基于广义基波功率的新型变压器主保护方案

Novel Transformer Main Protection Scheme Based on Generalized Fundamental Power

在分析正常变压器回路方程特点的基础上,提出了基于广义基波功率和回路方程差值的新型变压器主保护方案。理论上变压器正常时广义基波功率和回路方程差值均等于零,内部绕组故障时广义基波功率有很大的数值,引线上故障时回路方程差值有很大的数值,因此新方案可以反映变压器保护范围内的任何故障,且无需额外的励磁涌流识别判据。新型保护方案无需计算变压器各侧绕组的电阻和漏电感,只需利用变压器铭牌参数即可实现,易于应用。实验数据分析结果表明新方案能可靠地防止励磁涌流造成误动,内部故障时有很高的灵敏度,在性能上有很大的提高。

On the basis of the characteristics of transformer loop equation,a novel transformer main protection scheme based on the generalized fundamental power and the difference of loop equation is presented.Theoretically when the transformer is under sound condition the generalized fundamental power and the difference of loop equation are all equal to zero,when faults occur on transformer windings the generalized fundamental power is great and when faults occur on leading wires the difference of loop equation is great.Therefore the new scheme can reflects any faults within the protective zone,and additional inrush identification criterion is needless.There is no need to calculate the resistance and leakage inductance of transformer windings,only the name plate data are used,so the scheme is easy to be realized.The analysis results of test data show that by the novel scheme the mal-operation caused by inrush current can be prevented reliably,there is sufficient sensitivity when internal faults occur,and the performance of the transformer protection is improved considerably.