高阻接地系统单相漏电故障特征及其识别

针对选煤厂660V供电系统采用变压器中性点高阻接地方式的特点,研究了选择性漏电保护的判据、整定值、具体装置的实现等问题.通过分析高阻接地系统发生单相漏电故障时零序电压、零序电流的分布规律,验证了零序电流方向型漏电保护原理在高阻接地系统的有效性;通过自行编制的漏电计算器,分别计算了每条出线的动作整定值并在现场进行了整定.所研制的漏电保护系统已在现场运行3年多,从未发生过误动和拒动现象,实践表明所提出的保护原理和软硬件设计均符合实际情况.

The Characteristic and Identification of Single Phase Earth Leakage Fault in High-impedance System

Contraposed on the characteristic of which the coal-dressing plant was supplied by a 660V power network, whose transformers were grounded with a high resistance, a research on the problems of the criterion , adjust value and the achievement of concrete device in a selectivity relaying protection was given. Aim to carry out analysis on the distribution of zero-sequence voltage and current of single-phase fault within high resistance grounded system and develop a reliable algorithm for fault detection. With the proper motion established creepage calculator , the action adjust value of ever branch was calculated separatedly and was adjusted at the locale. This developed relaying protection system has worked in the locale for more than 3 years and has never mis-operated.