【摘要】 分析了CT饱和产生的机理以及CT饱和后二次电流的本质特征,根据一次电流过零点附近CT二次电流存在线性传递区的特点,提出基于虚拟制动电流采样点差动的识别CT饱和方法。理论分析与动模试验结果表明,该方法能够很好地解决变压器区外故障时由于电流互感器饱和造成变压器比率差动保护误动的问题,进一步提高了差动保护的可靠性,具有实际应用的价值。更多还原

【Abstract】 This paper analyzes the mechanism which caused CT saturation and the essential character of the current secondary side at CT saturation.According to the linear zone of secondary current of CT near the primary current across zero,a method is proposed to identify CT saturation by using the sampling differential protection based on the constructed restraint current. The theoretical analysis and experiments verify that the method can prevent the differential protection from mal-operating while the CT enters into saturation caused by the external fault.The reliability of differential protection is improved,and the method has been applied in the practice.更多还原