Research on the Reliability of EPDM Sealing Gaskets for HVDC Converter Valves

The EPDM sealing gasket products with different formulations and vulcanization processes are prepared by using EPDM rubber as the matrix, and their electrical and mechanical properties are tested. Research on the reliability of EPDM sealing gaskets is simultaneously conducted; an electrical corrosion accelerated aging test system is designed to simulate the real aging environment of EPDM sealing gaskets for DC transmission converter valves; and the mechanism of rubber corrosion aging is explored. The experimental results show that the leakage current in the deionized cooling water of the DC transmission converter valve will corrode the surface of the sealing gasket substrate, ionize the sulfur element in the molecular chain, and gradually age the rubber under long-term action. The continuous erosion by high-speed water flow causes further corrosion and degradation of the rubber, ultimately leading to aging failure; low conductivity, high density sulfur-sulfur bond maintenance network, and leakage current release electrode can effectively improve the electrical corrosion resistance level of EPDM sealing gaskets, slow down aging, and extend their service life.