基于PSCAD的距离保护作为变压器低压侧故障远后备保护的仿真分析

Analysis of distance protection used as remote backup protection for transformer based on PSCAD

应用对称分量法对YNd11变压器d侧小电阻接地系统发生不同类型短路故障时Y侧线路距离保护的测量阻抗进行推导计算,并利用电磁暂态仿真软件(PSCAD/EMTDC)进行仿真分析。根据某110 kV/35 kV供电系统的参数,选取电磁暂态仿真软件(PSCAD/EMTDC)中合适的元件搭建一、二次模型,针对不同类型短路故障进行仿真验证。将理论推导计算与仿真结果进行比较,得出线路距离保护能准确反应YNd11变压器d侧小电阻接地系统中除单相接地短路故障以外的其他类型短路故障,YNd11变压器的Y侧线路距离保护Ⅲ段可作为d侧小电阻接地系统的远后备保护。

The symmetrical component method is applied to deduce and calculate the measured impedance of Y-side line distance protection when different types of short circuit faults occur in the d-side small resistance grounding system of YNd11 transformer, and the electromagnetic transient simulation software(PSCAD/EMTDC) is used for simulation analysis. According to the parameters of a 110 kV/35 kV power supply system, select the appropriate components in the electromagnetic transient simulation software(PSCAD/EMTDC) to build the primary and secondary models, and carry out simulation verification for different types of short circuit faults. By comparing the theoretical derivation and calculation with the simulation results, it is concluded that the line distance protection can accurately reflect other types of short circuit faults in the small resistance grounding system on side d of YNd11 transformer, except the single-phase grounding short circuit fault. Section III of the line distance protection on side Y of YNd11 transformer can be used as the remote backup protection for the small resistance grounding system on side d.