Most of arresters are external gap arresters for limiting the lightning overvoltage on overhead transmission lines. Arresters for limiting operating overvoltage are not applied on power transmission lines. After the first installation of gapless arresters for limiting operating overvoltage on ±1 100 kV ChangjiGuquan UHV DC transmission line, the operating overvoltage for the whole line can be limited below 1.5 p.u., thus the clearance value is reduced, tower size and crossover distance are reduced, engineering investment is significantly saved. The installation schemes of arrester for line tangent and tension tower are proposed in this paper. Through comparative analysis, the hanging mounting scheme on the outer pick bracket is selected as the best scheme. The static and dynamic loads of arresters, innovative tower head layout design, drainage line selection and connection hardware design are analyzed on the basis of the best scheme. Through Installation and operation on real lines, the feasibility of installing gapless arresters on UHV DC lines is verified for the first time, and provides an example for the installation of gapless arresters.