基于模型参数识别法的小电流接地故障选线研究

由于故障电流小、电弧不稳定等原因，小电流接地系统单相故障选线问题始终没有得到彻底解决。文中提出了一种基于模型参数识别的小电流接地选线新方法，对每条线路建立其外部故障下的数学模型，利用零序电压、电流数据求解模型参数，依据得到的线路对地电容判断实际发生的故障是否符合所建立的模型，从而进一步识别出故障线路。经EMTP故障仿真和现场录波数据验证，该方法选线正确、有效，耐过渡电阻能力强，不受消弧线圈和间歇性电弧的影响，并且可以和馈线保护合为一体，满足自动化的要求。

FAULT LINE SELECTION IN THE NON-SOLID EARTHED NETWORK BASED ON THE MODEL IDENTIFICATION METHOD

On account of the weak fault current and unstable fault arc, the problems of the single phase to ground fault line selection in the non-solid earthed network have never been thoroughly resolved. A new line selecting method based on identifying the parameters of the line models is presented in this paper. The mathematical model for each line built under the condition of earth grounding fault beyond the line can be solved with the zero sequence voltage and current. Based on the grounded capacitance of the line obtained, a judgment will be made on whether the fault style accords with the actual one, thus further identifying the fault line. This principle has been verified via an EMTP simulator and the field data recorded. The results show that this method, which is free from the impact of arc-suppression coil and unstable arc, has higher sensitivity and reliability. In particular, it can be combined with the feeder protection to meet the requirement for automation.