Abstract: With the comprehensive advancement of China’s rural revitalization strategy and the continuous improvement of residents’ living standards, household electrical appliances and agricultural product processing equipment have been fully popularized in rural areas. The rapid development of planting and breeding industries has led to a steady annual increase in rural power load and a continuous expansion of the peak-valley load difference. Although multiple rounds of rural power grid upgrading and renovation have been completed in China, which have significantly improved the regional power supply reliability, the upgrading and renovation of power grids in remote villages with deep mountain terrain, complex geographical conditions and scattered households cannot be implemented synchronously due to multiple constraints such as line erection conditions, construction investment costs and ecological environmental protection policies. Such regions generally suffer from excessive power supply radii, large line losses and low terminal voltage. The minimum user-side voltage is only about 140 V during peak power consumption periods, which seriously restricts the reliable power supply for villagers’ production and daily life. Aiming at the low-voltage problem of power grids for scattered households in remote mountainous areas, this paper develops a three-gear centralized automatic voltage regulation device based on field measured load and voltage data. The device features automatic switching, centralized sharing for multiple users, low no-load loss and outdoor operational adaptability. It can solve the low-voltage governance problem in remote mountainous areas with low cost and high efficiency, and provide a reliable transitional engineering scheme for low-voltage governance in small-scale and scattered rural settlements.