To detect ground fault with high precision without erroneously detecting generation of the ground fault due to a DC voltage drop in a DC power circuit.
In an electric rolling stock, CPU21 changes an insulation resistance decrease determination threshold value for presetting and calculates a ground fault voltage value corresponding to the preset insulation resistance decrease determination threshold value, based on the DC voltage of a high-voltage battery 11 mounted as electrically insulated from the body. The CPU21 compares a voltage amplitude of a ground fault detection signal of a connection portion 18 as a ground fault detection point with the ground fault determination voltage value corresponding to the preset insulation resistance decrease determination threshold value, and detects the presence of ground fault between a vehicle body and a high-voltage battery 11. Thus, the electric rolling stock can detect the generation of ground fault with high precision even if a DC voltage value itself of the high-voltage battery 11 drops.
COPYRIGHT: (C)2005,JPO&NCIPI
Tomonaga Sugimoto
| JP2003125530A | ||||
| JP870503A | ||||
| JP2000197201A |
Iwa Saki Kokuni
Kawamata Sumio
Masakazu Ito
Shunichi Takahashi
Toshio Takamatsu