1. 1) Kimura, T., Sugai, S., Okui, A., Hase, S., "Development of the DC Ground Fault Detection System Using the Total Current of Two Substations," The 2007 Japan Industry Applications Society Conference, 3-40, 2007 (in Japanese).
2. 2) Hase, S., Okui, A., Sekijima, S., Sugai, S., Akagi, M., Kimura, T., "Development of High resistance Grounding Fault Detector by Making Use of Load Current," RTRI Report, Vol.21, No.10, 2007.