Breaker capable of tracking load change to automatically set rated value

Abstract

The invention relates to a breaker capable of tracking load change to automatically set a rated value. The breaker comprises an electric tripping mechanism, a reclosing mechanism and an electronic control system, wherein the electronic control system comprises an MCU, a keyboard, a display, a first A / D converter, a second A / D converter, a current sampling sensor, a voltage sampling sensor, a program storage, a strategy controller and a data storage. The breaker has the advantages that the rated value of the breaker is automatically set by the electronic control system, and the rated current Irof the breaker is allowed to constantly track the load change and be timely changed to the optimal value; the safety of load equipment and electric lines is sensitively, safely and reliably protected, and electric fire possibly caused by various causes is avoided.

Description

technical field [0001] The invention relates to a circuit breaker which automatically adjusts the rated value by following the load variation. Background technique [0002] Circuit breakers occupy an extremely important position in power transmission and distribution, and have a very high market share. Circuit breakers mainly have two functions of switching and protection. The protection function is a very important function of circuit breakers. The protection function of the circuit breaker is realized based on the rated value. The load current I n is compared with the rated value I r, and the judgment is made based on the comparison result, and then it is selected whether to enter the overload or short-circuit protection state. [0003] The circuit breakers in the prior art generally have customized ratings and specifications when they leave the factory, and the user selects them according to the current specification, and cannot customize the current specification. In th...

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Problems solved by technology

[0003] The circuit breakers in the prior art generally have ordered the size and specification of the rated value when leaving the factory, and the user selects according to the current specification, and cannot customize the current specification.

In the prior art, the rated current of some circuit breakers can also be adjusted by the user, but it is a one-time setting and cannot be automatically adjusted or changed during operation. When the user selects a circuit breaker, the basic principle is that the expected maximum load current can only be adjusted I n selects the rated value I r of the circuit breaker. However, according to the calculation formula of the safe load current of the circuit breaker, if the load current I n is less than 81% of the rated value I r, the overload protection of the circuit breaker will be out of control. If the load current I n is less than Below 67% of the rated value Ir, the circuit breaker will lose the short-circuit protection performance

Since the rated current of the circuit breaker in the prior art cannot be changed according to the load change during operation, when the load of the user is reduced, the circuit breaker will lose its effective protection function, which will cause great safety hazards, and even cause safety accidents such as fire.

[0004] In recent years, some manufacturers have adopted modern electronic technology and computer technology to develop and design some new intelligent circuit breakers, such as the M-PACTJnsCn air circuit breaker of GE, the 3WT universal circuit breaker of Siemens, and the Emax air circuit breaker of ABB. Circuit breakers, Schneider's EasyPactNS circuit breakers, etc. These intelligent circuit breakers generally have built-in circuit boards. Due to their small size, high internal temperature, and extremely poor stability, their basic principles and functions have not changed significantly.

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