A new method of single-end protection based on mutation characteristics in frequency domain

Due to the weak feed effect of new energy and the influence of frequency offset, the performance of traditional protection will be significantly reduced. At the same time, due to the unstable sequence impedance of the new energy power supply, the power frequency variation distance protection also has the risk of rejection. Therefore, a new method of single-end protection based on frequency domain mutation feature is proposed in this paper. The voltage drop at the fault point is equivalent to a step signal with full frequency domain information. Therefore, the high-frequency impedance model of inverter power supply is established in this paper, and the frequency selection principle is given to make it have a stable impedance Angle. On this basis, the principle of distance protection based on frequency domain mutation is constructed by comparing the high frequency mutation characteristics of operating voltage and fault point voltage. Finally, the simulation proves that the proposed protection meets the requirements of protection sensitivity and reliability for the safe and stable operation of the new power system.