Research On Planning Of Diankou Town Power Grid Reform

Grounding network is an important facility, which ensures the safety of the power grid, staffs, equipments and so on, so it plays an important role in the substation.500kV Yongchao substation is located in high resistivity place, the problem of grounding is particularly difficult. So researching on the new 500kV Yongchao substation’s grounding problem becomes a key of the instruction and the security of this substation. And it also can provide valuable experience to the instructions of other 500kV or even higher voltage level substations in future.Firstly, the soil model is established based on the soil resistivity of 500kV Yongchao substation. And then a preliminary design of the substation grounding system is designed, at the same time, the parameters of the preliminary grounding grid is calculated, which shows that the preliminary design can’t meet the needs. So, an optimization design is made to the preliminary grounding grid, joining some deep-well groundings to the horizontal groundings, but the calculation results show that its difficult for the grounding resistance reducing to the request value. In order to make a further optimization design, resistance reducing agent is added to the deep-well groundings, which make the grounding resistance reduced from 3.02Ω to 0.4379Ω, but the touch voltage is still can’t reach the request value. Finally, insulation floor is added on the top of the substation. And the simulation results of CDEGS software show that the insulation floor can reduce the touch voltage of substation obviously. Finally, the final design is made according to the simulation results. The substation’s practical parameters were measured after construction, it shows the actual grounding resistance is far below the calculated value, satisfying the relevant requirements.By using the traditional calculation combining with the CDEGS software simulation analysis software, this paper designed the grounding grid of 500kV Yongchao substation rapidly and correctly. And the design is proveed reasonably in practical.