Effect of grounding grid of power transmission line on buried pipeline under short circuit fault

In order to study the electromagnetic interference of the short-circuit current of grounding point when power transmission line is in fault operation, a model for grounding grid of transmission line towers and buried pipelines was established with the lightning protection and grounding analysis software CDEGS. In the model, the variation rules of pipeline surge voltage were analyzed at different short-circuit current, soil resistivity and pipeline spacing. Two new protective measures for pipelines were proposed. ① The variation rules of pipeline surge voltage were calculated and analyzed by changing shape parameters of grounding grid with shapes of # and square ray. The shape of grounding grid has great influence on grounding resistance, i.e., the bigger the grounding resistance, the smaller the surge voltage. ② Non-metallic shielded wire(flexible graphite composite grounding material) was buried along pipelines to protect pipelines with over voltage. The results show that non-metallic shielded wire could effectively reduce the surge voltage and protect pipelines. The research results could provide reference for design, construction and safety protection of oil and gas pipelines.