people's living standards, high-end residential, luxury villa came into being. The construction of electrical automation, intelligent building into people's life, domestic distribution automation system application requirements and improve the reliability of power supply quality, there is the intelligent and digital control with selective protection of small...

Abstract: with the improvement of people's living standards, high-end residential, luxury villa came into being. The construction of electrical automation, intelligent building into people's life, domestic distribution automation system application requirements and improve the reliability of power supply quality, there is the intelligent and digital control with selective protection of small circuit breaker demand.

Key words: selective protection of small circuit breakers, building electrical automation, intelligent buildings

In 50s and 60s China's first family residential distribution protection is the most knife gate type switch and fuse simple (porcelain plug RC1) assembly. When the short circuit occurs, the entire house was dark, not easy to replace a fuse. At the end of 60s to 70s, China has successively developed DZ5, DZ12, DZ15 series circuit breaker poles. At the end of 70s, the introduction of German technology in Beijing switch factory and the transfer of domestic manufacturers to produce S060 series of small circuit breakers, but for a variety of reasons not to large-scale promotion. In late 80s, Tianjin MGE company produces many manufacturers C45N and domestic production of DZ47 series miniature circuit breaker of large-scale production, I state circuit breakers for overcurrent protection up to a new level. These products make the home power distribution system into a standardized electric meter box, the application of the terminal box, the majority of residential users benefit from non shallow.

Since entering the new century, people's material life has been further improved, but also the corresponding part of the people to pursue high quality of life, high-end residential and luxury villa in the residential distribution system came into being, application in the field of automation and high reliability of the increasingly strong desire. They want to use electricity not individual system or individual unit short circuited effects of other systems and units, that is to say the main switch with selective protection is required in the residential distribution system, to solve the leapfrog trip fault occurrence, improve the stability and reliability of the system.

The so-called selective coordination of protection, it simply is short circuited in the scope of protection appliances next level, over-current fault should be the protective action of the electric appliances are not on the level of protection action, and when the protection of electrical resistmoves on the level of protection appliances to action, to the scope and priorities request. In general, the protection of the electrical installation in the protected lines, to the end of the distribution box at the outlet to install protective appliances, distribution box protection is to protect the end of backup protection electrical appliances at the head end, that is to say the higher breaker is a circuit breaker backup protection. Therefore in the distribution design according to the different circumstances of the project to consider the distribution plan, should be considered thoughtful, optimize the distribution system to simplify the protection device, improve the reliability of the system.

The selectivity of circuit breaker protection action is very important, the circuit breaker is divided into A, B two categories: a type of non selective type, B type for selection. In the design of the circuit breaker, the action between the circuit breaker is non selective, and if no action is taken, it is difficult to achieve the selective protection of the circuit breaker. A circuit breaker when the short-circuit fault occurs when installed in series on the lower will be action on the trip or trip, the trip may be subordinate circuit breaker fault tripping, or due to the discrete manufacturing, is also one of the defect structure of the circuit breaker.

Application of selective protection in low voltage distribution system was first used in circuit breaker, the circuit breaker such as circuit breaker DW15 series belt type semiconductor have this function, the new product has the function of DW450 and DW45. In recent years, MCCB also has some products initially have a selective protection function, wide application of these products to China's industrial distribution from top to bottom can achieve selective protection, greatly improves the stability and reliability of power quality. But the selective protection is not yet implemented in the domestic distribution system,. In this field is still a blank, we need to develop such a product to fill the vacancy.

In recent years, some foreign enterprises such as ABB, Hagrid are conducting research in this area, also introduced some products for use in their home, as the main switch family residential distribution, the main idea is that the selective overcurrent trip switch, and not simply rely on cooperation between the lower switch to achieve the purpose of selective protection.

Now the domestic manufacturers of small circuit breakers are only with over current protection or residual current protection, far can not meet the building electrical load use to improve the reliability of power supply protection needs.

Along with the development of China real estate industry and the construction industry, the new district and the transformation of the old city, and the residents for the quality of electricity demand increase, meter box every household or residential distribution box has a small circuit breaker product installation with selective protection requirements, can be expected to prospects for the development of miniature circuit breaker with selective protection. And the market demand will be huge. According to the relevant departments of Statistics: 2004 ~ 2005 China's small circuit breaker (MCB) annual output of 200 million