一种有效区分空投涌流与空投于故障的变压器保护新算法

A novel transformer protection algorithm to effectively distinguish switching the transformer with an internal fault from switching inrush current

在有功差动原理的基础上,提出一种基于变压器基波正序功率因数以实现变压器保护的新原理。该原理利用帕克变换,构造了d-q坐标系上变压器端口电压、电流的基波正序分量的旋转向量,进而可计算变压器在各种暂态过程中的基波正序功率因数。根据变压器基波正序功率因数的大小,来判断变压器是否发生内部故障。该原理基于能量守恒,物理意义清晰,算法简洁,无需任何先验参数,不受变压器接线方式的影响,易于工程实现。经仿真试验验证,新原理能够快速、可靠地切除变压器内部故障,在性能上优于传统的以波形特征为主的变压器保护原理,对空投轻微故障有足够的灵敏度。

On the basis of real power differential method,a novel principle of transformer protection using fundamental frequency positive sequence power factor is presented.By using the PARK transformation,the fundamental frequency positive sequence rotating vectors of the transformer＇s terminal voltage and current are generated,then the fundamental frequency positive sequence power factors of transformer in various transient process are obtained.According to the fundamental frequency positive sequence power factor of transformer,magnetizing inrush and internal fault can be distinguished.The principle based on energy conversation has clear physics significance,simple algorithm,easy engineering realization,and need not any transformer internal parameters,and is free from the impact of transformer wind connection mode.Simulation testing results verify that this scheme has stability during inrush current and is able to clear internal fault reliably and quickly,and its performance is superior to the traditional transformer protection principle based on the differential current waveform characteristics,having sufficient sensitivity for energizing into light turn-to-turn fault.