The invention relates to a low excitation
impedance transformer single-phase grounding protection device and a protection method. Through bypass grounding current
shunting, grounding arcs are eliminated, the grounding protection effect is improved, grounding and line selection can be realized, and line selection and fault positioning are accurate. The device comprises three single-phase breakers, a low excitation
impedance transformer, a
signal generator, a zero sequence
current transformer and a control detection device, wherein wire incoming sides of the three single-phase breakers are respectively connected with a corresponding
bus through an isolation switch or a separation breaker, wire outgoing sides are connected with an original edge winding of the low excitation
impedance transformer, the low excitation impedance
transformer is a single-phase three winding dry core
transformer having the original edge winding, a secondary edge main winding and a secondary edge secondary winding, one end of the original edge winding is connected with a ground network or a ground row through the zero sequence
current transformer, the secondary edge main winding is connected with the
signal generator, the secondary edge secondary winding is connected with the control detection device, the secondary edge main winding is for
signal injection, and the secondary edge secondary winding is for signal measurement.