二维空间重构电流特征轨迹的变压器差动保护判据

在故障电流的影响下,变压器差动保护两侧电流互感器(TA)易发生饱和,使传变的电流波形发生畸变,严重影响变压器差动保护的正确动作。针对TA饱和造成的变压器差动保护误动或拒动的问题,对不同故障类型下变压器两侧电流波形相位关系特性进行对比分析,提出将两侧电流进行二维空间重构,应用重构后的特征轨迹构造变压器差动保护新判据,以识别伴随TA饱和的变压器各类故障。通过仿真和动模试验,验证新判据有较高的可靠性和灵敏性,并且具备较强抗TA饱和的能力。

Transformer Differential Protection Criterion Based on Reconstructed Trajectory of Current Characteristics in Two-dimensional Space

With the influence of the fault current, the current transformers (TAs) on both sides of the transformer differential protection are prone to saturation, which would distort the current waveforms of the transformer and seriously affect the correct operation of the transformer differential protection. To solve the problem of misoperation or operation failure of transformer differential protection caused by TA saturation, the phase relationship characteristics between the currents on both sides of the transformer with different fault types are comparatively analyzed. A novel criterion for transformer differential protection is proposed to identify various faults accompanied by the TA saturation, which is based on the two-dimensional reconstruction of currents on both sides and the reconstructed characteristic trajectories. The results of simulation and experimental tests indicate that the proposed criterion has high reliability and sensitivity, as well as the high anti-saturation ability of TA.