The extending techniques such as vector transform, excitation inrush current , TA saturation and so on are analyzed, which resolves the question that the traditional optical differential protection can not satisfy the request of line-transformer unit.

• 同时对光纤差动保护运用于线路变压器组时涉及的矢量变换、励磁涌流、TA饱和等延伸技术进行了分析，解决了传统的线路光纤差动保护不能满足线路变压器组保护的要求。