Method of Reactive Power Compensation Switching of Low-voltage Thyristor in Metallurgical Electric Furnace

Abstract

The invention discloses a method for reactive power compensation switching of low-voltage thyristors in metallurgical electric furnaces. First, the capacitors and reactor groups in the reactive power compensation device are divided into several groups according to the three-phase A, B, and C currents of each group ≤ 200A, and each phase is 2 / The capacity of 3 is used as a fixed switching, and then the thyristor and the trigger circuit are assembled with the heat sink, and the heat sink adopts a water-cooled circulation method; the thyristor, the capacitor, and the reactor are connected and fixed through copper conductors to form a group of thyristors. unit, through the thyristor reactive power compensation switching controller, and finally select the static fixed thyristor switching compensation unit group number according to the requirement of power factor cosφ=0.9; the present invention can meet the requirement of reactive power compensation amount under normal production process conditions of metallurgical electric furnace Demand, the service life of the device is extended, the possibility of under-filling is eliminated, and the occurrence of over-filling is avoided.

Description

Technical field [0001] The invention relates to a control method of an executive element in a low-voltage reactive power compensation device of a metallurgical electric furnace, in particular to a method for reactive power compensation switching of a low-voltage thyristor of a metallurgical electric furnace. Background technique [0002] Metallurgical electric furnace is a kind of high energy consumption equipment, mainly divided into more than 20 series such as calcium carbide, industrial silicon, ferrosilicon, ferromanganese, nickel iron, and yellow phosphorus. During the production and operation of the equipment, the voltage is low, the current is large, and the electrode needs to be continuously adjusted according to the furnace conditions. The load changes quickly. Due to its low power factor (about 0.7 to 0.86), a reactive power compensation device needs to be installed for compensation. [0003] The traditional high and low voltage compensation device mainly consists of cont...

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Problems solved by technology

[0004] 1: Since the action elements of contactors and circuit breakers are all electromagnetic induction type, they cannot be switched when the voltage and current cross zero due to their action time of about 40-60ms, resulting in a large closing surge current and reducing the capacitor And the service life of actuators such as contactors

[0005] 2: Due to its inherent action characteristics, it is easy to cause operating overvoltage. After opening once, it must wait for the capacitor to discharge (about 3 minutes) before closing the next time. It cannot meet the requirements of fast switching of reactive power compensation during the lifting process of metallurgical electric furnace electrodes. process requirements

[0006] 3: Adopt the method of first cast first cut, the frequency of mechanical action is frequent, and the service life of components is short

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