Abstract:

Optimizing the design of EHV grading rings in post-insulation systems for cold weather applications will enhance their electrical performance. The electric field must be uniformly distributed over the post insulator to lessen the electrical stress which can lead to failure, grading rings help achieve that. In cold climates, grading ring performance is heavily affected by increased material brittleness, differing dielectric insulating materials, and thermal stress which all result in non-uniform stress distribution that alters the internal loading of the system. Conventional designs tend to fail more often due to lack of effective counters to harsh environmental conditions, which pose the primary concern. The proposed solution is applying FEM simulations to diagnose the exact temperatures where electrical stress is lowest at low temperatures. With FEM, grading rings can be optimized not only in shape, but also in material properties and position relative to the insulation surface. The design of the insulation own’s grading rings, if optimized, will greatly enhance the electrical performance and lifetime reliability of the EHV systems in cold climates. The simulation results confirm that the adjusted configurations of the grading ring yield great results of stress distribution, improving system reliability and endurance for cold weather. This method stands to offer greater resolution to more harshly conditioned power systems.