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矿热炉是一种高能耗设备,电能损耗很大.我厂1995年1月投建的1800kVA矿热炉,在运行中其短网铜排温度高达200～320℃,常发生烧坏短网铜排连接件的故障,造成频繁停炉.一、铜排高温的原因分析矿热炉电流变压器由低压侧到电极段连接导体称为短网,包括铜排、软母线、导电管和铜瓦四部分.矿热炉运行是采用大电流、低电压工作方式,二次电流达15000A,电压在72～96V之间.电流变压器允许超载10%～30%.原铜排各参数见表1.表1造成铜排温度过高的原因有:1.老式变压器体积大,考虑散热条件,短网铜排设计较长,达2～2.2m,故电阻较大.2.设计短网铜排时忽视了电流变压器的超载运行条件,故超载时铜排发热过甚.3.短网部分的连接件较多,又是采用铁螺丝压接(误认为铁螺丝压接牢固,可降低接触电阻).然而,当短网流过强大的电流时,在铁件周围产生较大的交流磁场而引
Submerged arc furnace is a high energy consumption equipment, power loss is very large. I cast the plant in January 1995 1800kVA submerged arc furnace, in operation its short-circuit copper temperature as high as 200 ~ 320 ℃, often burn short net Copper connection failure, resulting in frequent shutdown .. First, the analysis of the causes of high temperature copper heat exchanger Current transformer from the low voltage side to the electrode section connected to the conductor called the short network, including copper, soft bus, conductive pipe and copper tile The operation of the submerged arc furnace is a high current, low voltage mode of operation, secondary current up to 15000A, voltage between 72 ~ 96V. Current transformer allows 10% to 30% overload. Table 1 causes the copper bar temperature is too high for the reasons: 1. Old-fashioned transformer bulky, considering the cooling conditions, the short copper bar design longer, up to 2 ~ 2.2m, so the resistance larger .2. Ignore the current transformer overload operating conditions, so overloaded copper heat too much .3. Short network part of the connector is more, but also by the use of iron screw crimp (mistakenly believe that the iron screw crimp firmly, can reduce the contact resistance). However, when a short wire flows through a strong current, a large AC magnetic field is generated around the iron piece