Novel method of corrosion diagnosis for grounding grid

The steel grounding grid buried in earth will corrode and become hidden danger to safety of power system. It is difficult to get accurate status of corroded ground grid with traditional method. A novel method is proposed, by which corrosion status of grounding grid can be diagnosed from measured port resistances among the touchable down-lead conductors connected to the grounding grid. First, the mathematical relationship between the corrosion status of the grounding grid's all grounding conductors and the measured port resistances is deduced in detail based on circuit model and theory. Then, appropriate mathematical model is discussed for practicable computation. The completed corrosion diagnosis system, including hardware device of data measurement, diagnosis and analysis software, is also introduced concisely. Finally, the field test report is provided to validate this new method.