vacuum interrupter design is the core of the low voltage circuit breaker research and development. The performance of the interrupter is directly related to the breaking performance of the low-voltage circuit breaker, which determines whether the product can meet the requirements of intelligent, highly reliable new current selective protection and fault location. To this end, domestic and foreign scholars and research institutions have been committed to the field of technical research, and access to a large number of applications, such as through the double breakpoint arc technology to improve the arc voltage and mechanism speed; through gas production of reasonable settings, Improve the arc voltage and dielectric recovery strength, etc., to effectively improve the product breaking performance.
At present, the design and analysis of the low-voltage circuit breaker Vacuum interrupter for vacuum circuit breaker is mainly through the test method and simulation analysis method. The experimental method mainly uses high-speed photography, optical fiber array and so on to study the movement characteristics of arc; simulation analysis method mainly through the establishment of arc model to study the arc. Product design is often used decoupling approach to mechanical movement, magnetic blowing layout, gas flow, respectively, were designed. In this paper, the fluid analysis model is established by the airflow field of the interrupter, and the simulation software is used to simulate and evaluate the structure of a small circuit breaker.The arc of the arc chamber is assumed to be in the event of a fault current, and the static and static contacts are opened. The medium of the contact gap produces a very high temperature, which emits strong light and conducts the gas. The calculation analysis involves electromagnetic fields, Gas flow field and temperature field.
2017年5月23日星期二
2017年5月5日星期五
The working principle of the vacuum interrupter
The vacuum bottle interrupter in the vacuum bubble is an electric vacuum device which utilizes the high vacuum working insulating arc quenching medium to realize the on-off function of the power circuit by a pair of contacts sealed in vacuum.
When it breaks a certain value of the current, the static and dynamic contact in the separation of the moment, the current shrink to the contact just separated from the point, there is a sharp increase in resistance between the electrodes and the temperature increased rapidly until the occurrence of electrode metal evaporation, Extremely high electric field strength, resulting in a very strong launch and gap breakdown, resulting in 12KV vacuum interrupter, when the power frequency current close to zero, but also the opening distance increases, the vacuum arc plasma quickly spread to the surrounding, After the arc current is zero, the medium of the contact gap is rapidly changed from the conductor to the insulator, and the current is broken.
Due to the special construction of the contacts, the contact gap will produce a suitable longitudinal magnetic field during the arcing, which allows the arc to be evenly distributed on the contact surface to maintain a low arc voltage, so that the vacuum interrupter has a higher arc Post-medium strength recovery rate, small arc energy and small corrosion rate. In this way, it improves the ability and life of the vacuum interrupter to break the current.
When it breaks a certain value of the current, the static and dynamic contact in the separation of the moment, the current shrink to the contact just separated from the point, there is a sharp increase in resistance between the electrodes and the temperature increased rapidly until the occurrence of electrode metal evaporation, Extremely high electric field strength, resulting in a very strong launch and gap breakdown, resulting in 12KV vacuum interrupter, when the power frequency current close to zero, but also the opening distance increases, the vacuum arc plasma quickly spread to the surrounding, After the arc current is zero, the medium of the contact gap is rapidly changed from the conductor to the insulator, and the current is broken.
Due to the special construction of the contacts, the contact gap will produce a suitable longitudinal magnetic field during the arcing, which allows the arc to be evenly distributed on the contact surface to maintain a low arc voltage, so that the vacuum interrupter has a higher arc Post-medium strength recovery rate, small arc energy and small corrosion rate. In this way, it improves the ability and life of the vacuum interrupter to break the current.
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