Method and device for online monitoring power station and substation grounding grid

This invention discloses an on-line monitoring method of grounding net of power station and its device. The method includes following steps: bury state transmitter in soil where have station earthing net; survey electric resistance of transmitter electrode and self corrosion electric potential; add square wave signal to electrode of state transmitter, survey electric current; after smoothing surveyed data, deliver to microprocessor to compute corrosion rate of electrode, take it as corrosion rate of grounding electrode in corresponding area; use corrosion rate to compute corrosion deep and actual geometry size of grounding electrode of grounding net, and use computing method of grounding net numerus to compute electricity performance parameter of grounding net; compare computed electricity performance parameter and design value, judge safe performance of grounding net. This invention can do online monitoring to corrosion deep and electricity performance parameter of grounding net of power station. The invention provides a overall, effective, economic, real time solving method to survey and evaluate grounding net of power station.