Research on Prevention Measures of 380V Load Branch Over-step Trip in Substation

Over-step tripping often occurs in substation transformer and distribution lines. It enlarges the scope of power supply interruption and affects the reliability of power supply. This paper analyses the causes of jump tripping. Then, the zero sequence protection is set and inter-stage cooperation is improved. Finally, a novel relay protection scheme combining zero-sequence current protection and trip unit is designed. Field test shows that the scheme proposed in this paper can effectively solve the problem of over-step tripping, and avoid the expansion of power outage. It can effectively improve the reliability of power supply. The device can be widely used in intelligent distribution network and substation.