An on-line cable insulation monitoring method by injecting a signal into power grid

To ensure the safety running of power grid, the on-line monitoring of power equipment is essential to the power grid, compared with the traditional periodic maintenance. The existing on-line monitoring methods have some limitations. In this paper, a novel method combined low-frequency dielectric loss method with signal injection into power grid method is proposed. For this method, a low frequency signal is injected into the power grid from the open triangle side of the PT. Then the dielectric loss factor can be achieved to know the insulation situation of the cable. To validate the effectiveness of the novel method, simulation tests are done. For the simulation validation, a model is established in COMSOL software and a thermal aging cable and a water tree aging cable are both simulated. All the simulation results indicate that the insulation situation of power cable can be studied through the novel method effectively.