Abstract: 110 kV grafted polypropylene (PP) insulated cables were using grafted PP insulating materials. Through thermal performance tests of insulating materials, mechanical tests and electrical strength tests before and after aging, and type tests of cable system and current-carrying capacity tests, the feasibility of increasing operating temperature of PP insulated cables was analyzed. Results showed that grafted PP insulating materials had a higher melting point and initial melting temperature, as well as better aging resistance, meeting the requirements of cable type test when operating at 105 ℃. When operating temperature of 110 kV grafted PP insulated cables with a conductor cross-sectional area of 1200 mm² was raised from 90 ℃ to 105 ℃, current-carrying capacity could be increased by 10.2%, proving the feasibility of increasing operating temperature of 110 kV grafted PP insulated cables from 90 ℃ to 105 ℃.