An Operation Time On-line Setting Method of Distance Protection Section II&III for 220kV Transmission Line

Section II and section III of distance protection are widely used as backup protection for 220kV transmission line. In order to ensure that the line distance protection can act correctly and cooperate with each other, it is necessary to set the impedance and time setting value of distance protection. At present, the time setting values of section II and III of power grid distance protection are fixed action time limits calculated by manual calculation or computer setting calculation program offline. In this paper, an on-line setting technology for section II and section III of distance protection is proposed. The operation time of section II and section III of distance protection is determined by measured fault impedance. As long as the distance protection section II and section III operates, the operation time can be calculated according to the formula proposed in this paper, and the operation time of protection section II and section III of the upper and lower level lines can meet the coordination relationship, and the operation time difference meets the requirements. Through modeling and simulation, it is proved that the method proposed in this paper is feasible.