(1) Gas protection. It is used to reflect various faults in the transformer tank and the reduction of the oil level.

(2) Longitudinal protection. It is used to reflect the faults in the transformer winding, bushing and lead wire.

(3) Phase-to-phase overcurrent protection. According to the operating conditions, the composite voltage lockout and direction lockout can be introduced, and according to the requirements of setting, the short-circuit fault between the inner and outer phases of the transformer can be reflected.

(4) Impedance protection. When the interphase overcurrent protection does not meet the sensitivity requirements, impedance protection can be used.

(5) Zero-sequence current protection and zero-sequence current direction protection. According to the setting direction, the inner and outer ground short circuit faults of the transformer can be reflected.

(6) Overload protection. Reflects the overload state of the transformer, acting on the signal or tripping.

(7) Over-excitation protection. Reflects the over-excitation state caused by overvoltage or frequency reduction, and acts on the signal or trips.

(8) Other protections. Reflect protection in special states such as pressure release, temperature increase, etc.