Distribution networks contain numerous hybrid cable-overhead connections and branches, often causing excessive attenuation of fault-induced traveling waves, preventing traveling-wave fault location devices from activating. To address this issue, this paper proposes an placement method for device placement that ensures reliable fault location across all network segments by accounting for traveling-wave transmission attenuation. Using ground faults as an example, the study begins with a quantitative calculation of the initial voltage traveling wave. It then systematically analyzes the attenuation effects introduced by hybrid cable-overhead connection points and multi-branch T-junctions through quantitative modeling. By constructing a directed attenuation matrix for fault traveling wave propagation in a predefined network topology, the method identifies non-measurable lines in double-ended traveling-wave ranging based on the device detection threshold. Furthermore, by analyzing the transmission range of fault-induced traveling waves in non-measurable lines, additional devices are allocated at optimal nodes with the objective of minimizing the total number of deployed devices. The experimental results show that the placement method ensures the reliability of traveling wave distance measurement for the entire network due to the comprehensive consideration of various factors affecting the amplitude of fault traveling waves.