Novel method of corrosion diagnosis for grounding grid

Abstract

The steel grounding grid buried in earth will corrode and become a hidden danger to the safety of the power system. It is difficult to get an accurate status of corroded ground grids with traditional methods. A novel method is proposed, by which the corrosion status of a 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 models and theory. Then, an 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, a field test report is provided to validate this new method.