TY - Journal of Shandong University(Engineering Science) A1 - T1 - Earth fault protection method based on frequency band power factor Y1 - 2021-02-20 JF - Journal of Shandong University(Engineering Science) JO - Journal of Shandong University(Engineering Science) SP - 76 EP - 86 VL - 51 IS - 1 UR - http://gxbwk.njournal.sdu.edu.cn N1 - 10.6040/j.issn.1672-3961.0.2020.416 ER -