Abstract: Abstract:The principle and the composition of the injection type stator grounding protection of Asahan First Stage Hydropower Station in Indonesia were introduced. The stator grounding protection of the hydropower station tripped several times since the hydropower station was put into operation. The protection tripping behavior was analyzed. The problems, which deserve research and attention in practical application of the injection type stator grounding protection, were pointed out, and the matters needing attention in design, construction and operation of the injection type stator grounding protection were expounded emphatically.

Key words: Keywords:injection type stator grounding, protection settings adjustment, waveform analysis, field application