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How To Ensure Safe Operation Of High Power SCR Rectifier
Sep 07, 2017

How to ensure safe operation of high power SCR Rectifier
       SCR Rectifier is the core equipment of the electrolytic aluminum plant, once put into operation, does not allow a long time downtime. Otherwise it will cause huge losses, and even lead to aluminum in the electrolytic tank cooling condensation. At this time in addition to loss of output, customers have to invest heavily to repair the fault of the electrolytic production line. If the fuse selection is improper, causing an explosion, but also endanger the safety of the operator.
This article focuses on the application of fast fuses in high-power rectifier equipment in the electrolytic aluminum industry, and is also mentioned in other applications.
This paper first describes the semiconductor SCR Rectifier fuse protection principle, followed by the selection of several key parameters are described. The significance of these parameters for the safe and stable operation of SCR Rectifier will also be explained one by one. The problems and representations resulting from the small selection of the fuse rating are illustrated.
Introduction
High-parameter fast fuses are mainly used for the protection of high-power semiconductor devices. A typical semiconductor device is a high power SCR Rectifier that converts an AC power to a DC using a diode or thyristor. High-power rectification of many industrial applications, this article is only part of the mentioned.
Chlorine Electrolysis Usually chlorine is obtained from electrolyzed brine while generating hydrogen and caustic soda. Production of one ton of chlorine gas to consume about 4,000 degrees of electricity. SCR Rectifier Chlorine electrolysis process required DC current between 300-350kA, the required DC voltage can be as high as 1000Vdc.
DC Arc Furnace Modern Many large steel plants use DC arc furnaces to melt recycled scrap steel. The use of DC arc furnace has the advantage of large production capacity, SCR Rectifier high production efficiency and low noise. Iron and steel smelting arc furnace process current is about 100kA, the voltage is generally higher than 1000Vdc. The electrolysis process is generally clean and the continuous load current stably flows through the semiconductor and the fuse. Electric arc furnace applications are different, the characteristics of their production process makes the load current often have serious pulse components, SCR Rectifier so in the semiconductor and fuse selection requires a very careful calculation and verification.
Graphite furnaces Many graphite products are produced, such as electrodes, etc., also use the DC furnace. Typical process parameters: the voltage is generally not higher than 300V, the current may be as high as 160kA. Other metals smelting copper, zinc, lead, nickel, cadmium and other metal production process current also need to be generated by high-power rectification process.
Fast Fuse Applications
High Power SCR Rectifier: High Power SCR Rectifier's core components are semiconductors (diodes or thyristors) and fast fuses. The efficient use of power semiconductor components depends to a large extent on how the heat generated by semiconductor losses is distributed in a timely manner.
The solution is forced cooling, air cooling and water cooling are the industry standard practice. For high-power SCR Rectifier, cooling with deionized water (adding ethylene glycol as antifreeze) is more effective and is the choice for most mainstream SCR Rectifier manufacturers. Now the semiconductor components of the double-sided cooling has been the industry's standard practice, in order to increase the output current, fast-melting double-sided cooling than ever had more use. In the past, quick fuses were mostly single-sided cooled.
Modern production processes require increasingly high process currents, and to meet this need, Bussmann has developed a five-piece quick fuse for a single design. This design optimizes the overall thermal performance of the fuse during forced cooling.
Fast fuse rated voltage
A fast fuse with IEC 60269-1 & 4 standard is tested and tested at 110% of the rated voltage. The rated voltage is one of the most important parameters for fuse selection. In the event of a fault, if the voltage across the fuse is higher than the rated voltage of the fuse, the fuse is likely to not operate normally. Even if the fuse's test voltage is 10% higher than its rated voltage, we never recommend fuses used in systems above its rated voltage. 10% of the safety margin is considered in the harsh system conditions, specifically for the system voltage fluctuations and set.
In the rectifier application, the rated voltage selection is based on the SCR Rectifier input line voltage due to no regenerative load. If used in conjunction with a 3-inch or 4-inch diode or thyristor, the SCR Rectifier that can be formed as a DC 2100V will allow 440 electrolyzers in a production line to be connected in series, equivalent to an annual production capacity of 390,000 tonnes of aluminum.