Load variation tracking automatic rated value breaker

Abstract

The invention belongs to the technical field of high / low voltage electrical apparatuses. A load variation tracking automatic rated value breaker mainly comprises a movable / fixed contact component 1, an electric tripping mechanism 2, an electric reclosing mechanism 3, an electronic control system 4, current sensors L1, L2 and L3, an electrical leakage sensor L4 and a grounding sensor L5, wherein a signal acquisition and processing system which consists of a load voltage detection circuit, a load current detection circuit and a load current phase detection circuit is used as a main information source; variation in acquired load voltage and load current is used as a main basis for judging and differentiating a working state and a fault state of the breaker; meanwhile, the phase of the acquired load current and a calculated power factor are also used as main bases for judging and differentiating the working state and the fault state of the breaker; and a tripping protection program and a rated value updating and setting program are accessed according to judgment results; thus, a high-flexibility and high-precision protection characteristic is achieved, and accidents and fire disasters are avoided.

Description

technical field [0001] The invention belongs to the technical field of high and low voltage electrical appliances Background technique [0002] Modern society is inseparable from electric energy. 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: switching and protection. The protection function is a very important function of circuit breakers. [0003] The protection function of the circuit breaker is realized based on the rated value. The load current In is compared with the rated value Ir, 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. Generally, its rated value and size specification have been customized before leaving the factory, and the user chooses according to the current specification, and cannot customize its current specification. Although the...

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Problems solved by technology

[0005] The basic principle for people to use circuit breakers is to select the rated value Ir of the circuit breaker according to the expected maximum load current In. However, according to the formula for calculating the safe load current of the circuit breaker, if the load current In is less than 81% of the rated value Ir, the circuit breaker The overload protection will be out of control. If the load current In is less than 67% of the rated value Ir, the circuit breaker will lose its short-circuit protection performance, which will cause personal equipment accidents and fires

[0006] Since the rated current of the circuit breaker cannot be changed according to the change of load during operation, when the load of the user is reduced, the circuit breaker loses its effective protection function, causing great safety hazards, and even directly causing accidents and fires

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