A low-voltage line protection device and its control method

Abstract

The invention discloses a low-voltage line protective device which comprises a microprocessor, a voltage and current collection unit, a displayer, a displayer driving circuit, a storage unit, a switching value and button signal collection unit, a protective action relay output unit and a variable output unit, wherein the voltage and current collection unit collects three-phase voltage and current signals, carries out A / D conversion and transmits the three-phase voltage and current signals to the microprocessor, the displayer driving circuit is connected with the displayer and the microprocessor, and the storage unit, the switching value and button signal collection unit, the protective action relay output unit and the variable output unit are connected with the microprocessor. The low-voltage line protective device has advanced field buses, is based on the microprocessor technique, and adopts a modular structure. Due to the fact that the microprocessor executes a circuit monitoring function, and is matched with a contactor, a soft starter and a molded case circuit breaker to provide a whole set of solution integrating control, protection, monitoring and bus communication for low-voltage AC electromotors and low-voltage line loops, and the low-voltage line protective device has the protective functions against overload of circuits, short circuits, loss of phases, three-phase current unbalance, over undervoltage, electric leakage and the like.

Description

technical field [0001] The invention relates to a low-voltage line protection device. Background technique [0002] The supply of electricity plays a very important role in the normal production and work of the society. Therefore, in the fields of power automation and other fields, the use of low-voltage line protection devices has become more and more common, and the low-voltage line protection devices on power switchgear The reliability of the protection performance and the measurement accuracy play a very important role in the normal operation of the power switchgear. [0003] However, the low-voltage line protection devices currently used are difficult to take into account protection functions such as line overload, short circuit, phase failure, three-phase current imbalance, overvoltage and undervoltage, and leakage, so it is difficult to adapt to electric power, petrochemical, light industry, coal, paper, steel, etc. , metallurgy, textile and other industries producti...

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Problems solved by technology

[0003] However, the low-voltage line protection devices currently used are difficult to take into account protection functions such as line overload, short circuit, phase failure, three-phase current imbalance, overvoltage and undervoltage, and leakage, so it is difficult to adapt to electric power, petrochemical, light industry, coal, paper, steel, etc. , metallurgy, textile and other industries production needs

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