A high-current arc breaking technology

      With the increasing power capacity, low-voltage circuit breakers breaking capacity requirements continue to increase, low-voltage circuit breaker breaking performance in the higher demand.

      In order to improve the system reliability, the new generation circuit breaker generally achieve Icu = Ics = Icw, in improving the Icu, Ics the same time, focus on improving the Icw. Requirements of the new generation MCCB Icu = Ics, focus on improving the Ics. In order to improve breaking performance, mainly adopt the following measures.

    (1) arc system with double break contacts
        Double break contact system used to control electrical arcing in the more general use, its main purpose is to reduce product size. Low-voltage high breaking capacity circuit breaker, contact interrupter system is more complex. Such as the double break system, the product structure is more complex, a series of key technologies to be resolved. The two most important technical difficulties to design a reliable stuck agencies, without infringing the patent, and two contact closure when the synchronization problem with the disconnect, and the manufacturing process requires high. Double-break point of contact for this system is not a low-voltage circuit breaker arc direction of apparent disagreement. With the continuous development of modern design technology and application, the technical problems have been effectively resolved. MCCB products for high performance double break contact system is certainly the direction of development is the single point of structure could not be compared. He made molded case circuit breaker current-limiting performance is better, higher breaking capacity, the better to achieve the Icu = Ics. And selective protection to achieve the limit, and the dusk of product miniaturization, high life, high reliability, and environmental protection and create better conditions. However, as economic MCCB products, manufacturing costs should not be considered a dual break system. Therefore, how to reasonably constitute a new generation of high-performance series MCCB is worth exploring. The series type high off the traditional type, high breaking type, standard type, the same type of economic structure, the new generation MCCB may be inappropriate.
        ACB as a high-performance products, double-break interrupter system also contact one of the four direction. Breaking performance for the ACB is further improved, providing more space. In a very short period of time for the full current to create better conditions for selective protection. However, as the ordinary type (standard type) ACB products should not be double-break system.

    (2) the use of modern design and test low-voltage electrical contact interrupter system technology to optimize the design and use of aids such as the blowing arc fast, reliable access to interrupter. At the same time, effective way to control the spread of free gas, to avoid the white, relatively arc, arc distance control to a minimum.

2 new technique over current protection
      Low-voltage circuit breaker is mainly responsible for low voltage distribution system overcurrent protection, and other types of fault protection, basically meet the current performance of the system fault protection requirements. However, current protection for distribution system state, the current protection is imperfect. The following problems:

    (1) of the selective protection of low voltage circuit breaker off delay generally limited to the following current range. When the fault current to achieve higher instantaneous current, likely to cause, the lower circuit breaker tripped at the same time, or even grade trip.

    (2) The terminal with a small circuit breaker over-current protection limiting the present are smoothly moving type, so the terminal is not selective distribution system of basic protection.

    (3) of the current system of selective short circuit protection achieved by the short time delay, short delay time is generally 0.2 ~ 0.4s. On the third power supply system, the main switch short delay time of up to 0.6 ~ 1s, seconds or even more. Thus, the present selective protection of low voltage distribution system to achieve a longer time, low-voltage electrical appliances, complete sets of equipment and systems dynamic and thermal stability of high requirements.

(4) is difficult to ensure distribution system reliability

    New generation low-voltage circuit breaker over-current protection using new technologies to achieve the objectives and requirements mainly include two aspects:

    The full range of low voltage distribution system, all current selective protection.

    Selective protection in a very short period of time, the selective protection time from 1 ~ 1.2s reduced to 0.2 ~ 0.5s.

    To achieve these goals, a new generation of low voltage circuit breaker shall meet the following requirements:

    ACB to achieve full current range of next-generation selective protection.

    A new generation of current limiting MCCB should have selective protection.

    Develop a short delay protection MCB.

    A new generation of ACB, MCCB shall be used for regional selective protection technology.

    Over-current protection of new technologies to achieve the main effect after the following:

    Fundamental to avoid low-voltage distribution system and fault grade trip circuit breakers normal points up the rear, the higher gate circuit breaker at the same time points. The distribution system short circuit fault to a minimum range, greatly improve the distribution system reliability.

    Greatly shorten the time to achieve selective protection to reduce electrical equipment dynamic and thermal stability requirements, benefit and materials, energy, and product miniaturization.

      Research and promotion of this technology is a low voltage power system protection and reliable operation of a major leap forward, with good economic and social benefits, it is caused by the electrical industry and power industry attention.

        3 can be integrated intelligent communications and technology
        In order to improve low-voltage power distribution and control system reliability and the degree of automation to achieve the system network is the inevitable direction. Once the system is to achieve network-based, low-voltage electrical appliances must have a two-way communication, the communication adapter can be connected with a variety of field bus system. Development and application of industrial Ethernet technology, the power distribution system communication network has become more concise and more colleges and universities.

      Distribution systems to achieve network, to achieve low-voltage circuit breakers can be communication, the circuit breaker will be full of intelligent features and to promote the development of intelligent circuit breaker situation, the protection, measurement, fault warning, self-diagnosis, see empty energy management and other functions concentrated in one.

        4 low-voltage circuit breaker technology miniaturization and modular
        Product miniaturization technology is both a manifestation of low-voltage electrical appliances, equipment and systems is the need for miniaturization. The advancement of electrical products and materials, energy conservation is important. Mainly by means of small low-voltage circuit breaker of new technologies, new technology applications and product mix, innovation, next-generation products, compared with the third generation of products, reduce the size of an average of 20% to 50%.

        Low level is low-voltage electrical circuit breaker modular design and manufacturing capabilities embodiment is to achieve low-voltage electrical function, improve product performance and maintenance needs. Low-voltage circuit breaker parts, accessories modular level to some extent reflect a country of low-voltage electrical and manufacturing standards. Modular circuit breaker level, including: functional accessory module type, degree of standardization, manufacturability, ease of maintenance and module miniaturization.

        5 Low Voltage Circuit Breaker Reliability and surrounded by technology
        Improve the circuit reliability and the application of a new generation of environmental technology research and development of low-voltage circuit breaker of the main tasks. Low-voltage circuit breakers and low voltage distribution system reliability is a necessary condition reliability. Include the following:

       (1) operating reliability: operational reliability, including low voltage circuit breaker failure protection and system reliability. Through the operation mechanism motion and force simulation analysis, optimization of component design, can effectively improve the life of low-voltage circuit breakers and operating reliability.
Reliability analysis of an intelligent controller, to ensure that the circuit breaker operation after receiving fault signal characteristics of reliability and consistency of action.

       (2) breaking reliability: the use of modern technical analysis of the test circuit breaker during the arc movement and breaking off the process by optimizing the design of the circuit breaker performance and reliability of extinction: including climatic and environmental changes, such as high and low temperature operating reliability, electromagnetic environment changes in performance that is in full compliance with EMC standards.

       (3) reliability under environmental change: environmental change, including climate, such as high and low temperature operating reliability, electromagnetic properties of environmental changes that should be in full compliance with EMC standards.

       (4) the reliability of internal and external attachment work is low-voltage circuit breaker reliability the main issue, but also a new generation of products and other new product development time needed to solve problems.

        Attachment reliability, the reliability of their work, including accessories and attachments between the machine with the reliability and coordination and so on.

        Low-voltage circuit breakers environmental technology, including product manufacturing process, after running into the system does not pollute the environment, the end of product life so easy retrieval.