New energy delivery system based on half-bridge sub-module MMC has a broad development prospect. Existing half-bridge MMCs need to be additionally fitted with high-capacity DC circuit breakers and energy dissipation devices to cope with system overvoltage and overcurrent challenges caused by AC and DC faults, but the DC circuit breakers and energy dissipation devices contain hundreds of classes of expensive power electronic switches, which limits their large-scale applications. To address the above problems, this paper proposes a scheme to integrate DC circuit breakers and energy dissipation devices to achieve both DC on-off and resistance casting functions under faults by multiplexing the power electrical switches, which results in significant savings in device costs. The working principle and parameter design method of the proposed scheme are further analysed, and a system simulation model is built to verify the effectiveness of the proposed scheme. Finally, the techno-economic analysis of the proposed scheme is carried out, and the cost is reduced by more than 33% compared with the traditional scheme.