Research On Reducing Tower Ground Resistance Of Yamaiwa Region By Using Tower Foundation

Tower grounding of overhead line is vital to the safe and steady operation of power system, and reducing tower ground resistance is the main measurement to increase lightning resistance level, and to reduce lightning stroke trip rate. In area where soil resistivity is pretty high, specially in mountain area, it is quite difficult to reduce the ground resistance of tower ground device to defined value. Besides, it is fairly hard to construct in yamaiwa region, which makes it more difficult to reduce ground resistance.In order to reduce ground resistance more effectively, this paper proposes the idea that reduce the ground resistance when starting set the tower foundation, i.e. reducing tower ground resistance by using tower foundation. By study on 500kV transmission lines in Houshi~Quanzhou Fujian province, the paper introduces burying novel centralized grounding device around tower foundation to reduce ground resistance. Physical model is found when centralizing grounding device based on ground current field theory. Calculation equivalent model of ground device is established according to electric field method and physical model, together with calculation formula. Then, Matlab is adopted to do simulation analysis and calculation on centralizing grounding device by charge simulation method, which proves validity of theory and formula. By plenty simulation calculation, this paper analyzes the relationship among ground resistance of novel centralizing grounding device and soil resistivity, undersides size, height and buried depth of ground device, and amount of resistance-reducing agent, providing reference for ground device design.Field test was done in Zhangzhou, Fujian province, centralizing grounding device is designed for two tower foundations, together with the construction and measurement. Based on ground resistance of field test and theory calculation, the paper analyzes three aspects from influence of simplified model, influence in procession of construction and measurement, validating correctness of theory prove, calculation model and method.The novel resistance-reducing measurement that burying novel centralizing grounding device around tower foundation provides a new way to reduce tower ground resistance, supplies a gap on research of such area, meanwhile gives a new direction to resistance reducing for area with high soil resistivity, having good reality significance and practical value.