对IEC标准中高压熔断件保护电动机回路的理解及建议  

Comprehension of HV Fuse Protecting Motor Loop in IEC Standard and Recommendations

作　　者：张大文[1] 

机构地区：[1]东北电力设计院,长春市130021

出　　处：《电力建设》2007年第11期45-47,51,共4页Electric Power Construction

摘　　要：IEC标准考虑高压厂用电源为中性点接地系统,8.2条规定采用瞬时接地故障保护。但是我国高压厂用电源系统大多为不接地系统,故可取消瞬时接地故障保护。关于电动机定子两相接地故障,IEC标准按短路绝热过程和短路热稳定要求来选择电缆截面,偏保守,会增加投资。所以可取消反时限过电流保护,改由热控保护装置切除故障电动机电源,这样可选择较小的电缆截面。另外,易过负荷电动机现有保护方式可以简化,以利控制盘的设备布置。Considering HV auxiliary power supply uses neutral grounding system, Article 8.2 of IEC Standard specified that instantaneous ground fault protection should be used. However, because most HV auxiliary power supplies in China adopt nongrounded system, instantaneous ground fault protection is unnecessary. To motor stator double earth fault, IEC Standard specifies cable cross-section based on short circuit adiabatic process and thermal stability requirements, which is conservative, resulting in higher cost. Therefore, thermal control protection device can replace inverse time over-current protection to shut off motor power supply, so that a smaller sized cable can be used. In addition, current protection for easy to overloaded motors can be simplified, so that the instrument arrangement of the control panel can be facilitated.

关 键 词：IEC标准 厂用电动机回路 保护 建议 

分 类 号：TM621.71[电气工程—电力系统及自动化]