Abstract: 35 kV substations are widely used within county-level power supply networks, where problems such as over-aged equipment and insulation degradation have become increasingly prominent. The replacement of outdated equipment often requires long-duration and large-scale outages. Therefore, how to perform load transfer for outgoing lines using live working and mobile generation equipment is crucial to ensuring reliable power supply for end users. Taking the reconstruction of the 35 kV Penggezhuang substation as an example, this paper proposes and applies a load transfer strategy that combines line interconnection switching with a "work plus power generation" operation mode. The strategy achieves "zero user perception and zero load loss" throughout the entire substation reconstruction process.