Abstract:In order to study the application of flexible graphite grounding material in power distribution systems, a finite element simulation model of flexible graphite grounding device is constructed, by which the grounding resistance of a group of 10kV power distribution system flexible graphite grounding devices is calculated. It is proposed that the rectangular frame structure should be preferentially used in urban distribution networks to reduce grounding resistance by combining with the inherent characteristics of flexible graphite grounding material and common resistance reduction methods. The temperature rise of the flexible graphite grounding device under short-circuit fault and lightning fault has been simulated and calculated. The test device can operate normally under short-circuit fault conditions, but the local temperature rise is over standard under the lightning fault that once in 30 years.The research results have important reference value for the design, selection and application of flexible graphite grounding devices in 10kV urban distribution networks.

Abstract:Grounding resistance is an important parameter to measure the stability of power system. If the grounding system is buried in the soil with poor contact with the electrode, the resistance reduction effect of simple graphite grounding device in complex soil environment is general, which is difficult to meet the engineering requirements. conditions. Based on the principle of reducing resistance of grounding device, this paper puts forward a method of reducing resistance of grounding cloth to increase the area of stray current, and designs a grounding scheme of grounding device plus grounding cloth. Firstly, the simulation analysis is carried out, and the grounding experiment of graphite grounding device with grounding cloth is carried out in the simulation test platform. Several factors such as the location of grounding cloth, the depth of embedding and the amplitude of impulse current are mainly measured. Through the comparison of simulation test and simulation, the change of grounding resistance is measured, the influence law of various factors on grounding resistance is summarized and analyzed, and the auxiliary current dispersion scheme of using grounding cloth to reduce grounding resistance is proposed, which provides reference for reducing grounding resistance.