小矢量算法在发电机继电保护中的应用分析

提出一种基于小矢量算法的发电机差动保护新方案。发电机发生故障后的暂态电流中包含各种谐波分量，由于小矢量算法对谐波电流具有一定的放大作用，当两侧电流谐波含量区别较大时，将有利于保护动作。裂相横差保护和不完全差动保护由不同分支组成，两侧电流受故障影响程度也不同，电流谐波含量就有区别，因此可以采用小矢量算法提高保护性能。大型发电机内部故障产生的巨大短路电流可能引起其电流互感器饱和，从而影响保护的动作性能，而基于小矢量算法的差动保护方案具有较强的抗电流互感器饱和的能力。

Differential Protection Based on Phaselet Algorithm for Large Generator

This paper presents a new generator differential protection scheme based on phaselet. Analysis shows that phaselet algorithm can enlarge the harmonic current than Fourier algorithm. When internal faults occurs, the harmonic currents are different in two sides which can be used to improve the performance of the differential protection. Because the fault has the different influences on the different branches, the harmonic currents in the branches will be greatly different. The uncompleted differential protection and the split-phase transverse differential protection are composed of different branches, so they can obtain high sensitivity and reliability with phaselet algorithm. For large generator, the fault current will be greater, causing current transformer saturation which affects the protection performance. Research results show that the new scheme could get high performance at different conditions even when the current transformer is saturated.