A novel method for DC system grounding fault monitoring on-line and its realization

On the basis of comparison and analysis of the present grounding fault monitoring methods such as method of AC injection, method of DC leakage and so on, this paper points out their shortcomings in practical applications. A novel method named method of different frequency signals for detecting grounding fault of DC system is advanced, which can overcome the bad influence of distributed capacitor between the ground and branches. Finally a new kind of detector based on the proposed method is introduced. The detector, with C8051F041 as kernel, adopting method of different frequency signals, realizes on-line grounding fault monitoring exactly. The principles, hardware and software design are introduced in detail. The experimental results and practical operations show that the detector has the advantages of high-precision, better anti-interference, high degree of automation, low cost, etc.