| CDEGS is the international software of grounding analysis. In this paper,the tower grounding model was built based on the CDEGS software platform.some research was done on the tower grounding characteristics analysis,stress analysis and thermal analysis.The grounding device and footings of transmission line tower were modeled and analyzed.firstly,110kV,220kV,± 800kV tower grounding device and the footing model were built reference design standards. Secondly, four kinds of grounding schemes are designed,which include: the conventional grounding, the grounding device connected with footing steel bars, canceling the grounding device, canceling the grounding device and footings be connected. Then,the grounding schemes were discussed in detail,the main factors are: soil resistivity, concrete resistivity, grounding length, drag reducing agent, root span. Finally,according to the characteristic analysis, the feasibility of the tower grounding is given.Adding excitation of short current or lightning to established models, each segment of the conductor in footings was subdivided, the distribution of current and magnetic field were calculated, calculate the force of each conductor according to the Biosaval principle. The absorption of heat on each conductor can be calculated per unit time by the current on each section of the conductor, and tihen calculated steel conductor temperature rise according to the thermal equation, thus determine whether the basis is stability.The results of the research and simulation show that: when the length of the grounding device is small, the grounding resistance is obviously changed when the footing steels are connected with the grounding body. When the grounding length is large, the grounding resistance is not obvious when the footing steels are connected with the grounding device.The effect of conductive concrete in high resistance area is more obvious. The effect of drag reducing agent is good. The effect of increasing of root span is not obvious. Short current and lightning have little effect on the tower footings. |
